Vitamin, individual biotin

Besides these studies with individual vitamins, there are studies with rats that had received none of the vitamins of the B group (Morgan and Yudkin, 1957). With 20% sorbitol in the diet, the animals grew well for the 13 weeks of the experiment. The diets were such that they would not produce deficiences of vitamin B12, biotin, or niacin however, we can conclude that sorbitol can spare simultaneously at least thiamine, riboflavin, pantothenic acid, pyridoxine and folic acid. 

In an investigation of the water-soluble vitamins in human skin,71 it was found that 15 individuals showed relatively small ranges (less than 2-fold) for vitamin B12, folic acid, and biotin about 2-fold ranges in the cases of riboflavin, niacin, and thiamine about a 4-fold range in the case of ascorbic acid, and more than a 5-fold range in the case of pantothenic acid. In another study72 it was found that the total choline content of normal skin varied in four individuals over approximately a 10-fold range 127 to 1200 ig. per gm. The variation in the free choline in the same individuals was relatively small. 

Description. Also known as vitamin Bg or H, this vitamin is of great importance for the biochemistry of the human organism. Biotin is the cofactor for a small group of enzymes that catalyze carboxyla-tion, decarboxylation, and transcarboxylation reactions in carbohydrate and fatty acid metabolism. Deficiency of this vitamin is rare in humans, but can be induced in special circumstances in individuals with inborn errors of biotin metabolism, in individuals taking certain medications, and in some women during pregnancy. ... 

An Estimated Average Requirement (EAR) is the average daily nutrient intake level estimated to meet the requirements of half of the healthy individuals in a group. EARs have not been established for vitamin K, pantothenic acid, biotin, choline, chromium, fluoride, manganese, or other nutrients not yet evaluated via the DRI [cocess... 

A Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individutils in the general population. Unless otherwise specified, the UL represents total intake from food, water, and supplements. Due to alack of suitable data, ULs could not be established for vitamin K, thiamin, riboflavin, vitamin B, pantothenic acid, biotin, and carotenoids. In the absence of a UL, extra caution may be warranted in consuming levels above recommended intakes. Members of the general population should be advised not to routinely exceed the UL. The UL is not meant to apply to individuals who are treated with the nutrient under medical supervision or to individuals with predisposing conditions that modify their sensitivity to the nutrient As preformed vitamin A only... 

Potato extract, orange juice and yeast extract all stimulate the fermentation of glucose and acid production by propionic acid bacteria (Tatum et al., 1936). Stimulation by potato extract is associated with some essential growth factors. If synthetic medium is supplemented with yeast extract, then the addition of individual vitamins (biotin, pantothenate, thiamine or /7-aminobenzoic acid) is unnecessary (El-Hagarawy, 1957). In connection with the ability of P. shermanii to synthesize vitamins Karlin (1966) suggested to include these bacteria into dairy products. For example, kefir enriched with P. shermanii contained increased amounts of vitamin Bi, B2, Bg, PP, Bi2, pantothenate, folic and folinic acid as compared with control samples. Especially high increases in the latter four vitamins were observed. 

Water soluble vitamins are generally not stored in the body, or are stored only for a limited time and the excess is excreted in the urine. Lipophilic vitamins are stored mainly in the Hver. The reserve capacity, defined as the time during which the need for the vitamin is covered by the organism reserves, is the longest for corrinoids (3-5 years) and vitamin A (1-2 years). The reserve capacity for folacin is 3-4 months, for vitamins C, D, E and K, riboflavin, pyridoxine and niacin it is 2-6 weeks, and for thiamine, pantothenic acid and biotin it is only 4-10 days. Reserve capacity is affected by the history of vitamin intake, the metabolic need for the vitamin and the health status of the individual. 

After a dose of " C-labeled pantothenate, about 40% of the dose appears in muscle tissue and about 10% in the liver, with smaller amounts occurring elsewhere. The differential affinities of the various different tissues determines their individual contents of the coenzyme derivatives, CoA and ACP, since there is no other major store of the vitamin anywhere in the body. Most organs, including placenta, exhibit evidence of a unidirectional active transport process for the intracellular accumulation of pantothenate, which is dependent on sodium, energy, and pH. In placenta (and probably elsewhere) this transport process is also shared by biotin and by some of its analogs, which can exhibit competitive inhibition. The only tissues that have been shown to differ with respect to transport mechanisms are red cells and the central nervous system. 

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