We hear about “plant-based diets” everywhere these days, but what exactly are they and how do they impact health?
Plant-based diets include plant-derived foods, that is, foods of plant origin such as vegetables, whole grains, pulses (beans), oilseeds (nuts), seeds and fruits, with little or no animal products.
In practice, eating patterns that are plant-based comprise from vegan diets (which do not include any animal products, e.g. meats, honey, dairy or eggs), through to vegetarian diets and semi-vegetarian diets.
Semi-vegetarian, also called flexitarian diets primarily contain plant-based, vegetarian and vegan products, and occasionally include meat, poultry, fish and or other animal-based foods. - The frequency and portions of animal-based foods consumed would be reduced and most nutrients would come from plant foods.
Vegetarian diets, in their turn, are still plant based but can have variations. Pescatarians, for example, eat fish and/or shellfish while lacto-ovo vegetarians eat dairy and eggs, but not meat, poultry or seafood. Ovo-vegetarians eat eggs but avoid all other animal foods, including dairy, and lacto-vegetarians eat dairy but exclude eggs, meat, poultry and seafood.
Finally, vegan is the strictest type of plant-based diet – it excludes any animal products, even honey, dairy and eggs. Many store-bought ready-to-eat products may contain animal-origin ingredients, so the labels on all manufactured products need to be read carefully if a vegan diet is followed.
Why choose a plant-based diet?
Plant-based diets are generally perceived in a positive light and lately have become more popular for those looking to reduce their consumption of animal products. People may choose this dietary pattern for reasons related to personal health and climate sustainability, animal welfare, among others. In fact, plant-based eating patterns have been recognised for their benefits to our health and the environment.
Health benefits of a plant-based diet are not new news as these diets are rich in fruits, vegetables, whole grains, beans and pulses, which are well known for their health benefits. They are very much in line with the food guidelines - nutritional and healthy eating recommendations - of the health authorities in many countries.
These benefits of plant-based diets are the result of a combination of factors, such as a higher intake of fibre, unsaturated fats, vitamins, minerals and bioactive compounds, and a lower intake of calories, sugars, sodium, saturated fats, red and processed meats.
What are the health benefits associated with plant-based diets?
Some benefits associated with plant-based eating are related to the reduction of the risk of chronic non-communicable diseases, such as coronary heart diseases, type 2 diabetes, and some types of cancer. Available scientific evidence indicates that plant-based diet reduces by 8-12% the risk of cardiovascular disease, by 18% the risk of type 2 diabetes and by 8-15% the risk of cancer. In addition, they are associated with a healthier body weight, improved metabolic health and better gut health.
Are all plant-based diets nutritionally complete?
A well-planned plant-based diet should meet all nutrient recommendations. Nevertheless, choosing to eliminate entire food groups can put one at greater risk of nutritional deficiencies, especially if not well balanced with alternative foods. One aspect that deserves further consideration includes the quality of protein, since vegetable proteins tend to be less nutritionally complete compared to animal protein. But be assured that mixing different sources of plant protein can overcome this issue. For example, a combination of chickpea, oat and pea protein in the right amounts can create a balanced protein quality source.
If dairy products are avoided, a calcium deficiency can occur, while omega-3 fatty acids may be lacking if certain types of fish are omitted from the diet. The nutritional status of vitamin B12 and zinc may be compromised especially if all animal products are avoided, and the iron status may be impaired as iron from plants is poorly absorbed.
A health care professional can help you find the right balance and ensure adequate intake of all required nutrients.
Can I go plant-based for health’s sake?
In short, yes! Not all plant-based foods are equal and just cutting back on animal products may not necessarily lead to optimal health, but a well-balanced plant-based diet tends to be higher in fibre and other positive nutrients while reducing the intake of nutrients which can have a negative effect on our health, also supporting a lower environmental impact compared to diets with animal products.
Renata Cassar, Senior Nutrition Manager, Global Nutrition
Ieva Laurie, Senior Principal Scientist, Global Nutrition
BDA, Plant-based diet, Food Fact Sheet, September 2017.
Bechthold, A., Boeing, H., et al. 2019. Food groups and risk of coronary heart disease, stroke and heart failure: a systematic review and dose-response meta-analysis of prospective studies. Critical reviews in food science and nutrition, 59(7), pp.1071.
Benatar and Stewart. Cardiometabolic risk factors in vegans; A meta-analysis of observational studies. Format: AbstractSend to PLoS One. 2018; 20;13(12):e0209086
British Dietetic Association, Plant-based diet, Food Fact Sheet, September 2017
Corrin and Papadopoulos, Understanding the attitudes and perceptions of vegetarian and plant-based diets to shape future health promotion programs. Appetite. 2017, 1;109:40-47.
Davila et al. 2018 The Microbiome and the Epigenetics of Diabetes Mellitus. https://www.intechopen.com/chapters/61271
Dinu et al. Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Cr Rev Food Sci Nut 2017; 57(17)
Hemler, E.C. and Hu, F.B., 2019. Plant-based diets for cardiovascular disease prevention: all plant foods are not created equal. Current atherosclerosis reports, 21(5), p.18.
Medawar et al. The effects of plant-based diets on the body and the brain: a systematic review. Translational Psychiatry 2019; 9:226
Melina, V., Craig, W. and Levin, S., 2016. Position of the academy of nutrition and dietetics: vegetarian diets. Journal of the Academy of Nutrition and Dietetics, 116(12), pp.1970-1980.
Qian, F., Liu, G., Hu, F.B., Bhupathiraju, S.N. and Sun, Q., 2019. Association between plant-based dietary patterns and risk of type 2 diabetes: a systematic review and meta-analysis. JAMA internal medicine, 179(10), pp.1335-1344
Rocha et al. Multiple Health Benefits and Minimal Risks Associated with Vegetarian Diets. Current Nutrition Reports. 2019; 8:374–381
Satija et al. Healthful and unhealthful plant-based diets and the risk of coronary heart disease in US adults. J Am Coll Cardiol. 2017; 25; 70(4): 411–422.
Tomova et al. The Effects of Vegetarian and Vegan Diets on Gut Microbiota. Front. Nutr. 6:47. doi: 10.3389/fnut.2019.00047
Veronese and Reginster. The effects of calorie restriction, intermittent fasting and vegetarian diets on bone health. Aging Clinical and Experimental Research 2019; 31:753–758
World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Continuous Update Project Expert Report 2018.