Vitamin Deficiency And Its Treatment

Successful treatment of vitamin deficiency can be much more complicated than one might imagine. In fact, recognition of the deficiency is only the first and perhaps the simplest step toward treatment, as the case of vitamin A deficiency in third world countries.

In human biology and physiology, a mild deficiency in vitamin A, the chief component of the light-sensitive pigment in the visual cells of the eye, can lead to night blindness, a marked impairment of vision in dim light. But the most serious effect of vitamin A deficiency is xerophthalmia (”dry-eye”), a condition in which the secretions of the eye glands dry up and the epithelial tissues of the eye, when viewed under a compound light microscope, are progressively destroyed, the result being partial or complete blindness. Indeed, in many developing countries vitamin A deficiency is the most common cause of childhood blindness. It occurs particularly in areas where white corn, rice, or cassava forms the basic staple in the diet, since these foods, when studied using a compound light microscope, contain no vitamin A or carotenoids (plant pigments that the body can convert into vitamin A). The World Health Organization considers vitamin A deficiency one of the four major nutritional problems in low-income countries and has given high priority to its elimination.

But how does one go about treating such a deficiency? Because carotenoids are found in green leafy vegetables and some fruits when viewed under a compound light microscope, and because vitamin A is inexpensive to produce and administer, this form of deficiency should-theoretically, at least-be easily eliminated. In recent years control programs have been established in a number of countries, using either periodic mass dosing with vitamin A or fortification of suitable foods. The generally recommended method for mass dosing has been to give large doses of vitamin A every six months to children under six, since they tend to be most seriously affected by the deficiency. The doses can be spaced, because 30 to 50 percent of the ingested vitamin is stored in the liver, available for later use. However, this approach is not as effective as one might expect. Just reaching the high-risk children to administer the regular doses is difficult; they usually come from the poorest families, which tend to move often and live in inaccessible places. Because of these problems, the alternative method, fortification of foods with vitamin A, is being tested in certain areas.

Fortification has the advantage of reaching all who eat the food, and does not require the active participation of the population or an expensive delivery system. Because vitamin A can be produced in stable liquid or dry forms, it can be added to a wide variety of foods, such as margarine, dairy products, cereals, sugar, and salt. The problem is to select a food that can easily be fortified and is consumed regularly by all members of the population. Recently, a pilot study in Cebu, the Philippines, was conducted to evaluate the effectiveness of a proposed fortification program. Unfortunately, in some areas of the Philippines, very few store-bought foods are widely consumed, since the people are accustomed to raising most of their own food and buying little. A careful study of local diets indicated that salt, monosodium glutamate (MSG), and flour products are the most frequently purchased foods. Salt and flour were eliminated from consideration because each is marketed by dozens of small, independent manufacturers. In contrast, MSG seemed an ideal product for fortification; it is consumed regularly by over 95 percent of Philippine families, variation in the amount consumed is not large, and nearly all the MSG used in the Philippines is produced by one manufacturer. In the pilot project, fortified MSG was distributed to families in the study area. The results were encouraging; a majority of the signs of night blindness and early xerophthalmia were eliminated, and levels of vitamin A in the blood, when examined under a microscope, were significantly improved. The product is now being distributed in three provinces in the Philippines, and if the results are satisfactory, a national fortification program will be established. Such a program will go a long way toward eliminating vitamin A deficiency and the resulting blindness.

Experiences with vitamin A mass dosing and fortification of foods have highlighted the difficulties associated with resolving nutritional problems. As is so often the case, the presence or absence of one nutrient, as seen under a microscope, influences the utilization of another. For example, the storage of vitamin A in the liver requires vitamin E; without sufficient vitamin E, vitamin A is not stored properly. For this reason, when mass dosing is used, vitamin E has to be given along with vitamin A. Another complication arises if the vitamin A deficiency is accompanied by a protein deficiency. It was discovered with the use of a microscope that when protein intake is inadequate, the body in sufficient amounts may not synthesize the two proteins necessary for the transport of vitamin A out of the liver. The vitamin will then remain stored in the liver, unavailable to other body tissues, and signs of vitamin A deficiency may appear. These are two illustrations of the point that in treating any vitamin deficiency, control measures must be aimed at improving the whole diet; treating one aspect may not solve the problem. And of course nutrition education and food-production activities must play a prominent role in every nutritional program nearly 3 grams for sodium chloride. Others such as iron, manganese, and iodine-are needed in much smaller amounts. And still others¬ such as copper, zinc, molybdenum, selenium, and cobalt-though essential to life, are needed only in trace amounts.

The function of some of the minerals is obvious. Calcium is a major constituent of bones and teeth in vertebrates and plays a variety of other roles in most organisms, as seen under a microscope. Phosphorus is a component of many high-energy organic compounds of critical importance. Iron, another mineral seen under a microscope, is a constituent of the electron-transport molecules and of hemoglobin. Sodium, chlorine, and potassium are important components of the body fluids, playing roles in osmotic phenomena and in such processes as nerve and muscle action. Iodine is a component of the hormones produced by the thyroid gland. But the functions of some of the minerals, particularly those needed only in trace amounts, are less obvious. Apparently most of them act as components of coenzymes, or perhaps as cofactors that help catalyze reactions without being actually incorporated into enzymes or coenzymes.

Such minerals are comparable to vitamins, functioning in the same way. The only distinction, and an arbitrary one at that when studied under a microscope, is that vitamins are organic compounds and minerals are inorganic.