Biotin, daily recommendation

Deficiency can be due to two known genetic disorders of biotin metabolism or be induced by excess intake of avidin, which binds biotin and thus leads to poor absorption. Symptoms are alopecia, eczema around nose and mouth, conjunctivitis, hyperaesthesia, paraesthesia, depression, and muscle pain 29 The recommended daily allowance is 30 to 35 fig.112... 

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... 

The Food and Nutrition Board of the US National Research Council has released adequate intakes for infants, adults and pregnant women (Mock 2004 National Research Council 1989 Yates et al. 1998). These recommendations (Table 43.1) refer to studies assuming that, with a daily dose of 60 pg of biotin, adults on parenteral nutrition declared they were symptom-free for six months and with diets supplying 28 2pg/day, no inadequate biotin status was observed. The dietary biotin intake in Western populations has been estimated to be 35-70 pg per day (143-287 nmoles per day). 

The body s need for most vitamins is relatively low. The amounts needed to ensure the normal physiological function of humans is dependent on many factors such as age, sex, health status, lifestyle, eating habits and work-related activity. Many countries have recommendations for the daily intake of vitamins, which are continually revised in accordance with contemporary scientihc knowledge and dietary guidelines. Presently, Recommended Daily Allowances (RDAs) are set in the EU (upper number) and United States (lower number) as follows vitamin A (800/900 xg), vitamin D (5/15 xg), vitamin E (12/15 mg), vitamin K (75/120 xg), thiamine (1.1/1.2 mg), riboflavin (1.4/1.3 mg), niacin (16/16 mg), pantothenic acid (6/5 mg), vitamin Bg (1.4/1.3 mg), biotin (50/30 xg), folacin (200/400 (xg), vitamin Bj2 (2.5/2.4 xg) and vitamin C (80/90 mg). 

RECOMMENDED DAILY ALLOWANCE OF BIOTIN. It is difficult to obtain a quantitative requirement for biotin, for the reason that intestinal microflora make a significant contribution to the body pool of available biotin often humans excrete via the feces and urine considerably more biotin than they have ingested. However, the estimated safe and adequate intakes of biotin are given in the section on VITAMIN(S), Table V-5, Vitamin Table. 

---