Vitamin glucose tolerance

Brewers and bakers dried yeasts are used as dietary supplements. They contribute some protein and trace minerals, and some B vitamins, but no vitamin C, vitamin B 2 or fat-soluble vitamins. The glucose tolerance factor (GTE) of yeast, chromium nicotinate, mediates the effect of insulin. It seems to be important for older persons who caimot synthesize GTE from inorganic dietary chromium. The ceU wall fraction of bakers yeast reduces cholesterol levels in rats fed a hypercholesteremic diet. 

Rice bran is the richest natural source of B-complex vitamins. Considerable amounts of thiamin (Bl), riboflavin (B2), niacin (B3), pantothenic acid (B5) and pyridoxin (B6) are available in rice bran (Table 17.1). Thiamin (Bl) is central to carbohydrate metabolism and kreb s cycle function. Niacin (B3) also plays a key role in carbohydrate metabolism for the synthesis of GTF (Glucose Tolerance Factor). As a pre-cursor to NAD (nicotinamide adenine dinucleotide-oxidized form), it is an important metabolite concerned with intracellular energy production. It prevents the depletion of NAD in the pancreatic beta cells. It also promotes healthy cholesterol levels not only by decreasing LDL-C but also by improving HDL-C. It is the safest nutritional approach to normalizing cholesterol levels. Pyridoxine (B6) helps to regulate blood glucose levels, prevents peripheral neuropathy in diabetics and improves the immune function. 

Adipocytes have vitamin D receptors, and there is evidence that vitamin D may act as a suppressor of adipocyte development (Kawada et al., 1996). It has been suggested that vitamin D inadequacy may be a factor in the development of the metabolic syndrome ( syndrome X, the combination of insulin resistance, hyperlipidemia, and atherosclerosis associated with abdominal obesity). Sunlight exposure, and hence vitamin D status, may be a factor in the difference in incidence of atherosclerosis and myocardial infarction between northern and southern European countries in addition to effects on adipocyte development, calcitriol also enhances insulin secretion through induction of calbindin-D (Section 3.3.7.1), and there is some evidence vitamin D supplements can improve glucose tolerance (Boucher, 1998). 

Impaired glucose tolerance is common in pregnancy and may be severe enough to be classified as diabetes meUitus (so-called gestational diabetes), which usually resolves on parturition. A number of studies have shown that supplements of 100 mg of vitamin Bg per day result in improved glucose tolerance (Rose et al., 1975). 

Diet The diet should be evenly balanced and in accordance with the principles of present-day dietetics it must also be tolerated by the patient. There is no special diet for viral hepatitis patients. The water and electrolyte balance is often disrupted in cases of acute viral hepatitis, possibly with the occurrence of oedemas and ascites (so-called hepatitis oedematosa) (48, 77, 131) (s. p. 297) or impaired renal function (60, 120) - as is recognizable from the diuresis which normally develops at the onset of the convalescence phase. An even balance of water and electrolytes should be maintained - this is very much supported by the patient lying flat. In the event of inadequate nutrition or malnutrition, particularly when nausea and vomiting occur, substitution measures are advisable (e.g. vitamins, glucose and electrolyte infusions). 

It acts as a cofactor for glycogen phosphorylase in glycogenolysis. Decreased glucose tolerance may be associated with vitamin B-6 deficiency. 

Although requirements for vitamins and trace elements are known in health (Table 30-1), the effects of illness on these requirements are poorly understood and quantified. However, it is now apparent that as an individual develops progressively more severe depletion in vitamin or trace element status, the person passes through a series of stages with biochemical or physiological consequences. The metabolic or physiological penalty of such suboptimal nutritional status is usually not clear, but the assumption remains that the suboptimal metabolism is likely to have detrimental effects (e.g., subclinical deficiency of folic acid is associated with an increase in serum homocysteine concentration, which is an independent risk factor for coronary artery disease—see Chapter 26). Similarly, subclinical deficiency of chromium may be associated with impaired glucose tolerance in certain types of diabetes. 

In scorbutic animals, blood glucose levels are increased, glucose tolerance is lowered, and liver and glycogen content drop. Insulin restores everything to normal. Therefore, it was concluded that vitamin C deficiency also leads to insulin deficiency, and that the latter is responsible for the deviation in carbohydrate metabolism. 

Hirai, M., Suzuki, S., Hinokio, Y., et al. 2000. Variations in vitamin D-binding protein (group-specific component protein) are associated with fasting plasma insulin levels in Japanese with normal glucose tolerance. J Clin Endocrinol Metab, 85 1951-3. 

A diabetic-like state, abnormal glucose tolerance, has been observed in vitamin-C-deficient guinea pigs (48-50). This is associated with an increased concentration of dehydroascorbic acid in the tissues (38), a decreased insulin content of the pancreas (50), and a decreased GSH concentration in the blood (46%) and pancreas (48%) (38). 

Component of the glucose tolerance factor (GTE)— The complete identity of this hormonelike agent is not yet known, although it is certain that it contains chromium and the vitamin niacin, and perhaps amino acids such as glycine, glutamic acid, and cysteine. 

Brewers, yeast powder or tablets—This special product has long been used to prevent or treat malnutrition by providing extra protein and the vitamin B complex. However, it Is also one of the richest sources of both chromium and selenium —minerals that are likely to be supplied inadequately by ordinary diets. Furthermore, the chromium is present in an organic form (glucose tolerance factor) which is much more beneficial to the body than the inorganic forms of the mineral. 

Some of the symptoms that warrant dietary modification and/or other types of therapies are diabetic glucose tolerance high blood levels of cholesterol, triglycerides, and/or uric acid low blood levels of hemoglobin, iron, red cells, and/or certain vitamins and subnormal capacity for physical exertion, as evidenced by an electrocardiogram or stress testing on an exercise bicycle or a treadmill. Means of correcting these problems are described in the sections that follow. 

Although oestrogens do not cause vitamin Bg deficiency, the administration of vitamin Bg supplements has beneficial effects on some of the side effects of both administered and endogenous oestrogens. The supplements act in two main areas in normalizing glucose tolerance and as an antidepressant. 

Sorbitol is a sweetener often substituted for cane sugar because it is better tolerated by dia betics It IS also an intermediate in the commercial synthesis of vitamin C Sorbitol is prepared by high pressure hydrogenation of glucose over a nickel catalyst What is the structure (including stereochemistry) of sorbitoP... 

Of the water-soluble vitamins, intakes of nicotinic acid [59-67-6] on the order of 10 to 30 times the recommended daily allowance (RE)A) have been shown to cause flushing, headache, nausea, and moderate lowering of semm cholesterol with concurrent increases in semm glucose. Toxic levels of foHc acid [59-30-3] are ca 20 mg/d in infants, and probably approach 400 mg/d in adults. The body seems able to tolerate very large intakes of ascorbic acid [50-81-7] (vitamin C) without iH effect, but levels in excess of 9 g/d have been reported to cause increases in urinary oxaHc acid excretion. Urinary and blood uric acid also rise as a result of high intakes of ascorbic acid, and these factors may increase the tendency for formation of kidney or bladder stones. AH other water-soluble vitamins possess an even wider margin of safety and present no practical problem (82). 

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