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Suggested Citation:"Biotin." Institute of Medicine. 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. doi: 10.17226/11537.
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Page 196
Suggested Citation:"Biotin." Institute of Medicine. 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. doi: 10.17226/11537.
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Page 197
Suggested Citation:"Biotin." Institute of Medicine. 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. doi: 10.17226/11537.
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Page 198
Suggested Citation:"Biotin." Institute of Medicine. 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. doi: 10.17226/11537.
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Page 199
Suggested Citation:"Biotin." Institute of Medicine. 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. doi: 10.17226/11537.
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Page 200
Suggested Citation:"Biotin." Institute of Medicine. 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. doi: 10.17226/11537.
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Page 201

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

TABLE 1 Dietary Reference Intakes for Biotin by Life Stage Group DRI values (mg/day) AIa ULb Life stage groupc 0 through 6 mo 5 7 through 12 mo 6 1 through 3 y 8 4 through 8 y 12 9 through 13 y 20 14 through 18 y 25 19 through 30 y 30 31 through 50 y 30 51 through 70 y 30 > 70 y 30 Pregnancy £ 18 y 30 19 through 50 y 30 Lactation £ 18 y 35 19 through 50 y 35 a AI = Adequate Intake. b UL = Tolerable Upper Intake Level. Data were insufficent to set a UL. In the absence of a UL, extra caution may be warranted in consuming levels above the recommended intake. c All groups except Pregnancy and Lactation represent males and females.

PART III: BIOTIN 197 BIOTIN B iotin functions as a coenzyme in bicarbonate-dependent carboxylation reactions. It exists both as free biotin and in protein-bound forms in foods. Little is known about how protein-bound biotin is digested. Since data were insufficient to set an Estimated Average Requirement (EAR) and thus calculate a Recommended Dietary Allowance (RDA) for biotin, an Adequate Intake (AI) was instead developed. The AIs for biotin are based on data extrapolation from the amount of biotin in human milk. Data were insuf- ficient to set a Tolerable Upper Intake Level (UL). DRI values are listed by life stage group in Table 1. The biotin content of foods is generally not documented. It is widely dis- tributed in natural foods, but its concentration varies. Signs of biotin deficiency have been conclusively demonstrated in individuals consuming raw egg whites over long periods and in patients receiving total parenteral nutrition (TPN) solutions that do not contain biotin. No adverse effects have been documented for biotin at any intake tested. BIOTIN AND THE BODY Function Biotin functions as a coenzyme in bicarbonate-dependent carboxylation reactions. Absorption, Metabolism, Storage, and Excretion Biotin exists both as free biotin and in protein-bound forms in foods. Little is known about how protein-bound biotin is digested. It appears to be absorbed in both the small intestine and the colon. The mechanism of biotin transport to the liver and other tissues after absorption has not been well established. Avi- din, a protein found in raw egg white, has been shown to bind to biotin in the small intestine and prevent its absorption. The mechanism of biotin transport to the liver and other tissues after absorption has not been well established. Biotin is excreted in the urine.

DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 198 DETERMINING DRIS Determining Requirements Since data were insufficient to establish an EAR and thus calculate an RDA, an AI was instead developed. The AIs for biotin are based on extrapolation from the amount of biotin in human milk. Most major nutrition surveys do not re- port biotin intake. Special Considerations Individuals with increased needs: People who receive hemodialysis or perito- neal dialysis may have an increased requirement for biotin, as do those with genetic biotinidase deficiency. Criteria for Determining Biotin Requirements, by Life Stage Group Life stage group Criterion 0 through 6 mo Human milk content 7 through 12 mo Extrapolation from infants 1 through > 70 y Extrapolation from infants Pregnancy £ 18 through 50 y Extrapolation from infants Lactation £ 18 through 50 y To cover the amount of biotin secreted in milk, the AI is increased by 5 mg/day The UL The Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse effects for almost all people. Due to insufficient data on the adverse effects of excess biotin consumption, a UL for biotin could not be determined. DIETARY SOURCES Foods Biotin content has been documented for relatively few foods, and so it is gener- ally not included in food composition tables. Thus, intake tends to be underes-

PART III: BIOTIN 199 timated in diets. Although biotin is widely distributed in natural foods, its con- centration significantly varies. For example, liver contains biotin at about 100 mg/100 g, whereas fruits and most meats contain only about 1 mg/100 g. Dietary Supplements According to the 1986 National Health Interview Survey (NHIS), approximately 17 percent of U.S. adults reported taking a supplement that contained biotin. Specific data on intake from supplements were not available. Bioavailability This information was not provided at the time the DRI values for this nutrient were set. Dietary Interactions This information was not provided at the time the DRI values for this nutrient were set. INADEQUATE INTAKE AND DEFICIENCY Signs of biotin deficiency have been conclusively demonstrated in individuals consuming raw egg whites over long periods and in patients receiving total parenteral nutrition (TPN) solutions that do not contain biotin. The effects of biotin deficiency include the following: • Dermatitis (often appearing as a red scaly rash around the eyes, nose, and mouth) • Conjunctivitis • Alopecia • Central nervous system abnormalities, such as depression, lethargy, hal- lucinations, and paresthesia of the extremities Symptoms of deficiency in infants on biotin-free TPN appear much earlier after the initiation of the TPN regimen than in adults. In biotin-deficient infants, hypotonia, lethargy, and developmental delays, along with a peculiar withdrawn behavior, are all characteristic of a neurological disorder resulting from a lack of biotin.

DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 200 EXCESS INTAKE There have been no reported adverse effects of biotin in humans or animals. Toxicity has not been reported in patients given daily doses of biotin up to 200 mg orally and up to 20 mg intravenously to treat biotin-responsive inborn er- rors of metabolism and acquired biotin deficiency.

KEY POINTS FOR BIOTIN Biotin functions as a coenzyme in bicarbonate-dependent 3 carboxylation reactions. Since data were insufficient to establish an EAR and thus 3 calculate an RDA, an AI was instead developed. The AIs for biotin are based on extrapolation from the amount 3 of biotin in human milk. People who receive hemodialysis or peritoneal dialysis may 3 have an increased requirement for biotin, as may those with genetic biotinidase deficiency. Data were insufficient to set a UL. 3 The biotin content of foods is generally not documented. It is 3 widely distributed in natural foods, but its concentration varies. Signs of biotin deficiency have been conclusively 3 demonstrated in individuals consuming raw egg whites over long periods and in patients receiving total parenteral nutrition (TPN) solutions that do not contain biotin. The effects of biotin deficiency include dermatitis, alopecia, 3 conjunctivitis, and abnormalities of the central nervous system. No adverse effects have been associated with high intakes of 3 biotin.

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Dietary Reference Intakes: The Essential Guide to Nutrient Requirements Get This Book
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Widely regarded as the classic reference work for the nutrition, dietetic, and allied health professions since its introduction in 1943, Recommended Dietary Allowances has been the accepted source in nutrient allowances for healthy people. Responding to the expansion of scientific knowledge about the roles of nutrients in human health, the Food and Nutrition Board of the Institute of Medicine, in partnership with Health Canada, has updated what used to be known as Recommended Dietary Allowances (RDAs) and renamed their new approach to these guidelines Dietary Reference Intakes (DRIs). Since 1998, the Institute of Medicine has issued eight exhaustive volumes of DRIs that offer quantitative estimates of nutrient intakes to be used for planning and assessing diets applicable to healthy individuals in the United States and Canada. Now, for the first time, all eight volumes are summarized in one easy-to-use reference volume, Dietary Reference Intakes: The Essential Reference for Dietary Planning and Assessment. Organized by nutrient for ready use, this popular reference volume reviews the function of each nutrient in the human body, food sources, usual dietary intakes, and effects of deficiencies and excessive intakes. For each nutrient of food component, information includes:

  • Estimated average requirement and its standard deviation by age and gender.
  • Recommended dietary allowance, based on the estimated average requirement and deviation.
  • Adequate intake level, where a recommended dietary allowance cannot be based on an estimated average requirement.
  • Tolerable upper intake levels above which risk of toxicity would increase. Along with dietary reference values for the intakes of nutrients by Americans and Canadians, this book presents recommendations for health maintenance and the reduction of chronic disease risk. Also included is a “Summary Table of Dietary Reference Intakes,” an updated practical summary of the recommendations. In addition, Dietary Reference Intakes: The Essential Reference for Dietary Planning and Assessment provides information about:
  • Guiding principles for nutrition labeling and fortification
  • Applications in dietary planning
  • Proposed definition of dietary fiber
  • A risk assessment model for establishing upper intake levels for nutrients
  • Proposed definition and plan for review of dietary antioxidants and related compounds

Dietitians, community nutritionists, nutrition educators, nutritionists working in government agencies, and nutrition students at the postsecondary level, as well as other health professionals, will find Dietary Reference Intakes: The Essential Reference for Dietary Planning and Assessment an invaluable resource.

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