Health Benefits of Eating Seaweeds

Seaweeds are a huge resource that tends to be ignored in the UK, there could be lots of Health Benefits of Eating Seaweeds, very few are harvested for food although this is starting to improve. I think that as a country we are quite similar to the Japanese i.e. a small island nation with a dodgy imperial past. The typical Japanese diet is between 10-15% seaweed based yet in the UK it’s more like 0.0001%.

Many of the seaweeds loved by the Japanese are the same species that you’d find in our waters so why don’t we eat more of them? 

What is seaweed?

Seaweeds aren’t technically plants, they are complex macroscopic marine algae, and are divided into three groups according to pigmentation: green, red and brown. These groups are genetically distinct and unrelated and are the result of convergent evolution, whereby distinct life forms find similar solutions to shared environmental challenges. 

The variation in the colours comes from light-harvesting pigments that have evolved to maximize photosynthesis in different depths of water and levels of light. The colour of the seaweed indicates in reverse which kind of light it is able to use to harvest; everyone except the colour it is.

Because of the hostile environment they grow in, seaweeds have developed a variety of other adaptations. Most seaweeds use a solid holdfast or anchor to keep them attached to rocks. A bit like a root system but the seaweed obtains no nutrients from this source.

Many have also developed slippery coatings to allow them to slip freely through potentially destructive waves. These coatings are particularly high in alginates and glutamates are important compounds in food and medicine. 

Seaweeds in general are the most mineralised vegetables on earth, they’re very beginner friendly and some of the flavours will blow your mind. There’s a lot of research going on at the moment looking at the potential health benefits of eating seaweed and its popularity is growing so what are the main health benefits to eating seaweed?

W.carter, CC0, via Wikimedia Commons

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What are the health benefits of Seaweed?

In general seaweeds are a great source of vitamins A, C, B12 and calcium. All essential for a healthy body. They are also high in protein and low in fat but there are many other benefits to including them in your diet.

Thyroid function

Your thyroid is a small butterfly-shaped gland in the neck, just in front of the windpipe. It produces hormones that affect things such as your heart rate and body temperature. Having an underactive thyroid can lead to many symptoms such as swelling of the thyroid glands in the neck, weight gain, fatigue and weakness, thinning hair, dry skin, feeling colder than usual, slowed heart rate and learning and memory difficulties. The NHS says an adult needs 140 micrograms (μg) of iodine a day. Many of us get nowhere near that amount in our diet, vegans and vegetarians can be really lacking in this important element as it typically comes from cows milk, dairy products, meat and eggs. Supplements are available but why not go straight to the source? 1 gram of some species of brown seaweed contain between 5 and 50 times your daily iodine requirement.

Heart health

Seaweeds contain many compounds that have been shown to be beneficial for your heart.

Seaweeds are high in soluble fibre and omega 3 fatty acids both of which are thought to be beneficial to your heart.

Seaweeds are also high in sulfated polysaccharides, which studies have shown have the ability to reduce blood pressure and prevent blood clotting. They may also help reduce bad cholesterol and total cholesterol levels. 

Some human studies also report that high seaweed intakes may reduce blood pressure levels in kids and adults.

Blood sugar control

Research has found that some of the compounds found in seaweeds may reduce the risk of developing type 2 diabetes. One of these compounds is fucoxanthin, an antioxidant that gives brown algae its characteristic color. This compound is thought to help reduce insulin resistance and stabilize blood sugar levels.

The high soluble fibre content in seaweed may also slow down the speed at which carbohydrates are absorbed from a meal. This can make it easier for your body to stabilize your blood sugar levels.

Weight management

Seaweed is low in calories, but rich in glutamate, an amino acid that gives it a savory umami taste. So, seaweed snacks may help boost weight loss by providing a satisfying alternative to more calorie-rich snack options such as crisps.

Research has also found that seaweed’s can have the ability to affect your levels of the weight-regulating hormone leptin. Combined with seaweed’s high fiber content, this may help decrease hunger and enhance feelings of fullness.

Another sulfated polysaccharides, found in seaweeds called fucoidan, is also believed to enhance fat breakdown and prevent its formation.

Immune function

Seaweeds  contain marine plant compounds believed to have antioxidant, anti-allergenic, and disease-fighting properties. Research shows that these compounds may have the ability to fight viruses by blocking their entry into cells. A study in 73 HIV-positive women found that those given 5 grams of spirulina per day developed 27% fewer condition-related symptoms, compared to the placebo group.

Digestive health

Again the high fibre content of seaweeds improve your digestion by preventing constipation and ensuring smooth digestion. 

They also contain agars, carrageenans, and fucoidans, which are thought to act as prebiotics. Prebiotics are a type of nondigestible fiber that feeds the beneficial bacteria in your gut. The more good bacteria you have in your gut, the less space there is for harmful bacteria to thrive. Animal studies show that taking seaweed supplements may improve the amount of healthy bacteria and reduce the amount of harmful bacteria in the gut more effectively than other types of prebiotics. 

Researchers also believe that the prebiotics found in seaweed may have certain anti-inflammatory and antibacterial effects.

In addition, certain prebiotics may have the ability to block harmful bacteria from sticking to the gut wall, which may prevent the formation of stomach ulcers.

Cancer risk

Researchers believe that seaweed may help decrease estrogen levels, potentially reducing a woman’s risk of developing breast cancer. Some studies also suggest that a class of compounds found in brown varieties, such as kelp, may help prevent the spread of cancerous cells.

Other Potential health benefits

Seaweed may also offer some protection against skin damage and bone and inflammatory diseases.  Compounds in seaweed may help protect the skin from damage caused by UVB rays from the sun when applied directly to the skin. They may also help prevent wrinkles, sun spots and premature skin aging.  

When it comes to protecting against diseases, seaweed’s antioxidant and anti-inflammatory effects may help reduce the risk of developing rheumatoid arthritis and osteoporosis.

As you can see seaweeds really are a potential ‘super food’ for the future so why not come on one of our coastal foraging courses and learn more about this incredible resource? We’ll show you how to identify different seaweeds, where you can find them, what to do with them and how to harvest them in a safe and sustainable way.