Mixed Dishes are a Top Contributor to Vitamin K Intake in US Adults: Data from the 2011–2012 NHANES

Abstract

The primary dietary form of vitamin K in US diets is phylloquinone (PK), which is found in green vegetables and vegetable oils. PK content of foods are provided in the USDA National Nutrient Database for Standard Reference, which helps to estimate current dietary intakes. As our food supply diversifies and expands, food groups contributing to dietary PK intake are also expanding. It is important to identify the contributors to dietary vitamin K estimates to guide healthcare professionals and recommendations on food sources of vitamin K.The purpose of this study was to estimate: (1) the PK consumed in the diet of US adults; (2) the contribution of different food groups to PK intake in individuals with high or low vegetable intake (≥ 2 cups < 2 cups vegetables/day); and (3) to characterize the contribution of different mixed dishes to PK intake.We used data from adults (≥ 20 y; 2092 men and 2214 women) participating in NHANES 2011–2012, a nationally‐representative complex survey, to determine usual PK intake correcting for measurement error with the National Cancer Institute method. Food group classifications were determined according to the USDA What We Eat in America food groupings. The proportion of PK supplied by each food group and mixed dishes was compared between low and high vegetable consumers, using multiple t‐tests with Bonferroni‐Dunn correction for multiple comparisons.On average, 43.0% of men and 62.5% of women met the AI of 120 and 90 μg/day of PK, respectively. Vegetables were the highest contributor to PK intake, contributing 60.0% and 36.1% in high and low vegetable intake groups, respectively. Mixed dishes were the second highest contributor, contributing approximately 16% and 28% of total PK intake in high and low vegetable intake groups, respectively (all p<0.001 between vegetable intake groups). Within mixed dishes, grain based dishes including macaroni and cheese, pasta, and rice dishes contributed to 25% of dietary PK, followed by sandwiches (9.7%), and pizza (10%) in the low vegetable intake group. In individuals with high vegetable intake, primary sources of dietary PK in mixed dishes were soups (23%), “Asian” dishes (e.g., fried rice with soy sauce, 21.5%), and meat and poultry (17.9%).Our findings suggest mixed dishes are a significant contributor to PK intake in the United States. Unique to mixed dishes is the large contribution of grain‐based foods that often lack PK‐rich vegetables. Additional research is required to further quantitate other vitamin K forms in the US food supply, and to identify all dietary sources of vitamin K to better guide recommendations for vitamin K intakes in the U.S.Support or Funding InformationSupported by USDA Agricultural Research Service under Cooperative Agreement No. 58‐1950‐7‐707 and 58‐1235‐1‐193.