Here's what happens: Medications can cause improper absorption of vitamins and minerals -- or they can accelerate the elimination of nutrients from the body. The consequences may range from bothersome symptoms, such as fatigue or stomach upset, to serious heart, muscle or nerve damage.

Most doctors are aware of some minerals that are depleted through the use of diuretics (water-excreting drugs). However, few doctors are aware of the dangers of nutrient depletion caused by many other types of medication, because the problem is not widely reported.

Popular drugs that deplete the body of nutrients...

ANTIBIOTICS

The most commonly prescribed antibiotics include azithromycin (Zithromax), amoxicillin (Amoxil), ampicillin (Omnipen), ciprofloxacin (Cipro), ofloxacin (Floxin) and erythromycin (Eryc).

Nutrients depleted...

B vitamins. The B vitamins are essential for normal metabolism as well as immune and nervous system functioning.

Vitamin K. This vitamin is critical for blood clotting and bone strength.

"Friendly" intestinal bacteria known as Bifidobacterium bifidum and Lactobacillus acidophilus. Antibiotics kill not only harmful bacteria but also "good" bacteria that promote gastrointestinal health and help balance immune response.

If you are prescribed an antibiotic: Ask your doctor about also taking a B-complex vitamin -- 50 mg... vitamin K supplement -- 60 micrograms (mcg) to 80 mcg... and probiotic supplements providing 15 billion live B. bifidum and 15 billion live L. acidophilus organisms daily.*

*If you're taking any medications, consult your doctor before changing your diet or beginning a supplement. In rare cases, increasing a nutrient may interfere with a drug's potency or worsen your condition.

In addition, eat more vitamin B-rich foods, such as beef liver, chicken, pork, fortified breads and cereals, whole-grain pastas, legumes, nuts and dark, leafy greens.

To increase your intake of vitamin K, eat kale... collard, turnip or mustard greens... spinach... broccoli... and Swiss chard.

Caution: Do not take vitamin K supplements or eat excessive amounts of vitamin K-rich foods if you take warfarin (Coumadin) or another blood-thinning drug.

For additional B. bifidum, eat more asparagus, garlic and/or onions, which stimulate growth of this friendly bacteria. For L. acidophilus, yogurt containing live cultures is your best food source.

High-Cholesterol Drugs

The most widely prescribed cholesterol-lowering "statins" include atorvastatin (Lipitor), simvastatin (Zocor), fluvastatin (Lescol), lovastatin (Mevacor) and pravastatin (Pravachol).

Nutrient depleted...

Coenzyme Q10 (CoQ10). All cells require CoQ10 for the proper function of mitochondria (tiny energy-producing structures within the cells). The more energy a cell must produce, the more it depends on CoQ10. That's why cells of the heart, in particular -- because it is constantly beating -- require an abundance of CoQ10.

Unfortunately, statin drugs, which effectively block the production of harmful cholesterol, also prevent CoQ10 production.

Some doctors worry that long-term use of statins may worsen heart failure. Studies have found that patients with chronic heart failure have lower CoQ10 levels, and that CoQ10 supplements may improve their heart condition. Signs of CoQ10 deficiency include fatigue and muscle weakness.

If you are prescribed a statin: Ask your doctor about taking 30 mg to 100 mg of a CoQ10 supplement daily. This nutrient also is available in some foods, including beef, chicken, salmon, oranges and broccoli.

Painkillers

Millions of Americans take a nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen (Motrin, Advil), naproxen (Aleve), celecoxib (Celebrex) and nabumetone (Relafen), to help relieve arthritis and other inflammatory pain.

Nutrient depleted....

Folic acid. Your body needs this water-soluble B vitamin to produce new cells and DNA and to synthesize and utilize proteins.

Several large epidemiological studies have linked low folic acid levels to increased risk for colon, breast and pancreatic cancers.

Heart health is also affected by folic acid. As folic acid levels decline, levels of the amino acid homocysteine rise. Studies suggest that elevated homocysteine can raise the risks for blood clots, heart attack and stroke.

Low folic acid levels may cause loss of appetite, irritability, weakness, shortness of breath, diarrhea, anemia, headaches, heart palpitations and a sore tongue.

If you take an NSAID regularly (daily for at least one to two weeks): Talk to your physician about also taking 400 mcg to 800 mcg of folic acid daily.

You also can get more folic acid by consuming fortified breakfast cereals, orange juice, spinach and other leafy greens, peas and beans.

BETA-BLOCKERS

Beta-blockers, such as propranolol (Inderal), atenolol (Tenormin), betaxolol (Betoptic S), carteolol (Cartrol) and labetalol (Normodyne), are commonly prescribed for high blood pressure or glaucoma.

Nutrients depleted...

CoQ10. Not only does CoQ10 appear to improve cardiac function in patients with chronic heart failure, studies suggest that it also may prevent second heart attacks and possibly protect against Parkinson's disease.

Melatonin. The hormone melatonin is essential for healthy sleep-wake cycles, and there's some early evidence that it may slow aging.

If you take a beta-blocker: Ask your physician about taking 30 mg to 100 mg of CoQ10 daily... and 1 mg to 3 mg of melatonin nightly, just before bed, if you have trouble sleeping.

ACE INHIBITORS

Angiotensin-converting enzyme (ACE) inhibitors, such as enalapril (Vasotec), benazepril (Lotensin) and ramipril (Altace), as well as angiotensin II receptor blockers (ARBs), including candesartan (Atacand) and irbesartan (Avapro), are prescribed for high blood pressure and heart failure, and to help prevent heart attacks in high-risk patients.

Nutrient depleted...

Zinc. Zinc boosts immunity, and some studies have shown that it reduces the duration of cold symptoms.

Zinc also is necessary for wound healing, strong bones and male potency, and it may help slow the progression of age-related macular degeneration (AMD).

In a recent six-year National Eye Institute study involving 3,600 people with AMD, zinc and antioxidant supplements reduced the risk of developing advanced AMD by 25%.

If you take an ACE inhibitor or ARB: Ask your doctor about taking 50 mg to 100 mg of zinc daily and eating more zinc-rich foods, such as oysters, beef, dark-meat chicken, pork tenderloin, yogurt, milk, peas, beans and nuts. If you continue to take zinc indefinitely, do not exceed 50 mg daily.

Important: Many medications combine an ACE inhibitor or ARB with a diuretic -- for example, enalapril and hydrochlorothiazide (Vaseretic) is an ACE inhibitor plus a diuretic... candesartan and hydrochlorothiazide (Atacand HCT) is an ARB plus a diuretic.

If you're taking a combination drug, you'll need to compensate not only for zinc, but also for the electrolytes and nutrients excreted by the diuretic, including potassium, magnesium, thiamine (B-1) and calcium. Ask your doctor for advice.

Diabetes Drugs

People with type 2 diabetes are often prescribed tolazamide (Tolinase), acetohexamide (Dymelor), glimepiride (Amaryl) or glipizide (Glucotrol) -- all sulfonylurea drugs. These medications stimulate the pancreas to produce more insulin, which lowers blood sugar.

Nutrient depleted...

CoQ10. Diabetes more than doubles your chances of dying from heart disease or stroke -- and low CoQ10 levels exacerbate those risks.

If you're taking a sulfonylurea drug: Ask your doctor about supplementing with 30 mg to 100 mg of CoQ10 daily.

Reflux Drugs

Proton pump inhibitors, such as esomeprazole (Nexium), lansoprazole (Prevacid), omeprazole (Prilosec) and rabeprazole (AcipHex), are prescribed for chronic heartburn -- also known as gastroesophageal reflux disease (GERD) -- and ulcers.

Nutrient depleted...

Vitamin B-12. Vitamin B-12 is essential for producing red blood cells and maintaining a healthy nervous system. Deficits may cause fatigue, dizziness, shortness of breath, diarrhea, tingling in the hands or feet, unsteady gait, nervousness, cognitive changes and even dementia.

Vitamin B-12 is found in red meat, fish, eggs and dairy foods, but our bodies require stomach acid to release the vitamin from these foods. Proton pump inhibitors reduce the production of stomach acid, inhibiting the release and absorption of vitamin B-12.

Iron. Low iron reduces the amount of oxygen your red blood cells can transport to body tissues, leaving you feeling weak and fatigued. A serious iron deficiency results in anemia.

If you take a proton pump inhibitor: Ask your doctor about taking 500 mcg to 1,000 mcg of vitamin B-12 daily and for advice on the best way to increase your iron intake.

Caution: Never take an iron supplement without consulting your physician -- excess iron can accumulate in your major organs and cause severe damage. Most people, however, can safely eat more iron-rich foods, including liver, beef, dark-meat chicken or turkey, legumes and fortified cereals.

Bottom Line/Health interviewed Frederic Vagnini, MD, medical director of the Heart, Diabetes and Weight-Loss Centers of New York and an assistant clinical professor of surgery at Weill Cornell Medical College, both in New York City. Dr. Vagnini is coauthor of The Side Effects Bible: The Dietary Solution to Unwanted Side Effects of Common Medications (Broadway).