Wakame Seaweed Salad May Lower Blood Pressure

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Seaweed salad is put to the test for hypertension.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

I used to think of seaweed as just a beneficial whole food source of minerals—like iodine, for which it is the most concentrated dietary source. And, indeed, just a half-teaspoon of mild seaweeds, like arame or dulse, or two sheets of nori a day, should net you all the iodine you need for the day.

But, “the intake of seaweeds is advised” not only as a whole food source of iodine, but also, evidently, “for the prevention of lifestyle-related chronic diseases.” Based on what?

Well, you’ll see this kind of reasoning: the Japanese live long, and they eat seaweed. And so, they speculate that seaweed might have something to do with it, based on suggestive reports. But, when you see lists, like this, of all the supposed biological activities some food has, you want to know is this based on clinical data (meaning on actual people) or so-called preclinical data (based on test tubes and lab animals)? When a study like this is published, talking about the “Effects of seaweed-reconstructed pork diets” on rats, what do you do with that information? Seaweed is one of the ingredients they’re trying to use to improve the “image” of meat products. So, they try to add grape seeds, or flax seeds, or walnuts, or purple rice or, whatever this is. I had to look it up: thong-weed. How’s that for an image booster?

You can look at epidemiological studies (meaning looking at populations). And, indeed, Japanese preschoolers who eat seaweed tend to have lower blood pressures, suggesting seaweed might have beneficial effects—which would make sense, given all the minerals and fiber. But, you can’t prove cause and effect with that kind of study. Maybe it was the other components of the diet that went along with the seaweed-eating.

It’s even harder to do these kinds of studies on adults: so many people are on high blood pressure medications. University of Tokyo researchers took an innovative approach by comparing the diets of people on low-dose, versus high-dose, versus multiple blood pressure medications. And, although they all had artificially normalized blood pressure, those that ate the most fruit and sea vegetables tended to be the ones on the lower doses—supporting a dietary role for seaweed. But, why not just put it to the test?

A double-blind crossover trial found that seaweed fiber lowered blood pressure, apparently by pulling sodium out of the system. I know they couldn’t use real seaweed, because then you couldn’t fool people with a placebo; but, why not just, like, put whole powdered seaweed in pills? This was finally attempted, ten years later.

Compared to doing nothing, they got beautiful drops in blood pressure. But, if you look deeper into the study, they desalinized the seaweed—meaning they took out two-thirds of the sodium naturally found in it. So, that still doesn’t tell us if eating seaweed salad is actually going to help with blood pressure. What we need is a randomized controlled trial with just plain, straight seaweed. But, no one had ever done that study—until this study out of Ecuador.

Six grams of wakame, natural sodium and all, led to a significant drop in blood pressure, especially in those who started out high. Side effects were all minor, and what one might expect increasing fiber intake. And, the nice thing about whole food, plant-based interventions is you sometimes get good side effects as well, such as the resolution of gastritis—stomach inflammation that they’d been having—as well as the disappearance of chronic headaches.

Please consider volunteering to help out on the site.

Image credit: Silentpilot via Pixabay. Image was modified.

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

I used to think of seaweed as just a beneficial whole food source of minerals—like iodine, for which it is the most concentrated dietary source. And, indeed, just a half-teaspoon of mild seaweeds, like arame or dulse, or two sheets of nori a day, should net you all the iodine you need for the day.

But, “the intake of seaweeds is advised” not only as a whole food source of iodine, but also, evidently, “for the prevention of lifestyle-related chronic diseases.” Based on what?

Well, you’ll see this kind of reasoning: the Japanese live long, and they eat seaweed. And so, they speculate that seaweed might have something to do with it, based on suggestive reports. But, when you see lists, like this, of all the supposed biological activities some food has, you want to know is this based on clinical data (meaning on actual people) or so-called preclinical data (based on test tubes and lab animals)? When a study like this is published, talking about the “Effects of seaweed-reconstructed pork diets” on rats, what do you do with that information? Seaweed is one of the ingredients they’re trying to use to improve the “image” of meat products. So, they try to add grape seeds, or flax seeds, or walnuts, or purple rice or, whatever this is. I had to look it up: thong-weed. How’s that for an image booster?

You can look at epidemiological studies (meaning looking at populations). And, indeed, Japanese preschoolers who eat seaweed tend to have lower blood pressures, suggesting seaweed might have beneficial effects—which would make sense, given all the minerals and fiber. But, you can’t prove cause and effect with that kind of study. Maybe it was the other components of the diet that went along with the seaweed-eating.

It’s even harder to do these kinds of studies on adults: so many people are on high blood pressure medications. University of Tokyo researchers took an innovative approach by comparing the diets of people on low-dose, versus high-dose, versus multiple blood pressure medications. And, although they all had artificially normalized blood pressure, those that ate the most fruit and sea vegetables tended to be the ones on the lower doses—supporting a dietary role for seaweed. But, why not just put it to the test?

A double-blind crossover trial found that seaweed fiber lowered blood pressure, apparently by pulling sodium out of the system. I know they couldn’t use real seaweed, because then you couldn’t fool people with a placebo; but, why not just, like, put whole powdered seaweed in pills? This was finally attempted, ten years later.

Compared to doing nothing, they got beautiful drops in blood pressure. But, if you look deeper into the study, they desalinized the seaweed—meaning they took out two-thirds of the sodium naturally found in it. So, that still doesn’t tell us if eating seaweed salad is actually going to help with blood pressure. What we need is a randomized controlled trial with just plain, straight seaweed. But, no one had ever done that study—until this study out of Ecuador.

Six grams of wakame, natural sodium and all, led to a significant drop in blood pressure, especially in those who started out high. Side effects were all minor, and what one might expect increasing fiber intake. And, the nice thing about whole food, plant-based interventions is you sometimes get good side effects as well, such as the resolution of gastritis—stomach inflammation that they’d been having—as well as the disappearance of chronic headaches.

Please consider volunteering to help out on the site.

Image credit: Silentpilot via Pixabay. Image was modified.

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