18th December

Macroalgal minerals for a healthier diet

Dr Simon Faulkner, Ocean Harvest Technology

Macroalgae contain nutritional components such as proteins, lipids, carbohydrates, vitamins and minerals; however, the levels of these components are dependent on seaweed species, geographical location and a number of additional environmental factors.

12.1 OHT

In recent years, much attention has been given to the unique composition of macroalgae; in particular, the high levels of bioactive compounds including polysaccharides, proteins, amino acids and polyphenols.

(The Irish seaweed Fucus vesiculosus is high in minerals and trace elements such as Iodine. Harvested on the west coast, OHT produces extracts for various applications)

Seaweeds however are perhaps best known for their high levels of minerals and trace elements, represented by the crude ash content of up to 50% for certain species. Sufficient consumption of these minerals is important in order to achieve a healthy and nutritionally balanced diet but also to prevent serious chronic diseases such as cancer and Alzheimer’s disease.

Seaweed mineral content

Overall, the ash content in seaweed is high when compared to land vegetables, inferring a higher level of minerals and trace elemnts. As an example, the level of iron in the red seaweed Palmaria palmata (dulse) is 10 times higher than the levels found in sirloin steak.

In addition to iron, macroalgae are also an excellent source of additional mineral and trace elements such as iodine, calcium, zinc, manganese, potassium magnesium, sulphur and phosphorus.

With the exception of calcified seaweed, the level of calcium can often exceed 3% of the dried weight. Calcium has important roles in bone and teeth formation and is the most abundant element in the human body. Calcium is also required for vascular contraction and vasodilation, muscle function, nerve transmission, intracellular signalling and hormonal secretion.

Like calcium, potassium is also present at high levels in seaweed, with levels sometimes as high as 11%. Besides the well-known role of potassium in the regulation of blood pressure and water balance, potassium is also important for muscle contractions, nerve impulses and the proper functioning of the heart and kidneys.

The elements magnesium, sulphur, phosphorus (and others) present in seaweed also have important biological functions.

Seaweed is also an excellent source of trace elements, examples of which include zinc, manganese and iodine. Macroalgae represent the best natural source of iodine ― an essential trace element that affects almost every physiological process in the body.

Iodine deficiency is a common global problem and is currently considered to be the primary cause of impaired cognitive development in children by the World Health Organization.

In 2010, a published scientific paper estimated that 50% of Europeans do not consume sufficient iodine as part of their daily diet. Another study conducted in 2015 reported that 39% of schoolgirls surveyed in Northern Ireland were iodine deficient, and this agrees with a previous UK-based study that found 68% of UK schoolgirls were iodine deficient.

Therefore, incorporating seaweed and/or seaweed-derived products into the western diet would go a long way towards helping people meet their Recommned Daily Intake of iodine, thus having a significant impact on human health.

Another trace element present in seaweed, zinc, is important for the function of many enzymes and has important roles in the metabolism of RNA and DNA, signal transduction and gene expression.

Insufficient intake of zinc can result in liver damage and other chronic diseases; however, it is important to note that too little or too much of any element/trace element can have negative consequences for human health.

Incorporating seaweed minerals into our diet

Seaweed can be consumed in a variety of forms including raw, as part of a salad; in a drink; stir-fry or even incorporated into bread.

Ocean Harvest Technology is currently developing novel, seaweed-derived, functional products for the human food sector. These include those that have been developed by isolating and extracting key minerals or trace elements from Irish seaweed which are often lacking in the human diet - including iodine. 

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