Vegans adhere to nutrition recommendations in varying degrees, according to a new Finnish study. Some vegans who participated in the study followed a balanced diet, while others had dietary deficiencies. 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. The findings were published in PLOS ONE.
The serum vitamin D concentrations were below the reference values in 24 percent 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.
According to the researchers, the findings highlight the need of vegans to get nutrition guidance and to use the recommended nutrient supplements. Moreover, closer attention should be paid to the intake of vitamin D and iodine among vegans.
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.
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 percent of the vegan group and 78 percent of the control group. Vitamin B12 supplementation was used by 91 percent of the vegan group, vitamin D supplementation by 77 percent, 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 percent of the vegan group and in 6 percent 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.
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