Vitamin Supplements: When Will They Ever Learn?

The folksinger Pete Seeger, who died this week, years ago popularized an antiwar song called “Where Have All the Flowers Gone?” The recurring refrain at the end of each verse was “When will they ever learn, when will they ever learn?” Those words swam back to me last Sunday when I made my weekly visit to Costco and found that the first display after coming through the door, stacked 5 feet high against a wall about 40 yards long, was given over to vitamin supplements, fish oil, and other dietary supplements.

In 2011, The Medical Letter published an article titled “Who Should Take Vitamin Supplements?” That article presented evidence on the efficacy and safety of the various vitamins included in the usual supplements. It found that vitamin E alone or in combination with beta carotene and vitamin A was associated with an increased risk of death. High serum concentrations of vitamin A were associated with an increased risk of prostate cancer. Beta carotene in 2 randomized, placebo-controlled clinical trials significantly increased the risk of lung cancer in smokers and former smokers. Vitamin C had no beneficial effect on cancer, cardiovascular disease, or the incidence of upper respiratory infections, and in high doses could cause diarrhea and possibly kidney stones.

In 2012, The Medical Letter published an article on Fish Oil Supplements. That article concluded that while fish oil supplements are generally well tolerated, they can cause some mild gastrointestinal adverse effects, and in large doses they may worsen glycemic control in diabetic patients and increase bleeding time. Nothing terrible, really, but there is no convincing evidence that they are of any benefit, and they are not free.

In 2013, an evidence review prepared for the US Preventive Services Task Force and published in the Annals of Internal Medicine examined the effects of vitamin, mineral, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer. The majority of studies (24 of 26) found no beneficial effect.

The size and prominent location of the display at Costco indicate that all of these publications and many others along the same line have failed to get across the information that taking these supplements to prevent anything is probably worthless and should not be assumed to be harmless. When will they ever learn? I’m not sure. We haven’t stopped having wars either, and Pete Seeger is gone now.

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  1. Barbara A Weber MD says:

    “Vitamin supplements make expensive urine” – a quote I overheard by a medical student in Germany in 1980

  2. David Ch Burroughs says:

    What we need is vegetables galore at school cafeterias and cooking/gardening classes from K1 to K12. Houses built w/o kitchens should be heavily taxed.

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