VITAMINS to prevent cancer and heart disease – The current state of the evidence

For most vitamin and mineral supplements, there is insufficient evidence for or against taking them to prevent cancer and cardiovascular disease (CVD).

Although the evidence remains uncertain for most vitamin and mineral supplements, there is evidence that two products do not reduce the risk of these diseases. Scientific evidence to date has found vitamin E to provide no benefit and has in fact found harms associated with taking beta carotene (such as an increased risk of cancer).

The evidence shows that taking vitamin E has no benefit and that beta carotene may be harmful because, in people already at risk, such as smokers, it increases lung cancer risk and also increases the risk of death from heart disease and stroke.

This information applies to nonpregnant adults. It does not apply to individuals with known or suspected nutritional deficiencies or specific nutritional needs. There is a separate vitamin supplementation recommendation for women planning to become pregnant or who may become pregnant, and these individuals are advised to use folic acid supplements.

Two leading causes of death

Cancer and cardiovascular disease are the two leading causes of death in Turkey and many Western countries, together accounting for approximately half of all deaths.

Inflammation and oxidative stress play a role in both disease groups, and dietary supplements may have anti-inflammatory and antioxidative effects. This has provided the rationale for investigating dietary supplements as a way to prevent both cardiovascular disease and cancer.

Because cardiovascular disease and cancer are the two leading causes of death, whether taking vitamins and minerals helps prevent these important diseases has been a focus for many scientists. However, there is insufficient evidence to know whether taking vitamin, mineral and multivitamin supplements prevents these conditions.

Key recommendations on vitamin supplements

• There is sufficient evidence that beta carotene and vitamin E supplements provide no benefit in preventing cardiovascular disease or cancer.
• Sufficient evidence has shown that beta carotene causes small harms by increasing lung cancer risk in people at high risk.
• There is sufficient evidence that vitamin E and multivitamins cause minimal harm.
• Evidence on the benefits of multivitamin supplements in preventing cardiovascular disease or cancer is incomplete.
• There is insufficient evidence on the benefits of using single or multiple vitamin-mineral supplements, other than beta carotene and vitamin E, to prevent cardiovascular disease or cancer. Evidence on the potential harms of these supplements is similarly limited.
• Vitamin D supplementation requires further research to determine whether it has any effect on survival in patients with cancer.

More research is also needed to determine whether there is heterogeneity among particular races or according to baseline nutrient levels, especially among individuals without known deficiencies.

Vitamin and mineral needs should primarily be met through food and drink, particularly through a healthy diet (such as the Mediterranean diet). We recommend that healthy individuals obtain adequate nutrients by eating a variety of foods in moderation rather than taking supplements.

*

• Related topic: When should vitamin and mineral supplements be used?