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-one reason why this approach hasn’t yet been widely adopted in
preventative 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.
Now a new meta-analysis published in the Journal of the American College of
Cardiology provides some clarity.
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 do 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, he said.
“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 researchers looked at randomized,
controlled intervention trials evaluating 27 different types of antioxidant
supplements. They found strong evidence that several offered cardiovascular
benefit. These included omega-3 fatty acid, which decreased mortality from
cardiovascular disease; folic acid, which lowered stroke risk; and coenzyme
Q10, an antioxidant sometimes marketed as CoQ10, which decreased all-cause
mortality. Omega-6 fatty acid, L-arginine, L-citrulline, Vitamin D, magnesium,
zinc, alpha-lipoic acid, melatonin, catechin, curcumin, flavanol, genistein and
quercetin also showed evidence of reducing cardiovascular risk.
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. And beta carotene
supplements increased 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.
“Identifying the optimal mixture of
micronutrients is important, as not all are beneficial, and some may even have
harmful effects,” Liu said.
Reference:
Simin Liu, et al,Micronutrient Supplementation
to Reduce Cardiovascular Risk, Journal of the American College of Cardiology, DOI 10.1016/j.jacc.2022.09.048