Abstract
Background: Choline is an essential nutrient, which is required for brain development and methyl group metabolism. Betaine is produced by oxidation of choline, and is also important because of its role in the donation of methyl groups to homocysteine to form methionine. The requirement for choline was set as an Adequate Intake (AI) of ~ 550 mg and 425 mg/day for adult men and women, respectively, with additional choline recommended during pregnancy and lactation. Currently, there is no dietary requirement for betaine. Although choline and choline esters are widely distributed in food, recent data from US NHANES found that only a small portion of Americans were achieving the recommended intake. Betaine can also be found in a variety of food sources, and can be used as a methyl donor, thus sparing some choline requirements. To date, there are no dietary data on choline and betaine intakes in the New Zealand population, and it is therefore unknown whether choline intakes of New Zealanders meet the recommended AI level.
Objective: The overall aim of this study was to estimate choline and betaine intakes of a sample of New Zealand reproductive age women, and to compare these intakes with the Nutrient Reference Values for adequacy and excess.
Design: Cross-sectional dietary analysis of 140 healthy reproductive age women enrolled in a folate intervention trial. Dietary information was obtained in 2008 using 3-d weighed food records. Average nutrient intake was calculated using nutrient values obtained from the US Department of Agriculture (USDA) database for standard reference and the USDA Database for the Choline Content of Common Foods Release Two.
Results: Of the 140 participants enrolled in the study, weighed 3-d food records were analysed for 99 participants. The mean (SD) intake of choline and betaine was 302 (57) mg/d and 156 (64) mg/d, respectively. The total choline intake relative to energy intake and body weight was 0.17 mg/(kcald) and 4.9 mg/(kgd), respectively. Only 12.1% of participants met or exceeded the AI for adult women of 425 mg/d. The top five major food contributors of choline were egg, red meat, milk, bread and chicken; and of betaine were bread, breakfast cereal, pasta, grain and carrot/beetroot/parsnip/swede.
Conclusion: Our findings contribute towards the recent emergence of published reports on the range of dietary choline and betaine intakes consumed by free-living populations. In our sample of New Zealand women of child bearing age, few participants were meeting or exceeding the AI level. Nationally representative survey data should be used to determine the choline and betaine content of the diet of New Zealanders across the lifecyle. In the meantime, given recent epidemiological evidence suggesting health benefits of increased choline and betaine intakes, recommendations should be made to encourage the consumption of choline and betaine-rich foods.