Billions of pounds of seaweed are harvested each year, the “consumption of [which] has been linked to a lower incidence of chronic diseases,” both physical and mental. For example, women who eat more seaweed during pregnancy appear to be less depressed, and have less seasonal allergy symptoms.
But, the problem with these cross-sectional, correlational studies is that you can’t prove cause and effect. Maybe seaweed consumption is just an indicator that they’re following “traditional Japanese dietary customs” in general, which have lots of different aspects that could protect against disease. To know for sure if seaweed could modulate immune function, you have to put it to the test.
So, typically, researchers start out like this: in vitro (meaning, like, in a test tube), which makes for quicker, cheaper, easier experiments. Take eight different types of seaweed, and basically make some seaweed tea you can drip on human immune system cells in a petri dish.
It was studies like these that showed that the seaweed wakame, which is what you find in seaweed salad, can quadruple the replication potential of T cells, which are an important part of our immune defense against viruses like herpes simplex virus. Yeah, but no one actually tried giving seaweed to people with herpes, until this study.
They gave people suffering from various herpes infections about two grams a day of pure powdered wakame, which is equivalent to about a quarter-cup of seaweed salad. And, “[a]ll fifteen patients with active Herpetic viral infections experienced significant lessening or disappearance of symptoms.” This included herpes virus 1, the cause of oral herpes, which causes cold sores; herpes virus 2, which causes genital herpes; herpes virus 4, also known as Epstein-Barr virus, which causes mono; and herpes 3, which causes shingles and chicken pox. There was no control group, though—but with no downsides, why not give it a try? Anyway, if you’re on a date, and they order seaweed salad, you might want to ask them about their history.
Researchers also found that wakame boosted antibody production. So, might it be useful to boost the efficacy of vaccines? The elderly are particularly vulnerable to suffering and dying from influenza. Now, the flu vaccine can help, but ironically, the elderly are less likely to benefit, because immune function tends to decline as we get older.
So, they took 70 volunteers over the age 60. This is the level of antibodies they had against a flu virus at baseline. And, what you’re looking for in a vaccination is to get a two-and-a-half fold response. So, we’d like to see this get up to at least 25 to consider it an effective response. But, they only got up to here. Give them some wakame extract every day, though, for a month before the vaccination, and they jumped up to here. They used an extract rather than the real thing, because they needed to put it into a pill, so they could perform this randomized, placebo-controlled study—it’s kinda hard to make a convincing placebo seaweed salad.
“It is hoped that the popular seaweeds eaten daily in Japan, though almost unknown” everywhere else outside of Japanese restaurants, will start to be more widely “consumed…for possible immunopotentiation [boosting immunity] and for attenuating the burden of infectious diseases in the elderly.”
