Vitamins, Fish Oil, Minerals: Which Supplements Help or Harm the Heart?

Manufacturers make all kinds of health claims, but can taking a dietary supplement actually lower your heart disease risk?

A comprehensive analysis of prior research suggests that in certain cases the answer is yes. Some types of supplements – such as omega-3 fatty acids, folic acid and coenzyme Q10 (CoQ10) — do provide a cardiovascular leg up.

But many supplements were found to offer no heart health benefit of any kind, and others were potentially harmful.

“We evaluated 27 different types of supplements, and found that there are several that offered cardiovascular benefits,” said study author Dr. Simin Liu, director of the Center for Global Cardiometabolic Health at Brown University in Providence, R.I.

These included omega-3 fatty acids, which reduced the risk of early death due to heart disease.

Other supplements that were shown to benefit the heart included folic acid, L-arginine, L-citrulline, Vitamin D, magnesium, zinc, alpha-lipoic acid, melatonin, catechin, curcumin, flavanol, genistein and quercetin.

But some common supplements had no long-term effect on heart disease outcomes or risk for type 2 diabetes, Liu noted. They included vitamins C, D, E and selenium.

Beta carotene supplements, meanwhile, were associated with an increase in early death from all causes.

The findings are an outgrowth of a research review prompted by what Liu and his colleagues described as lingering confusion in the heart health community as to just how effective supplements can be at preventing heart disease.

The fact that foods rich in micronutrients can protect the heart has not been in question, said Liu, who noted that several large studies have linked a healthy diet to heart health benefits.

For example, micronutrients like antioxidants – which are present in the heart-healthy foods featured in the “Mediterranean diet” and DASH (“Dietary Approach to Stop Hypertension”) — have long been linked to a reduction in oxidative stress. Because cell tissue damage brought on by such stress poses a threat to heart health, antioxidant-rich diets are thought to be protective, reducing the risk for a number of serious diseases, including diabetes.

What’s been less clear, however, is whether consuming vitamins, minerals, phytochemicals and antioxidants in the form of supplements might offer a similar advantage.

For the new study, Liu’s team poured through 884 prior studies of supplements, some published as recently as this year. Collectively, the studies involved nearly 900,000 men and women.

In the end, the team concluded that some of the 27 micronutrient supplements under review did demonstrate some benefit.

Those included a number of omega-3 fatty acid supplements – including n-3 and n-6 fatty acids— which were found to help to reduce the risk for heart attacks and coronary heart disease, as well as the overall risk for dying as a result of heart disease.

Similarly, folic acid supplements were linked to a reduced risk for stroke, while CoQ10 was linked to a lower risk for premature death from any cause.

On the other side of the ledger, however, beta-carotene supplements were linked to an increase in the risk of dying early due to any cause, as well as a higher specific risk for heart disease death and stroke.

Dr. Gregg Fonarow is director of the Ahmanson-UCLA Cardiomyopathy Center in Los Angeles and co-director of the UCLA Preventative Cardiology Program.

After reviewing the findings, Fonarow offered a decidedly cautious take, noting that the apparent benefit of a handful of the nutrients were the “rare exception.”

“Beta carotene supplements were found to increase risk, [while] most other supplements demonstrated no benefits in randomized clinical trials,” he emphasized.

“The few exceptions,” Fonarow added, “did not show consistent benefit” when it comes to risk reduction.

His advice: Stick to a heart-healthy lifestyle and get adequate nutrients by eating a variety of foods in moderation.

A pair of nutrition experts agreed.

“What we do not know conclusively is if supplements alone can prevent disease risk or is it about the balance of nutrients?” cautioned Connie Diekman, a St. Louis food and nutrition consultant and former president of the Academy of Nutrition & Dietetics.

She said the latter is likely the case: “No single nutrient is the answer to disease avoidance.”

Diekman warned that while omega3’s do seem to provide heart health benefits, if consumed in a diet that is unhealthy overall, they “cannot create magic.”

“The same can be said about the other nutrients,” she said.

Regardless, she warned against starting supplements without the advice of a doctor or registered dietician, “since that can disrupt the nutrient balance.”

Lona Sandon, a program director in clinical nutrition at UT Southwestern Medical Center in Dallas, also offered cautions.

“Supplements are regulated, but not to the same degree as prescription drugs,” she noted. “Buyers still must beware, as supplements are not required to undergo safety testing prior to being marketed and sold.”

The upshot, said Sandon, is that “we cannot take all supplements at face value, unfortunately.”

Even when supplements are in the mix, “diet still matters,” she stressed. She offered some advice for those truly looking for a dietary leg up on heart health: “Add a few servings of tuna and walnuts each week, along with some leafy greens, and 100% orange juice for some omega-3s and folate.”

The new study was published in the December issue of the Journal of the American College of Cardiology.

More information

There’s more about supplements and heart health at Johns Hopkins Medicine.

SOURCE: Simin Liu, MD, MS, MPH, ScD, professor, epidemiology, medicine and surgery, and director, Center for Global Cardiometabolic Health, Brown University, Providence, R.I.; Gregg Fonarow, MD, director, Ahmanson-UCLA Cardiomyopathy Center, and co-chief, UCLA Division of Cardiology, Los Angeles; Connie Diekman, MEd, RD, food and nutrition consultant, St. Louis, and former president, Academy of Nutrition & Dietetics; Lona Sandon, PhD, RDN, LD, program director and associate professor, clinical nutrition, School of Health Professions, UT Southwestern Medical Center, Dallas; Journal of the American College of Cardiology, December 2022