Sea vegetables are wild ocean plants, or marine algae, enjoyed daily as staple and healing foods in many coastal parts of the world. Technically speaking, not all sea vegetables are plants, even though we refer to them that way.  Macroalgae are classified by three color groups: red (6,000 species), brown (2,000 species), and green (1,200 species).  The red and green groups (Rhodophytes and Ulvophytes) are classified on the same fork of the tree of life as plants, though different side branches.  The brown algae (Phaeophytes) are placed on a different fork unrelated to plants or the other macroalgae species.

While there are many species of marine algae, only about 145 of them have a history as human food. Popular American sea vegetables from the east coast are dulse, kelp, Alaria, and laver, and sea palm from the west coast. Asian varieties include nori, hijiki, arame, kombu and wakame. We offer dulse, sugar kelp, Alaria, laver, Irish moss, sea lettuce, rockweed, and bladderwrack. 

Small amounts of sea veggies add a rich flavor and enhance the nutritional value of most dishes. These exceptionally vital plants inhabit the fertile, energetic region where ocean meets land; from the very exposed
high tide mark to the constantly immersed bottom just below low tide. They inhabit all the world's oceans.

Sea vegetables have many culinary uses and they add distinctive flavor and trace ocean nutrients to our diet.  They are also very nutritious.  Sea vegetables are rich in minerals and iodine, high in fiber, and contain high quality protein.  They also contain unique polysaccharides that have been linked to a long list of health benefits, including absorbing and removing radioactive elements and heavy metals from the body; inhibiting tumor cells, pathogenic bacteria, and viruses; and acting as prebiotics for healthy gut bacteria.  Sea vegetables have even been linked to good mental health.  Our Medicinal Botanical FAQs address these benefits in more detail.

If flavor and healthy nutrition aren’t enough, consider the environmental benefits.  Sea vegetables require no fresh water, valuable agricultural land, pesticides, or fertilizers.  Whether wild or farmed, seaweed removes CO2 and is considered a carbon negative crop with a high potential for mitigating climate change.  Our wild sea vegetables are sustainably harvested to allow regrowth; some of the beds have been harvested for 40+ years! 

Case reports of allergic reactions from eating sea vegetables are exceedingly rare; we’re aware of just one report worldwide as of 2020! However, because they come from the sea, sea vegetables sometimes hold tiny dried shellfish such as snails, periwinkles, and mussels within their fronds. We do our best to remove these as we sort and package, but they occasionally get through anyways. We recommend that each person evaluate the risk for themselves.
Our facility does not process any tree nuts, peanuts, dairy, eggs, wheat, crustacean shellfish, or other seafood, so there’s no danger of cross contamination from these common allergens during processing or packaging.

For those with a botanical bent, following are the scientific names of the sea veggies we harvest and sell:

RED SEA VEGGIES
Dulse - Palmaria palmata
Laver - Porphyra umbilicalis
Irish Moss - Chondrus crispus
Truffle Seaweed - Vertebrata lanosa

BROWN SEA VEGGIES
Alaria - Alaria esculenta
Bladderwrack - Fucus vesiculosus
Sugar Kelp - Saccharina latissima (formerly known as Laminaria longicruris)
Rockweed - Ascophyllum nodosum

GREEN SEA VEGGIES
Sea Lettuce - Ulva spp (probably Ulva fenestra) 

Dried sea vegetables can remain good
for years when properly stored in airtight containers, out of direct sunlight, and not exposed to long stretches of hot temperatures.  Nutrients such as minerals, iodine, and fiber are likely to remain wholly intact for many years, although no one has ever shown this scientifically. Flavor and texture are also likely to be unaffected, and the flavor actually improves with age in some species, such as dulse. However, vitamins and lipids can deteriorate after many years’ storage.

Dried seaweed is rich in mineral salts
and contains very little available moisture.  This combination inhibits growth of bacteria, yeast, and molds, and ensures a prolonged shelf life. In general, we label our sea vegetables with a “best before” date of 3-5 years from harvest.  This date can be found on a white "BEST BEFORE" sticker adhered to the package.  If your sea vegetables are past this date (or the sticker is missing), that doesn’t mean they’re bad and should be thrown away.  We’ve had customers report that dried kelp purchased over 10 years
ago was still as good as the day they bought it.  Ultimately, you’re the best judge.

Dried sea vegetables can be stored in their
original resealable bags or in glass containers with tight lids. Refrigeration
is not necessary or desirable because it can contribute odors and moisture.  Storage at room temperature in a closed cupboard or on the counter is fine, but avoid direct sunlight.

When sea veggies are exposed to moisture or excessive heat, they may show signs of mold or deterioration, and the seaweed may have an off-odor similar to mushrooms or seafood past its prime. However, the whitish
powder that sometimes appears on sea vegetables should not be assumed to be
mold. Usually, it’s precipitated salts and sugars.  These add flavor and saltiness to the seaweed and it remains safe to eat. You can rinse or use as is. It is not a good idea to rinse sea veggies and store unless they’re used within 24-48 hours or refrigerated.

If your sea veggies get too dry and crispy, they can be rehydrated by adding a piece of lettuce, slice of apple or damp paper towel to the container for a day or two. Brittle kelp or Alaria can be lightly sprinkled or soaked until rehydrated to your preference.

Dried sea vegetables can be rinsed or soaked in fresh water before use, but this is usually unnecessary. Dulse, for instance, can be eaten right from the bag as a healthy, "salty" snack. Kelp can be lightly soaked and rehydrated (it expands!) to be cut into attractive shapes and sizes. In any case, a light rinse before use lessens the salty taste. You will lose some sodium and potassium salts, but very little if any calcium, iron, magnesium, etc. You can save the rinse water for cooking.  It is not a good idea to rinse sea veggies and then store them unless you immediately refrigerate and use within 24-48 hours.

You may want to inspect the plants for tiny shells (periwinkles) before use. We do our best but sometimes they hide in the folds. Simply dip the plants in water long enough to unfold them and release any shells.

Dried seaweed has a distinctive aroma that some people find strong or off-putting. One reason that it smells so strong is because it's a highly concentrated, dehydrated
food.  As long as there is no mold or other signs of deterioration (usually from being stored under damp and/or overly warm conditions) the product is fine to eat. Storing sea vegetables in a tightly sealed glass or
plastic jar helps keep the odor from permeating the kitchen or pantry.

Sugar kelp, Alaria, and dulse sometimes develop a white to grayish powdery coating on their fronds. The product may arrive this way or it may develop during storage.  This is nothing to worry about!  People sometimes mistake this powder for mold, but it probably is not. To learn more about whether mold occurs on dried seaweed, click on this link "Moldy Seaweed" for a
downloadable PDF on the topic, complete with photos.

As sea vegetables dry, salts and sugars often precipitate to the surface from the internal tissues. These salts and sugars
are easily rinsed off, but they contain much flavor and can be safely eaten as is.  In kelp, the principal sugar is mannitol and the salts are predominantly potassium and sodium. Mannitol is less sweet than most other
sugars, but it still adds a subtle sweetness. Along with kelps’ high mineral content and naturally occurring glutamate, mannitol is why kelp makes beans taste so great, cook so quickly and digest so easily!

In many Asian nations, beautiful healthy hair, skin, and nails are attributed to the regular use of seaweed in food, soap and
shampoo. It’s thought that a combination of factors including an abundance of
organic colloidal minerals, particularly calcium, silica, iron and phosphorous;
emulsifying alginates (fibers that become mucilaginous when moistened) that cleanse surface toxins, emulsify oils and de-acidify; and the abundance of iodine, amino acids, active enzymes, beta carotenes, and B-vitamins all contribute to this effect.

Try mixing 1 tsp. of our powdered  rockweed (Ascophyllum nodosum) with 3/4 cup of warm water, wait about 30 minutes
until the alginate gels fully develop, and then strain out any remaining particles. The remaining viscous liquid can be used as a shampoo or simple hand soap for cleansing and moisturizing. Or, add some whole kelp, alaria, bladderwrack, or Irish moss to your bath. A cheesecloth bag keeps the seaweed
from clogging the drain while allowing it to release the mucilaginous polysaccharides and minerals that are so beneficial for skin and hair. For more information, please read our cookbook and resource guide Sea Vegetable Celebration, pp 35-38.

Yes, but in moderation. Milled kelp (kelp meal) has been fed to cattle, sheep, chickens, and other barnyard animals for decades. Most domesticated animals are far from the diets of their wild ancestors, and in
need of broad-based mineral support just as we humans are.  Sea vegetables provide chelated, colloidal trace elements to the diet of your special animals, as opposed to the inorganic mineral salts that supplement many commercial animal feeds and leave free metal ions in the digestive tract.  Many
customers report feeding sea vegetables to their dogs, cats, fish, hamsters, iguanas, etc. with good results. Dog and cat owners claim not only healthier animals but also healthier, fuller coats, and we sell a dog-friendly seaweed supplement on our website at this link. For a more detailed discussion of this general topic, please read this blog post or our cookbook and resource guide Sea Vegetable Celebration, pp
32-33.

Coastal people have used seaweed for centuries to nourish plants and gardens. Besides contributing a broad spectrum of abundant minerals, the brown varieties such as kelp and rockweed contain plant
biostimulants such as cytokinins, natural plant hormones that stimulate growth
and flowering, intensify color, and increase yield.  Seaweed can also improve soil microbial ecology and tilth.  Rockweed (Ascophyllum nodosum) in particular is widely used as a sustainable alternative to
chemical fertilizers and pesticides. Science shows that rockweed extracts improve
not just plant health and vigor, but also the nutritional quality of many vegetable and fruit crops.  Maine supports a small but important rockweed fishery for production of plant biostimulants.  The Maine Seaweed Council website has links to Maine companies that sell seaweed-based agricultural products.

Beach-cast seaweed gathered from the shore can be tilled directly into the garden, composted with grass clippings, hay, or
manure, or used on top of the soil as mulch. Seaweed leaf compost additive and soluble
seaweed powder for plants can also be purchased from our web store at this link. Learn more about this topic in our blog post titled “Seaweed in the Garden.”

Sea vegetables generally have a strong, briny, minerally, and umami flavor, but each kind has its own additional flavor qualities.  They should never taste fishy, although some say the ocean flavor reminds them of fish. They all add umami flavor, but brown varieties (kelp, rockweed, bladderwrack and Alaria) have more umami than the reds (dulse, laver, nori, and Irish moss) or greens (sea lettuce).  Dulse is often described as having a smoky essence, and some people say that when it’s fried it reminds them of bacon.  Laver and nori have a slightly sweet and nutty taste.  Sea lettuce has a certain bitterness and is best used in recipes.

With careful processing we can package our dried whole-leaf sea vegetables so that they’re not too dry and definitely not too moist. However, whole-leaf kelp and Alaria can be crunchy or even brittle right out of the bag, especially over time after the bag has been opened. An easy way to soften the texture is to put a slice of fresh apple in the bag with the seaweed. Other sea vegetables such as dulse tend to remain softer and more pliable.

Most whole-leaf sea vegetables are good eaten raw straight from the bag, but people often prefer adding them in small amounts to other foods. Sea Seasonings and other milled forms are convenient for adding to food and a great introduction as well. Various recipes are found on the  Recipes page of this website or in our cookbook Sea Vegetable Celebration.  We offer sample sizes for most of our products and if you want to jump right in we also offer a Sea Starter Kit with an introductory selection of products.

It's really quite easy to include sea vegetables in your diet!  Whole leaf can be cut into bite sized pieces and added to  soups, salads, sandwiches, and stir-fries. Milled products (flakes, granules, and powder) can be added by the spoonful to smoothies, soups, and other recipes. Sea
Seasonings are great sprinkled on salads, soups, eggs, avocados, sandwiches,
and other foods to add flavor and as a salt substitute. Each Maine Coast package comes with instructions and recipe suggestions. To get started cooking
with sea vegetables, go to the  Recipes section and read the Basic Prep section for each sea veggie.

Sea vegetables' strong taste and odor can surprise people. Remember that dried sea vegetables are a vital wild food with highly concentrated nutrition — a little bit goes a long way, and most easy Maine Coast recipes use less than one quarter ounce per serving! Some people like to rinse or soak sea vegetables in fresh water before using them, but generally this is unnecessary. We suggest eating a variety of sea vegetables for maximum nutrition and taste.

It certainly is, and using sea vegetables instead of salt may be one of the easiest ways to incorporate them into your diet!  Our sea vegetables contain only between 1% to 4% sodium on a dry weight basis but they taste saltier than they actually are due to the presence of other minerals such as potassium and calcium. Glutamate, a naturally occurring amino acid found in seaweed, adds additional umami flavor.  Add 1-2 teaspoons of any of our dried, milled seaweeds to recipes to reduce the salt content while boosting the flavor.  They’re great in scrambled eggs, salads, noodles, and even a bloody mary! Our line of Sea Seasonings, specially made for this purpose, comes in convenient shakers or in bulk for those who want to fill their own shakers.

Yes, it is, and Maine Coast product packaging bears a gluten-free symbol.  Gluten is a naturally occurring group of
proteins found in certain grains like wheat, rye, and barley.  Gluten is also added to processed foods as a thickening or stabilizing agent. Sea vegetables are naturally gluten free because they don’t contain these proteins, and we certainly don’t add gluten to any of our products.  Since we don’t process any gluten containing products at our facility, there’s also no chance for cross contamination.

Reference

#1 Fradinho et al, “Edible Brown Seaweed in Gluten-Free Pasta: Technological and Nutritional Evaluation.” Foods (2019)8; doi:10.3390/foods8120622

No, we don’t believe it is because people have used Irish moss, a natural source of carrageenan, for centuries as a medicinal remedy and to thicken foods without reporting ill effects. However, carrageenan in processed food products has received bad press about potentially negative
health effects. This could be yet another example of how natural substances affect people differently in a highly processed form compared to their natural form. We discuss carrageenan in more detail in our blog post titled “There’s Carrageenan in My Seaweed! Is This a Bad Thing?”

Sea vegetables are suitable for vegetarian or vegan diets.  The red and green species are related to plants and the brown species, even though they're technically not plants, are clearly not animal either.  Nothing is
added...they come straight from the sea and are minimally processed.

Sea vegetables contribute important nutrients to vegetarian or vegan diets that may otherwise be lacking from diets based solely on land plants.  They have balanced amino acid profiles, are mineral rich, and it's been shown that some species even provide vitamin B12.

Sometimes, tiny dried animals such as mussels, barnacles, or even an occasional fish may be found hidden in the fronds. This is a natural consequence of life in the ocean, but this sort of accidental inclusion is common to all organic vegetable crops. The FDA even sets standards. A serving of canned or frozen spinach, for example, can have 50 thrips, aphids, and/or mites, or possibly the larvae of spinach worms — or even eight entire leaf miner bugs!

Many rabbinical scholars have concluded that seaweed is a clean kosher food, though not all agree.  It’s probably best to get your rabbi’s opinion if this is a concern.  Also, be aware that sea vegetables, since they come
from the sea, sometimes hold tiny dried shellfish such as snails, periwinkles, and mussels within their fronds. In order for most foods to bear the official hechsher “seal of approval”, food manufacturing facilities must be certified by a kosher certification agency.  As a small, employee-owned company, we have made the difficult financial decision to not incur the annual
certification cost.

Yes, our dried sea vegetables are a raw food. This is because they are sun or air dried at mild temperatures that never exceed 100°F. This helps ensure they retain enzymes, vitamins, proteins, lipids, and marine phytochemicals fully intact. This can’t be said of all sea vegetables; Japanese sea vegetables such as arame, hijiki, and wakame are often heat processed and may even be boiled or blanched. 

Although our sea vegetables can be eaten uncooked, right out of the bag, some may find them too dry or chewy eaten that way.  Soaking or marinating whole sea
vegetables in vinegar or citrus juice moistens and tenderizes them while still
preserving their raw food goodness.

Umami is a Japanese word that roughly translates as "delicious essence", and it's often described as being a savory meaty or brothy flavor.  Scientists have confirmed that umami is a fifth flavor that is neither salty, sweet, sour, nor bitter, with its own taste receptors on the tongue.  Various foods are umami rich, but seaweed is especially so due to glutamate, a naturally
occurring amino acid.  Including seaweed in recipes is a great way to add umami flavor without using MSG. The quintessential umami dish is Japanese dashi broth made with kombu.  Kombu is the name for a group of large brown seaweeds from the family Laminareacea.  Our own sugar kelp (Wild Atlantic Kombu) is a member of this family, and Alaria (Wild Atlantic Wakame) comes from a closely related group.  All of our seaweeds add umami to recipes, but
the brown seaweeds are especially rich in it! Read our blog post titled “What is Kombu
dashi?” to learn more.

The Recipes page of this website has many dried seaweed recipes developed by us and others over the years. We also sell seaweed cookbooks on our Online Store, including our very own Sea Vegetable Celebration written by Shep Erhart, MCSV founder, and noted organic chef Leslie Cerier. It contains over 100 vegetarian recipes plus 40 pages of biological, nutritional and practical info on all your favorite sea vegetables, American and Asian. 

Our regular retail packages have a “Nutrition Facts” panel showing nutrient content in a typical serving, but bulk packaging may not.  In those situations, you can go to our web store and find the Nutrition Facts
panel image for the retail product corresponding to the bulk product. For
example, if you purchase 5lbs of sugar kelp leaf, you can use the Nutrition Facts panel from the 2oz retail bag. Some customers may consume more or less than a typical serving. Since nutritional content remains proportional to serving size, you just need an accurate scale and some basic math to calculate the nutrient content of your favorite serving size.

In addition to the nutrients of concern required by the FDA, we try to include other nutrients that are present at significant levels. In general, we try to show anything that occurs at 2% or more of the RDI
(Recommended Daily Intake). However, just because a nutrient isn’t shown on the
Nutrition Facts panel doesn’t mean it’s not present. Seaweed contains many important minerals and other nutrients that might only occur at trace levels (<2% of the RDI) in a serving. Our Seaweed Nutritional Facts web page has more information on this topic, including a handy table showing levels of important nutrients per 100 grams for our eight most popular species.

Dried seaweed is a concentrated food best eaten in small portions. We advise not exceeding package serving sizes until you’ve given your body time to adapt.  Even in Japan, where per capita seaweed consumption is among the highest in the world, the daily intake rarely exceeds fourteen grams.

People often ask this question when they are trying a achieve a specific daily intake of a certain vitamin or mineral, such as iodine. The first thing to keep in mind is that the nutrient levels listed on our packages
or website are based on averages. Actual content may vary by as much as 20%
between bags or batches.  The question is
further complicated by the matter of bioavailability. Food nutrients are rarely fully
assimilated during digestion because of individual differences in digestion and
gut microbes, and because nutrients are often bound up with fiber or found in forms
that make them difficult to digest. We know, for example, that less than 100% of the iodine found in seaweed is fully absorbed by humans. The percentage varies between people depending on many variables, not the least of which is individual metabolism.

However, if you do wish to do the math, here’s an example: Let's say you want to know how much of our Kelp Blend Granules you need to eat to get the RDI of iodine. The RDI for iodine is 150 mcg per day. Our nutrition tables tell us that there are 54,600
mcg of iodine in 100 grams...which means there are 546 mcg in one gram. 150 divided by 546 = 0.27 grams. In other words, a very small amount of kelp blend granules, really just a sprinkle, will in theory provide the full RDI of iodine (1/4 tsp of kelp granules is about 0.8g).

Yes, seaweed is one of the most potent natural sources of dietary iodine there is. In fact, iodine was first discovered in seaweed and for much of the 18th century it was the only known source. Brown seaweeds such as kelps tend to contain more iodine than red or green seaweeds.  The “Seaweed Nutritional Facts” page has tables showing how much iodine is found in 100g of each species and in typical servings.  Please remember that the nutrient levels shown in the tables, including iodine, are averages and it’s not possible to know for sure exactly
how much iodine a serving may contain.

Iodine is an essential nutrient for thyroid health that affects many aspects of our physiology, especially metabolism.  Iodine is
critically important for proper prenatal brain development...so important that insufficient dietary iodine is considered the worlds' leading cause of childhood intellectual deficiency. This is mostly a problem in undeveloped countries with iodine poor soils and little access to seafood. A diet that
regularly includes sea vegetables helps ensure your thyroid always maintains
adequate levels of healthy iodine. The iodine found in seaweed can also protect the thyroid from harmful radioactive iodine released during nuclear accidents.  Many people who know this fact take special care to eat sea vegetables following a nuclear incident such as the Fukushima disaster.

The Reference Daily Intake (RDI) of iodine for adults is considered to be 150 micrograms (mcg or µg) per day, but most people can safely tolerate up to 1,100 µg per day.  It’s easy to meet the RDI by consuming
just a small portion of sea vegetables.  For example, just ½ tsp of bladderwrack powder contains about 1,164 µg of iodine. Most people safely “spill” excess iodine from their bodies, but sensitive individuals may experience adverse symptoms similar to those associated with iodine deficiency. In most cases, symptoms abate with reduced iodine intake.  You should consult with a health care practitioner if you have questions about your iodine consumption. The “Seaweed Science Resources” page has links to iodine research.

Sea vegetables provide all of the 20 or so minerals and trace elements required for
your body's physiological functions, often in amounts exceeding those of land plants.  Sea vegetables present these essential nutrients to your body in a chelated, colloidal bio-available form that helps them be readily absorbed and utilized.

Examples

Iron – Seven grams of dulse (about 1/3 cup) contains about 4mg of iron, about the same amount found in a 100g serving of spinach, and more than kidney beans, apricots, and
peas.

Potassium – Seven grams of Alaria contains as much potassium as a 100g serving of raw kale. Gram for gram, Alaria has 11 times more potassium than bananas (40.5 mg/g vs 3.6mg/g).

Calcium – Seven grams of sea lettuce contains nearly as much calcium (175mg) as one cup of milk (305mg).

Magnesium - Sea vegetables are a good source of magnesium.  Seven grams of laver contains nearly as much magnesium (32mg) as one cup of cooked collard greens (40mg).

Finally, consider this somewhat poetic image: we evolved from simple unicellular
creatures in the briny, mineral laden Mother Ocean. Now, billions of years later, our "inner ocean" — the saline fluids around and in our cells and organs — recreates the primal birthing environment, with a similar range and balance of minerals. Sea vegetables concentrate this mineral matrix. When you eat sea veggies, your cells welcome this natural, harmonious, health-giving balance.  

The briny flavor but modest sodium content of Sea Seasonings and other milled seaweed products makes them a healthy salt substitute. Most sea vegetables contain less sodium per 5-gram serving than ¼ tsp of table salt. Rockweed (Ascophyllum), our “saltiest” sea vegetable, contains about 40 mg of sodium per gram, or 200 mg in a 5-gram serving. A ¼ tsp of iodized table salt, on the other hand, contains 590 mg of sodium!

Sea vegetables are rich in potassium, calcium, and magnesium salts, which don't raise blood pressure like sodium does. They are also a healthy counter-balance to our modern, sodium rich diet. The diet of our
Paleolithic hunter/gatherer ancestors had a sodium to potassium ratio of about 1 to 16, but many processed foods reverse this ratio— potassium is leached out while sodium is added for flavor and as a preservative. Our bodies evolved to retain sodium as an adaptation to its scarcity in our natural diet.
Potassium, on the other hand, was plentiful in our natural diet of vegetables, nuts, seeds, and fruits, and so our bodies evolved to not retain it. This imbalance — along with the lack of magnesium and calcium — is implicated in high blood pressure, which is why people who have this condition were traditionally advised to limit their sodium intake. However, more recent medical advice is that lowering the salt to potassium ratio is more important than reducing sodium alone.

Sea vegetables help correct this imbalance because they have a sodium to potassium ratio of about 1:2. Susan Asanovic, M.S., R.D., states, "Almost everyone, except renal, severely hypertensive and CHF (congestive heart failure) patients, can enjoy organic Maine Coast Sea Vegetables in varying amounts. Even patients on modified clinical diets can healthfully incorporate moderate to liberal amounts of sea vegetables into
their diets; just remind them to limit shoyu, tamari, miso and processed foods. For patients on a no-added-salt diet (about 2500 mg), sea vegetables can give just the right saltiness, and are far better in nutrition and taste than commercial 'lite' salts. Used in moderation, they can be enjoyed in a typical serving of 5 to 10 grams (about 1/4 oz.)."

Please consult a health care provider or dietary counselor if you have questions about your sodium intake. In any case, whole sea vegetables can be lightly rinsed to reduce sodium and potassium content without affecting other minerals such as calcium or iron. If you're interested in using sea veggies as a salt substitute, check out our Sea Seasonings, milled sea vegetables in convenient shakers. 

Sea vegetables generally contain decent levels of vitamins, especially the B vitamins. Studies show that a 7g serving of most sea
vegetables (for example 1/3 cup dulse leaf) contains between 1% to 10% of the RDI for vitamins B1 (Thiamine), B2 (riboflavin), and B6.  Red seaweeds (dulse and laver) can also contain up to 10% of the RDI for vitamin C. Check out our Nutritional Charts for a more detailed accounting.

Japanese researchers found evidence decades ago that Pyropia seaweed (purple
laver), used to make nori sheets, contained high levels of Vitamin B12. This may also be true of Enteromorpha, a close relative of our Ulva sea lettuce.  However, it's unwise to rely on sea vegetables as a sole source of Vitamin B12. Tieraona Low Dog, MD, author of Fortify Your Life: Your Guide to Vitamins, Minerals, and More, writes “No matter what you might read, you cannot get vitamin B12 by eating non-fortified grains, nutritional yeast, algae, or seaweed.”

Tieraona Low Dog isn't the only expert with this opinion. It's also shared by the Academy of Nutrition and Dietetics and other authorities.  The difficulty lies in the fact that B12 comes in a form known as cobalamin, which is the form we humans can use, but also in analogue forms known as pseudocobalamin that are non-bioavailable to humans. The vitamin B12 found in seaweed actually comes from bacteria associated with the plant, and some of those bacteria manufacture the analogue forms. Older research finding B12 in purple laver used analytical methods that couldn't
detect the difference between the two forms.

However, many scientists suspect that up to half of all seaweed species actually could
contain bioavailable B12, and recent research findings support that view. Our
blog article titled “Deep Dive Update into Vitamin B-12 and Seaweed, and Why Sea Lettuce May Be an Especially Good Source” has more on this.

Most sea vegetables contain between 9% to 15% protein on a dry-weight basis, and some species such as laver can contain up to 40% protein.  Seaweed protein is
considered high quality because it usually contains all or most of the essential amino acids needed for human health. Seaweed protein also contains bioactive compounds, such as free amino acids, peptides, lectins, and phycobiliproteins, including phycoerythrin and phycocyanin, among others.

Check out our Nutritional Charts to learn how much protein is in our sea vegetables.

Sea vegetables are a low-fat food, typically having between 1-4% lipid content on a
dry-weight basis. However, what little fat they do contain is mostly heart and brain healthy Omega-6 and Omega-3 essential fatty acids. While these are present in only small amounts, they occur in a favorable ratio of between 1.5-2 Omega-6 to 1 Omega-3 (the NIH advises an optimal ratio of between 2 and 3 to 1). Our blog article “Seaweed and Omega-3 Fatty Acids” covers this topic in more detail.

Yes, it most certainly is! Dried sea vegetables contain 20% to 50% dietary fiber, depending on species. What’s more, seaweed contains unique fibers, known as sulfated polysaccharides, that aren’t found in land plants and that have been shown to
provide a broad range of potential health benefits.  Our Medicinal Botanical FAQs have more about those benefits.

Even though we don't digest fiber, it's extremely important for our health and nutrition.  A high fiber diet promotes the growth of healthy gut microbes and is
thought to help prevent certain types of cancer. It also helps slow glucose metabolism, which is especially important for diabetics. Including sea vegetables in your diet on a regular basis is an easy way to ensure you get the benefits of fiber.

Most of our wild sea vegetables are hand harvested from the Gulf of Maine, including coastal islands across the Bay of Fundy and on up to Nova Scotia. Some species (notably our Icelandic Kelp Blend) are harvested further north in Iceland. 

Sea vegetables are harvested following the tides, from small boats or by scrambling along rocky beaches at low tide. Some intrepid souls even don wet suits and wade into the cold Atlantic water to harvest! The plants are cut to leave the holdfast behind for regrowth, and many of the same beds have been sustainably harvested in this fashion for 40+ years.  The freshly harvested sea veggies are taken to drying facilities to be solar or air-dried at warm, mild temperatures.  The dried sea vegetables are then shipped to our processing plant, where they’re graded for quality and stored to await final packaging. 

Harvesting, drying, and processing are all done in accordance with National Organic Program (NOP) Standards. Please see The Harvest for more information on harvesting.

Most of our dulse is selectively hand-harvested from remote rocky beaches in the Bay of Fundy. Since dulse is a wild food, we are limited in how much we can sustainably harvest every year. Dulse's popularity means we sometimes ration sales so that more customers can share in the harvest. Read our blog post titled “Where's The Dulse!? An Explanation of Seaweed Shortages and Order Limits” to learn more about dulse harvesting. Luckily, we sell dulse in 3 milled and 3 whole leaf forms, so
you should always be able to get some form of dulse!

We mainly sell wild harvested, non-cultivated sea vegetables, though the rise of seaweed aquaculture in Maine means we may someday sell farmed sea vegetables as well. We're one of the few companies in the world to mostly sell wild harvested seaweed. 

Globally, over 97% of the seaweed that people eat is farm raised.  Seaweed
aquaculture is often known as mariculture and it may be one of the world's most
environmentally sustainable ways to produce food.  No fresh water, herbicides, pesticides, fertilizers, or precious crop land are required, and farmed seaweed is considered a carbon negative crop with a high potential for climate change mitigation. Most seaweed mariculture occurs in Asia, Indonesia, and the Philippines, but many new farms have recently started in Europe and elsewhere, including Maine.  As a company we've supported these new farmers with advice and advocacy, and as the supply of locally farmed seaweed grows, we anticipate offering it as a group of products.  When that day occurs, we will always differentiate between wild harvested and farm raised sea vegetables.

Shep Erhart, founder of Maine Coast Sea Vegetables, was among a group of early visionaries who worked in the early 1990’s to apply wild crop standards developed for maple, mushrooms, and ginseng to wild seaweed. In 1993, MCSV became the first US company to sell certified organic sea
vegetables. It's true that compared to land plants we have little control over the growing conditions of our wild marine plants. But we do have choices about
how, when, where, and how much we harvest, as well as how the plants are
transported, dried, stored and packaged. The NOP (National Organic Program)
Standards address all these areas and help ensure sustainability. NOP Standards give clear and uniform direction to all responsible parties for harvesting and handling these precious plants on their way to your table. Definitely worth the trouble!

Harvest Standards: These ensure that seaweed is harvested at sustainable levels, in particular that harvest beds or areas
remain healthy and productive (very much in our own best interest, as well!). Beds are inspected annually. Further, post-harvest handling and transport procedures are designed to ensure that no chemical contamination of the harvest occurs.  See The Harvest for a map and slide show.

Processing and Packaging Standards:
These maintain the integrity and purity of the sea veggies from the harvester to the packaged product at our certified facility.  Lot numbers are documented at every step so that each bag of finished product can be traced back to the source.

Testing Standard: Certification agencies randomly test our products for pesticide and herbicide residues.  We also voluntarily test most of our products for these residues as well as for other chemical contaminants and microbiological concerns.

Yes, but only when it’s harvested with that intention in mind. Sustainability is the
fundamental operating principle of this company. It's based on our belief that
these gifts from the sea come with the responsibility to maintain sustainable
practices in harvesting, processing and merchandising...leaving more than we
harvest, producing more than we consume, and giving back more than we take. Our
wild sea vegetables are harvested from the Gulf of Maine by hand: a simple and ancient technology that encourages mindful practice. The beds are lightly harvested to ensure regeneration; some of the same beds have been tended by harvesters for over 30 years. At times, market demand for some of our sea vegetables, such as dulse, exceeds the amount that's been harvested. 
When that happens, we prefer rationing our sales as opposed to putting more pressure on the resource. 

Each year it seems there are more reasons for concern about the health of our oceans, and each year we receive more inquiries about the purity of our seaweed products. An underlying assumption seems to be that
the world’s oceans are more polluted than the land, when in fact for most pollutants the opposite is true. Fortunately, the northern Gulf of Maine, where most of our sea vegetables are sourced, has very little industrial activity and no major metropolis.  Northern Maine is covered by a vast 3.5-million-acre forest known as the North Maine Woods, and with a population density of less than 25 people per square mile it’s the least populated region east of the
Mississippi.   Organic certification further ensures our sea vegetables are harvested away from marinas, aquaculture pens, and other sources of contamination, and that they’re handled and processed without the use of chemicals.  As a final precaution, every year 3rd party labs analyze our
seaweed for heavy metals and other contaminants.  The results are posted
here on the Product Testing page. .

Sea vegetables have been used for centuries in traditional Japanese and
Chinese medicine to treat cancer. Recent scientific research has begun to verify and validate this tradition.  Dr. Jane Teas, affiliated with the Harvard School of Public Health, first suggested a link in 1981 between seaweed consumption and the lower rate of breast cancer found in postmenopausal women in Japan, which she attributed to seaweed iodine. Subsequent research provided more evidence that iodine plays a role in maintaining healthy breast tissue and could even slow or prevent the development of breast cancer.  

In addition to iodine, macroalgae are rich in sulfated polysaccharides known as fucoidans, which are shown in lab studies to slow or stop the proliferation of cancer cells. These compounds, which are extracted from brown seaweeds, induced apoptosis (cell death) in a range of cancer cell lines without harming normal cells.

Algae also contain abundant levels of carotenoids, compounds responsible for pigmentation and known to be powerful anti-oxidants. One of these is fucoxanthin, an orange-colored pigment found in brown seaweeds.  Fucoxanthin has remarkable biological properties, including inhibition of several kinds of cancer cells.  Its ability to scavenge free radicals, a trait shared by
most carotenoids, is thought to play a key role in cancer prevention.

So far, the evidence that eating seaweed reduces cancer risk is circumstantial but
compelling.  Among other clues, researchers note a lower incidence of
breast and colon cancers in Asian cultures where seaweed is an important part of the diet. New findings continue to emerge showing the potential of seaweed bioactive compounds for cancer prevention and therapy. Visit our Science Resources page to access research papers about the findings described here.

Oriental medicine has long held that eating seaweed is good for the heart, and modern
medicine has found clues as to why.  An unbalanced diet is an important root cause of cardiovascular disease (CVD), but a balanced diet that includes seaweed on a daily basis may help prevent CVD. For one thing, seaweed is rich in soluble dietary fibers such as alginates, carrageenan, and agar.  Soluble dietary fiber is known to help lower cholesterol, reduce blood pressure, and decrease the risk of type II diabetes. 

Sea vegetables may taste salty, but only some of that is due to sodium. Seaweed is
rich in sea salts, such as potassium and calcium, that help reduce hypertension.  These salts exist in seaweed in a healthy ratio with sodium, so even if you’re trying to reduce sodium intake it may not be
necessary or wise to avoid seaweed. 

Finally, it’s worth mentioning seaweed’s lipid profile.  Although it generally has <3% fat, seaweed lipids consist mostly of heart healthy polyunsaturated fatty acids.

Consuming iodine-rich sea vegetables after a nuclear accident or other radiation release is a good strategy for protecting the thyroid against radioactive iodine-131. This poisonous isotope, which is released from nuclear power plant accidents, can cause cancer and other damage when it’s taken up by the thyroid. Loading the thyroid with non-radioactive healthy iodine-127, the form found in abundance in sea vegetables, minimizes iodine-131 uptake. Fortunately, iodine-131 has a short half-life of just 8 days and within about two weeks it becomes negligible.

Strontium-90 is another poisonous radioactive isotope released in nuclear accidents and bomb testing.  Strontium-90 easily contaminates food crops because it behaves chemically like calcium, and if
ingested in contaminated food, it accumulates in bone with adverse
long-term consequences.  In the 1960's researchers at McGill University in
Canada found that alginic acid (also called alginate), a polysaccharide found in brown algae like kelp and Alaria, could reduce the amount of strontium-90 absorbed through the intestinal wall.  Other studies by researchers in Japan and elsewhere confirmed these important findings.

After the Chernobyl nuclear disaster in Russia, we saw an increase in our sales of kelp, and we joined with other small producers in sending a kelp care package to survivors. There was a similar sales increase after the 2011 Fukushima nuclear disaster.  Dr. Ryan Drum tells us "… we
are regularly taking in radioactive isotopes from the total world contamination by continual radioactive fallout from all nuclear power plants, weapons facilities and past nuclear tests."  Another good reason to regularly eat seaweed! For iodine levels in our sea vegetables please refer to our Nutritional Chart.

Traditional uses of sea vegetables in Asia show they provide a therapeutic effect on the inflammatory response, particularly in
tissue wounds. Ryan Drum, Ph.D., herbalist and seaweed specialist, asserts that
fucoidan is the bio-active compound in brown seaweed responsible for lessening
the inflammatory response. This view is supported by recent scientific research showing how various fucoidan extracts from brown seaweeds modulate the body’s inflammatory response.

Fucoidan is a water-soluble compound that is easily extracted by boiling/simmering a quart of water with an ounce (about 1½ cups) of dried brown sea vegetable for 20 to 40 minutes. Dr. Drum recommends drinking this fucoidan extract daily for 1 to 2 weeks, either pre-surgically or after tissue wounding has occurred.

Sulfated seaweed polysaccharides (SSPs) exhibit antiviral properties in laboratory
studies against HIV, herpes simplex, dengue, and coronaviruses. SSPs include
agarins and carrageenans from red seaweeds and fucoidans from the browns. It's important to understand that, so far, these antiviral properties have only been
demonstrated in vitro (in a laboratory and not in humans). Because SSPs are a type of dietary fiber, they are not readily digested and absorbed by humans, so researchers are trying to develop antiviral medications from SSPs extracted from seaweed. Besides antiviral action, SSPs are being investigated for other medicinal properties, including immune modulation, intestinal, mental, and cardiovascular health, and fighting cancer. These benefits are described in other FAQs.

The widespread prevalence of heavy metals such as lead, mercury, and cadmium in the environment and in our food and water raises concern that these metals can accumulate in the body with adverse health effects. Heavy metal detoxification diets have become increasingly popular to address this concern, and several foods have been proposed for their cleansing abilities, including sea vegetables. Anthony William, a New York Times bestselling author known as the “Medical Medium”, promotes dulse flakes for this purpose.  Dr. Ryan Drum (aka Fucus man), an expert in herbal medicine, advocates eating brown seaweeds for heavy metal detox due to their high levels of fucoidans.  Fucoidan was first extracted in 1913 from bladderwrack Fucus vesiculosus.  In addition to its possible role as a chelator of heavy metals, fucoidan is being extensively studied for anti-cancer, anti-viral, and anti-inflammatory properties (reference #1).

Is there scientific evidence to support eating sea vegetable for detox?  Unfortunately, at this time such evidence is lacking.  In part, this may be because scientists haven’t really addressed the topic, which also means we can’t say for certain that sea vegetables don’t detoxify heavy metals.  There is evidence, though, that seaweed carbohydrates such as fucoidans and alginates readily bind to and absorb metals and other contaminants. Phycoremediation (removal of contaminants with algae) has been extensively studied and used for wastewater treatment for decades (references 2 & 3). 

If seaweed can trap and remove contaminants from the environment, it’s reasonable to think it can do the same in humans.  We do know that fucoidans, alginates, and other seaweed dietary fibers pass through the intestine mostly undigested and excreted. Anything bound within these dietary fibers, such as heavy metals, would also be excreted.  It seems plausible to speculate that as seaweed fiber passes through the intestine it can “sponge up” any heavy metals it encounters that may be present from the other food and drink we ingest.  However, for now this remains speculation, because to our knowledge there’s been no research demonstrating this occurs.  The ability of dietary seaweed to detoxify heavy metals from internal human tissue, organs, and bone is even more difficult to evaluate. No plausible mechanism has been proposed in the scientific literature to explain how dulse or other seaweeds could remove heavy metals or other toxins from organs and bone.  Since fucoidans and alginates are poorly digested, they’re not likely to occur at significant levels in our blood circulation.

This lack of empirical evidence makes it difficult to evaluate claims that sea vegetables can detoxify humans of heavy metals or other contaminants. For this reason, we can neither recommend nor disapprove of the practice.  Anyone concerned about their bodily burden of heavy metals should discuss the matter with their health care practitioner. We discuss this topic in greater detail in our FAQ “Do sea vegetables contain heavy metals?”

References

#1 Janet Helen Fitton "Therapies from Fucoidan; Multifunctional Marine Polymers." Marine Drugs (2011)9: pp. 1731-1760; doi:10.3390/md9101731

#2 Brinzaet al., “Marine micro and macro algal species as biosorbents for heavy metals.”Environmental Engineering and Management Journal (2007)6(3):237-251 http://omicron.ch.tuiasi.ro/EEMJ/

#3 Davisa et al, "A review of the biochemistry of heavy metal biosorption by brown algae." Water Research (2003) 37: pp. 4311–4330

Besides being good for the body sea vegetables are also good for the brain!  Seaweed is rich in iodine, an essential nutrient for proper brain development in fetuses and infants.  Iodine deficiency in pregnant and lactating woman is regarded as the world’s leading cause of mental deficiency in children; a problem with long-term consequences.  The US National Institutes of Health advises that pregnant women get 220mcg per day of iodine and lactating women up to 290mcg.  Modest amounts of seaweed included in the diet are a great way to get more iodine, but it’s important not to overdo it.  Pregnant and lactating women should always consult a health care professional before supplementing their diet with iodine!

In adults, eating seaweed may benefit the brain through its positive effects on another important organ – our gut!  In 2019 Chinese researchers got approval for a new Alzheimer’s treatment developed from a seaweed polysaccharide.  The polysaccharide – sodium oligomannate – was found to suppress intestinal dysbiosis and the resulting accumulation of phenylalanine/isoleucine, with reduced neuroinflammation and a measurable improvement in cognitive abilities. This finding adds further evidence that diet affects mental health through the gut brain axis (1).  The complex sulfated polysaccharides found only in seaweed are believed to exert a profound positive effect on the composition of our gut microbiota, as described in our FAQ Intestinal Health.  Another recent study showed that a seaweed extract eaten before lunch helped healthy volunteers perform better on cognitive tests after lunch (2).   Read our blog post “Seaweed and the Brain” to learn more about these exciting developments. 

References

#1 Luna & Foster. “Gut brain axis: diet microbiota interactions and implications for modulation of anxiety and depression”. Current Opinion in Biotechnology (2015) 32:35-41.

#2 Haskell-Ramsay et al, "Acute Post-Prandial Cognitive Effects of Brown seaweed Extract in Humans" Nutrients (2018) 10, 85; doi 10.3390/nu10010085

Dietary fiber is essential for intestinal health and sea vegetables are an excellent source, containing from 25% to 50% dietary fiber.  What’s more, the fiber found in seaweed has unique complex carbohydrates known as sulfated polysaccharides that are being extensively researched for having a broad range of health promoting properties.  These sulfated seaweed polysaccharides – SSPs for short – differ between the red, brown, and green seaweeds, but they all possess similar properties that may positively impact our health on a broad range of fronts: cardiovascular, anticancer, anti-inflammatory, diabetes, and mental health (1).  Perhaps most importantly, there’s evidence that, in conjunction with other seaweed phytochemicals, SSPs act as prebiotics to promote a beneficial microbial community in our gut.  Known as the gut microbiome, these microbes outnumber our own body’s cells by about 10 to 1.  Given these numbers it should come as no surprise that they strongly affect our health. Everyone’s gut microbiome is unique and a function of their diet.  Diets that include a variety of foods (especially unprocessed, whole foods and fermented foods) and that are also high in fiber promote a greater diversity of gut microbes and a healthier gut microbiome. Read our blog post “Seaweed and the Brain” to learn about how seaweed can promote a healthy gut microbiome that improves mental function.  The health benefits of SSPs are also described in some of our other Medicinal Botanical FAQs.  

 #1 Cherry et al., “Prebiotics from Seaweeds: An Ocean of Opportunity?” Marine Drugs (2019) 17, 327; doi:10.3390/md17060327

Plato said "The sea cures all ailments of man".  In Greek mythology Thalassa was the primeval spirit of the sea, and since ancient times Thalassotherapy has been practiced for healing through restorative seawater baths.  Seaweed, with its concentrated ocean minerals, is often included in these baths.  Victorian English flocked to the seaweed baths to immerse themselves in hot water filled with Bladderwrack (Fucus sp.) or other mucilaginous and high iodine seaweeds to ease their aches and pains. Immersion in warm water allows the ocean minerals to pass through the skin. Thalassotherapy spas still exist, many of them quite luxurious. France is renowned for having some of the best Thalassotherapy spas in the world, but unfortunately the concept hasn't quite caught on in the US.  But no worry...you can enjoy a luxurious seaweed Thallasotherapy spa experience right at home using any of our bulk kelp products! Simply place some dried seaweed in something like a cheesecloth bag with fine enough mesh to keep the seaweed from clogging the drain and add it to your hot bath.

We test our sea vegetables annually following each harvest season and throughout the year for microbial contamination, heavy metals, pesticides, petroleum residues, and radiation.  We also periodically test for nutrient composition. Annual test results are posted on our Product Testing page

Nutritional information is found on our Nutrition Page.

Humans have released radiation into the environment, whether intentionally or accidentally, ever since the US first tested atomic bombs in 1945. Because eating seaweed offers some protection from radiation, it’s important to ensure the seaweed itself is free of harmful radioactive isotopes. We began testing products for radioactivity in 2011 in response to the Fukushima, Japan nuclear catastrophe, and we’ve continued testing every year since.  On occasion, we've had customers contact us in alarm after testing their seaweed using a Geiger counter and finding "radiation". Please be assured that this finding was due to a harmless, naturally occurring isotope of potassium that's also found in bananas and other foods.  Our testing is done by 3rd party labs using sensitive methods that definitely don't involve a Geiger counter!  Please see our Product Testing page for more information.

Sea vegetables can often contain trace levels of the heavy metals arsenic, cadmium, and lead. These metals are widely distributed in the world’s oceans from both natural and human sources, and seaweed absorbs them just as it absorbs other minerals and elements. We annually test for these metals, as well as for mercury, and we report the results on our Product Testing page.

Heavy metals are present in many foods, not just sea vegetables.  They are of concern because exposure can lead to illness, impairment, and in high doses, death.  The risk doesn’t come from any one single food, but rather from eating many different foods containing heavy metals at low levels.  The FDA monitors and tests foods for heavy metals and sets standards. Go to this link “Metals and Your Food” to learn more about how the FDA regulates metals in food.

The significance of heavy metals in food varies from food to food.  We ourselves are not concerned about the trace levels found in our sea vegetables, for several reasons.  For one thing, sea vegetables are generally consumed in small portions, usually less than 7 grams per day.  For another, we have reason to believe that when heavy metals are present in seaweed, they have low bioavailability because they are bound within an indigestible matrix of dietary fiber.  Indeed, the ability of seaweed carbohydrates to trap and bind toxins has led some to propose the use of sea vegetables for cleansing and detoxifying the human body of heavy metals!  We cover this topic in more detail in the FAQ about heavy metal detoxing.  Finally, we believe that the nutritional and health promoting properties of sea vegetables far outweigh the presence of heavy metals.

Ultimately, of course, it’s up to each person to decide if they want to avoid all of the many foods and substances that contain heavy metals, including sea vegetables, or if they want to balance the risk against the benefit for each particular food.  The topic of heavy metals in sea vegetables and other foods is complicated, but if you want to take a deeper dive please continue reading.  Below, we discuss each of the four most common heavy metals found in sea vegetables in more detail.

Arsenic

Arsenic is the 22nd most abundant element in seawater and seaweed seems to have a particular affinity for it, accumulating arsenic at levels 1,000 to 50,000 times higher than in seawater. The reason this occurs isn’t clear, but what is known is that most seaweed species transform inorganic arsenic into organic arsenosugars, possibly to detoxify it. Arsenosugars are rapidly excreted by humans and considered harmless.  Of greater concern is inorganic arsenic (iAs), which is usually found at trace levels along with arsenosugars.  The US FDA has not established permissible iAs levels for any food other than apple juice and rice cereals for infants.  These two foods are regulated because they’re known to contain iAs and because infants and young children are especially vulnerable. Children three years and younger are most at risk because they eat 2-3 times more food per body weight compared to adults and they often have a limited diet, eating the same few foods day after day.  The FDA action level for iAs in apple juice is 0.01ppm and for rice cereal it’s 0.1ppm.  It’s important to understand that toxicity depends not just on the level in the food but also on serving size, frequency of consumption, and body size.  At 0.01ppm a 12-ounce glass of apple juice contains about 3.5µg (microgram) of iAs. By comparison, a 5g serving of dulse with 0.13ppm iAs contains a total of 0.65µg iAs.  In France the maximum allowable iAS level in seaweed is 3ppm; at this level a 5g serving contains 15µg iAs.  Hijiki seaweed, which has been eaten for centuries in Japan, contains 67-96 ppm iAs, one of the highest levels measured in edible seaweeds. This prompted European and North American government food safety agencies to advise against consuming hijiki.  Maine Coast Sea Vegetables has never offered hijiki for sale and it isn’t found anywhere in the North Atlantic.

Cadmium

Cadmium is readily absorbed by macroalgae, though it’s not believed to offer any nutritional or other value to the plant. Like other elements, cadmium is naturally present in seawater at very low concentrations, but mining and industrial products such as batteries and paint pigments contribute anthropogenic cadmium into the world’s oceans. Cadmium accumulates in the kidney and bones of humans with continuous long-term exposure, leading to toxicity and dysfunction. Cigarette smoke contains cadmium and smokers typically have twice as much cadmium in their bodies as non-smokers. Most cadmium exposure for non-smokers is through food, but the total amount of cadmium found in food is not absorbed into the body, only the bioavailable fraction. Cadmium bioavailability in seaweed may be low, because studies with other foods have found that copper, iron, and zinc inhibit cadmium retention (1, 2) and seaweed has relatively high levels of these micronutrients. The FDA has not yet established a Maximum Daily Intake (MDI) for cadmium in food, but other countries provide some guidance. The European Union recommends an upper limit in seaweed of 3ppm cadmium, but in France the limit is set at just 0.5ppm. The European Food Safety Authority advises a tolerable weekly intake (TWI) of 2.5 μg/kg body weight from all dietary sources.  An adult weighing 140 pounds would have to consume 75g per week of Alaria containing 2.1ppm cadmium before exceeding this level; or more than ten 7g servings.  These various thresholds differ because even though they’re based on the same science, they have different safety margins built in to them.

Lead

Lead has a wide range of known ill effects, but the brain is the organ most sensitive to lead poisoning.  Because of its long history as a paint and gasoline additive lead is widespread in the environment, and it is perhaps the most challenging heavy metal to regulate.  Scientists unanimously agree there is no safe level of lead exposure, particularly for children, while acknowledging it’s often found in food and drink.  The EPA action level for lead in drinking water is 15 parts per billion (ppb). At 10ppb someone drinking 8 glasses (about 2 liters) of water would ingest 20 µg of lead. The FDA established a much lower total dietary limit for adults of 12.5 µg/day to protect against fetal lead exposure in women who are unaware they are pregnant, and to reduce infant exposure during nursing. The FDA has also established lead thresholds for juice and candy, foods likely to be consumed by children. The acceptable juice level is 50 parts per billion and for candy it’s 0.1 ppm.  The FDA has not established a safe level for seaweed, but in France the acceptable level of lead in seaweed is <5ppm. The highest lead test result we’ve recently recorded in our sea vegetables was 0.69ppm (in bladderwrack, 2018).  One would have to eat about 18 g of bladderwrack to exceed the FDA total daily dietary lead limit of 12.5µg. The French seaweed standard is higher than the FDA candy standard in part because seaweed is generally eaten in small amounts, whereas children sometimes consume lots of candy.

Mercury

Mercury is the heavy metal most often associated with seafood.  The FDA has found that swordfish can contain as much as 3.22ppm mercury, with an average of about 1ppm.  This occurs as organic methylmercury, which unlike organic arsenosugars is the more toxic form. Mercury accumulates in fish, other seafood, and humans as a consequence of bioaccumulation.  However, studies from around the world have found that sea vegetables contain only trace levels of mercury, if any.  This is borne out by our own lab testing, which usually finds that mercury can’t be detected, and when it is found it’s at just trace levels.  Mercury exposure does not seem to be an issue when eating sea vegetables, but of course we will continue to monitor.

The Bioavailability Question

In nutrition, bioavailability is a measure of how much of a particular nutrient, element, or other substance is digested and absorbed into the bloodstream. A portion of the heavy metals found in seaweed are not bioavailable because they are chemically bound to complex carbohydrates, such as fucoidans and alginates.  These polysaccharides are dietary fibers that passage through the intestine largely undigested, meaning anything they absorb and chemically bind is also excreted.  Although we know that a portion of the heavy metals found in seaweed aren’t bioavailable, we don’t yet have a good sense of how that percentage varies between metals, seaweed species, and variations in human digestion.  This is a complex research topic, and we will update this information as advances are made.

Disclaimer

The above information is a summary of the best available guidance and evidence from regulatory agencies and the scientific literature as of 2020.  It is not intended and should not be used for diagnosis,treatment, or any other medical purpose, and we neither recommend nor disapprove of eating seaweed for heavy metal detoxification.  We advise anyone concerned about heavy metals and their health status to seek guidance from a trusted medical practitioner.  We believe sea vegetables are more than the sum of their parts, and that when included in a balanced diet they confer extraordinary nutrition and health.

References

#1 McLaughlin et al "Metals and micronutrients - food safety issues." Field Crops Research (1998)60 pp. 143-163

#2 Yanfang et al,  "Arsenic and cadmium in the marine macroalgae (Porphyra yezoensis and Laminaria japonica) — forms and concentrations." Chemical Speciation & Bioavailability, (2012) 24:3, 197-203, DOI:10.3184/095422912X13404690516133

Seaweed is very efficient at absorbing and concentrating minerals and various elements, including metals, from seawater.   Metals such as copper, iron, and zinc are considered essential minerals because they’re needed for health, but others such as arsenic, cadmium, lead, and mercury, known as heavy metals because of their high atomic mass, are toxic at high levels.  However, even essential minerals can be toxic if ingested at too high levels or out of balance with other minerals.

Metals occur naturally in the ocean due to weathering of the earth’s crust.  Unfortunately, over the past century anthropogenic (manmade) sources have elevated the levels of some heavy metals in the oceans.  These are widely distributed in all the world's oceans. This is why ‘where and how’ sea vegetables are harvested matters.  Some parts of the ocean contain more heavy metals and other contaminants than others, maybe because they receive industrial effluent or are located near a large metropolis. 

The northern Gulf of Maine, where most of our sea vegetables are sourced, has very little industrial activity and no major metropolis. Northern Maine is covered by a vast 3.5-million-acre forest known as the North Maine Woods, and with a population density of less than 25 people per square mile it’s the least populated region east of the Mississippi.  Organic certification further ensures our sea vegetables are harvested away from marinas, aquaculture pens, and other sources of contamination, and that they’re handled and processed without the use of chemicals.  As a final precaution, every year 3rd party labs analyze samples of our seaweed for heavy metals and other contaminants.  We post the results on our website for customers to see; we’re one of the few seaweed companies anywhere with this practice. 

Bromine is the seventh most abundant element in seawater and it's readily absorbed by seaweed. Some naturopaths and other healers have expressed concern that bromine, because it’s so closely related to iodine, competes with thyroid iodine receptors and potentially causes symptoms of iodine insufficiency and hypothyroidism.  Is bromide in sea vegetables something to be concerned about? Could the bromide found in seaweed adversely affect your thyroid? The short answer is we don't believe so. For a more comprehensive answer, read our bromine blog post on the topic

We've been hearing a lot about the sea of plastics polluting our oceans and how they eventually break down into barely visible or even microscopic microplastics. Customers sometimes ask if these microplastics pose a risk to sea vegetables or to those who eat them. So far, the evidence shows this isn't a concern. Read this blog post for a detailed answer.

You may have noticed a label on our sea vegetables warning about lead and/or cadmium and referring to California’s Proposition 65. Why would a Certified Organic natural food with a reputation for being healthy have this label?

Seaweed is renowned for its capacity to absorb and accumulate minerals, metals, and other elements from seawater.  This includes essential nutrients such as iodine, calcium, manganese, and zinc, but also undesirable elements such as lead, cadmium and arsenic.  The California law known as Proposition 65 requires businesses selling products in California to give consumers a “clear and reasonable warning” when their products contain listed chemicals known to cause cancer, birth defects or reproductive harm.  Because the levels of cadmium and lead found in our sea vegetables sometimes exceed Prop 65 thresholds, many of the products we market in California must bear a Prop 65 exposure warning. However, none of our products exceed the Prop 65 threshold for inorganic arsenic.

The Proposition 65 website states “A Proposition 65 warning does not necessarily mean a product is in violation of any product-safety standards or requirements”.  It’s up to you, the customer, to decide whether to use the product or not, and our website includes additional information to help you make an informed choice.  The Harvest page and several of our FAQs address how and where we source our certified organic sea vegetables. The Product Testing page displays test results for heavy metals and other concerns for most of our products, which can be used to calculate dietary intake.  Our FAQ on “Heavy Metals” presents science-based information on the presence of heavy metals in sea vegetables and other foods. If you wish to learn more about Proposition 65 you can visit the Proposition 65 website or visit our  Prop 65 page.