I think it was Winston Churchill who said that Americans always do the right thing… after trying everything else.

This observation applies in medicine. In a recent blog (see blog entry of February 28, 2022), I detailed the story of drugs and procedures that had leaked into the medical armamentarium without proof of effectiveness, only to eventually fall to the power of well executed studies that demonstrated their uselessness (and possibly their danger). Enter vitamin D.

Vitamin D in its Heyday

About 10 million tests for vitamin D levels are done yearly in the US, and over one-third of US adults over the age of 60 take the supplement. In 2017, consumers spent almost one billion dollars on vitamin D, and Medicare patients incurred a bill of $365 million on testing levels of the vitamin in the blood in 2016.

The leading advocate for vitamin D is Dr. Michael Holick, a Boston University endocrinologist, who, according to a 2018 article by a writer for Kaiser Health News, almost single handedly created the vitamin D sales and testing industry. He has realized significant financial benefit from the drug industry and laboratory testing concerns.

The supplement has enjoyed a remarkable run in recent years, with claims that it prevents cancer, cardiovascular disease, and falls. Among other maladies, it was alleged to improve cognitive function and decrease age-related macular degeneration. Perhaps it most prominent claim to fame was the assertion that it prevents osteoporosis and fractures.


It does none of these things.

Decisive Study on Vitamin D Supplementation

Researchers recently published a state of the art study (prospective, randomized, controlled) in the New England Journal of Medicine (July, 2022) that investigated the usefulness of vitamin D for the prevention of fractures in men over the age of 50 and women over 55. Parts of this study had already examined the effects of vitamin D supplementation on cardiovascular disease and cancer.

25,871 participants were randomized to vitamin D or placebo. Median followup was 5.3 years. Long story short, the placebo group had no different outcomes compared to the vitamin D group, no matter what the level of vitamin D in the blood.

In an editorial that accompanied the above noted research, the writer noted that the trial showed that the “lack of effect for preventing numerous conditions suggests that providers should stop screening for 25-hydroxyvitamin D levels or recommending vitamin D supplements, and people should stop taking vitamin D supplements to prevent major diseases or extend life.”

I predict strong pushback to this definitive study from the manufacturers of vitamin D. They may want to engage the services of the gifted advertisers of Prevagen, another multibillion dollar medicine that is wholly ineffective (see blog entry on May 28, 2022).

Nota Bene: there are legitimate medical indications for vitamin D supplementation. If you are taking vitamin D, you should not unilaterally stop it on the basis of this blog or the article cited in the New England Journal of Medicine. Consult your doctor.

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