By Claire McDonnell Liu, Nutritionist at Leafie.org
Recent years have seen exponential growth in people following a plant-based diet. Americans identifying as vegan increased by 600% from 2014-2018 , with women of childbearing age most likely to follow this diet practice .
Environmental, animal welfare and personal health are the most cited reasons for this switch away from animal-derived foods, such as meat, fish, poultry and dairy products. However, there are critical factors to consider when opting for a plant-based food regime. Animal-based foods are often thought of as simply a source of protein and iron, yet, some key nutrients for brain health are predominantly, or even exclusively, found in animal food sources.
Plant-Based Diet Dismantled
In her 2022 ‘Should we be vegan?’ talk, Dr Zoe Harcombe efficiently dismantles the key arguments for a plant-based diet, that: it’s healthier; better for the planet; better for animals.
Methodically examining the best quality evidence available Dr Harcombe demonstrates that a vegan diet is nutritionally deficient, and detrimental to health, including research indicating that vegan diets relate to poor mental health outcomes. Harcombe highlights the stark point that strict vegan diets will require supplementation. In contrast, complete proteins, essential fats, minerals, vitamins, retinol, and heme iron are found most densely, and often only from, animal food sources.
Dr. Zoë Harcombe – ‘Should we be vegan?’
Respected international nutrition researcher Harcombe also challenges the environmental messaging around plant-based foods. Dr. Harcombe criticised assertions that cattle grazing land could be better utilised for crops, whilst calling attention to the huge environmental impact from the decimation of topsoil, insect, butterfly and small mammal species from intensive large-scale crop production, using pesticides, herbicides, and other chemicals. She concludes with key points that there is nothing that we could eat that nothing has died for and that when you are eating meat or dairy you are sustaining the land.
Nutrition Researcher, Belinda Fettke, sets out the fascinating historical context of how plant-based nutrition ideology came to dominate nutritional policy and the food landscape.
Fettke’s in-depth investigations show a troubling aspect of nutrition science, driven by religious and environmental ideals and deficient in rigorous science.
Belinda Fettke ‘The Evolution of Plant-Based Dietary Guidelines’
Dr. Paul Mason – ‘Logical Fallacies of a Vegan Diet: Why you shouldn’t feed your child a vegan diet’
In his recent talk at Low Carb Sydney, Dr Paul Mason, addresses the key arguments for plant-based nutrition. Focusing on the nutritional risks to health, particularly for maternal and child health, Dr Mason presents cases in recent years of infant deaths due to adherence to strict vegan diets and introduces research demonstrating significant cognitive and behavioural implications from adherence to stitch plant-based diets.
Plant-based Diet Nutritional Risks
The risk of malnutrition and broader health problems due to micronutrient deficiencies arising from plant-based diets should not be underestimated . Plant-based diets can be low in essential micronutrients, such as iron, zinc, vitamin B12, vitamin D, omega-3 fatty acids, calcium, and iodine.
Several European agencies have released statements warning of potential harm to children in following plant-based diets due to the risk of insufficient nutrients. The German Nutrition Society does not recommend vegetarian or vegan diets during pregnancy, lactation, and childhood, due to the inadequate supply of essential nutrients . Belgium Royal Academy of Medicine labelled vegan diets for children “unethical”, discouraging vegan diets in teens and nursing mothers. While the Spanish Pediatric Association recommend that children require special care if following a
vegetarian diet .
Plant-based diets have a low content of essential micronutrients such as iron, zinc, vitamin B 12, vitamin D, omega-3 fatty acids, calcium, and iodine. Consequently, the risk of adverse effects due to micronutrient deficiencies that lead to the risk of malnutrition should not be underestimated .
Vitamin B12 deficiency is one of the most serious and well-known complications of strict vegetarian or vegan diets. Vitamin B12 is an essential nutrient that is needed to form healthy red blood cells, create DNA, and nourish the brain and nervous system. Vitamin B12, or cobalamin, occurs naturally in meat, fish, and dairy products.
Some of the low-level symptoms of B12 deficiency include headache, fatigue, poor concentration, brain fog, low mood, and depression. Deficiency in Vitamin B12 can lead to neurological and psychiatric manifestations , leave profound lesions on the brain  or even result in death.
Recent years have seen distressing cases of babies being hospitalised, or even dying, due to B12 deficiency after being born and exclusively breastfed by strict vegetarian or vegan mothers.
Since women under 40 are most likely to be vegans and vegetarians  it’s paramount for women of childbearing age restricting animal products to be aware of the importance of B12 supplementation.
Choline is another vital brain health nutrient found in animal products, such as egg yolk, liver, beef and oily fish. Your body uses choline to produce a neurotransmitter called Acetylcholine that plays key roles in learning, memory, attention and healthy sleep. The amount of choline in the diet influences how much Acetylcholine is available in the brain and central nervous system. Since plant-based foods contain much less this puts vegans at risk of insufficiency.
According to the World Health Organisation the single most important cause of preventable brain damage worldwide is iodine deficiency. Iodine is linked to cognitive and intellectual deficits  across populations. Iodine is a mineral, seaweed is naturally rich in seaweed, fish and seafood. It is also added to animal feed, making eggs and dairy good sources, and available in iodised salt in some countries. Studies show that omnivores meet or exceed minimum levels, whereas vegetarians have moderate to low amounts, and many vegans are deficient .
Omega-3 Fatty Acids.
Irreplaceable fats are the building blocks of brain cells, they are also essential for mood regulation, cell signalling, and switching off inflammation. Unfortunately, hardly anyone is eating enough of the food sources of these fats, oily fish. An algae-based omega-3 supplement may be helpful for those restricting animal products.
The Legacy of Poor Nutrition
Poor nutrition in pregnancy and childhood can influence child brain development, affect IQ, memory and attention. Less known is the long-term link between inadequate nutrition and violent and aggressive behaviours. The Mauritius Child Health Project found that children who had experienced malnutrition at age three were more likely to show aggression at age eight, and to exhibit externalising behaviours, like kicking, biting, stealing, or lying. At seventeen they were more likely to display aggressive and destructive behaviours .
It’s important to recognise that children have different food needs than adults. Rapid growth and brain development in toddlers and infants require more micronutrients compared to adult’s needs. Young children’s smaller stomachs limit their intake capacity, making it essential to provide a nutrient-dense diet.
The foods we eat today will influence our health over the next weeks and months, but many of us do not recognise that this nutritional foundation will also influence the health of our children and grandchildren, as demonstrated by the Dutch ‘Hunger Winter’ Birth Cohort Study . The study found that the impact of stress and undernutrition in the womb had a long-reaching impact on the health of the children and also on the health of their descendants.
Inadequate nutrition impairs our ability to think, reason and regulate our emotions. Nutrients don’t only help to fuel our bodies, they are powerful regulators of cell function, brain development and gene activity. What we eat or don’t eat can have a huge impact on our health and the health of the generations after us.
Given that women under 40  make up the largest proportion of vegans or vegetarians women of childbearing age restricting animal products must be aware of the need to supplement, particularly those planning pregnancy or breastfeeding.
In his book, Our Children Our Legacy – Passing on the Gift of Good Health, Dr Tim O’Dowd offers a guide on how families may build a strong nutritional foundation for lifelong health, starting before conception.
The bottom line is if you are cutting out animal-based foods from your regular diet be mindful of potential nutrient deficiencies and take steps to address them, particularly regarding prenatal, infant and child health.