Jean A.T. Pennington

Food Sources and Dietary Intakes of Vitamin K-1 (Phylloquinone) in the American Diet

OBJECTIVEnTo identify important food sources and estimate dietary intake of vitamin K-1 (phylloquinone) in the American diet.nnnDESIGNnCore foods from the US Food and Drug Administration (FDA) Total Diet Study (TDS), which was based on the 1987-88 Nationwide Food Consumption Survey (NFCS), were analyzed for vitamin K-1. These nutrient values were then applied to the FDA TDS consumption model.nnnSUBJECTSnOf the NFCS participants within the 14 selected age-gender groups, 3,634 who had 3 days of dietary data were included in the FDA TDS consumption model.nnnMAIN OUTCOME MEASURESnVitamin K-1 intakes were estimated for each of the age-gender groups; the percentage contribution of each food item to total intake of vitamin K-1 was calculated from the FDA TDS model.nnnRESULTSnOf the 14 age-gender groups selected, the 25- to 30-year-old women and men consumed less than the current Recommended Dietary Allowance (RDA) for vitamin K. In contrast, formula-fed infants had estimated vitamin K-1 intakes six times greater than the RDA. All other groups consumed amounts within the recommended daily intakes but lower than 90 micrograms/day. The top contributors to total vitamin K-1 intake were dark-green vegetables, although the fats and oils added to mixed dishes and desserts were also important contributors. The proportion of vitamin K-1 obtained from vegetables increased with age.nnnAPPLICATIONSnThe data identify important dietary sources of vitamin K-1 in the American diet. This knowledge can be used to develop dietary assessment instruments for use in epidemiologic studies.

Iron, zinc, copper, manganese, selenium, and iodine in foods from the United States Total Diet Study.

Abstract Data on the concentrations of iron, zinc, copper, manganese, selenium, and iodine in the 234 foods of the United States Total Diet Study from 1982 to 1989 were summarized per 100 g and per typical serving portion. Foods highest in these elements per serving were ready-to-eat cereals, mixed dishes, and meats for iron; meat, mixed dishes, and ready-to-eat cereals for zinc; meat, nuts, mixed dishes, and beans/peas for copper; ready-to-eat cereals, nuts, and beans/peas for manganese; fish, meat, poultry, and mixed dishes for selenium; and ready-to-eat cereals, dairy desserts, mixed dishes, fish, and dairy products for iodine. Coefficients of variation for the microelements in the top 20 food sources per serving averaged 28% for iron, 20% for zinc, 26% for copper, 25% for manganese, 32% for selenium, and 104% for iodine. In addition to genetic, environmental, processing, and analytic variables, causes for variability of these microelements in foods most likely include inconsistent and varying levels of fortification with microelements and food additives containing microelements.

Dihydro-vitamin K1: Primary food sources and estimated dietary intakes in the American diet

Dihydro-vitamin K1 was recently identified as a dietary form of vitamin K produced during the hydrogenation of vitamin K1-rich vegetable oils. Dihydro-vitamin K1 is absorbed, with measurable levels in human plasma following dietary intake. To determine the primary food sources of dihydro-vitamin K1 in the American diet, 261 foods from the U.S. Food and Drug Administrations (FDA) Total Diet Study (TDS) were analyzed by high-performance liquid chromatography. Of these foods, 36 contained dihydro-vitamin K1. Fast-food items that were otherwise poor sources of vitamin K1, such as french fries and fried chicken, contained appreciable amounts of dihydro-vitamin K1 (36 and 18 μg/100 g, respectively). These nutrient values were then applied to the FDA TDS consumption model to determine average dietary intake of dihydro-vitamin K1 in 14 age-gender groups. With the exception of infants, all age-gender groups had estimated mean daily dihydro-vitamin K1 intakes of 12–24 μg, compared to mean daily vitamin K1 intakes of 24–86 μg. The vitamin K1 and dihydro-vitamin K1 intakes were summed, and the dietary contribution of dihydro-vitamin K1 was expressed as a percentage of total vitamin K intake. Children reported the highest intakes of dihydro-vitamin K1 (30% of total vitamin K intake), followed by a progressive decrease in percentage contribution with age. There are currently no data on the relative bioavailability of dihydro-vitamin K1 but, given its abundance in the American diet, this hydrogenated form of vitamin K warrants further investigation.

Sodium, potassium, calcium, phosphorus and magnesium in foods from the United States total diet study

Abstract Data on the concentrations of sodium, potassium, calcium, phosphorus, and magnesium in the 234 foods of the United States Total Diet Study from 1982 to 1989 are summarized per 100 g and per typical serving portion. Per serving, mixed dishes and soups were higher in sodium; mixed dishes, root/tuber vegetables, and dairy products were higher in potassium; dairy products were higher in calcium; dairy products, mixed dishes, and animal flesh were higher in phosphorus; and nuts, mixed dishes, and legumes were higher in magnesium. Of the top 20 foods highest in each element per serving, the coefficients of variation averaged 20% (range 10–48%) for sodium, 15% (range 2–47%) for potassium, 21% (range 12–24%) for calcium, 14% (range 7–22%) for phosphorus, and 17% (range 7–24%) for magnesium. Nutrient variation reflects genetic, environmental, processing, and analytic factors. Sodium variability most likely reflects the variable amount of salt added to foods and recipe ingredients by industry.

Issues of food description

Food names and descriptions identify and distinguish among foods listed in databases. Descriptive terms may be captured in free form with the food name and in faceted systems. The INFOODS Food Description System is faceted with free text. The International Interface (which includes LANGUAL) is a faceted system with standardized vocabulary. Faceted systems provide a checklist to fully describe foods, and they allow for retrievals and matching of foods among databases. On-line dictionaries can be used to clarify implicit and complex food names. Relevant descriptive information varies among foods and food types. Information about cooking methods, ingredients, recipes, cuisine and preparation location is important to fully define some foods. Sample descriptions (as opposed to food descriptions) identify the products analyzed in the laboratory. Market share and default entries should be clearly identified. Pictures of foods (hard-copy or computerized) are useful for product identification. A universal system to describe foods will enhance the sharing and exchange of food composition data.