Are you one of the millions of Americans who currently take one or more dietary supplements and are also on prescription medication? In today’s world, the likelihood of taking both dietary supplements and drugs are quite high: studies show that about 50% of Americans use a complementary therapy like foods, herbs or vitamins and minerals. And that may underestimate the reality. Many folks are not very forthcoming about their supplement use when talking with healthcare providers. Consequently, the actual numbers of those who take both supplements and their prescription medications are still unknown.

Herbs, vitamins, minerals and amino acids are nutritional supplements that support the function or structure of the body; they should be taken along with a healthy diet. These substances are regulated by both the Food and Drug Administration (FDA) and the Federal Trade Commission (FTC) although rules of their formulation and sale are not the same as prescription medications. Both the FDA and the FTC can stop the marketing of dietary supplements that make false claims or pose a danger to the American public. These agencies can also prohibit manufacturers from distributing adulterated products. Less well known is that many of the herbs on store shelves today have been under the supervision of the FDA since 1906. Subsequently, users can rely on a 100 year history of safe, effective and supervised use of herbs.

All in all, dietary supplements have an excellent record of safety. Researchers shows that that the use of dietary supplements poses only minimal risks and that interactions are not serious (Arch Intern Med. 2004 Mar 22;164(6):630-6).  In a study at the Veterans Affairs Pittsburgh Healthcare System, 458 veteran outpatients were surveyed and potential supplement/drug interactions were identified. The study found that most of the interactions were insignificant. Millions of Americans are also finding this to be true.

Unfortunately, media reports of dietary supplement and drug interactions are often confusing and generally accompanied with inappropriate hysteria. Clearly, taking both supplements and multiple prescription medications simultaneously should be done cautiously. If side effects do occur, sorting out the source can be confusing and difficult. Unfortunately, the supplement  often receives the blame for ill effects when it’s much more likely the prescription medication at fault. Always check the established side effects of medications before jumping to the conclusion that an herb is causing problems.

The depletion of vital nutrients often result from taking prescriptions. For instance, statin drugs deplete the body of CoQ10 which can lower energy levels and cause of fatigue. It can also cause weight gain and compromise muscle performance. In addition, reduced levels of CoQ10 can ultimately lead to high blood pressure, congestive heart failure and death.

Antibiotics such as Sulfa drugs, deplete the body of folic acid and Vitamin B12; the result can increase homocysteine levels, a risk factor for cardiovascular disease. Reduced folic acid and B12 also contribute to anemia and fatigue and increase the incidence of some types of cancers.

Taking estrogen for a year or more can reduce vitamin B6. That may result in anemia and tiredness as well as elevated homocysteine. It can also cause depression, insomnia and nerve inflammation. In addition, estrogen therapy depletes body stores of magnesium and increases the calcium/magnesium ratio. That can lead to kidney stones and increased clotting as well as muscle spasms and contractions. Magnesium deficiency can also cause constipation, fatigue and high blood pressure. The general recommendation for women taking estrogen: 250 to 350 milligrams of magnesium daily.

Thyroid Supplements

Synthetic thyroid hormone supplementation increases calcium loss, reduced bone density and increased risk of osteoporosis. A study from Pennington Biomedical Research Center in Baton Rouge, LA, shows that taking synthetic thyroid accelerates bone turnover and that new bone formation does not offset the loss (Thyroid 2003 Apr;13(4):357-64). Synthetic thyroid can also bind with iron, resulting in anemia and fatigue. Other signs of low iron: hair loss, lowered immune system and brittle nails. Most practitioners don’t recommend supplementing with iron until laboratory testing is done to confirm an iron deficiency.

Drugs often interact with foods. For example, the sulfur compounds in onions, garlic and broccoli encourage the liver to produce detoxification enzymes. These enzymes can speed clearance of drugs from the body. Dark, green leafy vegetables such as collards, kale and turnip greens contain Vitamin K which can interfere with blood-thinners taken to reduce the risk of stroke or heart attack. And grapefruit significantly inhibits the metabolism of about 40% of all prescription medications including calcium channel blockers, cholesterol medications, estrogen, oral contraceptives, some psychiatric medications and most allergy medications. 

Orange juice and milk both interact with antacids, increasing the absorption of aluminum into the bloodstream. High fiber foods such as oatmeal can decrease the absorption of some medications. Caffeinated beverages mixed with asthma medication can cause nervousness and excitability.

Consult your pharmacist to find out if your medication can be taken with food or should be taken on an empty stomach.

While most supplements are safe at recommended levels, you should be cautious if you are pregnant or lactating, extremely ill, elderly or on multiple prescription medications. Also seek knowledgeable advice when giving supplements or medications to young children.

In most cases, dietary supplements need sufficient time to work and may take several weeks or months to achieve optimal effects or rebuild reduced nutrient stores.  Always let your physician or health care provider know which dietary supplements you take. Experts often recommend that you stop all supplements at least two weeks prior to surgery.

Educating yourself about your medications and supplements is a wise policy. Become an informed consumer.

General Considerations in Taking Dietary Supplements

• Pregnant or nursing women should always consult their physicians or healthcare professionals before taking any medications or dietary supplements.
• Consult a practitioner before taking any dietary supplements if you are elderly or take multiple prescription medications.
• Discontinue a product if symptoms of allergy develop.
• Take supplements with food to avoid digestive upset.
• Do not swallow prescription medications and herbs at the same time. Allow at least 2 hours between them. Herbs are water-soluble plant fibers which may inhibit the absorption of medication.
• Beware of faddish herbal advertisements, instant weight loss claims and guarantees of restored health.
• Never stop taking a prescription medication suddenly or without the monitoring of a physician.
• Do not take megadoses of vitamins, minerals or herbs without proper supervision.