Nutrient intake and haematological status of vegetarians and age-sex matched omnivores

Objective: The study was designed to investigate the nutritional intake and haematological status of adult vegetarians. Design: Cross-sectional comparison of vegetarians and age/sex-matched omnivores. Setting: Free-living community subjects. Subjects: Fifty vegetarians were recruited by local advertisement. Each vegetarian selected their own age/sex-matched 'friend' control. Outcome measures: Each subject completed a 12 day dietary record. Haemoglobin, red cell indices, and serum ferritin, B12 and folate were measured. Results: Protein, saturated fat and vitamin D intake were significantly lower in the vegetarians, particularly in the vegans. Dietary fibre was higher in the vegetarians, and intake of calcium and zinc was similar. Mean (SD) iron intake in the vegetarians and vegans of 16.8 (4.8) mg/day was significantly greater than that of the omnivores: 14.6 (4.3) mg/day (P = 0.02). All the iron consumed by the vegetarians was non-haem; for the omnivores 10% was haem iron. Serum ferritin concentrations were significantly lower in male vegetarians than omnivores: mean (SD): 36.6 (36.0) and 105.4 (78.7) ng/ml, respectively, P < 0.01; and significantly more had values below 12 ng/ml (P < 0.001), despite having higher iron intakes which exceeded the Recommended Nutrient Intake (RNI). Female vegetarians also had lower ferritin concentrations than omnivores; mean (SD) 13.6 (7.5) compared to 33.6 (54.3) ng/ml, P < 0.01, but similar numbers of women had values below 12 ng/ml (42% and 39%). The vegans all had B12 intakes below the RNI: and 35% of the long-term vegetarians and vegans had serum vitamin B12 concentrations below the reference range. Conclusion: Although the vegetarians had diets nearer to the recommended diet with a lower fat and salt content, a significant number need advice to improve their haematological status. Recommended intakes of iron may also need to be higher for vegetarians, particularly men.