Dietary supplements are big business with many Australians taking vitamins, minerals or other types of nutritional supplements daily. There are cases where supplements are warranted.

Folic acid for women planning pregnancy, iron supplements for people with iron deficiency, and additional nutrients for people with poor diets or malabsorption problems are all examples of appropriate supplement use.

When it comes to general health, the scientific evidence has for some time not been so favourable that supplementation makes a big impact on reducing the risk of chronic diseases such as heart disease and cancer. Now a major review has further reinforced this view.

A research team compiled an in-depth analysis of 277 randomised clinical trials that evaluated 16 different vitamins or other supplements as well as eight different diets. The outcomes they were interested in were overall mortality and cardiovascular disease including heart attacks, heart disease and stroke.

The news was not good for supplements. Taking multivitamins, selenium, vitamin A, vitamin B6, vitamin C, vitamin E, vitamin D, calcium or iron did not improve heart health or extend the lifespan.

The diets included a Mediterranean diet, several variations of a reduced saturated fat and/or a reduced fat diet, a low-salt diet, and a diet higher in plant foods higher in omega-3 or omega-6 fats such as nuts, seeds and vegetable oils.

The only positive news from the review was the conclusion that a low-salt diet may reduce the risk of earlier mortality in persons without high blood pressure. There was some indication that fish oil and folic acid supplementation may help with the risk of a heart attack and stroke respectively.

Even for folic acid, most of the positive research was from studies that took place in China where the food supply is not fortified with folic acid as it is in Australia and the United States.

Supplements that combined calcium and vitamin D were actually linked to a slightly increased stroke risk. There was no evidence that calcium or vitamin D taken alone though had any health risks.

Implications

The vast majority of supplemental multivitamins, vitamins, minerals and other associated nutritional products offer little benefit in extending life or reducing the risk of cardiovascular disease.

Searching for good health in the supplement aisle would seem to be a fruitless exercise when a good diet can offer this and more.

Last Reviewed: 04/05/2020

© Norman Swan Medical Communications.



References

For reference: Khan SU et al. Effects of nutritional supplements and dietary interventions on cardiovascular outcomes. An umbrella review and evidence map. Annals of Internal Medicine Epub online 9 July 2019 doi: 10.7326/M19-0341.