Dr. Scott Harris specializes in rheumatology and teaches classes, including a course on Public Health and Preventive Medicine, at Touro University in Las Vegas. As an osteopath, he focuses on total-body health. He shares insights on dietary supplements.

What supplements do you tell your patients to take?

What I always recommend to people is a one-a-day vitamin. I really believe in people trying to eat a more balanced, healthy natural diet than to be taking a lot of supplements.

What surprises you when it comes to supplements?

I never hear anybody complaining about the cost of over-the-counter supplements, and they are incredibly expensive.

Are there any supplements of particular concern right now?

I see people coming in taking extra large doses of vitamin D that may not be monitored by their doctors, and it’s a fat-soluble vitamin—A, D, E and K are vitamins that are fat-soluble, and therefore tend to remain stored in the body. … A [recent] study showed people who had an excess of vitamin D were now showing evidence of irregular heartbeats. As with everything, too much of it may be a problem.

Glucosamine and chondroitin seem to be all the rage. What do doctors say?

Glucosamine and chondroitin are part of the nutrient structure that goes into modeling and building joints, and has actually been used in animals, especially in dogs, and seems to be effective in helping manage symptoms of degenerative disease in animals. When we looked at really good randomized trials in rheumatology, there’s no data that supports it [in humans]. Therefore, the American College of Rheumatology does not ask us to go about recommending it to people wholeheartedly.