Nutrient Intakes of Vegetarians and Vegans

The table below shows the nutrient intakes of participants in the EPIC-Oxford study. A few caveats should be noted:

This data did not include supplements people were taking, but it did include fortified foods.

They list vitamin A as measured in micrograms of retinol, rather than retinol activity equivalents (RAE). Plant foods do not contain retinol, yet they list the vegans as having an intake. But that intake seems very low compared to what would be expected if they were including carotenoids. So, it is unclear how they determined vitamin A.

These nutrient intakes were based on food frequency questionnaires (FFQ) which are the least accurate way of measuring nutrient intakes. FFQs involve asking someone how often they eat a long list of foods. Two better ways to measure nutrient intakes are to ask participants to keep a food diary, or to analyze duplicate portions in a laboratory. EPIC-Oxford has plans to report nutrient intakes by using food dairies among a sample of the population. The authors reported that:

"Seven-day food diaries were completed by 31,000 participants and these will provide further information on energy intake. Preliminary analysis of a sample of 150 food diaries indicates that the FFQ does indeed underestimate intakes of energy, and therefore of most nutrients, among vegans (unpublished data)."

Footnotes

1. Davey GK, Spencer EA, Appleby PN, Allen NE, Knox KH, Key TJ. EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non meat-eaters in the UK. Public Health Nutr. 2003 May;6(3):259-69.