[The following note is sent by a medical friend. - Ed.]
It has been observed in the past that the incidence of dental caries in the West has increased in proportion to the increase in the consumption of sugar, candies, chocolates, etc. Sugar was regarded as the arch-enemy of teeth, the decay being set down to the fermentation caused by the presence of sugar in the mouth. Later on the deficiency of vitamin D came to be regarded as a contributive factor in the causation of dental caries. Lack of this vitamin leads to disturbance of calcium phosphorus metabolism in the body, and thus to deficient calcification of bones, teeth, etc. Moreover when vitamin D is deficient in diet various cereals have a decalcifying influence on teeth in different degrees, oats being the worst and rice and wheat being the least harmful in this respect. Recent research has, however, shown that it is not the excessive use of carbohydrates themselves nor the deficiency of vitamin D alone that is responsible for the production of dental caries. The use of refined carbohydrates, which is one of the features of the "spread of civilization', is an important factor. It has been experimentally proved that crude carbohydrates contain a 'protective agent' which checks the process of dental decay. This protective agent is lost in the process of refining.
The British Medical Journal, dated February 19 last, gives an account of the experiments of Osborne and his co-workers on the basis of which they have come to this conclusion.
Undecayed normal teeth were obtained from patients who had been advised extraction for various causes. These were immersed in various substances which had been held in the mouth for two minutes and well mixed with saliva; control being a mixture of saline and saliva. In one case the substance used was crude cane sugar juice, in another refined sucrose. In still others whole wheat meal and white flour, whole mealie meal and highly refined mealie meal (60-70 per cent), and whole mealie meal and 90 per cent of extraction mealie meal, were respectively compared. It was found in each case that the teeth in refined material decayed more than those in unrefined and in unrefined more than those in saline and saliva.
The diet of the African Bantu was also inquired into, to find out how civilization brings decay to Bantu teeth. It was found that dental caries was associated with machine-ground mealie meal, white bread and refined sugar. This further supports the conclusion arrived at from the above experiments that crude cane sugar and wheat are associated with some 'protective agent' which inhibits the process of dental decay and which is destroyed in the process of refining.
Thanks to the importance attached to the cleaning of the teeth the first thing in the morning and after every meal that has been handed down to us from the earliest times, and to the use of foodstuffs in their unrefined and natural form, the incidence of bad teeth is much less in India than among the people in the West. This splendid heritage of ours, however, is likely to be seriously imperiled, judging from the rate at which sugar and flour mills are multiplying in this country, unless the evil is checked in time.