Combination vitamin/mineral supplements (VM) have been popular dietary adjuncts for many years, but as research has progressed, various health benefits have been touted for some individual nutrients — some of which haven't been traditionally included in the typical combo products. Researchers, led by Dr. Elizabeth D. Kantor from the Memorial Sloan Kettering Cancer Center in New York City, found that while overall vitamin/mineral supplement use remained pretty stable (about half of participants said they used them) between 1999 and 2012, use of some individual supplements actually increased substantially, while that of combination products fell.
These researchers analyzed data from 7 repeated cycles of the NHANES Survey — the nationally representative survey that covers 2 years per cycle. The information they analyzed was derived from in person home visits to adult participants (over 20 years old). In all, nearly 38,000 persons were included; on average they were about 46 years old, and 52 percent were women.
Data analysis revealed that the use of multivitamin/mineral combo products declined from 37 percent of respondents to 31 percent over the period surveyed. In contrast, use of several of nutrients not usually included in combination products — the carotenes lutein and lycopene, coenzyme Q, omega-3, -6 and -9 fatty acids (to a large extent from fish oils) — all increased significantly. Other non-traditional supplements such as gingko biloba, garlic, echinacea and ginseng decreased. Two vitamins whose use increased significantly were vitamins B12 and vitamin D. Use of other individual supplements touted to provide antioxidant benefits, such as vitamins C and E and selenium, also decreased.
Dr. Kantor and colleagues suggest that much of the changes in supplement use reflected media reports of the efficacy of the various items in addressing the risk of various chronic ailments — they noted several expert bodies concluded that "there is either insufficient or no evidence to support uses of MVMM [multivitamin multimineral supplements] or supplements to prevent chronic disease". (See here for our take on those conclusions).
One result that's concerning is the large increase (from 5.1 percent of respondents in 1999 to 19 percent in 2012) in the use of vitamin D supplements (excluding that in combo products). Vitamin D can have deleterious effects when taken in large amounts over extended periods; yet media reports have encouraged its use to ameliorate anything from osteoporosis to immune function to cardiovascular health, as we explained nearly 2 years ago. In fact, research on the efficacy of vitamin D and fish oil is ongoing — the VITAL study being directed from the Harvard School of Public Health is investigating both in a placebo-controlled randomly assigned clinical trial. Until that is completed, we have no good reason to prescribe or take large quantities of either supplement.
On the whole, the results of the current study are encouraging, because they suggest that at least some Americans are realizing that the widely touted benefits of many supplements are mostly hyperbole.