Irish seaweed could prove boon in battle against high blood pressure

A common Irish seaweed could be used to reduce blood pressure, according to findings by Teagasc food scientists.

Members of the NutraMara marine research group, the scientists in Teagasc’s facility at Ashtown, Co Dublin, have found a renin-inhibitory peptide in the seaweed palmaria palmata, commonly known as dulse, a significant find as renin-inhibitory peptides have not been found in seaweed species before.

Commonly featured in pharmaceutical drugs, renin inhibitors are bioactive agents which are used primarily in the treatment of hypertension.

The Teagasc research could eventually have applications for foods and pharma companies.

Cardiovascular disease accounts for more than 4.3m deaths globally each year and high blood pressure is a main cause of the disease. Used as a protein source, the researchers have found that some seaweed proteins may have health benefits for use in functional foods.

The peptides are currently being assessed in bread products. Research work at Teagasc will also assess the effects of the seaweed protein hydrolysates on the technical and sensory attributes of bakery products, in particular bread.

Teagasc researcher Maria Hayes said: “Currently, analysis of a P palmata bread product is under way and the effects of the hydrolysate on the moisture content, ash, crude fat, fibre, and protein content have been assessed. The effects of the seaweed protein on the colour and texture profile of the bread are also being carried out.”

Teagasc researchers are looking to seaweed for proteins with health benefits for use as functional foods. Historically, seaweeds were consumed by coastal communities worldwide. Seaweed is a habitual diet in many countries, particularly in Asia.

Whole seaweeds have been successfully added to foods in recent times, ranging from sausages and cheese to pizza bases and frozen-meat products.

NutraMara programme manager Fiona Manning said: “NutraMara is trying to find bioactive components for use in functional foods. We are funded by the Marine Institute and we are looking specifically at marine sources; for example, how fish discards and waste streams can be used to have a positive effect in functional foods.”

The researchers have also shown that protein-rich red seaweeds such as dulse and porphyra (common name sleabhac or laver) species may potentially be used in the development of low-cost, highly nutritive diets that may compete with current protein crop sources such as soya beans.

For example, the protein content of dulse varies from between 9% and 25% depending on the season of harvesting.

The highest ratio of protein per gram in dried whole seaweed is normally found in dulse collected from October to January.

Dulse contains valuable amino acids such as leucine, valine, and methionine. In porphyra species, the amino acid profile is similar to those of peas or beans.

Bioactive peptides are food-derived peptides that exert a physiological, ‘hormone-like’, beneficial health effect. Proteins and peptides from food sources such as dairy, eggs, meat and fish are agents capable of reducing high blood pressure and are thought to be able to prevent cardiovascular disease.