The delicate balance between these factors permits many things to go wrong in this system—for instance a deficiency in calcium will cause the entire matrix of the bone to become weaker, or an upset in the Ca:P ratio/product can cause demineralisation of the bone. Under normal circumstances, if we adhere to the norms of Nature this system operates beautifully and permits us to achieve our life's ambitions with the utmost ease.

However, when things go wrong, there are arthritis of various types like osteo-arthritis (OA), rheumatoid arthritis (RA), cervical and lumbar spondylosis, etc., osteoporosis (softening of bones) leading to pathological fractures of bones and resultant morbidity, osteomalacia and a host of other disorders. utmost importance that the correct food be consumed in order to maintain our bones and joints in a healthy condition.

Various studies conducted on vegetarians, lacto-ovovegetarians, and omnivores have concluded that there are too many factors affecting bone mineral metabolism and hence it is not possible to state dogmatically the superiority of any one nutritional lifestyle over another. There are points in favour of both sides and both schools of thought have their disadvantages. The calcium content of vegetarian and non-vegetarian sources differs widely in quantity and the form in which it is present. There are many factors that affect calcium absorption and these factors determine the amount of calcium available. Hence the concensus is divided on the superiority of a vegetarian diet over a non-vegetarian diet.

However, on examining the problem many important points surface and come to the fore. The most important observation is that when sulphur-containing foods (e.g. meats) are consumed they change the pH of the blood. So also do the fried foods, sour foods and the spicy foods in our diet. But, meat has the strongest acid load owing to its rich sulphur content. This increases the acidity of the blood which, in turn, demineralizes bones. This leads to osteoporosis. Many surveys have demonstrated that post-menopausal women who are vegetarians have a higher bone mineral content as compared to their non-vegetarian (omnivorous) counter parts. Similarly it has also been observed that though young Caucasian whites measure equally with young Eskimos in bone mineral density, the older Eskimos have a much lesser bone mineral density as compared to an age matched Caucasian white.

The reason behind this seems to be the diet of the Eskimos, which is predominantly meat, the blubber of seals, and fish. The high sulphur content of these foods causes acidification of the blood which 'melts the bones' in an attempt to buffer this excess acid load.

Furthermore, it has also been noticed that there is a very strong relationship between joint pains like 'frozen shoulder, cervical spondylosis and arthritis of other kinds and the kind of food eaten. Fried foods, spicy, oily foods, excessive meats and refined foods like sweets, confectionery, bread and other refined wheat products are the main incriminating factors in joint diseases. The kind of food leads to excess acid load in the blood which the kidneys are unable to cope with. Hence this acid causes inflammation of all joints.

Constipation also initiates the formation of toxins in the gut, which get absorbed into the blood and increase its acidity. This, too, contributes, along with other factors, in the development of arthritis and bone demineralisation.

Hormones like oestrogen, testosterone, adrenocortical hormones, thyroid and growth hormone also play a very major role in the maintenance of normal body structure and function. A strong link between hormonal activity and the kind of food we eat has been established in several studies.

In perspective, a vegetarian diet, which is rich in fibre and, in the uncooked form, contains a lot of vitamins and minerals proves very beneficial as it prevents constipation, removes toxic matter from the gastrointestinal tract, thereby preventing increased acidity of the blood. The increased amounts of minerals and vitamins in vegetarian foods contribute richly to the smooth functioning of bone metabolism. The acidity (sulphur related) of a non-vegetarian diet initiates and perpetuates bone demineralisation as seen by serial bone mineral density studies done by direct photon absorptiometry. In contrast the vegetarian diet which contains predominantly uncooked food doesn't have this disadvantage. However, fried foods, spicy foods and excessively sour foods—whether vegetarian or non-vegetarian are detrimental to bone and joint integrity.

It is a common conception that vegetarians lack calcium in their diet and as a result they suffer from bone demineralisation leading to osteoporosis and osteomalacia. This is not true in the case of a lacto-vegetarian because milk and its products are a very rich source of calcium which is easily available to man. However, there are reports and it is our experience that as age advances the digestion of milk becomes more and more difficult owing to decreased gastric acid,enzyme content. The maldigestion of milk not only gives gastrointestinal discomfort but also gives an increased acid burden to the body which leads to joint pains and aggravation of arthritis. Cottage cheese (also known as paneer, clabbered milk, kefir) and whey (the water obtained during the preparation of cottage cheese) are excellent calcium sources for a vegetarian and are much less toxic than the nonvegetarian sources of protein.

Analysis of the available data shows that vegetarian diets by virtue of their:

• High fibre content,
• Low acid content,
• High vitamin and mineral content,

are helpful in preventing and, to a certain extent, relieving the pain and progression of arthritis and bone demineralisation. Owing to the high fibre content vegetarians are rarely constipated and this helps a lot in healthy bone and joint metabolism. Furthermore the reduced acid load and increased vitamin and mineral content of vegetarian food makes it the preferred food for preventing joint and bone complications.

Vegetarian Sources of Calcium

1. Milk: in order of preference
   1. Goat's
   2. Cow 's
   3. Buffalo 's
2. Cottage cheese (paneer, clabbered rnilk)
3. Almonds
4. Pulses (though bound to phytate)
5. Seeds especially Sesame (Til), Sunflower
6. Cheddar Cheese
7. Swiss Cheese
8. Soya beans and their products like TOFU

Factors that Hinder or Block Calcium Absorption

1. Foods containing oxalic acids
   e.g. spinach, lotus stem, horsegram
2. Lack of Vit. D.
3. Overuse of proteins
   e.g. excessive consumption of protein-rich foods like meat, fish, poultry, eggs, etc
4. Excessive use of common salt
5. Excessive use of alcohol
6. Excessive use of coffee
7. Excessive tobacco smoking
8. Excessive use of soft drinks containing phosphorus
9. Excessive use of fat

Finally, an analysis of the risk factors of osteoporosis shows that statistically vegetarians have a lesser risk of bone disease because of certain traits e.g. the decreased incidence of tobacco use, alcoholism, obesity, constipation and hormonal (especially oestrogen) imbalance amongst them.

Hence it is evident that vegetarian diets do offer substantial protection from bone and joint disease provided adequate care is taken to meet the daily calcium, protein and vitamin requirements.

REFERENCES

1. Mazess R.B., Mather W. Bone mineral content of North Alaskan Eskimos. Am. J. Clin. Nutr. 1974 27: 916-25.
2. Sanchez T.V. Mickeisen O., Marsh A.G., Garn S.M., Mayor G.H. Bone mineral in elderly vegetarian and omnivorous females. In: Mazess RB, ed. Proceedings of the fourth international conference on bone measurement. Bethesda, MD : NIAMMD 1980: 94-8. (NIH Publication 80-1983).
3. Marsh A.G., Sanchez T.V., Mickelsen O., Keiser J. Mayor G. Cortical bone density of adult lacto-ovo-vegetarian and omnivorous women. J. Am. Diet Assoc. 1980, 76: 148-51.
4. Licata A.A., Bou E., Bartter F.C., West F. Acute effects of dietary protein on calcium metabolism in patients with osteoporosis. J. Gerontol 1981, 36: 14-9.
5. Wachman A., Bernstein D.S. Diet and osteoporosis. Lancet 1968, 1: 958-9.
6. Marsh A.G., et al: Vegetarian lifestyle and bone mineral density: Amer. J. Clin. Nutr. 1988: 48, 837-41.
7. Gopalan C. Nutritive value of Indian foods. National Institute of Nutrition, Hyderabad, 1982.
8. Jensen, Bernard. Arthritis, Rheumatism and Osteoporosis: Correction through Nutrition.