Vitamin deficiencies causes

Vitamin deficiencies may produce a more mild form of homocystinemia. Mild homocystinemia is associated with increased risk for atherosclerosis, deep vein thrombosis, and stroke. The vitamin deficiencies causing homocystinemia include ... 

T8. Relationship between Folic Acid Deficiency and Anemia Folic acid deficiency, believed to be the most common vitamin deficiency, causes a type of anemia in which hemoglobin synthesis is impaired and erythrocytes do not mature properly. What is the metabolic relationship between hemoglobin synthesis and folic acid deficiency ... 

Vitamin deficiency causes pernicious anaemia — the release into the bloodstream of immature precursors of red blood cells (megaloblastic anaemia). As discussed in section 11.11.3.2, vitamin B deficiency impairs the metabolism of folic acid, leading to the development of functional folate deficiency this is what disturbs the rapid multiplication of red blood cells, causing immature precursors to be released into the circulation. 

The hazards of unknown factors are illustrated by our current lack of knowledge regarding trace niineral requirements, utilisation and interactions and in the past by vitamin deficiencies caused by artificial feeds. ... 

Fohc acid is a precursor of several important enzyme cofactors required for the synthesis of nucleic acids (qv) and the metaboHsm of certain amino acids. Fohc acid deficiency results in an inabiUty to produce deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and certain proteins (qv). Megaloblastic anemia is a common symptom of folate deficiency owing to rapid red blood cell turnover and the high metaboHc requirement of hematopoietic tissue. One of the clinical signs of acute folate deficiency includes a red and painhil tongue. Vitamin B 2 folate share a common metaboHc pathway, the methionine synthase reaction. Therefore a differential diagnosis is required to measure foHc acid deficiency because both foHc acid and vitamin B 2 deficiency cause... 

Alcohol dextrose solutions are used cautiously in patients with hepatic and renal impairment, vitamin deficiency (may cause or potentate vitamin deficiency),... 

A vitamin is defined as an organic compound that is required in the diet in small amounts for the maintenance of normal metabofic integrity. Deficiency causes a specific disease, which is cured or prevented only by restoring the vitamin to the diet (Table 45-1). However, vitamin D, which can be made in the skin after exposure to sunhght, and niacin, which can be formed from the essential amino acid tryptophan, do not stricdy conform to this definition. 

Vitamin 6 2 Deficiency Causes Functional Folate Deficiency—the Folate Trap... 

Iron-deficiency anaemia results from a discrepancy between iron availability and the amount required for production of red blood cells. The causes of acquired iron deficiency in so-called underdeveloped and developed countries must be differentiated. In underdeveloped countries, the main causes of iron deficiency are (a) the poor availability of iron in the diet due to low haem and high fibre and phytate content (D Souza et ah, 1987), and (b) chronic blood loss due to hookworm, schistosomiasis and malaria (Stoltzfus et ah, 1997 Olsen et ah, 1998 Dreyfuss et ah, 2000). Inflammation and vitamin A deficiency often interfere with the above causes of iron deficiency, causing a mixed type of anaemia. In underdeveloped countries diet improvement, iron fortification of natural foods and eradication of parasites will have a much higher impact than will refinement of diagnostic procedures and therapy of iron-deficiency anaemia. 

Radiographic study of the small intestine may provide useful information (A6, F12, F14, K4, L2, M2, P3). If a simple suspension of barium sulfate is used, the upper small intestine of a normal person usually displays a fine feathery appearance a similar pattern is seen in most patients with pancreatogenous malabsorption. In the patient with enteropathy, however, the opaque medium appears in massive clumps. This was at one time thought to be due to vitamin deficiencies, but it was demonstrated experimentally that the cause was flocculation of the barium sulfate with excessive secretion of mucus. This clumped appearance may be seen in normal children, possibly due to the... 

Vitamin deficiency can cause a megaloblastic anemia of the same type seen in folate deficiency (discussed in Chapter 17). In a patient with megaloblastic anemia, it is important to determine the underlying cause because Bjj defidency, if not corrected, produces a peripheral neuropathy owing to aberrant fatty acid incorporation into the myelin sheets associated with inadequate methylmalonyl CoA mutase activity. Excretion of methylmalonic acid indicates a vitamin Bjj deficiency rather than folate. 

Despite these clues, a definitive diagnosis often cannot be made. In that case, a prudent course is to treat what would be treatable. The initial evaluation should carefully look for treatable medical causes of dementia or depression. These include vitamin deficiency and hypothyroidism among others. If no medical causes are found, then treatment for depression should be started. If the patient is depressed and suffering from a pseudodementia, the patient can expect full recovery of memory as the depression resolves. But if the patient has a progressive dementia such as Alzheimer s disease, then treatment for depression has done no harm and may still provide some benefit. 

Nutritional Deficiency-Related Dementias. We have already mentioned that chronic alcoholics are subject to thiamine deficiency that can cause dementia. It usually occurs only after heavy, prolonged abuse of alcohol. In developed countries, the other key nutritional concern is vitamin deficiency. Vitamin deficiency can surprisingly strike even those with a healthy diet. Such people are missing a vital protein, intrinsic factor, which would enable them to absorb it from their digestive tract. 

Since only a few vitamins can be stored (A, D, E, Bi2), a lack of vitamins quickly leads to deficiency diseases. These often affect the skin, blood cells, and nervous system. The causes of vitamin deficiencies can be treated by improving nutrition and by administering vitamins in tablet form. An overdose of vitamins only leads to hypervita mi noses, with toxic symptoms, in the case of vitamins A and D. Normally, excess vitamins are rapidly excreted with the urine. 

The answer is D. Several vitamin deficiencies can cause anemia due to reduced DNA synthesis in the erythropoietic cells of the bone marrow, especially folic acid and vitamin Bj2 (cobalamin), which are particularly prevalent among elderly patients due to poor diet and reduced absorption. In addition, deficiencies of either folic acid or vitamin Bj2 could produce the megaloblastic anemia seen in this patient. However, the absence of neurologic symptoms, a hallmark of vitamin Bj2 deficiency, makes that diagnosis less likely than folic acid deficiency. 

If lack of response or failure to maintain response occurs, checkfor causative factors (e.g., folate or vitamin deficiency, occult blood loss, malignancy)... 

Vitamins are vital for normal metabolism in body. They vary in their chemical structure and are supplied in very small quantity in diet, because they are not synthesized in body or their rate of production is not sufficient for maintenance of health. Vitamin deficiency leads to development of deficiency symptoms. Different vitamin preparations are available for treatment and prophylaxis. Most of the vitamins are nontoxic but on chronic administration can cause toxicity especially vitamin A and D. 

A deficiency of vitamin B12 causes the accumulation of homocysteine due to reduced formation of methylcobalamin, which is required for the conversion of homocysteine to methionine (Figure 33-3, section 1). The increase in serum homocysteine can be used to help establish a diagnosis of vitamin B12 deficiency (Table 33-2). There is concern that... 

Folic acid (or folate) deficiency, one of the most common vitamin deficiencies in the population consuming few dietary fruits and vegetables, causes chromosome breaks in humans,34 analogous to those caused by radiation. Folate supplementation above... 

Decreased metabolism of lipids. Decreased mitochondrial oxidation of fatty acids is another possible cause of ethanol-induced steatosis. Other possible causes are vitamin deficiencies and the inhibition of the mitochondrial electron transport chain. 

T Humans cannot synthesize retinal from simpler precursors and must obtain it in the diet in the form of vitamin A (see Fig. 10-21). Given the role of retinal in the process of vision, it is not surprising that dietary deficiency of vitamin A causes night blindness (poor vision at night or in dim light). ... 

Oxidation of fatty acids with an odd number of carbons proceeds two carbons at a time (pro ducing acetyl CoA) until the last three carbons (propionyl CoA). This compound is con verted to methylmalonyl CoA (a reaction requiring biotin), which is then converted to succinyl CoA by methylmalonyl CoA mutase (requiring vitamin B )- A genetic error in the mutase or vitamin B12 deficiency causes methylmalonic acidemia and aciduria. 

Riboflavin (vitamin B2) 6,7-dimethyl-9-(D-l-ribityl)isoalloxazine (63), was discovered as a coloring matter in milk in 1879, but its importance was not then realized. Deficiency causes lesions of the eye and of the angle of the mouth. Riboflavin is phosphorylated by adenosine triphosphate (ATP) to give riboflavin 5 -phosphate (flavinadenine mononucleotide, FMN) and then flavinadenine dinucleotide (FAD) (64 R = riboflavin). These function as prosthetic groups in a number of flavoproteins which are dehydrogenation catalysts by virtue of the oxidation-reduction properties of the isoalloxazine system. 

Studies on growth factors required by certain microorganisms, for example Streptococcus faecalis and Lactobacillus casei, and of their relevance in animal nutrition, led to the isolation and characterization of folic acid, pteroylglutamic acid (104), the structure of which was determined in 1946. It is an essential vitamin for man and together with vitamin B12 it is involved in the development of blood cells. Deficiency causes macrocytic anaemia. Many microorganisms do not use exogenous folic acid, but synthesize their own, and some... 

A lack of vitamin D causes rickets, a disease of humans and other animals in which the bones are soft, deformed, and poorly calcified. Rickets was recognized by some persons to result from a dietary deficiency well over a hundred years ago, and the use of cod liver oil to prevent the disease was introduced in about 1870. By 1890 an association of rickets with a lack of sunlight had been made. 

---