How safe are water purifiers?

Dear doctor; There are health marketers who market water purifiers in societies, urging people to use them in drinking water. They say by adding required quantity of the water purifiers into tap water and such, it becomes clean and safe for drinking. But how sure is this? Can a chemical that kills germs in water be harmless to human beings in the long run? Nina, 22. Dear Nina, Water purifiers are very much in vogue and are used in offices as well as home. They are very useful to remove the disease causing microbes from drinking water, as water at its source whether a lake or river is contaminated by soil, human and animal waste. This always carries disease causing germs such as bacteria, protozoal infections, among others. For this purpose, various water purifying techniques have evolved, but recent studies have suggested that they can replace one set of health risks with another. The water purifiers particularly the ones using reverse osmosis technique remove minerals such as calcium and magnesium from water, they are also said to remove these minerals from body. Result is muscle cramps, body pain, osteoporosis, early fatigue and even cardiac problems in individuals. Due to de-ionising, one is at risk of developing electrolyte imbalance. Using highly purified water prevents exposure to many microbes thus preventing formation of disease forming antibodies against them. This reduces immunity of the individual against these diseases and whenever exposed even to small quantity of germ may acquire the disease. One should strike a balance between taking a balanced diet, including minerals and vitamins, with sufficient electrolytes and taking pure water.