An article by Paul Offit titled “The Vitamin Myth: Why We Think We Need Supplements” has been part of the media blitz surrounding so-called negative claims of vitamin and mineral supplements.
The Linus Pauling Institute at Oregon State University has a different point of view – one that is based on the totality of the evidence, rather than selective claims.
Paul Offit ignores much of the research on vitamins and health. It’s easy to select individual studies that support your point of view, and this appears to be the trap that has snared Offit.
Linus Pauling extolled the myriad health benefits of vitamin C, many of which have been validated by studies after his death. For instance, vitamin C has important benefits in cardiovascular health. A comprehensive meta-analysis of 29 randomized placebo-controlled trials has found that vitamin C supplementation reduces systolic and diastolic blood pressure (Juraschek et al., 2012). Hypertension causes about 350,000 preventable deaths in the U.S. each year through heart disease, stroke and kidney failure. Vitamin C also improves blood vessel dilation in patients with heart disease or coronary risk factors, such as hypertension, type II diabetes, or tobacco use. Many, but not all, large-scale, long-term epidemiological studies have found that a high intake of vitamin C from diet or supplements and high plasma levels of vitamin C are associated with a reduced risk for cardiovascular disease.
Studies on high-dose vitamin C and the common cold have had conflicting results but generally show that vitamin C shortens duration and ameliorates symptoms.
Recent studies at the U.S. National Institutes of Health and elsewhere have elucidated the anticancer mechanism of high concentrations of vitamin C achieved by intravenous infusion, a treatment pioneered in the early 1970s by Pauling’s Scottish collaborator, Ewan Cameron. The use of high-dose intravenous vitamin C as adjunctive cancer therapy, revitalized by new molecular and biochemical studies, has benefited many patients.
Offit seems to be unaware that the Mayo Clinic researchers gave vitamin C only orally, which, because of limited absorption, cannot produce blood concentrations of vitamin C sufficient to kill cancer cells.
Offit claims that “Pauling believed that vitamins and supplements had one property that made them cure-alls . . . : antioxidant.” Pauling never made such a claim; only a few vitamins have antioxidant properties. The word “antioxidant” does not even appear in the extensive index in his best-selling book, How to Live Longer and Feel Better.
Offit implies that high-dose vitamin C contributed to the death of Pauling and his wife. Pauling died at the age of 93 years, nearly 20 years longer than the average life expectancy for American men. It’s unscientific to ascribe either his mortality or very long life to supplemental vitamin C.
While Offit highlights only negative studies on multivitamin/mineral supplements, observational studies have found that many Americans do not get adequate daily amounts of many vitamins and nutritionally essential minerals, which may be remedied by judicious supplementation. For example, the National Health and Nutrition Examination Survey conducted by the National Center for Health Statistics has found that more than 40% of U.S. adults do not meet recommended levels, from usual food intake, of vitamins A, C, D, E and K, magnesium, calcium and potassium (Fulgoni et al. 2011). The largest and longest randomized placebo-controlled trial of multivitamin/mineral supplementation has shown that a daily multivitamin/mineral significantly lowers total cancer risk in men 50 years and older. While the observed 8% reduction in risk is modest, such a decrease would have public health significance, possibly preventing up to 130,000 cases of cancer each year in the U.S. alone.
For a balanced presentation of the role of vitamins, minerals and other dietary factors in human health, readers would be better served by visiting the online, peer-reviewed Micronutrient Information Center of the Linus Pauling Institute at Oregon State University, which, unlike Offit, presents the positive and negative studies. Readers will find references and links to the above-mentioned studies, as well as detailed information to help make health decisions to minimize risk and maximize benefit.