Vitamins, minerals, herbs, and supplements Archive

On call

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Q. I take fish oil supplements for heart health, but now I hear they aren't helpful. What's the truth?

A. Fish intake remains an important part of a healthy diet, but the enthusiasm for fish oil supplements has been dampened by several recent studies that showed no benefit for a variety of conditions.

Research we're watching

The FDA is warning consumers not to buy in to the idea that a pill can protect your skin from the sun.

In a statement issued May 22, FDA officials said they've found companies selling pills that are labeled as dietary supplements and that claim to protect skin from the sun.

News briefs

Vitamin D is an essential vitamin; low levels are associated with poor bone and muscle health and other chronic conditions, such as heart disease and cancer. Now, a study published online April 19, 2018, by PLOS One has tied higher vitamin D levels to a lower diabetes risk. Researchers followed 900 older adults (average age 74) for 12 years, checking their vitamin D and blood sugar levels during clinic visits. Compared with people whose blood levels of vitamin D were below 30 nanograms per milliliter (ng/ml), people with vitamin D levels of 30 ng/ml or more had one-third the risk for developing diabetes, and people whose D levels were 50 ng/ml or more had one-fifth the risk. This study does not prove that taking vitamin D supplements to raise blood levels of vitamin D would reduce the risk of diabetes, although that is possible. The Institute of Medicine maintains that a blood level of 20 ng/ml or higher is sufficient for 97% of the population. Other authorities think that levels higher than 20 ng/ml are better for health. Large studies are under way to help resolve these differences of opinion.

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In the journals

Having a low blood level of vitamin D may be linked to a higher risk of developing some cancers, suggests a study published online March 7, 2018, by The BMJ. However, taking extra vitamin D to raise already normal levels does not appear to offer more protection.

Vitamin D is made by the skin from sunlight exposure and can also be obtained through fortified foods like cereal and milk, as well as from supplements. Researchers analyzed data from the Japan Public Health Center–based Prospective Study, involving 33,736 people ages 40 to 69. The people gave blood samples and were classed into four groups, ranging from the lowest to highest levels of vitamin D. They were then monitored for an average of 16 years, during which time 3,301 new cases of cancer were recorded among the participants.

You may need to stop taking blood thinners, certain painkillers, herbs, and supplements to reduce your risk for bleeding.

 Image: © Steve Debenport/Getty Images

No one wants to have surgery, even minor surgery, but sometimes minor procedures, such as a tooth extraction or a colonoscopy, are unavoidable. When that happens, you may hear that it's important to stop taking certain medications. Understanding exactly which drugs to suspend — and when — can be confusing. "I get a lot of questions about this," says Joanne Doyle Petrongolo, a pharmacist at Harvard-affiliated Massachusetts General Hospital.

Blood thinners

All surgery involves cutting body tissue, and that leads to bleeding. Blood thinners—medications like anticoagulants and antiplatelet drugs—can boost the risk for bleeding by keeping the blood from clotting.

Q: A friend recently recommended that I take the herb ginkgo biloba to protect against getting dementia. Is it effective, and is it safe?

A: The first thing you should consider is that the FDA doesn't regulate the manufacture of any herbal remedy, so the purity and potency of the ginkgo biloba you buy hasn't been checked.

Q: A friend recently recommended that I take the herb ginkgo biloba to protect against getting dementia. Is it effective, and is it safe?

A: The first thing you should consider is that the FDA doesn't regulate the manufacture of any herbal remedy, so the purity and potency of the ginkgo biloba you buy hasn't been checked.

In the journals

Taking a daily omega-3 fatty acid supplement might not reduce your chance of heart attacks or strokes if you already have heart disease or are at high risk for it, suggests a meta-analysis published online Jan. 31, 2018, by JAMA Cardiology.

The researchers compared 10 trials that included almost 78,000 people, approximately 47,000 of whom were men, with an average age of 64. Each trial involved at least 500 people who took daily doses of either an omega-3 fatty acid supplement or a placebo for at least a year. All participants had heart disease, had experienced a stroke, or were at high risk for these conditions.

On call

Q. I have read that vitamin K supplements can help prevent heart disease. Should I take them?

A. Vitamin K — which is found in high levels in green leafy vegetables like spinach, kale, and romaine lettuce — plays a role in helping the body make blood clotting proteins. Although some observational studies have suggested a heart benefit from diets high in vitamin K, studies of supplements have not shown a protective effect.