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Aug 13, 2023

Are turmeric supplements safe and good for health?

Every day before work, orthopedic surgeon Nick DiNubile swallows a

Every day before work, orthopedic surgeon Nick DiNubile swallows a 1,000-millgram capsule of turmeric as a hedge against joint inflammation.

"As an aging athlete with joint issues, it's an integral part of my plan to keep moving," said DiNubile, who would rather take a dietary supplement than a prescription medication or a nonsteroidal anti-inflammatory drug (NSAID). "I like the safety of it."

DiNubile, who practices in the Philadelphia area, said he was persuaded by research suggesting the supplement showed some efficacy against the pain and inflammation of arthritis. But he warns: "You’ve got to give it time — about two months — and not everyone responds. You have to be honest with yourself about whether it provides any improvement."

He believes it has helped him. "Is it the placebo effect?" he said. "I don't think so."

The National Center for Complementary and Integrative Health (NCCIH) says there isn't enough data from human studies to determine the efficacy of turmeric supplements. Most of the available research comes from labs — in cell lines and animals — rather than in humans.

Turmeric is a plant in the ginger family native to Southeast Asia. It is used in various dishes such as Indian curries and historically has been used in Eastern Asian medical systems, such as in India and China.

Nontraditional approaches are not typically regarded as mainstream, but natural plant-based therapies have long been dominant in many developing countries and enjoyed heavy use historically, especially during pandemics.

Turmeric has been promoted for numerous ailments, including arthritis, digestive disorders, respiratory infections, allergies, depression and dementia. (Curcumin, which gives turmeric its yellow color, is a major component of turmeric. The two names are often used interchangeably, with the activities of turmeric commonly attributed to curcumin and vice versa.)

Research suggests that curcumin is an anti-inflammatory agent and a strong antioxidant, that is, a substance capable of neutralizing dangerous free radicals. (Free radicals are unstable molecules produced during cell metabolism which can build up in the body, causing damage to other cells and raising the risk of cancer and other diseases.)

It's probably safe (for those who aren't pregnant) to take orally in the recommended amounts, says the NCCIH, which is part of the National Institutes of Health. (Recommended amounts are usually found on bottle labels. DiNubile suggests 1,000 milligrams a day.)

Turmeric is difficult to study because curcumin is unstable and poorly absorbed, the NCCIH says.

"There is a mountain of literature on curcumin, but the vast majority is preclinical," or tested in the lab, "which can't be easily projected to how it will or will not work in humans," said D. Craig Hopp, the NCCIH's deputy director of extramural research. Also, numerous clinical trials have not been able to replicate the activity observed in cells or animals, a fairly common occurrence not only in herbal medicine but also in pharmaceutical research, he said.

Rui Hai Liu, professor of food science at Cornell University's College of Agriculture and Life Sciences, agreed that what happens in the test tube doesn't always happen in humans. "Many diseases result from oxidative stress, and curcumin is an excellent antioxidant, but we still don't have enough data from humans" to prove these effects, he said.

"In general, marketing moves faster than the research on any supplement," said Michael Ormsbee, professor of nutrition and integrative physiology and director of the Institute of Sports Sciences and Medicine at Florida State University's College of Health and Human Sciences.

For those experiencing pain and inflammation, or who engage in physical activities that induce chronic inflammation, however, "turmeric use seems to have some evidence to a mild benefit," he said. Ormsbee cited one study that reported four weeks of curcumin supplements of 1,500 milligrams daily was as effective as 1,200 daily milligrams of ibuprofen for the symptoms of knee osteoarthritis.

"Individuals’ responses are almost certainly to vary with use, and more research is needed for other purported benefits of turmeric extract," he said. But "there appears to be little downside to including turmeric extract in the diet," he added.

Debbie Fetter, a nutritional biology expert, said it is hard to evaluate human studies of the product. "It's difficult to compare across studies because of the variability in the curcumin used, as products can differ in composition and dose," said Fetter, an assistant professor of teaching at the University of California at Davis.

Turmeric should be avoided during pregnancy and breastfeeding in amounts greater than those found in foods, the NCCIH says.

Turmeric or curcumin is poorly absorbed, thus many supplements combine it with piperine — black pepper extract — or with lipids such as soy lecithin to improve absorption. When buying turmeric supplements, check the label to see if these have been added.

Fetter said consumers should inform their doctors when they take turmeric or any dietary supplement.

Side effects usually are minimal, but some people have reported experiencing gastrointestinal distress — diarrhea — after taking it, she said.

Americans seem to like their dietary supplements. Nearly 60 percent of U.S. adults reported taking them, mostly multivitamin-mineral products, vitamin D and Omega-3 fatty acids, according to 2017-2018 survey data from the Centers for Disease Control and Prevention.

Also, millions of Americans rely on what are known as home remedies to treat various ailments, a term used along with "complementary" or "alternative" medicines to distinguish them from Western practices, which often rely on doctor visits and conventional drugs.

The Food and Drug Administration does not regulate dietary supplements the way it does conventional drugs, which must demonstrate safety and efficacy before the agency will license them. Supplements, on the other hand, do not require FDA approval before they can be marketed.

Supplement companies must have evidence that their products are safe, but don't have to provide it to the FDA to sell their products. Moreover, the agency can't act against a potentially dangerous dietary supplement until it already is on the market.

Dietary supplement labels may include certain types of health-related claims, but they must be followed by the words: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."

Pieter Cohen, associate professor of medicine at Harvard Medical School and internist with the Cambridge Health Alliance, studies the safety of dietary supplements. He advises consumers to be wary of supplement claims which "don't need to be supported by any evidence in human trials," he said. "If you don't see claims, even better."

He recommends buying products certified by an independent third party, either NSF or USP, the United States Pharmacopeia. Both "test products at the request of the company, so if you see them on the label, you know that company is trying to do the right thing," Cohen said.

Cohen — whose research has uncovered numerous cases of adulterated supplements — added that, as yet, "turmeric hasn't risen onto my radar screen as something to worry about."

Do you have a question about healthy eating? Email [email protected] and we may answer your question in a future column.

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