Young Vegans May Lack Some Essential Nutrients

Teens who choose a vegan lifestyle (a vegetarian diet without dairy products) may not get enough riboflavin, vitamin B-12, vitamin D, calcium and selenium in their daily diets without taking dietary supplements, according to Swedish nutritionists.

Since about 5% of Swedish students aged 16 to 20 eat a vegetarian school lunch, this group of teens posed an ideal testing ground for the nutritionists, Drs. Christel L. Larsson and Gunnar K. Johansson, of Umea University (Am J Clin Nutr 2002; 76:100). The two researchers studied the dietary intakes of 30 vegans (15 males and 15 females) and 30 sex-, age- and height-matched omnivores. The mean age was 17.5 years. All 30 vegans had stopped eating meat primarily for ethical reasons; 4 also added health reasons. Nutritional intake was established through diet histories taken during interviews, use of the doubly labeled water method, and measurements of nitrogen, sodium, and potassium excretion in urine. Iron status and serum vitamin B-12 and folate concentrations were measured through blood samples.

Results

First, male vegans weighed less than, and had a lower body mass index (BMI) than, male omnivores (22.0 and 20.5, respectively). There was no difference in BMI and body weight between female omnivores and female vegans.

Next, both vegans and omnivores got a large portion of their daily energy intake from between-meal snacks (33% and 40%, respectively). The vegans had dietary intakes (excluding supplements) that were lower than the average daily requirements for riboflavin (males only), vitamin B12 and vitamin D (females only), calcium, and selenium. Calcium and selenium intake remained low for vegans even with dietary supplements. Six (20%) of female vegans and 7 (23%) of omnivores had low iron levels; low iron was as common among omnivores as vegans. As a group, the vegans had lower vitamin B12 levels and higher folate concentrations than did omnivores.

Finally, the authors note that it is important for adolescents in general, and teenaged vegetarians in particular, to be given practical information about how to combine and prepare a healthy daily diet.