Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the product-precursor ratio [corrected] of α-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort

Am J Clin Nutr. 2010 Nov;92(5):1040-51. doi: 10.3945/ajcn.2010.29457. Epub 2010 Sep 22.

Abstract

Background: Intakes of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) are important for health. Because fish is the major source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), non-fish-eaters may have suboptimal n-3 PUFA status, although the importance of the conversion of plant-derived α-linolenic acid (ALA) to EPA and DHA is debated.

Objective: The objective was to determine intakes, food sources, and status of n-3 PUFAs according to dietary habit (fish-eaters and non-fish-eating meat-eaters, vegetarians, or vegans) and estimated conversion between dietary ALA and circulating long-chain n-3 PUFAs.

Design: This study included 14,422 men and women aged 39-78 y from the EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk cohort with 7-d diary data and a substudy in 4902 individuals with plasma phospholipid fatty acid measures. Intakes and status of n-3 PUFAs were measured, and the product-precursor ratio [corrected] of ALA to circulating n-3 PUFAs was calculated.

Results: Most of the dietary intake of EPA and DHA was supplied by fish; however, meat was the major source in meat-eaters, and spreading fats, soups, and sauces were the major sources in vegetarians. Total n-3 PUFA intakes in non-fish-eaters were 57-80% of those in fish-eaters, but status differences were considerably smaller [corrected]. The estimated product-precursor ratio [corrected] was greater in women than in men and greater in non-fish-eaters than in fish-eaters.

Conclusions: Substantial differences in intakes and in sources of n-3 PUFAs existed between the dietary-habit groups, but the differences in status were smaller than expected, possibly because the product-precursor ratio [corrected] was greater in non-fish-eaters than in fish-eaters, potentially indicating increased estimated conversion of ALA. If intervention studies were to confirm these findings, it could have implications for fish requirements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Animals
  • Cohort Studies
  • Diet Records
  • Diet*
  • Diet, Vegetarian*
  • Fatty Acids, Omega-3* / administration & dosage
  • Fatty Acids, Omega-3* / biosynthesis
  • Fatty Acids, Omega-3* / blood
  • Female
  • Fishes*
  • Humans
  • Male
  • Meat*
  • Middle Aged
  • Seafood*
  • Sex Factors
  • alpha-Linolenic Acid / metabolism*

Substances

  • Fatty Acids, Omega-3
  • alpha-Linolenic Acid