NutriBase Research Quality Data

NutriBase includes nutrient data for Vitamin A (IU), Vitamin A (RE), Thiamin (mg), Riboflavin (mg), Niacin (mg), Pantothenic Acid (mg), Vitamin B-6 (mg), Folate (mcg), Vitamin B-12 (mcg), Ascorbic Acid - Vitamin C (mg), Vitamin D (IU), Vitamin E (a-tocopherol), Vitamin H (mcg)*, and Vitamin K (mcg) - phylloquinone. * Data for Vitamin H (Biotin) was provided by manufacturers. Ascorbic acid In the current database system, all data for ascorbic acid are listed under Nutrient No. 401 (total ascorbic acid), though reduced ascorbic acid content is reported for many food groups, especially those that are major nutritional contributors of ascorbic acid, such as fruits and vegetables. Total ascorbic acid was reported for food groups 1 (Dairy and Eggs), 2 (Spices and Herbs), 4 (Fats and Oils), 12 (Nut and Seeds), and 17 (Lamb, Veal, and Game). Food group 10 (Pork and Pork Products) contains a mixture of total and reduced forms. Reduced ascorbic acid was determined by the dichloroindophenol method and total ascorbic acid by the fluorometric method. Vitamin A In foods of animal origin, such as eggs, beef, pork, poultry, lamb, veal, game, and fish (except for some organ meats and dairy), all of the vitamin A activity is contributed by retinol. For these foods, when analytical data was not available, µg RAE and µg of retinol were calculated by dividing the IU value by 3.33. In foods that contain both retinol and provitamin A carotenoids, the amount of these components must be known to calculate RAE. Most of the vitamin A data in the database were received as IU. Therefore the amounts of the provitamin A carotenoids and retinol had to be estimated based on the amount of retinol and provitamin A carotenoids in the ingredients. Once the components had been estimated, µg RAE were calculated as (IU from carotenoids/20) + (IU from retinol/3.33). µg of retinol were calculated as IU from retinol/3.33. Thiamin was determined chemically by the thiochrome procedure or by microbiological methods. Riboflavin was measured using the fluorometric or microbiological methods. Niacin values are for preformed niacin only and do not include the niacin contributed by tryptophan, a niacin precursor. The term "niacin equivalent" applies to the potential niacin value, that is, to the sum of the preformed niacin and the amount that could be derived from tryptophan. In estimating the amounts of niacin available from foods, the mean value of 60 mg tryptophan is considered equivalent to 1 mg niacin (National Academy of Sciences 1989). Pantothenic Acid was determined microbiologically. Vitamins B6 and B12 were determined by microbiological or chromatographic methods. Vitamin B12 is found in foods of animal origin or those containing some ingredient of animal origin; i.e. cake that contain eggs and/or milk. For foods that contain only plant products, the value for vitamin B12 is assumed to be zero. Vitamin B12 has been reported in certain fermented foods (i.e. beer, soy sauce, and miso). It is believed that this B12 is synthesized not by the microorganisms responsible for the fermentation of the food, but rather by other contaminating microorganisms that may be present. Therefore, one should not consider these foods a reliable, consistent source of vitamin B12 (9). Folate - In this release, in addition to a total folate value that has been reported in the past, we are reporting values for folic acid, food folate, and total folate reported as g of DFE. This change responds to new Dietary Reference Intakes (DRI's) for folate issued by the national Academy of Sciences, Institute of Medicine, (NAS-IOM, 1998). Recommended Dietary Allowances for folate are expressed in dietary folate equivalents (DFE). DFE take into account the greater bioavailability of synthetic folic acid compared to naturally occurring food folate. To calculate DFE it is necessary to have separate values for naturally occurring food folate and added synthetic folic acid. µg DFE = µg food folate + (1.7 X µg folic acid) In 1998 (SR release 12), the folate values in the database were updated to reflect regulations requiring the addition of folic acid to enriched cereal grain products subject to standards of identity (CFR, Title 21, Pts. 136, 137). These products include flour, cornmeal and grits, farina, rice, macaroni, noodles, bread, rolls, and buns. Folic acid may continue to be added (with some restrictions on amounts) to breakfast cereals, infant formulas, medical foods, food for special dietary use, and meal replacement products. For the most part, values for this database were calculated based on enrichment levels specified in the regulations, since analytical values were not yet available. For those foods where the enrichment level is given as a range, the midpoint was used to set the value. Food items containing any of these enriched products as ingredients, such as baked products made with enriched flour, were also updated. In enriched and fortified foods, total folate includes both food folate and added folic acid. The total folate values found in SR11-1 preceded the implementation of the new enrichment standards and represent the amount of folate naturally occurring in foods. For this release we calculated folic acid by subtracting the food folate value in SR11-1 from the total folate content we estimated in fortified foods for SR12. For unenriched foods, the total folate value is food folate. Therefore the value for total folate with number of data points and standard error, if present, was also used for food folate. The folic acid value was assumed to be zero. Enriched ready-to-eat (RTE) cereals have generally included folic acid fortification for over 25 years. Therefore, food folate values were not readily available for these products. Food folate was estimated by means of the databank formulation program for a variety of high consumption cereals. Mean folate values were calculated for categories of RTE cereals based on grain content. Added folic acid was then calculated by subtracting estimated food folate from the total folate content reported in SR17. Most analytical values shown for folate were determined by the use of conjugase and Lactobacillus casei. Beecher and Matthews (1990) reported that the methodology used in determining folate values needed improvement, particularly, in the areas of extraction procedures and applications to specific foods. Research on determining the folate content of high-protein and high-carbohydrate foods indicates that additional improvements in methodology are needed (Martin et al. 1990). Limited amounts of data generated by USDA were obtained by the tri-enzyme extraction using additional enzymes, amylase and protease, to release bound forms of folate. Microbiological methods measure total folate; for enriched foods, folic acid and food folate are not distinguished from each other. Vitamin D Much of the data for vitamin D were published earlier (Weihrauch and Tamaki 1991). Values for breakfast cereals were updated based on data received from the food industry. Vitamin E - Vitamin E activity as defined by the DRI report (NAS/IOM 2000) is now limited to the naturally occurring form and three synthetic forms of a-tocopherol. For this reason, a-tocopherol equivalents, which included vitamin E activity from a-, ß-, ?-, and d-tocopherols and a-, ß-, and ?-tocotrienols, were dropped from the database in SR16. Tocopherols were determined by gas-liquid chromatography (GLC) or high-performance liquid chromatography (HPLC). For those items in FNDDS, values are presented for a-tocopherol. If analytical data were unavailable, values for a-tocopherol were imputed. When available, values are also presented for the other tocopherols. In the new Dietary Reference Intakes for Vitamin E (NAS/IOM 2000), different factors were used to calculate the milligram amount of a-tocopherol from IU of vitamin E. The factors vary depending upon the chemical form of a-tocopherol used to fortify the food where mg of a-tocopherol in food, fortified food, or multivitamin = IU of the RRR-a-tocopherol compound X 0.67 and = IU of the all rac-a-tocopherol compound X 0.45. Before SR16-1, the conversion factor for RRR-a-tocopherol was used for all vitamin E fortified foods. New a-tocopherol values have been calculated for breakfast cereals, most infant formulas and a few other foods, where we have confirmed that all rac-a-tocopherol was used. For more information about vitamin E in breakfast cereals, see the article in the January 2004 issue of the American Journal of Clinical Nutrition by Leonard et al. Vitamin K - Much of the data for vitamin K were generated under NFNAP and supersede the values in the Provisional Table (PT-104) (Weihrauch and Chatra 1994). Vitamin K is extracted with hexane, purified with solid phase extraction using silica columns, and quantitated using HPLC with chemical reduction and fluorescence detection. Losses are corrected using vitamin K1(25) as internal standard (Booth et al. 1994). Related topics include Proximates, Minerals, Amino Acids, Fatty Acids.

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