Vitamins & Supplements Archive

Ask the doctors

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Q. I suffer from vertigo and have heard that taking a magnesium supplement might help. Is that true? If so, how much should I take?

A. Vertigo can be caused by almost anything that interferes with the normal function of the inner ear, which is instrumental in preserving balance. The most common form of vertigo — benign paroxysmal positional vertigo (BPPV) — results when tiny calcium carbonate crystals migrate from one part of the inner ear to the semicircular canal in another part of the ear, triggering a false message to the brain about the direction in which the head is moving and the speed of its motion. Dizziness is a result of the brain's attempt to resolve the conflicting messages from the ear and the other senses.

In the journals

Adequate levels of vitamin D can help strengthen bones and lower the risk for diabetes and some cancers. But research published online April 5, 2017, by JAMA Cardiology found that high monthly doses of supplemental vitamin D did little to ward off cardiovascular disease.

The recommended daily amount of vitamin D is 600 international units (IU) for men ages 51 to 70 and 800 IU for men ages 71 and older. It is not yet clear how vitamin D may improve heart health, but studies have found a higher rate of cardiovascular disease among people with low levels of vitamin D.

Dietary supplements may be natural but not risk-free.

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A quick stroll through your pharmacy or supermarket wellness aisle will show you that dietary supplements and herbal remedies are big business. Americans spend over $32 billion annually on thousands of herbal products, many of which claim to improve heart health.

Popular misconceptions

People look to herbs and supplements as a natural, safe alternative to the conventional medications they're taking, says Dr. Pieter Cohen, an assistant professor of medicine at Harvard Medical School. Providers, on the other hand, may think of supplements as fancy placebos — expensive but benign. "These are all misconceptions," says Dr. Cohen.

Research we're watching

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Do you swallow a daily multivitamin, hoping to make up for a less-than-ideal diet? Sorry, but this strategy won't stave off heart disease, according to a study published online April 5, 2017, by JAMA Cardiology.

Previous research has also failed to find convincing evidence that a daily multivitamin lowers the risk of heart disease or cancer. But these studies didn't always account for the participant's dietary habits, which could potentially skew the results. In theory, people with poor diets might reap greater benefits from vitamins than those who eat healthier diets.

In the journals

Much research has shown that oxidative stress plays a key role in the development of neurodegenerative disorders, such as Alzheimer's and Parkinson's disease. As a result, antioxidant supplements like vitamin E and selenium have been proposed to prevent dementia. Yet a new study on older men published online March 20, 2017, by JAMA Neurology found no evidence they can help.

The Prevention of Alzheimer's Disease by Vitamin E and Selenium clinical trial included 7,540 men, average age of 67. Over a five-year period, the men were randomly assigned to receive 400 international units of vitamin E each day, 200 micrograms of selenium, both supplements, or a placebo. The supplements were stopped and 3,786 of these men agreed to be followed for an additional six years. They were routinely screened for cognitive problems and encouraged to see their doctor if the results suggested any kind of cognitive impairment.

It's easy enough to look up how much vitamin C or calcium you should get each day. It is also easy to read the back of a vitamin bottle to see just how much of a given vitamin or mineral the product provides. But how can you tell if what you eat — which should be your primary source of important nutrients — is giving you what you need?

One way is to focus on the big picture: eat a balanced diet that contains a variety of colorful fruits and vegetables, whole grains, beans, nuts, dairy products, seafood, lean meats, and poultry. Focus on nutrient-dense foods like these, which are packed with vitamins and minerals relative to the number of calories they deliver, and you should be fine.

Research we're watching

Dietary supplements made from red yeast rice contain substances called monacolins, which are similar to the active ingredient in cholesterol-lowering statin drugs. And like statins, red yeast rice products may cause rare but serious side effects, such as muscle injury and liver damage, as noted in a study published online January 19, 2017, by the British Journal of Pharmacology.

The study, based on a review of 13 years of patient data by Italian researchers, notes that people who can't tolerate statins often take red yeast rice supplements. But there are no studies testing the safety of red yeast rice compared with statins. In the United States, the FDA considers red yeast rice products that contain more than trace amounts of monacolins to be unapproved new drugs and therefore illegal to sell. Yet dozens of these unregulated products remain on the market.

It’s unclear why, but it appears that people with psoriasis are more likely to also suffer from diabetes.

When it comes to fighting high blood pressure, the average American diet delivers too much sodium and too little potassium. Eating to reverse this imbalance could prevent or control high blood pressure and translate into fewer heart attacks, strokes, and deaths from heart disease.

Normal body levels of potassium are important for muscle function. Potassium relaxes the walls of the blood vessels, lowering blood pressure and protecting against muscle cramping. A number of studies have shown an association between low potassium intake and increased blood pressure and higher risk of stroke. On the flip side, people who already have high blood pressure can significantly lower their systolic (top number) blood pressure by increasing their potassium intake when they choose to eat healthy foods.