It may seem perfectly harmless to feed kids a meat-free diet. In fact, many parents feel that it’s “cleaner” and “more pure” to eliminate meat (vegetarian) or eliminate all forms of animal foods like eggs milk & cheese (vegan).
The Academy of Nutrition and Dietetics (AND), says a correctly planned vegan or vegetarian diet can be “appropriate for all stages of the life cycle including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes” in their 2016 position paper. The AND and the US Department of Agriculture (USDA) recommend that fortified soy products replace animal products as “healthy alternatives”.
But what are these organizations basing their recommendations on? What does the evidence show?
There have been several long-term epidemiological studies that have shown that vegetarian or vegan diets may lower the risk of certain diseases IN ADULTS. But, focusing specifically on children, who are most dependent upon high quality nutrition for proper growth, is there actual evidence that exists that vegetarian diets are safe?
A new paper by Nathan Cofnas published in Critical Reviews in Food Science and Nutrition takes a deep look at the existing research on children and meat-free diets. I know a lot of my readers don’t have time to read the entire article, so I’ve highlighted some of the best nuggets in this post. I want to make it clear that the author did NOT state that a meat-free diet is unhealthy, but after reviewing the research, his conclusion is the evidence showing a vegetarian diet is healthy for children is weak, and further states the AND is not in a position to recommend it as “safe” without more research.
Vegetarian diets and pregnancy
Growth starts with a healthy pregnancy, which allows the fetus to develop appropriately. One of the markers of healthy pregnancies and adequate nutrition is male to female sex ratio, which is usually 105:100. In stressed populations, for example during times of war, there tends to be an increase in miscarriage of male fetuses, resulting in a lower sex ratio. Malnutrition and lack of adequate calories during pregnancy has been identified as one cause of lower sex ratios. A 2000 study of over 6,000 pregnant women found that those who followed a vegetarian diet had a considerably lower sex ratio when compared to those who followed an omnivorous diet and were 23% less likely to give birth to a boy. The low birth ratio of vegetarian women may be an indication of physical stress caused by this eating pattern and impact fetus viability. There is no mention of this study, nor the risk of spontaneous abortion of male fetuses in the AND 2016 position statement referenced earlier.
Milk vs. Meat in Children
The AND recommends substituting meat with dairy, soy, or other vegetarian sources of protein, stating that these are nutritionally adequate and comparable substitutions for children. There has only been one controlled study to date that examines the exchange of milk for meat. This 2014 study evaluated the impact of the addition of meat, milk, or just additional calories to the diet of largely vegetarian children in Kenya and compared them to a control group, who received no additional food.
The results were fascinating. When measured for growth, intellectual ability, behavior, and academic performance, after two years, the meat group had by far the best outcomes. The milk group showed the least improvement on Raven’s Progressive Matrices (RPM—a measure of fluid intelligence), even when compared to the children that didn’t receive any additional calories. The meat group showed remarkably more physical ability, leadership, and significantly more physical growth during the study period. Those who only received milk, lagged behind the meat group in every aspect. Researchers believe that these results may be related to the impact milk has on iron absorption, which influences cognitive ability. They also suggest the improvements in performance in the meat group could be due to the intake of high quality protein, vitamin B12, zinc, and iron in the children’s diet all of which positively impact development.
Although this is only one study with some limitations, it’s the ONLY controlled study on milk vs. meat in children, and basically, it shows milk can’t replace meat. It’s completely reasonable to question how the AND can definitively say that milk is an adequate substitute for meat in a child’s diet.
Additionally, milk has been shown to have a huge connection to acne. What teen wants acne? The paper cites several studies showing an association between milk and acne, so substituting meat for milk, especially in teens, could lead to worse skin and all of the stress that comes along with a teen dealing with acne.
What About Soy and Kids?
The AND also recommends soy as a substitute for meat and a quality source of protein for vegetarians. The concern with a high intake of soy for children is the impact that phytoestrogens may have on their development. Phytoestrogens are naturally occurring substances in legumes and soy that may disrupt on how hormones function in the body. Endocrine (hormone) disruption may be of particular concern for children, especially during periods of development.
A 2010 review of the available evidence on the impact of phytoestrogens found that a high intake may lead to malformations of sex organs, infertility, abnormal hormonal cycles, and problems with ovarian function. One study evaluated in this review found that males born to vegetarian mothers were 3.5x more likely to have malformed genitalia. Most of the studies reviewed in this particular article were animal studies, which may or may not translate to humans, but further research is still needed to determine the impact of encouraging children to eat more legumes and soy, instead of meat.
Legumes and soy are high in an anti-nutrient called phytate, which inhibits the absorption of minerals such as iron and zinc. Deficiencies in these two minerals can have a serious impact on the cognitive and reproductive development of children. Additionally, plant-based sources of iron are not as bioavailable as animal-based, leading to an even greater risk of deficiency in children.
How About Eggs for Protein?
The paper criticizes the idea that eggs alone can meet the nutritional needs of pregnant women and children because of their low relatively content of protein, iron and zinc and high ratio of omega 6 to omega 3 fatty acids. Omega 6’s are pro-inflammatory, and although our bodies need some, we generally get way too much as it is. Typical eggs have a ratio of 15:1.
Other Nutrients Deficiencies from Avoiding Meat…
The AND seems to minimize the impact of missing nutrients and the evidence pointing to how it may affect the growth and development of children following vegetarian diets. In addition to the phytates in soy blocking absorption of certain minerals, other nutrients are often deficient in populations that avoid meat.
Vitamin B12 is a concern for vegetarian children as it is the only vitamin that is only found in animal sources. 52% of adult vegans have been found to be deficient in B12, as well as 26% of vegetarians, so this deficiency likely translates to children following these diets as well. A deficiency in B12 can lead to irreversible consequences for children including delayed cognitive development, lower academic performance, nerve damage, and failure to thrive. Due to the severity and long-term impact of these of these symptoms, the AND does recommend supplementation of B12 via fortified foods or supplements (I like this one) for all vegans and vegetarians. But, is it realistic to expect children to supplement this vitamin their entire lives? Is a diet that requires supplementation a biologically appropriate diet for growing kids?
Creatine is low in vegetarian diets and may also influence healthy brain development. Creatine supplementation has been shown in one study to improve cognitive performance (by a significant level) in vegetarians. Similar improvements were not seen in omnivores, suggesting that vegetarians were performing lower on the tests due to existing low creatine levels.
The results of this study suggest that a creatine deficiency may lower fluid intelligence and working memory by up to one standard deviation, approximately 15 IQ points. The decrease in cognitive function is reversed with supplementation of creatine. This particular study was with adults and there have not been any long-term studies on the impact of creatine intake and brain development in children, therefore we cannot determine what the effect might be.
Here’s a great quote from the article:
“It is possible that, although vegetarianism appeals to people with higher intelligence, becoming vegetarian reduces fluid intelligence and working memory… People may not notice a reduction in cognitive functioning when they become vegetarian if fluid but not crystallized intelligence is affected. (That is to say, becoming vegetarianism may impair one’s ability to solve problems without causing one to forget what one has learned, so the effect may not be noticeable.)”
Taurine works in the body as a neurotransmitter and impacts central nervous system development. This amino acid is traditionally low in vegetarian diets and absent in vegan diets. It is unclear what impact this has, but it is known that low taurine levels in infancy can impair long-term brain development.
EPA and DHA for Growing Brains
Lastly, eicoaspentaeoic acid (EPA) and docosahexanaenoic acid (DHA), the essential omega-3 fats found primarily in fish, are generally low or absent in vegetarian diets. DHA in particular is critical for normal brain, retina, and cell development. Low intake of EPA has been associated with depression and low meat intake with an increased risk of suicide in teenagers. To date are no studies on the long-term effects of inadequate intake of these particular nutrients during childhood, therefore the risks are unknown. Chris Kresser has a great post here on why vegans and vegetarians should supplement with DHA, (I like this supplement for DHA).
So, Is a Vegetarian or Vegan Diet Safe for Kids?
Again, Nathan Cofas did an excellent job combing through the literature and presenting a strong case that we just can’t be sure that it’s safe for kids to avoid meat. I know many that feel a well-planned vegetarian diet is better than a Standard American Diet, which could be so depending on what nutrients are being consumed, but considering the possible harm, and especially when B12 deficiency can cause permanent damage, I personally feel that the dangers of excluding meat are very real. Making a blanket statement about safety of vegetarian diets for the entire life cycle by simply extrapolating evidence from epidemiological adult studies is, in my opinion, irresponsible. There is simply not enough evidence to say a vegetarian or vegan diet is safe for kids, and it’s time that parents learn about the risks.