Researchers have pinpointed specific antioxidant supplements that offer heart-protective benefits, according to a meta-analysis published in the Journal of the American College of Cardiology.
Healthy diets are rich in antioxidants like amino acids, omega-3 fatty acids, and vitamin C, but exactly how beneficial these micronutrients are for cardiovascular health has long been controversial.
Scientists systematically reviewed 884 studies available to date on micronutrients taken as dietary supplements and analyzed their data. They identified several micronutrients that reduce cardiovascular risk—as well as others that offer no benefit or even have a negative effect. More than 883,000 patients were involved in the combined studies.
“For the first time, we developed a comprehensive, evidence-based integrative map to characterize and quantify micronutrient supplements’ potential effects on cardiometabolic outcomes,” said Simin Liu, MD, MS, MPH, ScD, professor of epidemiology and medicine at Brown University and a principal investigator for the study. “Our study highlights the importance of micronutrient diversity and the balance of health benefits and risks.”
The findings could be used as the basis of future clinical trials to study specific combinations of micronutrients and their impact on cardiovascular health, Liu said.
Antioxidant supplementation has long been thought to play a role in heart health. That’s because these nutrients work to reduce oxidative stress, a known contributor to many cardiovascular diseases. Heart-healthy diets like the Mediterranean diet and the Dietary Approach to Stop Hypertension (DASH) feature foods that are naturally rich in antioxidants. However, results from studies of antioxidant supplements have been inconsistent.
“Research on micronutrient supplementation has mainly focused on the health effects of a single or a few vitamins and minerals,” Liu said. “We decided to take a comprehensive and systematic approach to evaluate all the publicly available and accessible studies reporting all micronutrients, including phytochemicals and antioxidant supplements and their effects on cardiovascular risk factors as well as multiple cardiovascular diseases.”
The scientists looked at randomized, controlled intervention trials evaluating 27 different types of antioxidant supplements. They found strong evidence that several offered cardiovascular benefits.
- Omega-3 fatty acids, which decreased mortality from cardiovascular disease
- Folic acid, which lowered stroke risk
- Coenzyme Q10, an antioxidant that decreased all-cause mortality
Other nutrients that showed evidence of reducing cardiovascular risk:
- Omega-6 fatty acids
- Vitamin D
- Alpha-lipoic acid
Not All Antioxidants Showed Benefits
Vitamin C, vitamin D, vitamin E, and selenium showed no effect on long-term cardiovascular disease outcomes or type-2 diabetes risk, according to the study authors. And beta carotene supplements were associated with an increase in all-cause mortality.
According to the researchers, the findings point to the need for more personalized, precision-based dietary interventions that involve specific combinations of beneficial supplements. Further study is needed, including large, high-quality interventional trials to investigate the long-term effects of certain micronutrients on health.
Supplementation of some but not all micronutrients may benefit cardiometabolic health. This study highlights the importance of micronutrient diversity and the balance of benefits and risks to promote and maintain cardiovascular health in diverse populations.