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OCR for page 270
TABLE 1 Dietary Reference Intakes for Pantothenic Acid by Life Stage Group DRI values (mg/day) AIa ULb Life stage groupc 0 through 6 mo 1.7 7 through 12 mo 1.8 1 through 3 y 2 4 through 8 y 3 9 through 13 y 4 14 through 18 y 5 19 through 30 y 5 31 through 50 y 5 51 through 70 y 5 > 70 y 5 Pregnancy £ 18 y 6 19 through 50 y 6 Lactation £ 18 y 7 19 through 50 y 7 a AI = Adequate Intake. b UL = Tolerable Upper Intake Level. Data were insufficient 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.

OCR for page 270
PART III: PANTOTHENIC ACID 271 PANTOTHENIC ACID P antothenic acid functions as a component of coenzyme A (CoA), which is involved in fatty acid metabolism. Pantothenic acid is widely distrib- uted in foods and is essential to almost all forms of life. Since data were insufficient to set an Estimated Average Requirement (EAR) and thus calculate a Recommended Dietary Allowance (RDA) for pantothenic acid, an Adequate Intake (AI) was instead developed. The AIs for pantothenic acid are based on pantothenic acid intake sufficient to replace urinary excretion. Data were insufficient to set a Tolerable Upper Intake Level (UL). DRI values are listed by life stage group in Table 1. Major food sources of pantothenic acid include chicken, beef, potatoes, oat cereals, tomato products, liver, kidney, yeast, egg yolk, broccoli, and whole grains. Pantothenic acid deficiency is rare, and no adverse effects have been associated with high intakes. PANTOTHENIC ACID AND THE BODY Function Pantothenic acid is involved in the synthesis of coenzyme A (CoA), which is involved in the synthesis of fatty acids and membrane phospholipids, amino acids, steroid hormones, vitamins A and D, porphyrin and corrin rings, and neurotransmitters. Absorption, Metabolism, Storage, and Excretion Pantothenic acid is absorbed in the small intestine by active transport at low concentrations of the vitamin and by passive transport at higher concentra- tions. Because the active transport system is saturable, absorption is less effi- cient at higher concentrations of intake. However, the exact intake levels at which absorption decreases in humans are not known. Pantothenic acid is ex- creted in the urine in amounts that are proportional with dietary intake over a wide range of intake values. DETERMINING DRIS Determining Requirements Since data were insufficient to set an EAR and thus calculate an RDA, an AI was instead developed. The AIs for pantothenic acid are based on pantothenic acid intake sufficient to replace urinary excretion.

OCR for page 270
DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 272 Criteria for Determining Pantothenic Acid Requirements, by Life Stage Group Life stage group Criterion 0 through 6 mo Human milk content 7 through 12 mo Mean of extrapolation from younger infants and from adults 1 through 18 y Extrapolation from adults 19 through > 70 y Pantothenic acid intake sufficient to replace urinary excretion Pregnancy £ 18 y through 50 y Mean intake of pregnant women Lactation £ 18 y through 50 y Pantothenic acid sufficient to replace amount excreted in milk + amount needed to maintain concentration of maternal blood levels 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 adverse effects of oral pantothenic acid consumption, a UL for pantothenic acid could not be determined. DIETARY SOURCES Foods Data on the pantothenic acid content of food are very limited. Foods that are reported to be major sources include chicken, beef, potatoes, oat cereals, to- mato products, liver, kidney, yeast, egg yolk, broccoli, and whole grains. Food processing, including the refining of whole grains and the freezing and canning of vegetables, fish, meat, and dairy products, lowers the pantothenic acid con- tent of these foods. Dietary Supplements Results from the 1986 National Health Interview Survey (NHIS) indicated that 22 percent of U.S. adults took a supplement that contained pantothenic acid. Bioavailability Little information exists on the bioavailability of dietary pantothenic acid. Val- ues of 40–61 percent (average of 50 percent) have been reported for absorbed food-bound pantothenic acid.

OCR for page 270
PART III: PANTOTHENIC ACID 273 Dietary Interactions This information was not provided at the time the DRI values for this nutrient were set. INADEQUATE INTAKE AND DEFICIENCY Pantothenic acid deficiency is rare and has only been observed in individuals who were fed diets devoid of the vitamin or who were given a pantothenic-acid metabolic antagonist. The signs and symptoms of deficiency may include the following: • Irritability and restlessness • Fatigue • Apathy • Malaise • Sleep disturbances • Nausea, vomiting, and abdominal cramps • Neurobiological symptoms, such as numbness, paresthesias, muscle cramps, and staggering gait • Hypoglycemia and increased sensitivity to insulin EXCESS INTAKE No adverse effects have been associated with high intakes of pantothenic acid. KEY POINTS FOR PANTOTHENIC ACID Pantothenic acid functions as a component of coenzyme A 3 (CoA), which is involved in fatty acid metabolism. Since data were insufficient to set an EAR and thus calculate 3 an RDA for pantothenic acid, an AI was instead developed. The AIs for pantothenic acid are based on pantothenic acid 3 intake sufficient to replace urinary excretion. Data were insufficient to set a UL. 3 Major food sources of pantothenic acid include chicken, beef, 3 potatoes, oat cereals, tomato products, liver, kidney, yeast, egg yolk, broccoli, and whole grains. Pantothenic acid deficiency is rare and has only been observed 3 in individuals who were fed diets devoid of the vitamin or who were given a pantothenic acid metabolic antagonist. No adverse effects have been associated with high intakes of 3 pantothenic acid.