Vitamins & Supplements Archive

Q. I'm 52 years old. Should I take glucosamine and chondroitin to relieve my osteoarthritis pain and maintain cartilage?

A. Glucosamine and chondroitin are compounds found in healthy cartilage. Because osteoarthritis involves the degradation of normal cartilage, it would seem to make sense that taking supplements of these compounds could help maintain cartilage in people with the condition. Early anecdotal reports and small studies did suggest that the two compounds held great promise for relieving pain related to osteoarthritis. However, glucosamine and chondroitin—either together or alone—did not pass muster when they were studied in large controlled clinical trials. Their effect on pain and cartilage was no better than that of a placebo (inactive treatment) in patients with osteoarthritis of the knee or hip.

Vitamin D supplements do not appear to be effective for reducing pain and slowing the progression of knee osteoarthritis.

Q. I've heard that age-related macular degeneration is a common cause of blindness. Do copper, zinc, or lutein help prevent it?

A. There's no clear and certain answer, but there are few large randomized studies of nutritional supplements in preventing age-related macular degeneration (AMD). A study called the Age-Related Eye Disease Study (AREDS) included 3,640 people ages 55 to 80. Some did not have AMD, but others already had mild to severe AMD. The people were assigned to one of four treatment groups: antioxidants (vitamin C, vitamin E, and beta carotene); zinc and copper; antioxidants plus zinc and copper; or placebo. The combination of antioxidants, zinc, and copper seemed to reduce the risk that people who had mild AMD would go on to more severe AMD. However, it didn't protect people without AMD from getting AMD. Another large randomized trial called AREDS2 is under way to test if lutein, zeaxanthin, or omega-3 fatty acids slow the progression of the most common type of AMD, called dry AMD. It is possible that results will be known later this year. One large randomized trial including 5,205 women reported that B vitamin supplements might reduce the risk of developing AMD. The women were given either a placebo or a combination of vitamins B6 and B12 and folic acid. After more than seven years, the women given vitamins had about a 30% lower risk of developing AMD. The results of this study are encouraging, but they need to be confirmed by other studies before they are accepted as valid.

Q. I'm confused by conflicting reports about the benefits of multivitamins. Should I take one?

A. What a simple, straightforward question! I wish I had a simple, straightforward answer. Here's the simple, uncomplicated part: foods rich in the major vitamins are indisputably good for our health. Most of the vitamins were first discovered because severe deficiency of them produced a particular disease. For example, deficiency of vitamin C caused scurvy. Such severe vitamin-deficiency diseases are rarely seen in the developed countries. However, eating foods rich in vitamins still brings benefits, beyond preventing such diseases. Vitamin-rich foods also reduce our risk of most of the major killers, including heart disease and many types of cancer.

Memory slips are aggravating, frustrating, and sometimes worrisome. When they happen more than they should, they can trigger fears of looming dementia or Alzheimer’s disease. But there are some treatable causes of forgetfulness.

Multivitamins may slightly reduce the risk of cancer but don't prevent heart disease. Keep the focus on diet, not supplements.

Up to half of all adults in the United States may already take a multivitamin. Most probably expect it to make them feel better and prevent common illnesses, even though the evidence has always been a little sketchy. Is the one-a-day multivitamin habit truly healthful—or just wishful thinking?

Like most vitamins, B₁₂ can't be made by the body and must be gotten from food or supplements. A B₁₂ deficiency –– which might stem from a vegan or vegetarian diet, or problems with absorption due to weight loss surgery or aging –– can seriously harm nerves, mood, thinking, energy, and more.

What you need to know before taking a vitamin or mineral supplement.

The average American diet leaves a lot to be desired. Research finds our plates lacking in a number of essential nutrients, including calcium, potassium, magnesium, and vitamins A, C, and D. It's no wonder that more than half of us open a supplement bottle to get the nutrition we need. Many of us take supplements not just to make up for what we're missing, but also because we hope to give ourselves an extra health boost—a preventive buffer to ward off disease.

You may hear each winter that vitamin C can fight off the common cold. But is it just hype, or does it really help?

"The findings of a large number of studies on the subject are mixed," says Dr. Bruce Bistrian, chief of clinical nutrition at Beth Israel Deaconess Medical Center and professor of medicine at Harvard Medical School.