Ecklonia cava

Ecklonia cava is a perennial brown alga and exists mainly in subtidal areas off the coast of Japan and Korea, especially in kelp forests along the central Pacific coast in Honshu, the southern coast along the Sea of Japan, and the coast in Kyushu.[6] It usually creates marine forests in water 2 to 25m deep, and can grow to be over 130 cm.[7] As a brown alga, it plays an important role in the ecosystem and habitat of where it lives, providing a source of food and shelter for many marine organisms.[8] They are the primary producers of their ecosystem, and many animals use them as locations for reproducing.[9]

Despite its importance in ecosystem functioning and uses for humans, Ecklonia cava has been decreasing in numbers within recent years.[6] Many factors could contribute to the decline, such as an increase in water temperature, overgrazing, and overuse by humans, but the direct cause of the decrease has not yet been extensively studied. Some evidence suggests an increase in water temperature is responsible, while the low availability of nitrogen in the water can also cause higher death rates.[10][9] A combination of both factors is likely responsible, since higher temperatures cause lower availability of nitrogen.

Ecklonia cava is an important food source for snails, such as Littorina brevicula (Philippi) and Haliotis discus (Hannai Ino), and other marine organisms.[11] Interestingly, it has also been shown that Ecklonia cava has a defense mechanism that causes it to be less palatable after having already been attacked by a herbivore, and these defenses are specific to each species of herbivore.[11] Many species of seaweed and other plants have defenses similar to this, but the specificities of each defense have not been pinpointed.

The health benefits of Ecklonia cava and its chemistry have been somewhat studied, leading to its uses in dietary supplements and herbal remedies. One study notes, “Ecklonia cava (EC) is known to have antioxidant, anti-inflammatory, antidiabetic, and anticancer properties...”[12] The study later goes on to include that it is very likely to be a safe treatment for some diseases, since there were no or almost no negative side effects in any on the animals it was tested on, even at relatively high doses. Testing on humans further suggests its safety. It is the major ingredient in the supplement called SeaPolynol,[13] which has been shown to reduce fat accumulation in obese mice.[14] This suggests that Ecklonia cava can someday be especially useful for treating diabetes and obesity in some patients.

Though its health benefits are not yet entirely understood, it is also regularly touted as an herbal remedy for insomnia, hair loss, high cholesterol, asthma, and even erectile dysfunction. Although it is likely safe to consume in most cases, there is limited or no evidence to support many of these claims.

Ecklonia cava’s use in food can be traced back to the fourth century in Japan.[13] It is usually consumed in salad and soups, but is also used for coloring in other foods, such as candies and rice cakes.[13]

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