Dietary Supplements May Not Improve Cardiovascular Health

Long-term multivitamin use not found to reduce the risk of cardiovascular events or mortality.

Vitamin deficiency can cause multiple health events, including a lack of energy, illness, and poor overall health. Since older individuals may have a greater risk of events related to vitamin deficiency, more than 50% of this population have been advised to take multivitamins.

The American Heart Association recommends eating a healthy diet rich in vitamins and minerals prior to taking dietary supplements. Vitamins and minerals from food can be more easily absorbed by the body compared with supplements, but sometimes seeking additional sources of nutrition is necessary.

However, evidence of health benefits from dietary supplements among older adults, especially those eating a poor diet, is lacking. Results from a long-term study published by JAMA Cardiology suggests that diet has no identifiable effect on cardiovascular disease or mortality among older adults taking daily multivitamins, which calls into question the efficacy of multivitamins.

The Physicians’ Health Study II (PHS II) clinical trial explored whether multivitamins could reduce the risk of cardiovascular disease over a period of 11 years. The authors of the study initially discovered that men who took the vitamins were no less at risk of major cardiovascular events compared with men taking a placebo.

Included in the study were more than 14,000 male physicians aged over 50 who completed food frequency questionnaires. The research team was able to account for various factors that may influence results due to long-term evaluation.

The authors were also able to assess dietary factors, including the consumption of fruit, vegetables, whole grains, nuts, dairy, red meat, and processed meats. The intake of key nutrients, such as vitamins B6, B12, and D, were determined for each participant.

Patients who had a poor diet at baseline were expected to have more profound benefits from supplements than those with a good diet at baseline, but the study authors were surprised to find that this was not the case.

The researchers discovered that food, vitamins, dietary patterns, or supplement use before the clinical trial did not influence the effect of multivitamins on cardiovascular disease risk among these patients, according to the study.

Additional research is needed to explore the impact that dietary supplements may or may not have on cardiovascular risks and death.

"Intuitively, many had thought that men with 'poor' nutritional status at baseline may benefit more from long-term multivitamin use on cardiovascular outcomes; however, we did not see any evidence for this in our recent analysis," said corresponding author Howard Sesso, ScD, MPH. "Given the continued high prevalence of multivitamin use in the US, it remains critical for us to understand its role on nutritional status and other long-term health outcomes through clinical trials such as PHS II and other new research initiatives."