MOST of the medicines prescribed by doctors and the ones bought over-the-counter interfere with vitamins and supplements and sometimes prevent the body from absorbing. They  and even zap the body’s nutrients.

Learn what these medicines are and ask your doctor how and when you should take the vitamins.

* Antibiotics. Generally, these  interfere with the B complex and vitamin K, partly because they destroy some of the natural bacteria in the gut which are involved in the body's manufacture of some parts of the vitamin B group.

* Anti-coagulants. Warfarin, aspirin and all their relatives of anti-coagulants affect vitamin K - part of the body's blood clotting mechanism. These drugs are usually prescribed for that very purpose. So if you're taking them to 'thin' your blood, don't take extra doses of vitamin K. These medicines can also reduce the absorption of vitamin D.

* Cholesterol-lowering drugs. These can cause poor absorption of iron, betacarotene, vitamins A, D, K, and folic acid when used for several months continuously. A multivitamin and mineral supplement is advisable on a daily basis.

* Laxatives. Constipation will drive you to take laxatives. When used regularly, it lower the body's levels of calcium, iron and vitamins A, D and E. Laxative abuse is a common cause of drug induced malnutrition and may seriously increase the risk of osteoporosis in later life. Even natural laxatives like linseeds have the same effect.

* Diuretics. Many of these drugs deprive the body of vitamin B complex, potassium, magnesium and zinc. Those containing slow release potassium may have a particularly bad effect on your B12 levels.

* Sleeping pills and anti-depressants. The barbiturate-type sleeping pills affect the uptake of vitamin D. Anti-depressants interfere with B2 absorption and with the uptake of zinc and magnesium. Chronic fatigue may be caused by zinc deficiency, yet patients are often prescribed anti-depressants which lower their zinc levels even more.