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Should I be taking vitamins? Am I taking too many?

Lorren Donmoyer, MD

By Lorren Donmoyer, MD

One of the most common questions you get when you visit your doctor is:  What medications are you taking?

Patients often list their prescribed medications, without mentioning the vitamins or supplements that they also take.

According to a 2016 survey by the Council for Responsible Nutrition, 70% of adults between the ages of 18 and 34 use supplements – that’s up from 65 percent in 2015. And, if I were to guess, that percentage is likely even higher today, especially with the concerns about catching COVID-19.

It is extremely important to include over-the-counter supplements and vitamins in discussions with your doctor, because in many cases, those vitamins or supplements might cause negative interactions with your prescriptions or increase your risk of developing a problem with your health.

Here are some of the common vitamins and supplements and the interactions they might cause:

  • Vitamin A: Too much vitamin A is associated with an increased risk of osteoporotic fractures.
  • Vitamin E: Excessive vitamin E intake has been associated with increased all-cause mortality when taken at or above a dose of 400 units daily.
  • Vitamin B-12: It has been found that too much B-12 may cause skin conditions such as acne and rosacea, as well as headache, dizziness, and diarrhea.
  • Calcium: Excessive calcium intake can decrease absorption of medication taken for osteoporosis, interfere with the effectiveness of certain blood pressure medications, and may increase the mortality rate in patients with severe kidney disease.
  • The herb fenugreek has been found to adversely affect diabetes medications and blood thinners, and has demonstrated cross-reactivity with peanut, cashew, and sumac berry (which could be very dangerous for patients with food allergies).
  • Green tea extract has been found to counteract sleep medications like Ambien.
  • St. John’s Wort: This herbal supplement has been found to interact with many medications: birth control (causing nausea and vomiting in addition to decreased effectiveness, possibly resulting in unplanned pregnancy), blood thinners like Warfarin (reduced effectiveness), HIV medications (reduced amount of medication circulating in the blood), certain eye drops used in the treatment of glaucoma (treatment failure), heart medications like digoxin (reduced concentration in blood), medication used to prevent rejection of transplanted organs (treatment failure, which can result in death), and interactions with some antidepressant medications (serotonin syndrome).
  • Diet supplements: Many diet supplements include Ephedra, which has been linked to hypertension, myocardial infarction (heart attack), stroke, and seizures.

This is only a partial list of interactions from some common vitamins and supplements.  There are likely other medication interactions with supplements and excess vitamin levels that have yet to be discovered, due to inadequate research or conflicting data.  We should also keep in mind that the industry responsible for the manufacture of over-the-counter vitamins and supplements is not subject to regulation by the Food and Drug Administration. There could be significant variation in the actual levels of ingredients in over-the-counter vitamins and supplements.

Over-the-counter vitamins and supplements could also contain additional substances or additives that may lead to unexpected reactions or illness.

Obviously, adequate levels of vitamins and minerals are important for maintaining good health.  However, we should remember that just because some is good, more is not always better.  This is especially true for vitamins and minerals.
The best bet is to always talk to your doctor about all your vitamins and supplements.


How to Talk to Your Doctor

When you are going for your annual visit or if you are on Medicare, when you are going for your free Medicare Annual Wellness Visit, it is a good idea to pack up everything you take – all the prescription and non-prescription medications – and bring them with you to your doctor’s office.

This will allow your provider to inspect each label for both the dose of what you are taking and any additives that might be included in a specific brand you are taking.

You can then have a conversation about potential negative interactions between the vitamins and the prescriptions you are taking.
There is no reason to be embarrassed about the number of medications you are taking and you will likely find the conversation about vitamins and supplements to be very eye-opening and educational.

Beebe Primary Care providers are accepting new patients. Call 302-645-3332 to schedule today.

Learn more about Beebe Primary Care and Medicare Annual Wellness visits:

Lorren Donmoyer, MD, is a primary care provider and family doctor with Beebe Primary Care – Georgetown. He has more than 15 years of experience in the medical field. He is a member of Beebe Medical Group, Beebe’s employed physician group. Learn more: