Questions about drug/nutrient interactions are becoming more common. That's not surprising, since nearly half of Americans currently take at least one prescription drug, according to the Centers for Disease Control and Prevention.
While we often hear about the dangers of mixing supplements and drugs, rarely publicized scientific evidence shows that nutrients can just as often reduce drug toxicity and side effects or even make medications work more effectively. Yet in most doctors' offices, the subject is virtually taboo.
"Don't ask, don't tell," is the prevailing attitude, says Leo Galland, MD, a board-certified internist, director of the Foundation for Integrative Medicine in New York City (mdheal.org), and longstanding leader in nutritional medicine. Doctors don't ask about supplement use because, he says, "If you told them, they wouldn't know what to do with the information." And patients don't tell because they're concerned that the doctor will advise them to stop taking supplements.
Deciphering the Maze
Galland is arguably the world's most knowledgeable professional when it comes to the influence of nutrients and drugs upon each other. More than 10 years ago, he began studying scientific literature on the subject, initially spending more than 1,000 hours analyzing studies. He compiled the information into a database and continues to review all emerging research. "I was pretty amazed at the large number of drugs that either depleted or interfered with the activity of specific nutrients," he says.
He also discovered that the negative effects of supplements on drugs are mostly based on anecdotal reports. "That doesn't mean they're not important since the first goal here is not to do anything harmful," he points out. "But the positive interaction data is more scientifically sound because most of that is based upon controlled studies."
The result of Galland's ongoing work is PillAdvised.com, a Web site where anyone can look up specific drugs and supplements and get a complete summary of scientific findings about both positive and negative interactions.
"What really matters is the specifics of the interactions," says Galland, who points out that each individual's regimen of supplements and medications is unique. However, there are some general principles:
- Drugs can deplete nutrients.
- Nutrients can alter the way a drug is metabolized, increasing or decreasing its effectiveness, toxicity, and safety.
- Depending on the drug, various nutrients can enhance its benefits or reduce side effects and toxic damage.
These, says Galland, are some of the most common interactions and their underlying mechanisms:
The depletion of CoQ10 by statin drugs, widely used to lower cholesterol, is one of the most common, well-documented, and well-understood drug/nutrient interactions. When statins interfere with the production of cholesterol in the liver, they simultaneously interfere with the body's production of CoQ10. Taking additional CoQ10 may correct the shortage, but sometimes the situation can be more complex.
People who take statins often take additional medications that further complicate matters. For example, diuretics that lower blood pressure interferes with the body's ability to use CoQ10; if they're taken in conjunction with statins, there is a greater depletion.
Vitamin E can also deplete CoQ10 levels. When your body uses vitamin E to fight free radicals, the vitamin becomes oxidized and CoQ10 is used to recycle it back into an antioxidant form. In the process, the CoQ10 gets used up. This mechanism may account for some of the negative results in trials of vitamin E among patients with heart disease.
"A single depleting effect may not be significant," says Galland, "But multiple effects can be significant, and supplements, as well as drugs, may enter into the mix." In some cases, it's a good idea to have a doctor perform a blood test to check CoQ10 levels, and supplement according to individual needs.
B12 Depletion: Marketed under a variety of brand names, metformin is a common medication used to treat diabetes. It depletes vitamin B12 by blocking its absorption, but taking the drug with calcium prevents the depletion without detracting from metformin's benefits. For anyone who has used metformin long-term, Galland recommends getting tested for B12 levels-anything below 400 pg/ml may indicate a deficiency, although technically, 200 is the deficiency threshold. A more sensitive B12 test measures serum methylmalonic acid in blood or urine-levels are elevated when B12 is low.
B6 Depletion: Birth control pills deplete vitamin B6, more so with stronger prescriptions. To reduce general side effects, Galland suggests taking a B-complex supplement.
Nutrients Helping Drugs
In many cases, various nutrients can actually enhance the action of certain medications. Notable examples include:
Fish Oil: Omega-3 fatty acids have the greatest number of published studies indicating beneficial interactions with medications. In the case of anti-inflammatory drugs for arthritis, for example, fish oil supplementation can lead to decreased drug dosages. "The omega-3s create a milieu in the cell that is anti-inflammatory," says Galland. "And then you don't need as much of the drug." Studies documenting the effectiveness of fish oil generally use 3-4 g daily of an EPA/DHA combination. Research has found no negative drug/fish oil interactions.
N-Acetyl Cysteine (NAC): A special form of the amino acid cysteine, NAC detoxifies and enhances antioxidant production. It improves the actions of the ACE-inhibitor class of blood pressure-lowering drugs, as well as nitrate drugs, such as nitroglycerin, taken for angina.
Although drugs save lives in many situations, Galland recommends alternatives when possible. "Basically, 80 percent of what's wrong with people in America can be treated without drugs," he says, but it takes more effort to live a healthy lifestyle. "I think that's a good thing, not only for the body," he adds, "I think it's good for the soul."
Of all supplements and herbs, St. John's wort has the greatest number of negative interactions, impacting about 30 different drugs. "It's such a powerful inducer and blocker of enzymes in the liver and the intestine, it alters the drug levels," says Galland. In the case of birth control pills, for instance, the herb can speed up breakdown of hormones to reduce the effective dose by half, causing them to fail. These are some other common ones:
Flavonoids: This class of nutrient is also referred to as bioflavonoids, and quercetin is a popular one. Unlike grapefruit juice, which typically increases concentrations of drugs, flavonoids can either increase or decrease drug levels in the human body.
Calcium: The mineral binds with many drugs, decreasing absorption. For example, calcium impairs the effectiveness of many antibiotics, including those with names that end in "-cycline." It can also negatively impact synthetic and natural thyroid hormone prescriptions, as well as L-dopa, a class of drugs used to treat Parkinson's disease. Such medications and calcium should be taken at different times of day.
Magnesium: In large doses, magnesium has the same effect as calcium, and should be taken at a different time than a drug.