Anti-Aging Dizziness

Because of the lack of any government oversight, it is not even guaranteed that what is in the dietary supplements is what it says on the package. In one investigation, only two of the twelve manufacturers examined labeled their products correctly. FDA inspectors even found that seven out of ten supplement producers did not even comply with the minimal requirements of proper manufacturing, such as truthful labeling or basic hygiene. Not 7 percent, but 70 percent violations.

The problem is also not limited to shady providers lurking in dark corners of the internet. The Attorney General of the State of New York ordered DNA tests for 78 packages of common herbal supplements sold by GNC, Walgreens, Target, and Walmart, and four fifths of them did not contain a single one of the herbs named on their label. Instead, the capsules contained hardly more than cheap fillers like rice flour and “houseplants.”

If it is only houseplants, you are still getting off easy. Some dietary supplements are contaminated with pharmaceuticals—sometimes even prohibited substances that already had to be pulled from the market. As I describe in see.nf/adulterated, recalled supplements can show up again right back on store shelves, and sometimes they then contain even more prohibited substances. A founding member of the Institute for Science in Medicine commented: “The fines for violations are nothing compared to the profits.”

Paying to die sooner?

In a nationally representative sample with thousands of Americans over 60 years of age, 70 percent of respondents reported taking dietary supplements. It should be 100 percent, because the Institute of Medicine officially recommends that everyone over 50 take vitamin B12 (or foods fortified with it), but the most common supplement was a multivitamin. How does that affect lifespan?

As I show in see.nf/multi, there have so far been nine randomized controlled trials of multivitamin and multimineral supplements in which more than 50 000 men and women were randomized, usually for several years, to take such supplements, and none of the studies found a positive overall effect on mortality. “For us, the case is closed,” said an editorial in Annals of Internal Medicine titled “Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements.” A 2021 review concluded that, instead of obtaining nutrients from pills, one should “switch to a more plant-based diet, as is now recommended internationally.”

Multivitamin supplements at least appear to be harmless. The fact that they apparently do not kill anyone was announced as good news after the Iowa Women’s Health Study saw an association between multivitamin supplements and an increased risk of premature death. But there are actually a few supplements for which people seem to spend money to shorten their lives. Meta-analyses of randomized controlled trials concluded that high-dose vitamin A, beta-carotene, and sustained-release niacin raise the risk of death more than a placebo.

However, dietary supplements can do more harm than just to customers’ wallets due to a fascinating failure of human psychology called “moral licensing.” In see.nf/glitch I explore why smokers smoke more and dieters eat more than usual when they are randomized to take “supplements” that are in truth placebos.

What vitamin D can do—and what it cannot

What does the research have to say about so-called life-extending agents? Scientists fed mice a combination of the highest-quality supposedly life-extending supplements with over 100 ingredients, but none of them extended lifespan. One mixture even shortened the mice’s lives. (The scientists suspected fish oil was at least partly responsible.)

One supplement extended life in randomized controlled trials in humans: vitamin D. So why is it not among my eight anti-aging agents? Vitamin D is practically promoted as a panacea, but as I explain in my video see.nf/dpanacea, randomized controlled trials have shown that vitamin D supplementation is ineffective for the prevention and treatment of most diseases the studies examined. It helped neither with cardiovascular disease nor with type 2 diabetes, multiple sclerosis, obesity, or prostate cancer. It is the old story of reverse causation and confounding factors. Sick people go out in the sun less, and a low vitamin D level may simply be a marker of lack of activity. Just because low vitamin D levels and high disease rates occur at the same time does not mean the low vitamin D levels cause the disease.

There are a few exceptions. Aside from obvious vitamin D deficiency diseases—rickets and osteomalacia—vitamin D supplementation has been shown to prevent asthma and chronic obstructive pulmonary diseases such as emphysema from worsening in people with low vitamin D levels. In the prevention of depression, vitamin D proved ineffective, but it does seem to support treatment. With acute respiratory infections, however, the opposite was true—here vitamin D provided prevention, but no longer had any effect on the disease.

Fighting death with vitamin D?

The majority of population observational studies show that people with a higher vitamin D level in the blood have a lower risk of premature death. But does this life-extending effect also hold up under scrutiny? For a long life, you do not necessarily need adequate vitamin D. A study of 100-year-olds found alarmingly low vitamin D values. Strictly speaking, in most participants they were not even detectable with standard tests. But could taking vitamin D supplements increase the chances of a longer life?

A Mendelian randomization study found that people with a genetically determined lifelong low vitamin D level tend to live less long, but intervention studies that examined intermediate risk factors for the most common causes of death—such as stiffening or impaired function of the arteries—were unable to show any positive effect of vitamin D supplements. The decisive evidence, however, comes from randomized placebo-controlled double-blind trials that deal with the most important endpoint: premature death. Don’t worry—there are 65 of them!

The reason I made videos in which I recommended vitamin D supplements for a longer life (see.nf/dlongevity) was a Cochrane network review published in 2014 of the first 65 trials of this kind. But by 2019, 17 additional randomized controlled trials had appeared, some of them so large that they could have turned the tide. In the VITAL trial, for example, more than 25 000 men and women were randomized for five years to receive vitamin D, fish oil, both, or nothing (placebos). Neither vitamin D nor fish oil could prevent major cardiovascular events or cancer, and they did not avert premature death either. Critics complain that only a small percentage (12,7 percent) of participants had a vitamin D deficiency at the start of the study and that all participants—including those in the placebo group—were allowed to take additional vitamin D on their own. It was considered ethically unacceptable to randomly deny those who might have had a deficiency an essential nutrient they otherwise would not have been getting enough of. That is a common problem in vitamin D studies. In the VITAL trial, more participants in the placebo group took vitamin D on their own than in the group with regular vitamin D supplementation, probably because they had low levels. You can imagine how that skews the results.