Seaweed or sea vegetables is a common name used to describe several different species of marine algae that grow in the sea, oceans and rivers. Seaweeds have long been used as a food, folk remedy, dye and fertiliser. Seaweed is most commonly consumed in Asian countries where it has been a prominent part of diets.
Health Benefits Of Seaweed
1. Fights free radical damage
Seaweed is chock-full of antioxidants and beneficial plant compounds, including carotenoids and flavonoids, which helps protect the body from free radical damage. Fucoxanthin is the main carotenoid found in brown algae, such as wakame. Studies showed that fucoxanthin has 13.5 times the free radical scavenging activity as vitamin E, an essential antioxidant.
2. Supports digestive health
Seaweed is an excellent source of fibre, an important nutrient that plays an important role in digestive health. Seaweed also contains sulphated polysaccharides that have been shown to increase the growth of good bacteria in the gut, which contributes to better gut health .
3. May lower blood sugar levels
The antidiabetic activity of edible seaweed has been shown in numerous studies. A 2017 study found that fucoxanthin present in seaweed may aid in improving blood sugar levels . Animal studies have also pointed out that seaweed can lower blood sugar levels .
4. May help in weight loss
Seaweed contains a good amount of fibre and consuming it can help you feel full for longer and make you feel less hungry, which could potentially help in weight loss. Animal studies have shown that the presence of fucoxanthin in seaweed may help reduce body fat 
5. May reduce heart disease risk
Some research studies show that seaweed can help reduce cholesterol levels and protect against heart disease . A 2013 study found rats that were fed a high-fat, high cholesterol diet supplemented with seaweed powder, resulted in a reduction in total cholesterol levels, LDL cholesterol and triglyceride levels .
6. Supports thyroid function
Seaweed is a great source of iodine, an essential mineral that is required by the thyroid gland to produce hormones, which are involved in energy production, repairing damaged cells, regulating muscle function and metabolism. An iodine deficiency will cause symptoms such as weight changes, hair loss, fatigue and swelling of the neck.
7. May manage cancer
Noted studies have shown the anticancer activity of seaweed . Seaweed contains a compound called fucoidan, which exhibits anti-cancer effects. Animal studies have shown that fucoidan stops the growth of melanoma, a type of skin cancer. Another study published in the Marine Drugs reported that seaweed can stop the growth of colon and breast cancer 
Possible Risks Of Seaweed
Although seaweed is considered healthy, however, there are possible risks if you consume in excess. Seaweed is rich in iodine and consuming it in excess quantities can affect thyroid function and this can cause symptoms like swelling or tightness around the neck or weight gain . In addition, seaweed also contains heavy metals, this is because seaweed absorbs minerals from the sea. As seaweed contains toxic metals, consuming it can pose several health risks. However, studies show that edible seaweed contains low levels of toxic metals like aluminium, cadmium and lead which did not pose any health risk . Nevertheless, if you eat seaweed daily toxic metals may build up in your body over time. So, it is better to consume seaweed in moderation and choose organic seaweed.