In my recent blog post “Are Vegan and Vegetarian Diets Optimal During Pregnancy?" I discussed the problems with research comparing vegan/vegetarian pregnancies to omnivorous ones and addressed the many nutrient deficiencies that may cause harm to a growing fetus. In this post, I discuss the potential health implications of vegan and vegetarian diets for kids.
The Academy of Nutrition and Dietetics recently issued a position statement stating that “appropriately planned vegetarian, including vegan, diets are… appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, [and] adolescence.”(1) This statement shook me up because it clearly ignores the evidence that veganism and vegetarianism pose risks of altered brain and body development in infants and children. The reality of the matter is that children are rapidly-growing creatures with high macronutrient and micronutrient needs, many of which cannot be obtained in sufficient amounts (or in some cases, at all) from a vegan or vegetarian diet. According to a recent review published in Critical Reviews in Food Science and Nutrition, “realistic vegetarian [and vegan] diets put children at risk for deficiencies that may have both short-term and permanent negative health consequences.” (2) Let’s cover some of these nutrient deficiencies and their health implications for infants and children:
Problem #1: Long-term studies of vegetarianism and veganism have been conducted on adults, not children
In nutrition research, epidemiological studies are helpful for elucidating associations between specific dietary patterns and health outcomes. While there have been a number of long-term epidemiological studies of adult vegetarians and vegans, there have been no long-term studies examining the effects of these diets in children. This is a significant problem because growing infants and children have different nutritional needs from adults! For example, they require very high amounts of an omega-3 fatty acid called DHA for brain growth; coincidentally, the richest source of DHA is seafood, a food group absent from vegan and vegetarian diets. DHA can be made from the plant-based omega-3 fatty acid alpha-linolenic acid (ALA), but this conversion is inefficient in many people, necessitating the consumption of straight DHA for optimal brain development. I will cover the other nutrients especially crucial for children’s health in the following sections.
Problem #2: Vegan and vegetarian diets are low in B12
In my previous blog post about the risks of veganism and vegetarianism in pregnancy, I discussed the prevalence of B12 deficiency in these diets due to their low levels or complete omission of animal foods. Low B12 intake is extremely harmful for children and is one of the most pressing concerns in children on vegan and vegetarian diets.
B12 plays intrinsic roles in DNA synthesis, methylation reactions, maintenance of genomic stability, and neurological development and function. Central nervous system development begins during week 3 of gestation and continues throughout infancy and early childhood. A deficiency of B12 during this gestation and early life adversely affects brain development by causing imbalances in neurotrophic and neurotoxic cytokines in the brain and by inhibiting myelination or causing demyelination of nerves (myelin is an insulating sheath that surrounds nerves and facilitates nerve transmission). (3) These effects can cause irritability, failure to thrive, apathy, wasting, and developmental regression in infants. In children, B12 deficiency is associated with lower scores of fluid intelligence, impaired cognitive and school performance, depression, weakness, fatigue, and nerve damage. (4) Children who are B12 deficient are also at an increased risk of school absenteeism and grade repetition compared to children with sufficient B12 levels.
How do omnivorous children compare to vegan children in regard to B12 status and B12-related health outcomes? A study in the Netherlands compared adolescents who had grown up on a macrobiotic vegan diet to children raised on an omnivorous diet; adolescents on the macrobiotic diet had significantly lower scores of fluid intelligence compared to omnivorous adolescents. This difference was attributed to low intake of B12 in the vegan adolescents. (5) In another fascinating study of elementary school children in Israel, higher meat consumption was associated with better school performance, presumably due to the rich vitamin B12 content of meat. (6) Clearly, an omnivorous diet offers significant health benefits over a vegan diet regarding promoting optimal B12 status and B12-related health outcomes.
Problem #3: Vegan and vegetarian diets are low in creatine
Creatine is a compound formed in protein metabolism that plays a little-known but crucial role in cognitive functioning. It is most abundant in red meat, pork, poultry, and fish, with lesser amounts in dairy, eggs, and shellfish. This means creatine is typically absent from vegan diet and present only in low quantities in vegetarian diets.
A double-blind, placebo-controlled study (the gold standard in scientific research) found that six weeks of oral creatine supplementation significantly improved test scores of fluid intelligence and working memory in vegetarians. According to the authors, “the difference in performance between the control and the creatine-supplemented vegetarians was enormous.” (7) However, creatine supplementation has no effect on meat-eaters. (8) These findings indicate that creatine deficiency in vegans and vegetarians impairs cognitive function and reduces performance on tests that have a strong relationship with IQ. This means that while vegetarianism often appeals to people with higher intelligence, becoming vegan or vegetarian may actually reduce intelligence and working memory! These implications are especially significant for children, who are undergoing formative stages of brain development.
Problem #4: Vegan and vegetarian diets are low in taurine
Taurine is an amino acid that plays a role as a neurotransmitter, promotes the development of the central nervous system, and acts as a neuromodulator and neuroprotectant. The highest amounts of taurine are found in shellfish and dark meat chicken and turkey. Vegetarians and vegans have a low taurine intake. (9) Studies of infants indicate that low taurine impairs brain development; (10) this harmful effect may extend into childhood if a child’s diet is deficient in taurine. Furthermore, researchers think that dietary taurine intake may be responsible for the neurodevelopmental benefits of breastmilk; if a vegan or vegetarian woman is deficient in taurine, this may impact her breastfed infant's neurodevelopment. (11)
Problem #5: Low and poor-quality protein intake on vegan and vegetarian diets
Children require adequate protein for optimal growth and development. Vegan and vegetarian diets contain less-bioavailable and lower quantities of protein than omnivorous diets and may put a child at risk for protein deficiency.
The protein-digestibility corrected amino acid score (PDCAAS) evaluates the quality of a protein in terms of its amino acid profile and how much of it is digested (aka its bioavailability). The PDCAAS scale rates proteins on a scale of 0-1, with values close to 1 representing more complete and better-absorbed proteins than ones with lower scores. On the PDCAAS scale, animal proteins are consistently rated much higher than plant proteins. (12)(13)(14) For example, dairy proteins, chicken, turkey, fish, and beef rank between 0.92 and 1.00 on the scale whereas plant proteins rank much lower; wheat gluten is rated 0.25, lentils are 0.52, and kidney beans are 0.68. Unfortunately, the PDCAAS does not consider antinutrients in plant foods, such as phytic acid. If it did, the PDCAAS scores for plant proteins would rate even lower because antinutrients reduce the bioavailability of protein.
Poor-quality protein intake is not the only problem with vegetarian and vegan diets; Children on these diets are also at risk for low protein intake in general. A study of macrobiotic vegan children found that 59 percent of the infants had a protein intake of less than 80 percent of the recommended daily intake.
Problem #6: Vegetarian and vegan diets are low in long-chain omega-3’s
Omega-3 fatty acids are a family of polyunsaturated fats that can’t be made by the human body and therefore must be consumed in our diet. There are three main omega-3’s in the human diet: Alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). EPA and DHA come mainly from fish (it is possible to get these omegas from certain types of algae) whereas ALA is found in walnuts, flax, chia seeds, and leafy vegetables. ALA can be converted into EPA and DHA, but the conversion is very limited.
DHA is essential for brain and eye development in infants and children. Vegans typically don’t consume any EPA or DHA, and vegetarians consume very little (egg yolks from pastured hens contain some EPA and DHA). (15) Studies have found that plasma concentrations of EPA and DHA, which reflect dietary intake of these omega-3’s, are 52.8% and 58.6% lower in vegetarians and vegans, respectively, than in omnivores. (16) These findings suggest that vegan and vegetarian children are at risk for omega-3 fatty acid deficiency, which is associated with ADHD, dyslexia, dyspraxia (poor coordination/clumsiness), depression, and autism spectrum disorders. (17)
Problem #7: Vegan diets are low in calcium
Adequate calcium intake is needed to support bone and dental health. Calcium also plays essential roles in cell signaling, blood clotting, muscle contraction, and nerve function. Calcium intake for vegan children is likely below current recommendations. (18) While there are plant foods that contain calcium, such as spinach, almonds, and sesame seeds, these foods are also high in phytic acid and oxalates, which inhibit calcium absorption. For example, you would need to eat 16 cups of spinach to get the same amount of bioavailable calcium as one glass of milk. (19) Furthermore, meat enhances the absorption of calcium. (20) Low bioavailable calcium intake in vegan children (this is less of a concern for vegetarian children if they are eating dairy) may compromise bone and tooth enamel formation and maintenance. Can’t vegan and vegetarian children just take calcium supplements? While this may seem like an easy solution, I do not recommend it. Calcium supplements are associated with increased risks of kidney disease, arterial calcification, and heart disease in adults; whether these potential harms extend to children is unknown, but I would nonetheless be cautious and avoid giving calcium supplements to kids. (21)(22)
Problem #8: Vegan and vegetarian diets are low in iron and zinc
Iron and zinc are the most bioavailable when consumed in animal foods. While some plant foods contain non-heme iron (the less bioavailable of the two forms of iron – heme and non-heme) and zinc, these foods are simultaneously high in phytic acid, which significantly inhibits the absorption of minerals.
Iron and zinc deficiencies have serious consequences for children. Iron deficiency causes impaired neural processing and problems with learning and memory. Zinc deficiency impairs growth, causes neurosensory disorders, and impairs cognitive and motor development. (23)
Clearly, vegan and vegetarian diets pose some significant risks for children. In light of this information, I do not believe it is wise or responsible for health authorities to deem vegan diets as safe for children. Vegetarian diets are much safer than vegan diets, if they contain eggs and dairy, but may still not be optimal for growth and development compared to omnivorous diets.