Vitamins & Supplements Archive


Fish oil and vitamin D supplements might offer some health benefits

In the journals

Vitamin D and omega-3 fatty acid supplements have had mixed results when it comes to preventing heart attacks, strokes, and cancer in people who have already developed these problems or are at high risk for them. Yet a new study published online Nov. 10, 2018, by The New England Journal of Medicine found they may actually prevent these conditions among people who have never had these problems before.

Researchers recruited almost 26,000 people, ages 50 and older, who had no history of heart disease or cancer. The participants were divided into four groups. People in one group were given daily doses of 2,000 international units of vitamin D (an amount found to be linked to lower disease risk in observational studies) and 1 gram of a drug called Lovaza, which contained 840 milligrams of omega-3s (two to four times the amount in two servings of fish per week). The second group took vitamin D and a placebo, the third group took the omega-3s and a placebo, and the final group took two placebos. After more than five years, the researchers found that those given omega-3s were 28% less likely to suffer a heart attack compared with those given a placebo. Those who ate fewer servings of fish (less than the average of 1.5 servings per week) appeared to have a greater benefit from the additional omega-3s while those with higher fish intake had minimal benefit.

What’s in your supplements?

Millions of Americans take some kind of supplement, but because supplements are not regulated like prescription drugs are, taking one is not always safe. Researchers have found many instances of hidden ingredients and inaccurate quantities listed on the label.

Can fish oil stave off heart disease?

Ask the doctor

 Image: © Elena_Danileiko/Getty Images

Q. I'm taking fish oil supplements to keep me from getting heart disease, because my doctor said they may help, though it's controversial. I hear new studies come to different conclusions. What's the truth?

A. In these pages, the best we can promise you is a balanced assessment of sometimes different study results: the "truth" usually is elusive. Your question likely was prompted by two important new studies published in November 2018, and they do seem to point in different directions. I'll do my best to give you my current "bottom line" and resolve the confusion. I reserve the right to change my mind as new studies are reported.

Vitamin D and omega-3 fatty acids supplements fall short when it comes to disease prevention

 Image: © Hunterann/Thinkstock

Research we're watching

For years, many have speculated that taking vitamin D and omega-3 fatty acid supplements might help to prevent heart attacks, strokes, and certain cancers. But a study by Harvard researchers published online November 10, 2018, by The New England Journal of Medicine has found that the benefits may be more limited than originally hoped.

The results of the Vitamin D and Omega-3 Trial (VITAL), which enrolled more than 25,000 people and ran for more than five years, showed that while omega-3 supplements did appear to reduce the risk of heart attack, particularly among African Americans, they did not appear to be effective in preventing stroke or cancer. Vitamin D supplements also saw few benefits when it came to preventing heart attack, stroke, or cancer — but they were associated with a drop in cancer deaths in people who had taken the supplements for at least a year or two.

Understanding antioxidants

Some vitamins and minerals — including vitamins C and E and the minerals copper, zinc, and selenium — serve as antioxidants, in addition to other vital roles. 

"Antioxidant" is a general term for any compound that can counteract unstable molecules called free radicals that damage DNA, cell membranes, and other parts of cells. Because free radicals lack a full complement of electrons, they steal electrons from other molecules and damage those molecules in the process. Antioxidants neutralize free radicals by giving up some of their own electrons. In making this sacrifice, they act as a natural "off" switch for the free radicals. This helps break a chain reaction that can affect other molecules in the cell and other cells in the body. But it is important to recognize that the term "antioxidant" reflects a chemical property rather than a specific nutritional property. 

How much vitamin D do you need?

Despite widespread assertions in the popular and scientific press that many Americans have a vitamin D deficiency, the term "deficiency" isn't strictly accurate. The official definition of a vitamin deficiency means that specific health problems stem solely from the lack of (or inability to use) a specific nutrient. An actual vitamin D deficiency results in bone disease, such as rickets, which is rare in the United States. 

On the other hand, lower-than-optimal levels of specific vitamins, including vitamin D, may increase your risk of numerous health problems, even though they are not solely responsible for these problems. "Insufficiency" may be a better term for these lower levels than "vitamin D deficiency". 

Are you missing this simple treatment for restless legs?

Iron supplementation may be all it takes to reduce symptoms of restless legs syndrome. But many doctors don't know about it.

 Image: © AlexRaths/Getty Images

People with restless legs syndrome (RLS) experience an overwhelming need to move the legs, particularly at night or as they fall asleep. But a simple treatment that may help reduce RLS symptoms is often overlooked as a potential first line of defense.

"The concern is that people are being started on medications first when iron might be a valuable treatment. It's simple, with relatively few side effects," says Dr. John Winkelman, an RLS specialist at Harvard-affiliated Massachusetts General Hospital.

Omega-3s for anxiety?

News briefs

 Image: © emiliozv/Getty Images

Omega-3 fatty acid supplements may help ease anxiety symptoms in people diagnosed with a range of physical and mental health problems, according to a review published in the Sept. 14, 2018, JAMA Network Open. The report pooled findings from 19 different studies and included 1,200 people. Most of the studies compared omega-3 supplements to a placebo. Taken together, the studies included people with a range of health problems, including heart attacks, attention deficit disorder, substance abuse, depression, and Parkinson's disease, as well as some groups without any specific clinical diagnosis. Researchers found that people who took high doses of omega-3s (up to 2,000 mg a day) seemed to have the most reduction in anxiety symptoms. Omega-3 fatty acids, which are usually derived from fish oil, have a number of biological effects in the body. Brain membranes contain a high proportion of these fats, and human studies suggest that a lack of omega-3s in the brain may induce various behavioral and psychiatric disorders. For now, it's too soon to recommend high-dose omega-3 supplements for treating anxiety. Larger trials testing the supplements (both alone and combined with standard treatments) are needed, the study authors say.

What’s in that supplement? Sometimes more than you bargain for

Research we're watching

Do you know someone who is using a supplement for weight loss, muscle building, or sexual enhancement? You might want to recommend a dose of caution. An analysis published on October 12 by JAMA Network Open found that many of these supplements contain unapproved and potentially dangerous pharmaceutical ingredients. From 2007 to 2016, FDA reviewers detected contaminants in 776 dietary supplements, produced by 146 different companies. Contaminants included sildenafil, which is the generic form of the drug Viagra; sibutramine (Meridia), a weight-loss drug taken off the market in the United States in 2010; and anabolic steroids or steroid-like substances. And 20% of products contained more than one unapproved ingredient.

These supplements could prove harmful for those who take them because their ingredients may interact with other medications or cause problems for people with underlying health conditions.

Free Healthbeat Signup

Get the latest in health news delivered to your inbox!

Sign Up
Harvard Health Publishing Logo

Thanks for visiting. Don't miss your FREE gift.

The Best Diets for Cognitive Fitness, is yours absolutely FREE when you sign up to receive Health Alerts from Harvard Medical School

Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health, plus the latest advances in preventative medicine, diet and exercise, pain relief, blood pressure and cholesterol management, and more.

Harvard Health Publishing Logo

Health Alerts from Harvard Medical School

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss...from exercises to build a stronger core to advice on treating cataracts. PLUS, the latest news on medical advances and breakthroughs from Harvard Medical School experts.

BONUS! Sign up now and
get a FREE copy of the
Best Diets for Cognitive Fitness

Harvard Health Publishing Logo

Stay on top of latest health news from Harvard Medical School.

Plus, get a FREE copy of the Best Diets for Cognitive Fitness.