 Welcome to the Nutrition Facts podcast. I'm your host, Dr. Michael Greger. The coronavirus pandemic has made many of us very aware of the importance of maintaining and improving our health. Make that your silver lining. Because the more positive change we can make to our diet and lifestyle, the better. 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're 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 that poor vitamin B12 status. Vitamin B12 deficiency may negate some of the cardiovascular disease prevention benefits of vegetarian diet. So in order to further reduce the risk of cardiovascular disease, vegetarians should be advised to use 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 that 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. Under diagnosis of the condition results largely from failure to understand that a normal B12 blood level may not reflect adequate functional B12 status. The levels of B12 in your blood does not always represent the level 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, then there's 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, or 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 arises 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 an 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 flower 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. Measure it this way, the prevalence of functional B12 deficiency is dramatically higher than previously assumed, like 10 to 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 should 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 better 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. 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 of 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. I mean, even laughing gas can do it. Even 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 homocysteines normalize right down into the safe zone under 10. Or just 2,000 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. But now, presumably if they had kept it up, their levels would have continued to fall, like in the other study. But if your plant-based have been taking your B12 and your homocysteine levels are 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 levels still too high, then I'd suggest trying, as an experiment, taking 1 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 also can take in some creatine through our diet. We need about 2 grams a day, so those who eat meat may get like 1 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 make as much as we need to maintain normal concentrations in our muscles. When you cut out meat, the amount of creatine floating around your bloodstream goes down, but the amount in your brain remains the same. Showing dietary creatine doesn't influence the levels of brain creatine, 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? Okay, 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. Now, B6 is found in both plant and animal foods, it's rare to be deficient, but B12 is mainly in animal foods, and so it 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 it 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 byproduct. 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. But 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 byproduct. 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, but didn't seem to work in another study. 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 effectively already supplementing with creatine every day in the form of muscle meat. So they were basically just testing higher versus lower supplementation. Those eating strictly plant-based make all their creatine from scratch so maybe 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 levels threw the roof a few as high as 50 when the ideal was more like under 10. But after taking some creatine for a few weeks, all of their homocysteine levels normalized. Now, they didn't really normalize, which would have been 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 normalized in a matter of months. But the fact that even without B12, that 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 may be worth experimenting with supplementing with a gram of creatine for a few weeks and see if your homocysteine levels come down. Why one gram? That's approximately how much non-vegetarians 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 like 20 grams a day. A concern was raised that creatine could potentially form a carcinogen known as N-nitrososarcazine when it hit the acid bath of the stomach, but when actually put to the test, this does not appear to be a problem. Bottom line, doses up to 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, may contain contaminants, or not actually contain what's on the label. Contaminants generated during the industrial production. When researchers looked at 33 samples of creatine supplements made in the US 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 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 disease 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 2,500 microgram chewable tablet of cyanocobalamin. In fact, you can just use 2,000 micrograms once a week and cyanocobalamin is the most stable source of B12. Take that once a week and then a backup plan. For those doing that and still, having elevated homocysteine is an empirical trial of one gram a day of creatine supplementation, which has been 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 of stroke may represent an Achilles heel. Nonetheless, they have the potential to achieve a truly exceptional health span. 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 optimum strategies to eat plant-based, along with going out of the 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 with cream-charging canister gas. 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