Fucoxanthin
Fucoxanthin is a carotenoid found in edible brown seaweed such as wakame (Undaria pinnatifida) and hijiki (Hijikia fusiformis), which is widely used in Asian cuisine. Wakame is the seaweed used in miso soup. Fucoxanthin is also found in much smaller quantities in red seaweed (the type typically used in Japanese sushi rolls) and green seaweed. Both wakame and hijiki are available in Japanese specialty stores, some health stores and online. Although brown seaweed is the richest source of fucoxanthin, one would have to eat unrealistically large amounts of it to reach the fucoxanthin levels used in research studies. Fucoxanthin is also available in capsule form as a dietary supplement and can be found in drugstores and online.
Why do people use fucoxanthin
Weight loss
Fucoxanthin is being studied in the context of weight loss. So far, some studies have been conducted on animals. Japanese researchers have found that fucoxanthin (isolated from wakame) promotes the reduction of abdominal fat in rats and mice. The animals lost 5 to 10 % of their body weight. Although the exact mechanisms of action of fucoxanthin are not yet known, it appears to target a protein called UCP-1, which increases the rate at which abdominal fat is burned. Belly fat, also known as white adipose tissue, is the type of fat found around our internal organs and is associated with heart disease and diabetes. Fucoxanthin also appears to stimulate the production of DHA, one of the omega-3 fatty acids found in fatty fish such as salmon. While these results are promising and fucoxanthin has already become a popular supplement, more research is needed to find out if fucoxanthin works in the same way in humans. If it proves to be effective, then fucoxanthin could be used to develop a diet pill for overweight people.
Diabetes
Animal studies have also shown that fucoxanthin can lower insulin and blood sugar levels. The researchers suspect that the anti-diabetic effect of fucoxanthin could be related to the fact that fucoxanthin promotes the formation of DHA (an omega-3 fatty acid found in fish oil). DHA is thought to increase insulin sensitivity, improve blood lipid levels and reduce bad LDL cholesterol.
Cancer
Preliminary studies in test tubes indicate that fucoxanthin has anti-tumor properties. No studies have yet investigated whether this is also true in humans or when taken orally. It is still too early to use fucoxanthin as an adjuvant agent in cancer therapy.
Side effects
As there have not yet been many studies carried out on humans with fucoxanthin, no side effects are yet known.
You should not consume large quantities of wakame or other seaweed as a source of fucoxanthin. Seaweed is rich in iodine and excessive iodine intake could result in iodine toxicity. High iodine levels can impair the function of the thyroid gland. Furthermore, consuming excessive amounts of iodine-containing foods is also not recommended if you have a known allergy or hypersensitivity to iodine.
References
- Maeda H, Hosokawa M, Sashima T, Funayama K, Miyashita K. Effect of medium-chain triacylglycerols on anti-obesity effect of fucoxanthin. J Oleo Sci (2007) 56.12: 615-621.
- Maeda H, Hosokawa M, Sashima T, Funayama K, Miyashita K. Fucoxanthin from edible seaweed, Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues. Biochem Biophys Res Commun. (2005) 332.2:392-397.
- Maeda H, Hosokawa M, Sashima T, Miyashita K. Dietary combination of fucoxanthin and fish oil attenuates the weight gain of white adipose tissue and decreases blood glucose in obese/diabetic KK-Ay mice. J Agric Food Chem (2007) 55.19: 7701-7706.