Deficiency dietary

Magnesium is essential to most plant and animal life (see Mineral NUTRIENTS). Dietary deficiency, rather than toxicity, is the more significant problem. 

In 1913, Goldberger demonstrated that pellagra was due to a dietary deficiency. Pellagra had been eadier described by Thiery, who had coined the term mal de la rosa for this disease. Several decades later, Elvehjem and co-workers isolated nicotinamide from a Hver extract and identified it as a peUagra-preventing factor (1). 

Clinical manifestation of vitamin B 2 deficiency is usually a result of absence of the gastric absorptive (intrinsic) factor. Dietary deficiency of vitamin B 2 is uncommon and may take 20 to 30 years to develop, even in healthy adults who foUow a strict vegetarian regimen. An effective enterohepatic recycling of the vitamin plus small amounts from bacterial sources and other contaminants greatly minimizes the risk of a complete dietary deficiency. Individuals who have a defect in vitamin B 2 absorption, however, may develop a deficiency within three to seven years. 

Dietary deficiency in the absence of absorption defects can be effectively reversed with oral supplementation of 1 p.m of vitamin B 2 daily. If deficiency is related to a defect in vitamin absorption, daily doses of 1 pg adininistered subcutaneously or intramuscularly are effective (33). However, a single intramuscular dose of 100 pg of cobalamin once per month is adequate in patients with chronic gastric or ileal damage. Larger doses are generally rapidly cleared from the plasma into the urine and are not effective unless the patient demonstrates poor vitamin retention. 

The complex series of events in collagen maturation provide a model that illustrates the biologic consequences of incomplete polypeptide maturation. The best-known defect in collagen biosynthesis is scurvy, a result of a dietary deficiency of vitamin C required by... 

In experimental animals, vitamin E deficiency results in resorption of femses and testicular atrophy. Dietary deficiency of vitamin E in humans is unknown, though patients with severe fat malabsorption, cystic fibrosis, and some forms of chronic fiver disease suffer deficiency because they are unable to absorb the vitamin or transport it, exhibiting nerve and muscle membrane damage. Premamre infants are born with inadequate reserves of the vitamin. Their erythrocyte membranes are abnormally fragile as a result of peroxidation, which leads to hemolytic anemia. 

Pernicious anemia arises when vitamin B,2 deficiency blocks the metabohsm of folic acid, leading to functional folate deficiency. This impairs erythropoiesis, causing immature precursors of erythrocytes to be released into the circulation (megaloblastic anemia). The commonest cause of pernicious anemia is failure of the absorption of vitamin B,2 rather than dietary deficiency. This can be due to failure of intrinsic factor secretion caused by autoimmune disease of parietal cells or to generation of anti-intrinsic factor antibodies. 

Nutritional surveys indicate that children of low-income groups consume less than recommended dietary allowances of calcium and iron. Dietary deficiencies of these two minerals have been shown to potentiate the toxicity of lead (Johnson and Tenuta 1979 Yip et al. 1981 Ziegler et al. 1978). Thus, nutrient deficiencies in conjunction with a developmental predisposition to absorb lead makes this subset of children at a substantially elevated risk. More information on children s susceptibility to lead is presented in Section 2.6. 

Clancy, J. J., Caldwell, D. F., Oberleas, D., Sangiah, S. 8r Villeneuve, M. J. (1978). Effect of chronic tryptophan dietary deficiency on the rat s sleep-wake cycle. Brain Res. Bull. 3, 83-7. 

The lipotropic factors exercise a marked effect on the biosynthesis of phospho-lipids and triglycerides. As has been mentioned above, they facilitate the phospho-lipid synthesis. The dietary deficiency of lipotropic factors favours the triglyceride production in the organism. 

General undernourishment or dietary deficiencies of specific substances can lead to a preferential reduction in myelin formation 649... 

Much of the toxicological interest in cyanide relating to mammals has focused on its rapid lethal action. However, its most widely distributed toxicologic problems are due to its toxicity from dietary, industrial, and environmental factors (Way 1981, 1984 Gee 1987 Marrs and Ballantyne 1987 Eisler 1991). Chronic exposure to cyanide is correlated with specific human diseases Nigerian nutritional neuropathy, Leber s optical atrophy, retrobulbar neuritis, pernicious anemia, tobacco amblyopia, cretinism, and ataxic tropical neuropathy (Towill etal. 1978 Way 1981 Sprine etal. 1982 Beminger et al. 1989 Ukhun and Dibie 1989). The effects of chronic cyanide intoxication are confounded by various nutritional factors, such as dietary deficiencies of sulfur-containing amino acids, proteins, and water-soluble vitamins (Way 1981). 

Anemias in children are often due to a primary hematologic abnormality. The risk of iron-deficiency anemia is increased by rapid growth spurts and dietary deficiency. 

While the dog is a carnivore, it is able to adapt to an omnivorous diet. Requirements for dietary sources of energy, amino acids, glucose precursors, fatty acids, minerals, vitamins, and water have been established based on recommendations by the National Research Council (NRC, 1985). Adult beagles maintained in a laboratory environment function well with one feeding of standard laboratory chow per day. In safety assessment testing, however, some compounds may induce serious dietary deficiencies through induced loss of appetite, malabsorption, or vomiting, and, in these cases, it may be advisable to provide a dietary supplement. 

The Chinese are also counting on petrochemical feedstock to promote synthetic substitutes for the huge quantities of edible oils used industrially (i.e., in the paint industry). Edible oil supply is still deficient in China (China imported 36 million worth of soybean oil from the U.S. in 1979 to help alleviate the shortage), and is rationed. The use of petrochemical derivatives should help boost the per-capita edible oil consumption (less than one-quarter kg/month), and correct some dietary deficiencies. 

A number of dietary deficiencies may increase the risk of deleterious cyanide effects. Iodine deficiency is involved in the etiology of such thyroid disorders as goiter and cretinism. These disorders may be exacerbated by excess exposure to cyanide (Delange and Ermans 1971 Ermans et al. 1972). Protein deficiencies and vitamin B12, riboflavin and other vitamins and elemental deficiencies may subject people... 

Pantothenic acid and biotin were thus found to be growth factors for yeast. Like riboflavin these molecules are incorporated into larger molecules in order to exert their essential metabolic function. Unlike the other vitamins there has been no evidence of pathological signs in man which can be attributed to dietary deficiencies in biotin or pantothenic acid. 

It should not be assumed that all birth defects and functional abnormalities in children are caused by drugs or environmental chemicals. It is clear that environmental factors such as extreme heat or cold, certain forms of radiation, infections (particularly German measles and syphilis), dietary deficiencies, and genetic disorders in the parents can all put the developing fetus at risk. 

At the time, the medical community widely believed that pellagra was an infectious disease in spite of clear evidence that this was not the case. The hero in this story is Dr. Joseph Goldberger, aphysician in the U.S. Government s Hygenic Laboratory, the forerunner of the National Institutes of Health. Goldberger was correctly convinced that pellagra is a dietary deficiency disease. He made a heroic effort to persuade critics that pellagra was not an infectious disease ... 

Parathyroid hormone a peptide hormone that acts to mobilize calcium from bone. Peiiagra a dietary deficiency disease of niacin. 

Approximately 60% of the dry weight of the brain is fat, a considerable proportion of which is polyunsaturated fatty acids that are present in plasma membranes. It would not be surprising if replacement of the unsaturated acids by the saturated fatly acids in membrane structure due to a dietary deficiency of polyunsaturated fatty acids played some part in development of mental illness. Indeed, it has been found that supplementation of a normal diet with polyunsaturated fatly acids can improve some mental disorder (see chapter 11). 

Deficiency of vitamin E is rare it can occur from abnormalities in lipid absorption as well as dietary deficiency. Its deficiency affects the muscular system, causing dystrophy and paralysis and, if the heart is affected, death by myocardial failure. This is probably caused by demyelin-ation of axons due to oxidative damage. Vitamin E is incorporated into chylomicrons within the enterocyte, so that its uptake into cells requires the activity of lipoprotein lipase. 

Thiamine (vitamin Bi), in the form of thiamine diphosphate (TPP), is a coenzyme of some considerable importance in carbohydrate metabolism. Dietary deficiency leads to the condition beriberi, characterized by neurological disorders, loss of appetite, fatigue, and muscular weakness. We shall study a number of... 

Riboflavin is widely available in foods dietary deficiency is uncommon, but it manifests itself by skin problems and eye disturbances. 

Thyroid suppression therapy of euthyroid goiter (B). The cause of goiter (struma) is usually a dietary deficiency of iodine. Due to an increased TSH action, the thyroid is activated to raise utilization of the little iodine avail-Liillmann, Color Atlas of Pharmacology 2000 Thieme All rights reserved. Usage subject to terms and conditions of iicense. 

Magnesium deficiency, usually the result of decreased absorption or excessive excretion, results in neuromuscular weakness and ultimately convulsions. Dietary deficiency in catde is known as the grass staggers. Magnesium toxicity from impaired excretion or excessive consumption of antacids results in vomiting, hypertension, and central nervous systems effects. Inhalation of magnesium oxide from welding can cause metal fume fever similar to that from zinc. 

Pyridoxine is present in food in the free form and as a glucoside, which may undergo partial hydrolysis in the gut lumen, or may be absorbed intact. Although pyridoxine is associated with the enzyme glycogen phosphorylase in muscles, it is not released in response to a dietary deficiency therefore it cannot be regarded as a storage form of the vitamin. 

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