Have you ever wondered if there’s a natural way to lower your high blood pressure, guard against Alzheimer's, lose weight, and feel better? Well as it turns out there is. Michael Greger, M.D. FACLM, founder of NutritionFacts.org, and author of the instant New York Times bestseller “How Not to Die” celebrates evidence-based nutrition to add years to our life and life to our years.

Strokes and Diet: Part 4

There are ways that vegetarians can prevent stroke risk. Today we have the final episode in our series on stroke and diet.

This episode features audio from How to Test for Functional Vitamin B12 Deficiency, Should Vegetarians Take Creatine to Normalize Homocysteine?, and The Efficacy and Safety of Creatine for High Homocysteine. Visit the video pages for all sources and doctor’s notes related to this podcast.


Today, we have the final episode in our series on stroke and diet.

In our first story, we find that many doctors mistakenly rely on serum B12 levels in the blood to test for vitamin B12 deficiency.

Two cases of young strictly vegetarian individuals with no known vascular risk factors—yet suffering a stroke, or multiple strokes. Why? Most probably because they weren’t taking vitamin B12 supplements, which leads to high homocysteine levels, which can attack your arteries.

So, those eating plant-based failing to supplement may increase one’s risk of both heart disease and stroke. Now, vegetarians have so much heart disease risk factor benefit that they are still at lower risk overall, but this may help explain why vegetarians were found to have more stroke.

Compared with non-vegetarians, vegetarians enjoy all these other advantages: better cholesterol, blood pressures, blood sugars, and obesity rates. But, like what about that stroke study? And, even among studies that show benefits, they’re not as pronounced as one might expect, which may be a result of poor vitamin B12 status. Vitamin B12 deficiency may negate some of the cardiovascular disease prevention benefits of vegetarian diets; so, in order to further reduce the risk of cardiovascular disease, vegetarians should be advised to use vitamin B12 supplements.

How can you determine your B12 status? By the time you’re symptomatic with B12 deficiency, it’s too late, and initially the symptoms can be so subtle you might even miss them. And, well before you develop clinical deficiency, you develop metabolic vitamin B12 deficiency: a missed opportunity to prevent strokes, where you have enough B12 to avoid deficiency symptoms, but not enough to keep your homocysteine in check. Underdiagnosis of the condition results largely from failure to understand that a normal B12 blood level may not reflect an adequate functional B12 status. The levels of B12 in your blood does not always represent the levels of B12 in your cells. You can have a severe functional deficiency of B12 even though your blood levels are normal or even high.

Most physicians tend to assume that if the B12 level in your blood is “normal”, there is no problem. But, within the lower range of normal, 30% of patients could have metabolic B12 deficiency, with high homocysteine levels.

Measuring methylmalonic acid levels or homocysteine directly are a more accurate reflection of vitamin B12 functional status. Methylmalonic acid can be a simple urine test; you’re looking for less than a value of 4 (micrograms per milligram of creatinine). “Elevated MMA is a specific marker of vitamin B12 deficiency, while homocysteine rises in [the context of] both vitamin B12 and folate deficiencies”; and so, metabolic B12 deficiency is defined by an elevation in MMA levels or by elevation of homocysteine in people getting enough folate. Even without eating beans and greens, which are packed with folate, folic acid is added to the flour supply by law; and so, high homocysteine levels these days may be mostly a B12 problem. Ideally, you’re looking for a homocysteine level in your blood down in the single digits.

Measured this way, “the prevalence of functional vitamin B12 deficiency is dramatically higher than previously assumed,” like 10%-40% of the general population, and more than 40% in vegetarians, and the majority of vegans who aren’t scrupulous about getting their B12. Some suggest that those on plant-based diets check their vitamin B12 status every year, but you shouldn’t need to if you’re adequately supplementing, and evidently there are rare cases of vitamin B12 deficiency that can’t be picked up on any test; so, maybe better to just make sure you’re getting enough. If you do get your homocysteine tested and it’s still up in the double digits even despite B12 supplementation, I do have a suggestion in the final videos of this series, which we’ll turn to, next.

“Almost universally, research findings show a poor vitamin B12 status among vegetarians,” because they’re not taking vitamin B12 supplements like they should, and this results in an elevation in homocysteine levels that may explain why vegetarians were recently found to have higher rates of stroke.

Of course, plant-based eating is just one of many ways to get B12 deficient. Even laughing gas can do it… in as short as two days… thanks to the recreational use of whipped cream canister gas—that’s something new I learned today.

Anyways, if you do eat plant-based, giving vegetarians and vegans even as little as 50 micrograms once a day of cyanocobalamin, the recommended, most stable form of vitamin B12 supplement, and their homocysteine levels start up in the elevated zone, and within 1 to 2 months, their homocysteine normalizes right down into the safe zone under 10. Or, just 2000 micrograms of cyanocobalamin once a week, and you get the same beautiful result, but not always. In this study, even 500 micrograms a day, either as a sublingual chewable or swallowable regular B12 supplement, didn’t normalize homocysteine within a month. Now, presumably, if they had kept it up their levels would have continued to fall like in the other study. But, if you’re plant-based and have been taking your B12 and your homocysteine level is still too high, meaning above 10, is there anything else you can do?

Now, inadequate folate intake can also increase homocysteine, but folate comes from the same root as foliage, it’s found in leaves, concentrated in greens, as well as beans. But, if you’re eating beans and greens, taking your B12, and your homocysteine level is still too high, then I’d suggest trying, as an experiment, taking one gram of creatine a day and getting your homocysteine levels retested in a month to see if it helped.

Creatine is a compound formed naturally in the human body that is primarily involved in energy production in our muscles and brain. It’s also naturally formed in the bodies of many animals we eat; and so, when we eat their muscles, we can also take in some creatine through our diet. We need about two grams a day; so, those who eat meat may get like one gram from their diet, and their body makes the rest from scratch. There are rare birth defects where you’re born without the ability to make it, in which case you have to get it from your diet, but otherwise, our bodies can make as much as we need to maintain normal concentrations in our muscles.

When you cut out meat, the amount of creatine floating around in your bloodstream goes down, but the amount in your brain remains the same, showing dietary creatinine doesn’t influence the levels of brain creatinine, because your brain just makes all the creatine you need. The level in vegetarian muscles is lower, but that doesn’t seem to affect performance, as both vegetarians and meat-eaters respond to creatine supplementation with similar increases in muscle power output. And, if vegetarian muscle creatine was insufficient, then presumably they would have seen an even bigger boost. So basically, all that happens when you eat meat is that your body just doesn’t have to make as much. What does this all have to do with homocysteine?

In the process of making creatine, your body produces homocysteine as a waste product. Now, normally this isn’t a problem, because your body has two ways to detoxify it, using vitamin B6, or using a combination of vitamins B12 and folate. Vitamin B6 is found in both plant and animal foods, and it’s rare to be deficient, but B12 is mainly in animal foods, and so, can be too low in those eating plant-based who don’t supplement or eat B12 fortified foods. And, folate is concentrated in plant foods, so, can be low in those who don’t regularly eat greens or beans or folic-acid fortified grains, and without that escape valve, homocysteine levels can get too high. If, however, you’re eating a healthy plant-based diet and taking your B12 supplement, your homocysteine levels should be fine, but what if they’re not? One might predict that if you started taking creatine supplements, the level of homocysteine might go down, since you’re not going to have to be making so much of it from scratch, producing homocysteine as a by-product, but you don’t know, until you put it to the test, which we’ll cover, next.

The average blood levels of homocysteine in men is about one and a half points higher than in women. Maybe that’s one of the reasons why men tend to be at higher risk for cardiovascular disease. Women don’t need to make as much creatine as men, since they tend to have less muscle mass, and that may help explain the ‘gender gap’ in homocysteine levels. If you remember from my last video, in the process of making creatine, your body produces homocysteine as a by-product. So, maybe for people with stubbornly high homocysteine levels that don’t sufficiently respond to B vitamins, perhaps creatine supplementation may represent a practical strategy to draw homocysteine levels down into the normal range.

It seemed to work in rats but in humans, it worked in one study, this one, but didn’t seem to work in another study, this one, or this one…and in this study, homocysteine levels were even driven up. So, this whole suggestion that taking creatine supplements would lower homocysteine was called into question. But, all those studies were done in non-vegetarians, so they were already effectively supplementing with creatine every day in the form of muscle meat, so they were basically just testing higher vs. lower supplementation. Those eating strictly plant-based make all their creatine from scratch, so may be more sensitive to an added creatine source, but there were never any studies on creatine supplementation in vegans for homocysteine lowering … until, now.

They took a bunch of vegans who were not supplementing their diets with vitamin B12; so, some of their homocysteine’s were through the roof, a few as high as 50 when the ideal is more like under 10, but after taking some creatine for a few weeks all of their homocysteine levels normalized before, and… after. Now, they didn’t really normalize, which would be under 10, but that’s presumably because they weren’t taking any B12. Give vegetarians and vegans vitamin b12 supplements, either daily dosing or once a week, and their levels really normalize in a matter of months, but the fact that even without any B12, you could bring down homocysteine levels with creatine alone suggests—to me at least—that if your homocysteine is elevated on a plant-based diet, meaning above 10, despite taking B12 supplements (and eating greens and beans to get enough folate), well then, it might be worth experimenting with supplementing with a gram of creatine for a few weeks and see if your homocysteine comes down.

Why one gram? That’s approximately how much nonvegetarians are not having to make themselves; that’s how much erased vegetarian discrepancies in blood and muscle, and how much has been shown to be safe in the longer-term.

How safe exactly is it? Well, one can take a bit of comfort in the fact that it’s one of the world’s best-selling dietary supplements, with literally billions of servings taken, and the only consistently reported side effect has been weight gain, presumed to be from water retention. The only serious side-effects appear to be among those with pre-existing kidney diseases, taking whopping doses of like 20 grams a day. A concern was raised that creatine could potentially form a carcinogen known as form N-nitrososarcosine when it hit the acid bath of the stomach, but when actually put to the test, this does not appear to be a problem.

Bottomline, doses of up 3 grams a day are unlikely to pose any risk provided high purity creatine is used, and as we all know, dietary supplements are not regulated by the FDA and may contain contaminants or not actually contain what’s on the label, contaminants generated during the industrial production. When researchers look at 33 samples of creatine supplements made in the U.S. and Europe, they all did actually contain creatine, which is nice, but about half exceeded the maximum level recommended by food safety authorities for at least one contaminant. The researchers recommend that consumers give their preference to products obtained by producers that ensure the highest quality control. Easier said than done.

Because of the potential risks, I don’t think people should be taking creatine supplements willy-nilly, but the potential benefits may exceed the potential risks if, again, you’re on a healthy plant-based diet, taking B12, and your homocysteine levels are still not under 10, I would suggest giving a gram a day of creatine a try to see if it brings it down.

The reason I did this whole video series all goes back to this study, which found that although the overall cardiovascular risk is lower in vegetarians and vegans combined, they appeared to be at slightly higher stroke risk. I went through a list of potential causes, arrived at elevated homocysteine, and the solution? A regular, reliable source of vitamin B12. The cheapest, easiest method that I personally use is one 2500 mcg chewable tablet of cyanocobalamin. In fact, you can just use 2000 mcg once a week. Cyanocobalamin is the most stable source of B12. Take that once a week.

And then, a back-up plan for those doing that and still having elevated homocysteine is an empirical trial of one gram a day of creatine supplementation, which was shown to improve at least capillary blood flow in those who started out with high homocysteine levels.

The bottom line is that plant-based diets appear to markedly reduce our risk of multiple leading killer diseases—heart disease, type 2 diabetes, and many common types of cancer, but an increased risk for stroke may represent an ‘Achilles heel’. Nonetheless, they have the potential to achieve a truly exceptional ‘healthspan’ if they face this problem forthrightly by restricting salt intake and taking other practical measures that promote brain artery health. Nonetheless, these considerations do not justify nutritional nihilism. On balance, even strictly plant-based diets offer such versatile protection to long-term health that they remain highly recommendable. Most likely, the optimal strategy is to eat plant-based, along with going out of your way to eat particularly protective foods as I talked about before, regular aerobic exercise, and most importantly taking your vitamin B12. Oh, and try not to huff whipped cream charging canister gas.

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