Healthy diets are rich in antioxidants like amino acids, omega-3 fatty acids and vitamin C, but exactly how these micronutrients are beneficial for cardiovascular health has long been controversial. Now, a new meta-analysis published in the Journal of the American College of Cardiology provides some clarity.

The researchers systematically reviewed a total of 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 participated in the combined studies.

“For the first time, we have developed a comprehensive evidence-based integrative map to characterize and quantify the potential effects of micronutrient supplementation on cardiometabolic outcomes,” he said. simin liu, MD, MS, MPH, ScD, professor of epidemiology and medicine at Brown University. and a principal investigator of the study. “Our study highlights the importance of micronutrient diversity and the balance between health benefits and risks.”

The findings can be used as a basis for future clinical trials to study specific combinations of micronutrients and their impact on cardiovascular health, he said.

Antioxidants

Supplementation with antioxidants is thought to play a role in heart health. This is because these nutrients work to reduce oxidative stress, a known contributor to many cardiovascular diseases. Heart-healthy diets such as the Mediterranean diet and the Dietary Approach to Stop Hypertension (DASH) include foods that are naturally rich in antioxidants. However, results from studies of antioxidant supplements have been inconsistent, one of the reasons why this approach has not yet been widely adopted in preventive cardiology.

“Research on micronutrient supplementation has primarily focused on the health effects of one or a few vitamins and minerals,” Liu said. “We decided to take a comprehensive and systematic approach to evaluate all publicly available and accessible studies reporting all micronutrients, including phytochemicals and antioxidant supplements, and their effects on cardiovascular risk factors as well as various cardiovascular diseases.”

The investigators analyzed randomized controlled intervention trials that assessed 27 different types of antioxidant supplements. They found strong evidence that several offered cardiovascular benefits. These included:

  • Omega-3 fatty acids, which have lowered mortality from cardiovascular disease
  • Folic acid, which reduces the risk of stroke
  • Coenzyme Q10, an antioxidant sometimes marketed as CoQ10, which has decreased all-cause mortality.

They also showed evidence of reduced cardiovascular risk:

  • omega-6 fatty acid
  • L-arginine
  • L-citrulline
  • Vitamin D
  • Magnesium
  • Zinc
  • Alpha lipoic acid
  • melatonin
  • catechin
  • curcumin,
  • flavanol,
  • genistein
  • quercetin

Not all are beneficial

Not all supplements were beneficial. Vitamin C, vitamin D, vitamin E and selenium showed no effect on long-term cardiovascular disease outcomes or type 2 diabetes risk. beta-carotene supplements increased all-cause mortality.

According to the researchers, the findings point to the need for more personalized and precise dietary interventions involving specific combinations of beneficial supplements. More studies, including large, high-quality interventional trials, are needed to investigate the long-term health effects of certain micronutrients.

“It’s important to identify the optimal combination of micronutrients, as not all are beneficial and some may even have harmful effects,” Liu said.