Adherence to Nutrition Recommendations and Use of Supplements Essential for Vegans

Typical deficiencies were an unbalanced use of protein sources, a low intake of berries, fruits and nuts, as well as failure to use nutrient fortified food products. The majority, however, used vitamin B12 and D supplements and calcium-fortified drinks as recommended.

Serum vitamin D concentrations were below the reference values in 24% of the vegan group. They also had lower concentrations of beta-carotene, selenium, iodine and essential fatty acids than the control group following a non-vegetarian diet.

 

Vegetarian and vegan diets are increasingly common in western societies. However, in order to ensure the intake of all the necessary nutrients, vegetarian and vegan diets need to be composed in a well-rounded manner. Research into the nutritional status of vegans nevertheless remains scarce.

 

The study analyzed the nutritional status of young adults who had been following a vegan diet for an average period of eight years. The study involved six male vegans and 16 female vegans, and the matched control group comprised eight men and 11 women who followed a non-vegetarian diet. The researchers were especially interested in the intake and concentrations of nutrients that are limited or lacking in vegetarian foods, for example vitamin B12, vitamin D, selenium, iodine and essential fatty acids. The food intake of the study participants was analyzed from three-day food records, and their nutritional status was measured from blood and urine samples.

 

Some vegans follow an unbalanced diet
The diet of the vegan group was exclusively limited to plant-based foods, and their intake of legumes, tofu and soy flour was higher than the control group's, but no other significant differences were observed. Nutrient supplements were used by 91% of the vegan group and 78% of the control group. Vitamin B12 supplementation was used by 91% of the vegan group, vitamin D supplementation by 77%, and the majority also used calcium-fortified drinks.

 

The vitamin B12 concentrations of the vegan group were within the reference values, as were the values of the control group. The serum vitamin D concentrations were below the reference values in 24% of the vegan group and in 6% of the control group. Vegans also had lower concentrations of beta-carotene, selenium, iodine and the essential EPA and DHA fatty acids. All in all, however, vegans had higher polyunsaturated fatty acid concentrations and lower saturated fatty acid concentrations than the control group. In addition, the concentrations of soy polyphenols were high in vegans.

 

The median concentration of iodine in urine was below the recommended levels in both groups. Earlier research shows that the intake of iodine has decreased in Finland over the past years. Iodine is present in milk and iodine-fortified salt, the use of which have declined.

 

According to the researchers, closer attention should be paid not only to intake of vitamin D, but also to iodine intake among vegans.

 

“In several European countries, iodine intake is on the lower side and doesn't reach the recommendation. Milk is the most important dietary source of iodine in many countries, because iodine is added to cow fodder (to keep them healthy),” Iris Erlund, Research Manager, National Institute for Health and Welfare in Helsinki, told NutritionInsight.

“Vegans do not consume milk products, so that's the main reason why their intake was lower compared to the controls,” Erlund added. “For Finnish vegans, iodized table salt is likely the most important source of iodine. But if someone doesn't eat many home-made meals, or if they switched to non-iodized salt, their iodine intake can be low.”

 

“An adequate intake of iodine prevents goiter caused by iodine deficiency. But it's also important not to get too much iodine,” she concluded.

 

According to nutrition recommendations, a vegan diet should involve a balanced, daily intake of whole grain products, legumes, seeds and nuts as sources of protein, as well as vegetables, fruits, berries and unsaturated fats. In addition, vegans should consume calcium-fortified drinks and use vitamin B12, vitamin D and iodine supplements to complement their diet.

 

The article published in PLOS ONE constitutes part of a larger study addressing vegetarian foods and analyzing the exposure of vegans to pesticides and nitrate. The leaders of the study are Professor Anna-Liisa Elorinne from the University of Eastern Finland's School of Applied Educational Science and Teacher Education, and Senior Officer Juha Laakso from the Finnish Safety and Chemicals Agency. The study also involved researchers from the University of Eastern Finland Institute of Public Health and Clinical Nutrition, the National Institute for Health and Welfare, and Helsinki University Hospital.