Focus: Wakame seaweed

The Wakame alga is a brown alga belonging to the Alariaceae family, whose scientific name is Undaria pinnatifida. It is a species from the seas of Japan, China and Korea, and has been appreciated for hundreds of years both as an ingredient of traditional cuisine and for its beneficial properties on the body. Precisely because of the various uses that can be done, since 1983 the Wakame seaweed is also cultivated in European seas, especially along the French coast of Brittany. The seaweed is also produced in the Tasmanian seas, and used primarily to supply the Australian domestic market.
The Wakame is presented as a seaweed of length that reaches the meter and a half, with broad leaves generally no more than 30 centimeters, which grows in turbulent waters and characterized by strong currents at a depth between 6 and 12 meters.

This algae lives a moment of strong vegetative growth during the winter season, so the harvest takes place in spring: to make it we use boats, and using long rakes or hooks tear the algae from the substrate. The collected algae are extremely delicate and perishable, once removed from the water; for this they must be immediately worked. Generally these are hung from special support structures and dried, an operation which is sometimes preceded by a short preventive boiling. This scalding is mainly carried out in order to eliminate microorganisms capable of causing seaweed decay but, no less important factor, to improve its appearance. The high temperatures in fact give the Wakame alga a green color and therefore a more pleasant appearance compared to the natural brownish shades.
In Japan it is the most important harvested or cultivated species in terms of value and production (Tseng, 1982). In China this species is less popular because growers find it more difficult to manipulate. In order to increase the natural production in the past, stones were placed on the bottom or the cliffs were exploded to increase their engrafting surface. Currently, artificial seeding is done in unpolluted and controlled areas, using zoospores or sporophyll suspensions (specialized leaflets that bring zoosporangi). The cultivation on ropes inseminated with sporophylls has been carried out since 1955. After harvesting, the algae are washed with fresh water and then dried or dried.
The rapid reproduction and growth rates of the Wakame seaweed are particularly high, as well as its resistance and adaptability to different environmental characteristics. For this reason the species has been included among the 100 most invasive species in the world, listed in the (Global Invasive Species Database). Currently the uncontrolled spread of the Wakame seaweed has meant that it represents a serious problem in several coastal areas worldwide, such as the United States, Australia, New Zealand, Argentina, Great Britain, Spain, France. Even the Italian coasts have been affected by this proliferation without control, and especially the Adriatic ones.

It is the main source of alginic acid, a polymer composed of D-mannuronic acid and L-galuronic acid, structurally similar to pectin.

Alginic acid is a polysaccharide widely present in the cell walls of brown algae, it is not synthesized in the human body and the digestive enzymes are not able to break it down. The ability of these polysaccharides to bind with the salts present in the intestine (not only of potassium, sodium, calcium and magnesium, but also of heavy metals such as strontium and cadmium), facilitating their elimination, can have positive reflections hypertension due to the excessive consumption of sodium and as a detoxifying action with regard to the elimination of toxic metals.

Anti-hypertensive action
24 rats with moderate hypertension (systolic blood pressure> 160 mmHg) were subdivided into 4 groups (n = 6 / each) and each of them treated, by gastric route, with one of the 4 inhibitory peptides of the Angiotensin-II conversion enzyme, dipeptil-carboxypeptidase (ACE, 10mg / day / kg body weight of Tyr-His, Lys-Tyr, Phe-Tyr and Ile-Tyr) extracted from the Hund algae. (60 g) for 7 days The measurement of systolic and diastolic blood pressure (UR-5000®, Eda Co., Tokyo) performed at the beginning and every 3h until the end of the treatment, showed a significant reduction in blood pressure and (p <0.01 ep = 0.05 for systolic and diastolic pressure, respectively). This experimental study (Suetsuna K, Maekawa K, Chen JR. 2004) addresses a possible anti-hypertensive use of the compound.

Anticoagulant action
20 healthy volunteers of both sexes (age: 23-58 years) were recruited for a pilot study, randomized in two groups (n = 10 / each) and fed with 3 capsules / day based on legumes (3g), control , with 3 capsules / day containing fucoidan (3 g) extracted from the Hund, for 12 days (Liu F, Wang J, Chang AK, et al. 2012) Coagulation tests (Berichrom Antitrombin III®, Dade Actin FSL, Liquid Anti -Xa) performed on plasma samples before and after treatment showed a significant increase (p = 0.01) of the activated thromboplastin partial time (a-PTT) (from 28.41 mg / l to 34.01mg / l, respectively ) and of the level of anti-thrombin III (AT-III) (from 113.5% to 117% after 4 days of treatment) in group 2; as well as a reduction (p = 0.04) of the thrombin coagulation time (TT). The fucoidane extracted from the alga has therefore a modest but significant anticoagulant action, to keep in mind among the cumulative side effects in the habitual users of this food.

Antidiabetic action
Fucoxanthin, an important component in wakame, exerts an anti-diabetic effect. A 2009 study conducted in Japan examined the anti-obesity and anti-diabetic effects on obese mice. When wakame seaweed was added to the high fat diet, it significantly suppressed body weight. Prior to seaweed treatment, mice showed signs of hyperglycemia, hyperinsulinemia and hyperleptinemia, and the addition of the same in the diet showed normalizing these conditions. The researchers concluded that wakame seaweed has the ability to prevent diabetes, related disorders and obesity by reversing insulin resistance due to a high fat diet. (Buettner R, Schölmerich J and Bollheimer 2007).

Promotes fat burning

A Japanese study conducted at the University of Hokkaido suggests that the fucoxanthin present in the wakame alga promotes the burning of fats within the fat cells of animals. According to the study, fucoxanthin fights fat in two ways: it encourages the action of proteins that cause fat oxidation and promotes the production of DHA in the liver, which helps reduce bad cholesterol or LDL. Fucoxanthin also reduced abdominal white weights adipose tissue of rats and mice, thereby making it one of the great fat-burning foods. (Asia Pac J Clin Nutr. 2008)

Wakami helps to balance hormones

Wakame seaweed is a natural source of manganese, iron and calcium, three minerals that help to balance hormones naturally. Manganese and calcium help to improve the symptoms of PMS; in fact, a study published in the American Journal of Obstetrics and Gynecology found that women who have lower levels of manganese in their blood have more symptoms related to pain and mood during PMS and menstruation. (Am J Obstet Gynecol, 1993) Strengthens the bones

One hundred grams of wakame seaweed provide 15% of the daily calcium value, essential for preventing osteopenia or osteoporosis. Calcium-rich foods help increase bone growth and accelerate bone repair, while calcium deficiency occurs easily because we lose the mineral through our bowels, kidneys and skin. Osteoporosis is a common feature of aging; involves bone loss that begins in women at the time of menopause and in men of about 55 years. It can lead to an increase in fracture rates, so it is so important to get enough calcium in your diet. (Nordin BE, 1997).

Reduces the risk of breast cancer

A small body of research suggests that there is a relationship between algae and a reduced risk of breast cancer. In traditional Chinese medicine and Japanese folk medicine, alga is used to treat tumors. People who eat algae regularly, especially in Japan, have drastically lower rates of breast cancer. (Kang et al., 2012) In 2013, researchers at the University of California assessed the possibility of introducing wakame seaweed into the diet of postmenopausal American women. Fifteen healthy postmenopausal women were recruited for the three-year clinical period; five of the women did not have any form of breast cancer (they served as a control group) and 10 had survived breast cancer. The consumption of the alga has lowered urokinase-receptor concentrations, plasminogen activator (uPAR), a protein involved in the processes of cell migration and tissue invasion. UPAR is over-expressed in tumors and is considered a negative prognostic factor in various types of cancer. and usually present in higher concentration among postmenopausal women. Researchers believe that wakame seaweed has the ability to lower levels of these receptors and may therefore help explain the lower incidence of mortality caused by breast cancer in postmenopausal women in Japan. (Maruyama et al., 2003) Another interesting study published in 2004 suggests that the fucoxanthin present in wakame may act as a chemopreventive and chemotherapeutic compound in colon cancer cells. (Hosokawa M, Kudo M, Maeda H, Kohno H, Tanaka T, Miyashika K. 2004)
There is no doubt, science is supporting these extraordinary benefits of using wakame seaweed and its effectiveness as a preventive treatment against cancer.

Wakami supports a healthy pregnancy

Folic acid or vitamin B9 and vitamin B12 are essential vitamins for the correct functioning of our body. Vitamin B9 is water-soluble and acts as a coenzyme, together with vitamin B12, in the decomposition and utilization of proteins. The two vitamins are closely related: vitamin B12 deficiency can cause folic acid deficiency, and deficiency of either vitamin can cause anemia. Folic acid is necessary to copy and synthesize DNA, produce new cells and support nerve and immune function. Folate is known to be one of the most important vitamins in a healthy and vibrant pregnancy. For pregnant women, folate deficiency is particularly risky, as it can lead to neural tube defects such as spina bifida, anencephaly, limb malformations and cardiac complications. Because folate is necessary for DNA duplication and for the construction of new cells, it is essential that pregnant women eat foods rich in folate, such as wakame seaweed, to decrease the risk of development problems. (Molloy AM et al., 2008).

Hypocholesterolemic action

The fucoxanthin present in the wakame alga stimulates the liver in the production of DHA (docosahexaenoic acid) helping to reduce the amount of harmful cholesterol in the body. Therefore, it is a great cholesterol-lowering food. A study published in the Journal of Nutrition found that dried wakame powder altered the activities of the enzymes involved in the metabolism of fatty acid in the liver in rats. The rats fed on diets containing wakame powder had low levels of triacylercercene, suggesting that its consumption is useful for preventing hyperlipidemia. (Tsuda et al 1957)

Inolte, wakame seaweed is a rich source of omega-3 fatty acids, essential fatty acid in regulating blood cholesterol levels. And since we are talking about cholesterol: algal fibers present in algae are fibers of the original composition that cause hypocholesterolemic and hypoglycemic effects, not to mention the improvement of the intestinal transit they induce.

Use in supplements
While in the countries of origin it is usually consumed as food, its excellent nutritional profile means that in the West the Wakame seaweed is marketed mainly as a food supplement.
The excellent protein content and the good quality of the proteins make it the object of an advertising promotion that paints it as the ideal complement of vegetarian food in its various forms and macrobiotic. Substantially, the wakame seaweed can be considered a tonic, a useful aid to reach the needs of the various nutrients in case of food shortages or increased need. Vitamin and mineral deficiencies, weakness, fragility of nails and hair, fatigue and reduced concentration, are the classic indications of supplements based on wakame seaweed.
The commercial boost to the consumption of Wakame seaweed derives also and above all from the alleged slimming properties, with a stimulus on energy expenditure.
The physiological basis of these characteristics must be sought first of all in the excellent content of iodine and selenium, two minerals essential for the proper functionality of the thyroid, which with its hormones directly affects the body metabolism.
In second analysis, like other Brune algae, wakame seaweed is a known source of fucoxanthin, a carotenoid that appears to activate the UCP1 disaccopating protein. This protein – particularly expressed in brown fat – promotes the oxidation of fats to generate heat, “burning” them and preventing them from depositing as an adipose reserve.
This effect, now well demonstrated on laboratory mice, is awaiting clinical confirmations in humans: it is however considered that the bioavailability and absorption of fucoxanthin contained in the wakame algae are rather modest.
Due to its richness in soluble fibers (alginates), wakame seaweed, taken in the form of a supplement, can promote weight loss through the satiating effect conferred by the swelling of these colloidal fibers in contact with water inside the stomach. The distension of the gastric walls is in fact one of the signs that favor the onset of the sense of satiety, removing the hunger pangs. Also at the gastric level, alginates contribute to form a sort of protective film on the stomach walls, protecting them from the acid insult of gastric juices; it is not by chance that alginates are used in the problems of gastric acidity and gastroesophageal reflux.
Probably these characteristics also explain the results of a recent study, according to which the daily consumption of 4/6 grams of seaweed, typical of most Japanese, can be associated with a low incidence of metabolic syndrome. These benefits would be amplified by the generous presence in the diet of marine fish, also typical of Japanese cuisine.

Recommended intake doses
The recommended intake doses are generally between two and four grams of dried wakame seaweed per day. Naturally, this content significantly reduces the actual amount of beneficial nutrients assumed through the integration of Wakame, making only the contribution of iodine significant.

Alga Wakame as Iodine supplement
Iodine is one of the most significant and characteristic nutrients of wakame. The recommended daily intake of this mineral is 90-150 mcg, a quantity that – given to the hand – is covered by the simple ingestion of 557 mg (0.557 grams) of dried wakame seaweed.
The maximum dose of iodine that presumably does not cause harm in a healthy person is 1100 mcg per day, a threshold that would be exceeded by the consumption of wakame seaweed in doses higher than 4.23 grams.
Therefore, it is recommended not to exceed the recommended dose and to consult the doctor before taking supplements based on Wakame seaweed, especially in case of diseases or thyroid dysfunction.


Suetsuna K, Maekawa K, Chen JR. Antihypertensive effects of Undaria pinnatifida (wakame) peptide on blood pressure in spontaneously hypertensive rats. J Nutr Biochem 2004
Liu F, Wang J, Chang AK, et al. Fucoidan extract derived from Undaria pinnatifida inhibits angiogenesis by human umbilical vein endothelial cells. Phytomedicine. 2012;19(8-9):797-803
Irhimeh MR, Fitton JH, Lowenthal RM. Pilot clinical study to evaluate the anticoagulant activity of fucoidan. Blood Coagul Fibrinolysis 2009; 20(suppl7):607-10

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