You work hard to get the important nutrients you need to be healthy and prevent disease. You take a vitamin supplement and eat all the right foods. But did you know that some foods you eat -- or lifestyle habits you practice -- can interfere with the digestion, absorption or utilization of nutrients? Here are some of the villains and their victims.

• The Victim:
Calcium -- Essential for strong bones, regular heartbeat and proper nerve and muscle functioning, calcium also helps to prevent osteoporosis, high blood pressure and colon cancer.

• The Villains:
Alcohol -- May inhibit the absorption of calcium by interfering with vitamin D utilization needed for calcium absorption.
Fiber -- Fiber? Yes! The more you eat, the more your calcium level drops. A fiber-rich diet is healthy, so don't skip the fiber, just add more calcium -- about 150 mg for every 25 grams of fiber.
Smoking -- A study by the Mayo Clinic showed that smokers have twice the risk for osteoporosis as non-smokers.
Phytic Acid -- A component of many whole grain foods that have not been subjected to fermentation by yeast (like during bread making), phytic acid binds minerals such as calcium, lowering its absorption. Keep whole grains in your diet, but eat them separately from calcium rich foods. Or simply increase your calcium intake.
Excessive protein -- Too much protein accelerates calcium loss. Keep protein intake to no more than twice the RDA.
Oxalic Acid -- Present in spinach, Swiss chard and chocolate, it combines with calcium to form calcium oxalate, a chemical salt that the body excretes.