What the Health: Is a vegan diet healthier?

22 Nov 2021

Is a vegan diet more beneficial for health - for the consumer and for the environment? Well… it all depends!  

The vegan diet contains exclusively plant-derived food products, excluding animal issued products such as meat, eggs, seafood, dairy products, and any food products that include ingredients derived from animals (such as biscuits made with butter or eggs).

Plant derived foods aren’t all classified as “healthy.” Plant derived food can be ultra-processed, devoid of nutritional value, contain an unfavourable ratio of sugar, salt and unhealthy fats. These products can require numerous industrial processing steps that add to the global greenhouse gas emissions and environmental footprint. Therefore, like any other dietary patterns, the choice of food products in a vegan diet is key.

A healthy diet provides all nutritional characteristics to meet physiological prerequisites to sustain health and should be environmentally sustainable to support food security with limited negative impact on natural resources.

Physiological requirements include: 1) the energy to maintain all biological functions, and 2) the food constituents needed as co-factors for biochemical pathways, antioxidant function, and as building blocks of body structures. The characteristics of a sustainable diet include 1) the consumption of primarily locally cultured foods, 2) variation according to seasons, and 3) limitation of excessively processed foods.

A vegan diet can certainly achieve all of this, assuming a good knowledge of food composition and how human requirements are adequately met. For example, vitamin B12 is crucial for neurological and cardiovascular health and is found naturally exclusively in animal products. It is also found in fortified food products where the synthetically produced vitamin is added through processing methods. The belief that certain algae provide vitamin B12 is a misconception because the apparent cobalamin-analogue in such algae is not bioavailable for humans, therefore inactive in the body.

Another example is the omega-3 essential fatty acid alpha linoleic acid (ALA), which is the precursor of the long chain polyunsaturated fatty acids EPA and DHA. ALA must come from the diet as the body is unable to produce it. ALA is found in a variety of plant products such as flaxseed, hempseeds, walnuts. EPA and DHA are the fatty acids important for cardiovascular, brain and eye health. They are produced in the body from ALA through elongation and desaturation, however these processes are poorly efficient in humans.

Luckily, EPA and DHA are found in the diet in generous amounts in oily fish (therefore fish oil) and in red meat, especially from game animals. EPA and DHA are also found is phytoplankton (microalgae), which fish consume. These unicellular microorganisms are used to produce industrially EPA and DHA rich oils for supplementation. Acceptability in a vegan diet remains an individual choice however, as they are bacteria, not plants.

When choosing to consume these essential nutrients as supplements or via fortified foods, the added processing steps need consideration: is this the healthiest way to meet one’s requirements? On the other hand, as sustainability of the fish supply is largely challenged, biotechnology developments target novel sources of essential fatty acids with promising outcomes.

 A vegan diet can be a very healthy diet when food sources are carefully selected, with consumer and environmental health in mind. Is it a “healthier diet”? Not necessarily, because it all depends on the comparator diet, and on the individual’s requirements and circumstances.

Veronique Chachay is the coordinator and lecturer of the nutrition science courses in the undergraduate nutrition major Programs, and the applied food science for dietetics course in the Master on Dietetics Studies, in the School of Human Movement and Nutrition Sciences. Her nutrition science expertise is applied in a wide range of research fields, including regulation of energy expenditure via brown fat activation, dietary factors modulating alpha diversity in inflammatory bowel disease, and energy intake meeting requirements in motor neuron disease.