18th December

Seaweed carotenoids: diverse nutrients from the ocean

Laura Kealy, Ocean Harvest Technology

Carotenoids are organic pigments often present at significant levels in brown seaweed and other photosynthetic organisms. As powerful antioxidants, carotenoids prevent cancer, heart disease and enhance immune response to infections. Present in all algae, higher plants and photosynthetic bacteria, carotenoids are produced from fats and other basic organic metabolic building blocks by these organisms.9.3aquaculture seaweed

And although humans are incapable of synthesising carotenoids, recent research suggests that a carotenoid-rich diet can result in improved health, reduced mortality rates and a lower instance of certain chronic diseases.

Seaweed source

In the marine environment carotenoids are widely present in seaweed, the most notable being astaxanthin, β-carotene and fucoxanthin - all of which have been reported to be effective antioxidants. Algal carotenoids have been associated with the prevention of cardiovascular and neurodegenerative diseases as well as certain types of cancer. As antioxidants, they protect the body from oxidative stress, a physiological state which is putatively involved in the development of cancer, Parkinson’s disease and Alzheimer’s disease - to name but a few.

Antioxidant activity

Fucoxanthin has recently received considerable attention due to its wide array of beneficial effects on human health. This compound has an unusual allenic bond, which is responsible for its high antioxidant activity. It is also one of the most abundant carotenoids in nature, and contributes to more than 10% of total carotenoid production.

 

For this reason, fucoxanthin has been isolated from several brown seaweeds in many recent studies in order to investigate its bioactive potential. Many of the edible brown seaweeds abundant on Ireland's shores contain significant amounts of fucoxanthin. These include Fucus serratus (serrated wrack), Ascophyllum nodosum (bladder wrack), Laminara digitata (kelp) and Saccharina latissima (sugar kelp).

Anti-obesity potential

The human obesity epidemic - now at a global scale - is linked with insulin resistance and an increased risk of certain chronic diseases. Indeed, there is a strong association between obesity, diabetes, impaired glucose tolerance and cardiovascular disease. While lifestyle changes - including improved diet and increased physical inactivity - can indeed help prevent obesity, much attention is being given to the anti-obesity potential of fucoxanthin.

For example, a study in mice found that fucoxanthin induces the expression of a specific protein called UCP1 in abdominal white adipose tissue (WAT) which in turn leads to oxidation of fatty acids and increased heat production. The authors also reported that fucoxanthin has the potential to reduce white adipose tissue, blood glucose and plasma insulin, resulting in a 5-10% weight loss.

Further research also suggests that the anti-diabetic activity of fucoxanthin could be due to the fact that it seems to promote the production of Docosahexaenoic acid - a fatty acid known to reduce the risk of cardiovascular disease and protect against Alzheimer’s disease, depression and rheumatoid arthritis. The chemo-preventive and anti-cancer activity of fucoxanthin is being investigated too, with promising results already for leukaemia, prostate, bladder and colon cancer.Additional studies have reported that this carotenoid can even significantly decrease the damage caused by exposure to UV radiation from sunlight.

In summary, growing evidence from numerous scientific studies suggests that fucoxanthin is a multi-functional, bioactive nutrient with wide-ranging beneficial health-promoting properties, as well as protecting against a number of life-threatening diseases and, notably, combatting obesity.

And with more than thirty per-cent of the population considered to be obese and five per cent suffering from type II diabetes, this is critically important. There is no doubt therefore that integrating seaweed - a 100% natural ingredient - into the Irish diet will contribute to improved overall health and well-being.

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