Special to The Washington Post Mankind has been drinking the milk of fellow mammals for millennia. Milk has long been regarded as a nutritional mainstay, vital to building strong bones, particularly among Western cultures. But in recent years a rising chorus of critics has come to argue that cow's milk, far from doing a body good, is in fact bad for our health. The question comes at a time when America's milk market is in turmoil, with many dairy farmers being forced out of business. Last week a group of them brought their case before Congress: In light of milk surpluses (cows need to be milked whether we drink the stuff or not) and reduced demand apparently spurred by a weak economy, prices for their product have dropped so dramatically that many are having to slaughter their herds just to stay solvent. A week earlier, President Obama authorized spending $350 million to help keep dairy farms afloat until the market improves. But the farmers hope more help in the form of stabilized milk prices (i.e., higher prices, paid by either the consumer or the government) is on the way. If it doesn't come, there may soon be far fewer dairy farms in the country. Not that I'm a particular fan of milk myself. While my brother drank it by what mothers in the 1960s called 'the tumblerful,' I sipped only what was required of me. Now that I'm raising teen-agers of my own, though, it seems worth sorting out milk's role in a healthful diet. Near the forefront of the anti-milk movement is the Physicians Committee for Responsible Medicine, a pro-vegetarian/vegan organization. Susan Levin, the group's director of nutrition education, says, 'I recommend people get dairy out of their diets. Its main selling point is calcium, which is touted for helping build strong bones. But there isn't any research to show dairy products are any more beneficial than plant sources' of calcium, which she says the body is better able to use when it comes from plants. Greens such as kale and broccoli, she says, are excellent sources of calcium; plant-based beverages such as orange juice and almond and soy milks are fortified with both calcium and Vitamin D. As evidence that people and cow milk don't mix, Levin cites research suggesting that lactose intolerance -- the body's inability to tolerate one of the sugars in milk and milk-based foods -- is widespread. 'The dairy industry would say you should force (milk) down or take a pill so you can tolerate it,' Levin says. 'But it's not normal. No mammal drinks its mother's milk after weaning.' Stephanie Atkinson, a spokeswoman for the American Society for Nutrition (whose list of 'sustaining' members includes the National Dairy Council) and a professor in the department of pediatrics at McMaster University in Hamilton, Ontario, says that, contrary to Levin's statement, it's the fiber in plant sources of calcium that interferes with the body's ability to absorb the mineral. Regarding lactose intolerance, Atkinson says that the medical community views that condition -- different from milk allergy, which she says is common among young infants but almost always outgrown -- as wildly over-diagnosed and that most people tolerate lactose just fine if they take milk products in small doses. Having said all that, though, Atkinson allows that vegetarians, vegans and others who avoid milk can manage, perhaps with some difficulty, to get all the necessary calcium, Vitamin D and phosphorus (a trio required for bone health) from non-animal sources. But to get the Vitamin B12 the body needs, non-dairy users must take a supplement, she says, as that essential vitamin is available only from animal products. Even many non-vegetarians object to milk based on concerns about the use of artificial growth hormones and antibiotics in dairy cattle and on worries that pesticides in feed end up in your glass of milk. But Greg Miller, executive vice president for research, regulatory and scientific affairs at the National Dairy Council, maintains that milk is safe. 'Milk is one of the most regulated food products out there,' Miller says. When the Food and Drug Administration each year conducts 'market basket' samplings for pesticides and other contaminants in foods, 'dairy products come out clean every time,' he says. And, he explains, 'every tanker-load of milk is tested for antibiotics. If any residual traces are found, the whole truckload is dumped. There's a very large financial incentive for farmers' to keep milk free of antibiotics. As for growth hormones, Miller says the FDA, the World Health Organization and other health organizations have found their use safe. As for the argument that humans are the only animals that drink milk throughout life, Miller says that's because, unlike other creatures, 'we have the intelligence to understand the nutritional value of dairy products. 'There are lots of things about which we can ask, `Were we meant to do that?' ' Miller continues. 'I mean, were we meant to drive cars?' 