Vegetables and Mixed Dishes Are Top Contributors to Phylloquinone Intake in US Adults: Data from the 2011-2012 NHANES

Abstract

Background: Phylloquinone is the most abundant form of vitamin K in US diets. Green vegetables are considered the predominant dietary source of phylloquinone. As our food supply diversifies and expands, the food groups that contribute to phylloquinone intake are also changing, which may change absolute intakes. Thus, it is important to identify the contributors to dietary vitamin K estimates to guide recommendations on intakes and food sources.Objective: The purpose of this study was to estimate 1) the amount of phylloquinone consumed in the diet of US adults, 2) to estimate the contribution of different food groups to phylloquinone intake in individuals with a high or low vegetable intake (≥2 or <2 cups vegetables/d), and 3) to characterize the contribution of different mixed dishes to phylloquinone intake.Methods: Usual phylloquinone intake was determined from NHANES 2011-2012 (≥20 y old; 2092 men and 2214 women) and the National Cancer Institute Method by utilizing a complex, stratified, multistage probability-cluster sampling design.Results: On average, 43.0% of men and 62.5% of women met the adequate intake (120 and 90 μg/d, respectively) for phylloquinone, with the lowest self-reported intakes noted among men, especially in the older age groups (51-70 and ≥71 y). Vegetables were the highest contributor to phylloquinone intake, contributing 60.0% in the high-vegetable-intake group and 36.1% in the low-vegetable-intake group. Mixed dishes were the second-highest contributor to phylloquinone intake, contributing 16.0% in the high-vegetable-intake group and 28.0% in the low-vegetable-intake group.Conclusion: Self-reported phylloquinone intakes from updated food composition data applied to NHANES 2011-2012 reveal that fewer men than women are meeting the current adequate intake. Application of current food composition data confirms that vegetables continue to be the primary dietary source of phylloquinone in the US diet. However, mixed dishes and convenience foods have emerged as previously unrecognized but important contributors to phylloquinone intake in the United States, which challenges the assumption that phylloquinone intake is a marker of a healthy diet. These findings emphasize the need for the expansion of food composition databases that consider how mixed dishes are compiled and defined.

Keywords: NHANES; dietary assessment; nutrition counseling; phylloquinone; vitamin K; warfarin.

FIGURE 1

Contribution (%) of vegetable (A) and mixed-dish (B) subgroups to dietary vitamin K intake in the diets of US adults (aged ≥20 y; high vegetable intake, n = 1117; low vegetable intake, n = 3133) in NHANES 2011–2012 by food group categories. Data are presented as means ± SEs. *Different from high vegetable intake, P < 0.01.