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Evidence Summary
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Key messages from scientific research that's ready to be acted on
Got It, Hide thisFolic acid or B-complex vitamins may reduce risk for heart attack and stroke
Jenkins DJA, Spence JD, Giovannucci EL, et al. Supplemental Vitamins and Minerals for CVD Prevention and Treatment. J Am Coll Cardiol. 2018;71:2570-84.
Review question
Does taking vitamin or mineral supplements treat or reduce risk for heart attack, stroke, or death due to heart disease?
Background
Taking vitamin or mineral supplements may help to correct or prevent nutrient deficiencies. However, it is unclear whether supplements can treat or prevent heart attacks, strokes, or death due to heart disease.
How the review was done
179 randomized controlled trials were published up to October 2017.
The key features of the studies were:
- multivitamins and many individual vitamins and minerals were tested;
- supplements were compared with not taking the supplements; and
- studies lasted 6 months or more.
What the researchers found
Compared with not taking the supplement:
- folic acid reduced risk for heart attack, stroke, or death due to heart disease;
- B-complex vitamins reduced risk for stroke but not other outcomes; and
- antioxidants, beta-carotene, calcium, iron, magnesium, multivitamins, selenium, vitamin A, vitamin B3 (niacin), vitamin B6, vitamin C, vitamin D, vitamin E, and zinc did not reduce risk for any of the outcomes.
Interpretation
The reduction in risk for heart attack, stroke, or death due to heart disease by taking folic acid primarily occurred in China where foods are not routinely fortified with folic acid. It is unclear whether the same benefit would be seen in places like North America where foods are fortified with folic acid.
Conclusions
Taking folic acid or B-complex vitamins may reduce risk for heart attack, stroke, or death due to heart disease, but most supplements do not appear to provide any benefit. Eating a healthy diet that includes plant-based foods will provide most people with the vitamins and minerals required without the need for supplements.
Note: Vitamin and mineral supplements are not safe for everyone. Ask your doctor if taking supplements is a good idea for you.
Vitamins or mineral supplements vs control to prevent heart disease events
| Supplements | Outcomes | Number of trials and people | Rate of events with supplements* vs control | Absolute effect of supplements |
| Folic acid | Heart attack, stroke, or death due to heart disease | 5 trials (21,5667 people) | 4.0% vs 4.9% | About 1 less person out of 100 had a heart attack, stroke, or death due to heart disease. |
|
| Stroke | 7 trials (24,525 people) | 2.5% vs 3.1% | About 1 less person out of 200 had a stroke. |
| B-complex vitamins | Stroke | 12 trials (43,339 people) | 4.5% vs 5.0% | About 1 less person out of 200 had a stroke. |
Glossary
Studies where people are assigned to one of the treatments purely by chance.
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