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Better Nutrition as a Health Measure (excerpt)
Excerpted chapter from Nutrition in Everyday Practice, published by The Canadian Medical Association.
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Turning to the vitamins, we find eminent medical opinion supporting the view that many people do not get enough of several of them because their diets are not well chosen. I can mention only the most important practical applications.
Vitamin A is closely associated with the health of the mucous membranes lining the respiratory, gastrointestinal, and urinary tracts. Healthy mucous membranes are an effective barrier against the entrance of bacteria, and as a general health measure it pays to take a diet abundant in this vitamin. It is provided by all green and yellow vegetables, by milk, butter, liver, kidney, fish, etc., but not by white vegetables such as potatoes, white turnips and white cereal products. It is very abundant in fish liver oils.
A striking relation exists between deficiency of vitamin A and the functioning of the eye. There is a pigment called visual purple in the retina of the eye, which is, in part, made of vitamin A. When we become depleted of this substance vision is impaired. This condition is widely prevalent among people who subsist upon poor diets.
Many people, especially children and pregnant and lactating women, are not getting enough of vitamin B1, which is necessary for the health of the nervous system. The prevalence of neuritis, poor appetite, and of the smooth, bald tongue, point to deficiency of this vitamin.
Vitamin C is found in fresh, uncooked fruits and vegetables, and in other raw and commercially canned foods. Deficiency causes scurvy, which is still fairly common in infants. The health of the blood vessels is dependent upon an adequate supply of this substance. When the body becomes depleted in vitamin C it is much more susceptible to injury by bacterial poisons which arise through infections than is the case when the body reserves are high. Arterial damage resembling that seen in arteriosclerosis seems to result from bacterial poisons in persons who run short of this vitamin.
Vitamin D is of outstanding interest in relation to health. Only twenty years ago rickets, a disease of the bones, was common. The discovery of vitamin D and its power of promoting normal bone growth represents one of the major contributions of nutritional science to public health. Now rickets in infants and children is much less common than formerly, and when the disease exists it is much milder. Now almost all mothers in Europe and America know that the baby must be given cod liver oil or one of the other sources of vitamin D. The benefits to infants and children resulting from the application of this knowledge have already been incalculable, and the boon of this knowledge is a permanent possession for the future.
There are three ways in which tooth structure may be influenced by diet. The organ which forms the enamel is very dependent for its health and function on vitamin A. If a deficiency of this vitamin occurs in the infant or child whose teeth are still forming the enamel will contain pits and fissures, which are potential food traps, in which particles of carbohydrate food lodge and ferment, with the formation of acids which dissolve away the enamel. If the diet contains an abundance of vitamin A but not enough vitamin D the content of phosphate in the blood will fall, as it does in rickets, to so low a level that calcium phosphate, the substance of enamel, cannot be laid down, and poor enamel will result from this deficiency. The dentin-forming organ is especially dependent upon an abundance of vitamin C. If an infant or child whose teeth are forming does not get enough of this factor the dentin of the teeth will be badly formed and the future health of the tooth will be impaired.
Teeth of perfect structure, free from imperfections such as pits and fissures, and with smooth, polished enamel surfaces, are far less likely to decay than are teeth exhibiting these imperfections. Hence the fundamental importance to the individual of having optimum nutrition during the period when the teeth are developing. Decay of the teeth is not only a source of discomfort, as from toothache, but also an inconvenience because of the early loss of the teeth. Tooth decay is a menace to health, since the dead tooth is frequently the source of an abscess from which bacteria or their poisons find their way into the blood stream. Secondary infections in the joints, kidneys, gall bladder, and other places, have not infrequently been traced to an infected tooth. Decayed teeth have been and are the cause of much ill health. The prevention of tooth decay would constitute one of the greatest possible achievements in improving the public health. If our present day knowledge of nutrition could be applied to the entire population there is no doubt that tooth decay could be reduced to a small fraction of its present ravages.
Optimum nutrition is so important in the minds of the leaders in the field of public health that in Europe and America a great movement is under way to improve the dietaries of the peoples. Governments are now taking active measures to provide the better-class foods at lower cost. In Canada an abundance of the better class foods are available. The great need is for the dissemination of knowledge about the selection of foods so that the daily diet will be complete.
In summary, let me emphasize that through diet we may accomplish:
- Improvement of the health of the mucous membranes, making them more effective as barriers against the entrance of infective agents, with consequent reduction in the incidence and severity of respiratory diseases.
- Improvement in the structure of the teeth, and reduction in their liability to decay and subsequent infection; relief in great measure from secondary infections of the joints, kidneys and heart.
- Safeguarding the health of the nervous system, especially as respects neuritis and the secondary effects of nerve injury, such as heart and digestive disorders and disease of the digestive tract.
- Protection of the blood vessels against injury caused by bacterial poisons acting upon them when the body’s reserves of vitamin C are low.
We do not claim to have found in adequate nutrition the panacea for all human ills. We do claim that malnutrition is widespread and of a degree of severity which is reflected in many people in ill health in one of the categories mentioned. Attention to the proper selection of foods throughout life will go far toward reducing the incidence and severity of these conditions. When the body is not functioning normally, as in malnutrition, its capacity is lowered to withstand the effects of infections, fatigue, and emotional strain.