The topic of human diet is as controversial as any other subject of human interest. There are vegans, lacto vegetarians, ovo vegetarians and non-vegetarians, all based on whether one consumes milk, egg or meat and fish. While vegans depend solely on foods of plant origin others get their vital nutrients from rich foods like milk, egg, meat and fish. For many it is intriguing as to how human beings growing up in the early stages with mother's milk can shun milk at later stages because milk is one of the most complete foods in nature. Of special interest is the calcium content in milk which is biologically more potent in terms of absorption through the intestine and its critical role in bone and skeleton development. More crucial is the fate of post-menopausal women whose bone density tends to fall due to hormonal disturbances at that stage in life.
The recent findings in a limited study in Australia that the vegan women had bones as healthy as those eating animal foods regularly have surprised many health pundits because of the fiction built up over the years about bone health and animal derived foods. Though the intake of protein and calcium by Buddhist women covered under the study were lower than that by non-vegetarians, the bone density values were not much different in both the groups. Milk has been hailed as the major source of calcium for ordinary vegetarians who consume this nutrient rich source regularly and naturally exclusion of milk in the diet of vegans was expected to cause some problems in terms of bone health including early development of osteoporosis. The fact that this was not true raises the pertinent question as to whether milk and milk products have such an important role in human diet as being touted, especially for adults. The Daily Value for calcium for human beings is in the range of 1000 mg to 1300 mg and a cup of milk gives about 30% of this need. Other sources like vegetables also contain calcium with collard green giving 357 mg per cup, spinach 352 mg per cup and Okra 180 mg per cup.
Probably one does not have to look far to understand the reality that milk is not as crucial as it is being made out to be, especially for an adult. Take the example of the most important herbivore on earth, the elephant which is totally a 'vegan' as far as the diet is concerned. Weighing 8-12 tons, Elephants require about 60 gm of calcium every day to maintain its huge body mass which is derived from 140-270 kg of forage it consumes each day. Except during its early childhood when the calf depends on its mother's milk, Elephant derives all its nutritional needs from plant sources. To add to its dietary problem, the digestive system in Elephant wastes almost 60% of the food it consumes with the remaining providing the nutrients vital for growth and maintenance. Green leaves, grass and tree barks on which this animal depends for most of its food supply contain calcium to the extent of 0.4-1.5%. Sugarcane liked very much by Elephants is both juicy as well as rich in calcium. The black strap molasses, a by-product of sugar milling industry contains calcium as high as 200 mg per table spoon. Same is true with jaggery which is often an important ingredient in animal feeds.
One of the important questions that remains unanswered is the role of protein in utilizing and/or maintaining calcium present in the food by the body. Otherwise why should a typical Western women get osteoporosis when her diet is invariably rich in calcium from sources like meat, fish, milk, cheese and others which also incidentally contain high levels of proteins. Could it be possible that high levels of proteins cause demineralization in the bones, in spite of the presence of high calcium content in the food? The vegan population, estimated at 5% of the population in the World by willful choice, can derive comfort from the thought that their food is as healthy as that consumed by others, if not better!