Research briefing: Book review – Eating Plant-Based: Scientific Answers to Your Nutrition Questions

Researcher Network member, Gelareh Salehi, reviews Eating Plant-Based: Scientific Answers to Your Nutrition Questions by RAC member Dr Shireen Kassam and Dr Zahra Kassam, a Q&A style book answering commonly asked questions and concerns about plant-based diets.

Vegan Society researcher Gelareh Salehi reviews the book Eating Plant-Based: Scientific Answers to Your Nutrition Questions, which is co-authored by Dr. Shireen Kassam (MB, BS, FRCP ATH, Ph.D., DmIBLM) and Dr. Zahra Kassam (MB, BS, FRCPC, MSc, DIPABLM). Dr Shireen Kassam and Dr Zahra Kassam are sisters, both medical doctors specialising in the treatment of cancer and with a combined 40 years of clinical experience. Eating Plant-Based provides the most recent scientific evidence, appropriate for all socio-demographic profiles (e.g., all genders or age categories) who are either following, or motivated to follow, a plant-based diet.

Motivation to follow a plant-based diet mainly relates to health, ecological, or animal rights concerns¹. Although there is a lack of precise definition, the term ‘plant-based’ addresses a diet centered around whole plant food sources, and which minimises the intake of animal-origin food products². According to Eating Plant-based, a diet that is centered at least 85% on whole plant foods fits under the umbrella term of plant-based.

Eating Plant-Based provides scientific evidence to answer common nutrition questions regarding the plant-based diet. These include questions about protein sources, iron, calcium, and iodine deficiency, reducing saturated fats, excess sugar, and gluten) as well as other myths such as those related to the consumption of coconut oil or B12 supplements.

Eating Plant-Based explains how swapping small percentages of dietary choices from the animal origin with plant-based alternatives contributes to the reduction of mortality³; risk of cardiovascular diseases⁴, cancers⁵, and diabetes⁶.

The authors undertake a classified approach in two main stages of transition to the plant-based diet, decreasing (1) animal-based food (meat; dairy; eggs, and fish); as well as increasing (2) plant-based food (fruits, vegetables, beans and nuts).

The authors shed light on the mythical link between too much fruit (fructose) consumption and diabetes. No study to date has shown findings that prove this idea. The authors quoted the acronym coined by Dr. Joel Fuhrman as an excellent guide to some of the healthiest plant-based nutrition sources: "G-BOMBS: Greens, Beans, Onions, Mushrooms, Berries, Seeds, and Nuts¹¹."

Legumes, beans, and pulses are the primary staples of a nutritious diet, containing B vitamins and fibre, manganese, copper, magnesium, zinc, phosphorus, iron, and potassium¹². Substituting animal-origin food sources for beans and legumes decreases the risk of type 2 diabetes and cancers¹³. In terms of consuming legumes, the authors explained that the claimed toxicity of the lectin in beans noted in some books is only related to the consumption of raw beans¹⁴. However, legumes are usually consumed cooked rather than raw. The observed longevity in the ‘Blue Zones’ where people consume a high number of legumes and vegetables also contributes towards the evidence that this is a health-promoting habit. 

Nuts are highlighted as a great source of nutrients such as protein, fibre, vitamin E, unsaturated fats, vitamin B6, folic acid, copper, calcium, zinc, magnesium, phosphorus, selenium, arginine, potassium, phytosterols, niacin, and polyphenols, to name a few¹⁵. Consuming nuts has been related to decreased risks of cancers, heart disease, and type 2 diabetes and also assists in controlling blood sugar. Authors top pick for the healthiest nut to consume is walnuts. Also, seeds from pumpkin, flax, or hemp are healthy choices as they are sources of protein, unsaturated fatty acids, and fibre.

Throughout the book, the authors Dr Kassam and Dr Kassam highlight the fact that plant-based diets should be well-planned to ensure they provide all necessary nutrients and contributing health-related benefits. Prevention of fatty liver disease¹⁶, kidney stones¹⁷, urinary tract infections¹⁸, migraines¹⁹, cataracts²⁰ (protein builds up in the eyes' lenses and makes them cloudy), or gallstone²¹; as well as decreasing arthritic pain²² and period pain in women²³; alleviating menopausal symptoms in women²⁴; improvement in autoimmune diseases²⁵ (e.g., rheumatoid, multiple sclerosis) are just some of the health-related benefits of plant-based diets that are documented in the book. In addition, exercise and other lifestyle determinants are also important for achieving health-related outcomes.

Eating Plant-Based presents tips about interpreting the health-related claims toward foods. For example, many research projects are funded by the producer of the specific food sources in question. However, a research project being industry-funded does not guarantee biased or unreliable findings. In this case, it is advisable to have a detailed look at the research design to evaluate the quality and reliability of the results.

Eating Plant-Based also sheds light on the environmental (ecological) impacts of mainstream food-related choices. For example, producing, distributing, and consuming animal-based food results in the production of greenhouse gas (GHG) emissions which are the main contributors to global warming and climate change²⁶. Moreover, animal agriculture is also responsible for land contamination, water pollution, and biodiversity loss. However, when a person switches to a vegan diet, 56% of their food GHG emissions are decreased and the nutritional quality of their diet can improve²⁷. Moreover, releasing the 70% of land mass currently used for agricultural purposes and creating a more efficient food system can help solve world hunger and bring justice for all²⁸.

In Eating Plant-Based, drawing on the existing scientific evidence, Dr Kassam and Dr Kassam also analyse how shifting to a more plant-based lifestyle will increase health outcomes and well-being during and beyond the current Covid-19 pandemic²⁹.  Studies have shown a direct relationship between animal farming, biodiversity loss, and zoonotic infections. These infections can be passed on to humans and cause pandemics. Another pandemic is predicted, a more significant threat than COVID-19 or avian influenza virus strains, such as the H5N virus (Bird Flu). Although rare if the transmission to humans occurs, a 60% chance of dying is expected for H5N³⁰. 90% of individuals who died in the first COVID-19 wave suffered from at least one underlying chronic disease, providing a new perspective on the importance of reducing the risk of chronic diseases through lifestyle changes.

The views expressed by the author are not necessarily the views of The Vegan Society

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