In a systematic review and meta-analysis published in the journal Critical Reviews in Food Science and Nutrition, scientists provide a detailed overview of the health effects of a vegan diet among children and adolescents.
Review: Health aspects of vegan diets among children and adolescents: a systematic review and meta-analyses. Image Credit: kuvona / Shutterstock
Plant-based diets, including pescetarian, lacto-ovo-vegetarian, and lacto-vegetarian, are gaining importance because of potential individual and planetary health reasons. Increasingly, vegan diets are becoming popular due to the negative impact animal food consumption has on human and planetary health.
A vegan diet is characterized by the consumption of only plant-based foods and the complete elimination of animal-based foods, including dairy and eggs. Evidence indicates that about 6% of Americans and 3% of Europeans are following vegan diets.
The vegan diet is associated with lower protein, fat, and total energy intake and higher intakes of carbohydrates and unsaturated fatty acids. The diet is known to reduce cardiometabolic risks among adults. However, the diet may have a negative impact on bone health. However, not enough evidence is available about the health effects of a vegan diet among children and adolescents.
This systematic review and meta-analysis were carried out to analyze available human studies on the health effects of a vegan diet among children and adolescents.
A total of 2075 studies published up to August 2023 were selected from various scientific databases for the initial screening. Of these studies, 18 were included in the systematic review and meta-analysis. A high or very high risk of bias was observed in 7 out of 18 studies.
The findings of the meta-analysis revealed higher intakes of carbohydrates, fibers, and polyunsaturated fatty acids among vegan children compared to omnivorous children who eat both plant-based and animal-based foods. In contrast, lower intakes of proteins, saturated fatty acids, and cholesterol were observed among vegan children.
Vitamin and mineral intake
The meta-analysis found that vegan children consume more folate, vitamins C and E, magnesium, potassium, and iron than omnivorous children. However, they showed lower intakes of vitamin B2 than omnivorous children.
Although a lower intake of calcium was observed among vegan children in the selected original studies, the meta-analysis could not find any significant difference between the two groups. A higher blood level of vitamin B12 and a lower blood level of ferritin were observed among vegan children compared to omnivorous children.
The meta-analysis showed that vegan children have comparatively lower height than omnivorous children. However, no significant differences in body weight and body mass index (BMI) were observed between the two groups.
As mentioned by the scientists, the observed changes in height among vegan children could be due to the inclusion of younger vegan children in one study. The meta-analysis excluding this study found no significant differences in height between vegan and omnivorous children. Overall, significant differences in demographic characteristics, including age and sex, were observed between vegan and omnivorous children in the selected studies.
The meta-analysis found lower blood levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol among vegan children. However, the two groups' blood levels of triglyceride, hemoglobin, holotranscobalamin (a marker of vitamin B12), and homocysteine remained comparable.
Randomized controlled trial
A randomized controlled trial involving children with high BMI and blood cholesterol levels was included in this systematic review. The trial was designed to compare the nutritional impact of a vegan diet, a diet recommended by the American Heart Association, and a Mediterranean diet.
According to the trial findings, vegan children had a higher reduction in protein, vitamin B12, and vitamin D intake. A reduction in cholesterol intake, waist circumference, fasting glucose, systolic and diastolic blood pressure, and myeloperoxidase (an inflammatory enzyme) was observed in all studied groups.
Single study findings
Some of the selected studies indicated lower intakes of docosahexaenoic acid and eicosapentaenoic acid, higher intakes of alpha-linolenic acid, and lower bone mineral content among vegan children. However, these outcomes could not be meta-analyzed because of a lack of a sufficient number of studies.
This systematic review finds both positive and negative health effects of a vegan diet among children and adolescents. Given the lower intake of proteins among vegan children, scientists suggest that future studies should specifically focus on the protein quantity and quality among these children.
Deficiencies in certain vitamins and minerals observed among vegan children might impact their bone health. This health issue can be resolved by supplementing the diet with appropriate minerals and vitamins. The scientists recommend that future studies assess the risk of osteoporosis and fractures among adults who have been consuming a vegan diet since childhood.
Lower LDL and total cholesterol levels observed among vegan children might indicate a lower risk of cardiovascular disease. Previous evidence indicates a lower 10-year risk of cardiovascular disease and related mortality among vegan adults.