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Taking Your Vitamins? Don’t Forget to Tell Your Doctor.



You exercise and eat healthy foods. And to boost your immune system, you take a multivitamin every day. It can only help, right? Perhaps. But you should let your clinician know to make sure those vitamins aren’t actually a danger to your health.

Every year, American consumers spend billions of dollars on vitamins, herbs, minerals and supplements. National health surveys show that more than half of all American adults take some kind of vitamin or dietary supplement, a percentage that increases with age. About 80 percent of women over the age of 60 take one or more dietary supplement, the same report shows.

Consult an expert

“If you are considering taking a vitamin or supplement, you should talk with your clinician about what you hope to get from that medicine. They can help you figure out if there is good evidence for taking it and what the risks might be,” said Katherine Reeve, MD, a primary care physician with Northeast Medical Group who sees patients at the Yale New Haven Health Uncasville Medical Center at Mohegan Sun. “Most people don’t need multivitamins and other supplements, though there are a few exceptions.”

“A number of supplements can enhance, diminish or negate a prescription drug in ways that can be consequential and unpredictable,” she said. “Many supplements can contain ineffective or harmful ingredients, especially if combined with prescription drugs.”

Impact on medications

According to Kelley, supplements and vitamins can change the “ADME” of prescription medications that you may be taking. ADME stands for absorption, distribution, metabolism and excretion of drugs. Depending on the person and the drug they are taking, interactions can be serious. Vitamins and supplements can cause harmful reactions, or they may reduce effectiveness of the prescription meds.

For example, warfarin is a drug that is often prescribed to treat or prevent blood clots in veins or arteries. Gingko biloba (an herb) and vitamin E supplements can thin your blood – so taking them with warfarin may increase your risk for internal bleeding or stroke. Vitamin C is often taken as a supplement to ward off the common cold —but high-dose vitamin C supplements may reduce the effectiveness of some types of cancer chemotherapy and interfere with your statin medications.

Natural doesn’t mean safe

Kelley says that many people also think that because a vitamin or supplement is promoted as “natural” it automatically means the product is “safe.” This can be a dangerous assumption.

“Vitamins and supplements are regulated as foods, not drugs. This means the Food and Drug Administration does not evaluate the quality of the supplement or assess its effect on the body before the product hits the shelves,” she said. “Some supplements can have a range of ingredients instead of exactly the amounts listed on the labels – which is why, even though supplements are ‘natural,’ they can sometimes be unsafe.”

To help avoid any health hazards that can arise from mixing supplements and medications, Dr. Reeve recommends that you talk to your clinician before starting any new over-the-counter medication or supplement. Bring a list of everything you take — over-the-counter medicines (pain pills, allergy relief, etc.), herbals, minerals, vitamins, dietary supplements and prescription drugs — with you to your next routine appointment to make sure your information is up to date. And be sure to keep track of the dosages and how many times a day you take them.

“I encourage my patients to show me what they are reading, such as ads or articles. They can send it in via MyChart or bring it to a visit and we can weigh the pros and cons together,” said Dr. Reeve.

Also, if you’re planning a surgery, don’t be surprised if your doctor asks you to stop taking dietary supplements two or three weeks before the procedure to avoid changes in heart rate, blood pressure or bleeding risk.

Have an honest chat with your clinician

Talking with your clinician about your desire to implement vitamins and minerals into your diet may have other benefits. If you feel you need something else in your diet, your clinician can make sure there aren’t any underlying conditions that may be the reason you feel the need to supplement.

“Consider whether you really need to take vitamins and supplements. The best way to get all the essentials is by eating a healthy diet with lots of fruits, vegetables and whole grains, and watching out for processed foods and supplements that are advertised as health foods,” Dr. Reeve said. “For most of my patients, I would recommend adding a banana or a handful of blueberries to their morning routine rather than a handful of vitamins.”