seaweed (wakame) – Healthy superfoods
by Dr.Helly Hernandez
The sea can not only give us fish and shellfish to add to the diet, but also a great variety of algae that have been gradually introduced into our diet. Seaweed contains a high level of humidity, which can reach up to 94% of the total weight in some species. They are characterized by containing important amounts of proteins and amino acids, minerals, fiber and phenolic compounds responsible for the antioxidant capacity. The fat content of algae, on the other hand, is very low (generally less than 1%). One of the most relevant nutritional characteristics is its low caloric intake, despite presenting an important content in polysaccharides. This is because most of these polysaccharides cannot be digested by the human digestive system since they are part of the dietary fiber.
It has been proven that the chemical composition of the algae is directly conditioned by the species, the geographical situation, the environmental conditions and especially the season of the year. For example, the highest protein concentrations have been observed in winter and spring, while the lowest concentrations have been obtained in summer and autumn
Regarding the influence of the species, the major polysaccharides vary depending on whether they are green, brown or red algae. In brown algae, alginates, fucans and laminars predominate. Red algae contains mostly sulphated galactans such as agar and carrageenans
Due to its nutritional composition, seaweed is considered one of the richest and healthiest foods nutritionally speaking.
The total production of seaweed in the year 2017 was up to 20 million tons, highlighting the wakame species (Undaria Pinnatifida) as the most consumed, it is especially appreciated in Korea, where its production reached 33,000 tons in dry weight. Like other seaweed, the wakame is marketed in its fresh or dried form.
Nutritional components of wakame
Over the years, many beneficial effects have been attributed to the consumption of fiber in the human diet. The consumption of foods containing fiber is directly related to a decrease in cardiovascular diseases, colon cancer, and diabetes. It has been seen that it has prebiotic activity, which reduces the absorption of cholesterol and fat in the intestine, prevents constipation, diverticulosis, etc.
Some studies have shown that the soluble fiber content is higher in red algae, such as nori, while brown algae have a higher content of insoluble fiber. It should be noted that daily recommended fiber intake is of the order of 25-30 g / day (FAO, 2015), with the recommended ratio of 25-35% soluble fiber and 70-75% insoluble fiber. Taking into account these data, brown algae such as wakame provide a greater health benefit.
The algae contain high levels of proteins. As mentioned above, the protein fraction that can be found in marine algae varies significantly throughout the year and also with the species. Generally, brown algae contain lower levels, ranging from 3 to 15% (dry weight), except for the wakame species that can contain up to 24%. One of the newest uses of algae has been dedicated to the sports field based on the incorporation of algae in the diet in order to achieve greater muscle mass.
Although the algae contain minimum or very low lipid values, they have a composition in high-quality fatty acids. The fatty acid composition of algae is greatly influenced by the geographical situation and the environment that surrounds them in their habitat, as well as by different genetic factors that determine a certain variability of these compounds within each species. Brown algae as wakami present a greater quantity of these compounds.
The content of minerals in marine algae is significantly high, representing between 8 and 40% expressed in dry weight. Seaweed is one of the most complete foods in terms of the type of minerals if compared with terrestrial plants and products of animal origin. The brown algae like the wakame correspond to the group with the highest percentages of minerals. In the mineral composition presented by the algae, Na, K, Ca and Mg stand out as essential macroelements.
Phenolic compounds are found, generally, in plants and vegetables. Within this large group are phenolic acids, polyphenols, and flavonoids. It is a series of compounds of great interest because they have an antioxidant capacity, which implies a beneficial effect on our organism. In many investigations have been related some of the phenolic compounds with the ability to prevent cardiovascular problems, cancer, arthritis and immune disorders, by acting to protect the tissues from oxidation
The antioxidant capacity present in foods of vegetable origin is due to the synergistic action of a wide variety of antioxidants, among others, vitamins C and E, and polyphenols. This property is considered as the biological activity responsible for the preventive effect in certain cardiac and immunological diseases. The main antioxidants in algae are phenolic compounds, vitamins, and carotenoids, which are found in significant amounts in wakame.