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We know taurine abundance decreases during aging, and a reversal of this decline through taurine supplementation increases the healthspan and lifespan in mice and worms, and health in monkeys. So, this means taurine deficiency is a driver of aging in these species. To test whether taurine deficiency is a driver of aging in humans too, long-term, well-controlled taurine supplementation trials that measure human healthspan and lifespan as outcomes are required. Why haven’t these happened already? You know why. As a naturally occurring substance, taurine cannot be exploited through a commercial patent. You can buy pure taurine powder literally by the bucket at hardly a penny per gram. So, who’s going to fund studies on it?
In population studies, higher blood taurine levels are associated with less obesity and a lower prevalence of type 2 diabetes. But when put to test, as reviewed in this 2020 meta-analysis of randomized controlled trials, taurine supplementation had no significant effect on blood sugar control, LDL cholesterol, or body weight––though it did drop blood pressures and triglycerides a few points, at a daily dose of half a gram to six grams a day between 15 days and six months. A 2024 systematic review and meta-analysis of randomized controlled trials found the same small blood pressure and triglycerides benefit, as well as a small six-point drop in fasting blood sugars, though none of those few trials on people with diabetes showed that blood pressure benefit––though it did help their blood sugars.
Taurine can also slow our heart rate by three or four beats per minute, which is considered a good thing, and in addition to lowering blood pressures, it can improve heart muscle function in patients with heart failure. What about artery function? People with type 1 diabetes were given 500 mg of taurine three times a day for two weeks, and researchers saw a significant improvement in their artery function. As you can see, those with type 1 diabetes start out with reduced artery function compared to healthy controls, and giving them a placebo doesn’t seem to help. But the taurine seemed to elevate their artery function closer to healthy levels.
What about improving artery function in people without diabetes? In this study of individuals with prehypertension—about 130 over 80—who took about the same amount, 1.6 g a day for 12 weeks, they got the same blood pressure benefit seen in the other trials, and, importantly, improvement in artery function compared to placebo.
What about effects on inflammation and oxidation? Taurine can decrease the levels of c-reactive protein, a marker of oxidative stress, though it doesn’t appear to have much effect on some other markers of inflammation. So, okay, some modest effects, but there is a substantial mismatch between the strong scientific foundation supportive of the health benefits of taurine in animal studies, and the quality of clinical trials and their outcomes in assessing the efficacy of taurine in human health.
What’s the harm in taking it, though? It’s cheap and easy to find. A one-gram dose would cost as little as a penny a day. Most Americans are getting about 150 mg a day in their diet, mostly from meat. We make taurine ourselves, and so do many of the animals we eat. In fact, our realization that we made so much on our own came from studies of vegans who had taurine levels that were not significantly different from those eating meat, though they were about 15 percent lower. A subsequent study found the taurine levels of vegans were more like 20 percent lower than meat eaters, which did reach statistical significance. The clinical implications of reduced blood taurine levels in vegans are not known. Our ability to make taurine is supported by the fact that taurine deficiency has never been found in vegetarians, but just because vegan levels aren’t deficient doesn’t mean they are necessarily optimal.
Taurine is considered nonessential in adults because it can be readily synthesized within our own bodies—though infants may need to get it in breast milk until they can ramp up their own synthesis. But can adults make enough for optimal health, especially as we get older and all our levels decline? Why do our levels even decline as we age? It’s not just that because we may be getting less in our diet, since if you get none in your diet, your levels may only be like 20 percent lower, but levels over a lifespan decline by about 80 percent, suggesting we lose some of our capacity to churn it out.
Taurine has been envisioned as a longevity vitamin, meaning it isn’t like an actual vitamin-vitamin, where we die if we don’t get it. But even though we make it, we may also need to get some in our diet to optimize metabolism.
In a review of what clinicians might want to discuss with their patients on a plant-based diet who are suffering from some kind of problem, are these conditionally essential nutrients, where under normal conditions, they can be produced in our body in sufficient amounts, but something may interfere with synthesis, or conditions may arise where we may need more. Taurine is included in this list, as is carnitine, another compound found in meat that we can make on our own.
Imagine if people started taking carnitine supplements, thinking why not? What harm can it do? Of course, we now know that carnitine is one of the things we try to avoid in meat, because it turns into TMAO and may increase the risk of heart disease, kidney disease, and many of our other leading killers. Indeed, if you give people carnitine supplements, their TMAO levels shoot up; so, might that be a precautionary tale when it comes to taurine?
Take arginine, for example. It’s another non-essential amino acid in adults that has a variety of functions other than being part of proteins, including delaying the aging senescence of arterial lining cells. Animal studies have shown all sorts of heart-healthy benefits of arginine supplementation, including improved artery function and inhibition of atherosclerotic plaque, just like taurine. So, reviews like these studies strongly support favorable cardiovascular effects accruing from L-arginine supplementation based on short-term studies, just like taurine, but long-term treatment with L-arginine actually accelerates the aging process in human artery lining cells.
Did this paradoxical effect cause any actual problems?
Short-term supplementation showed an improvement in artery function. In contrast, long-term therapy with arginine supplementation did not improve artery or heart function. Instead, it led to premature death.
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