,
Health

Is Meat Consumption Essential for a Healthy Diet? (A Scientific Perspective)

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Professor Amtul Razzaq Carmichael & Aroosa Mahmood

Veganism and vegetarianism have become increasingly popular in society, especially after athletes and professional trainers promoted the health benefits of a fully plant-based diet. The increasing trend in veganism and vegetarianism has encouraged the debate surrounding the controversy concerning meat consumption. In some parts of the world, people are forced to adopt a vegan or vegetarian diet because of the lack of resources and economic constraints. In the West, the benefits and controversies of meat consumption are debated, and morality and ethical justification of a non-plant-based diet are raised. Controversies of meat consumption include ethics of killing animals for human consumption, added nutritional value of animal sourced-food, health risks associated with eating meat and the practical implications of a total meat-free diet. In this article, we will investigate from a scientific perspective the role of meat in a healthy and balanced diet.

Human Beings and Meat Consumption; How Far Back Does This Go?

Meat has played an important and central role in the development and progress of the human species. The archaeological evidence suggests that early humans consumed meat as a source for food and energy as early as four million years ago.[1] It is suggested that meat consumption led to numerous adaptations, including a rapid increase in brain size, and altered gut structure. For their physical size, humans have a maximally large brain and a minimally small gut. Therefore, to optimise energy intake for a physically demanding existence of human beings, a certain amount of meat intake was essential.[2]

Historically, meat consumption was justified based on the anthropocentric view by Saint Aquinas, who argued that the high value of human life justified the consumption of animal meat. Even a cursory reflection on the natural food chain makes it abundantly clear that lesser and weaker animals are eaten by the stronger and superior animals in the food chain. Traditionally, the Islamic concept of meat consumption is not based on the food chain philosophy because humans have a sense of morale and have the intelligence to make the right choices. The concept of eating meat is rooted in the philosophy of dedication, commitment, and self-sacrifice to attain a greater cause.

What are the Scientific Recommendations About Eating Meat?

The United Nations food intake guidelines that are adopted by the Public Health England endorse eating meat as part of a balanced and healthy diet.[3] Meat is the main source of proteins, vitamins and minerals, such as vitamin B12, selenium, zinc, niacin, phosphorus and iron in bioavailable forms. A moderate intake of a variety of foods, including meat remains the best nutritional advice.

What are the Benefits of Eating Meat?                    

Meat is one of the most nutrient-dense foods, providing high-quality protein and vitamins B6 and B12.[4] Professor Nigel Scollan, (Director of Institute for Global Food Security) – Queen’s University, Belfast, asserts animal-based proteins have a higher nutrient density when compared to plant-based proteins. Meat is not only energy-dense but is also rich in high-quality proteins which contain more essential amino acids than plant equivalents. In particular, essential amino acids such as lysine is largely lacking in plant-based food. Meat has a high score for digestibility as measured by a protein–digestibility–corrected amino acid score (PDCAAS). As compared to the meat PDCAAS score of 100, plant-based food such as potatoes, rice and wheat have the PDCAAS score of 82, 62 and 51, respectively.[5] Thus, a diet containing any amount of meat can easily provide human requirements of total protein and amino acids. Poultry and fish are a rich source of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) essential for brain health. All the essential components of nutrition are easily available in a balanced diet containing red meat and poultry. However, for those who chose to or are forced to avoid meat for social or economic reasons, deficiency of some micronutrients can become a problem, unless they obtain their food from a wide range of plant sources.

Meat is also a rich source of iron called ‘haem iron’; this form of iron is readily available for the body to use (bio-available) as it is absorbed two to three times more readily than non-haem iron.[6] As people mature with age, their ability to absorb Vitamin B12 decreases, making it essential to include rich sources of Vitamin B12 in everyday diet.[7] Though Vitamin B12 deficiency can be common, evidence suggests that those who do not consume meat are more vulnerable to Vitamin B12 deficiency[8]. A study of 689 male participants found that half of the vegan participants were classified as Vitamin B12 deficient. Vitamin B12 deficiency in women can increase the risk of congenital abnormalities in their babies, such as neural tube defects[9].

Is Meat Consumption Required to Maintain a Healthy Body Weight?

As part of a balanced and nutritious diet, meat is a vital food component of weight gain. An intake of 250g meat leads to the annual weight gain of 422g, which is higher than the average weight increase with a similar diet of lower meat intake. This is likely to be due to the high energy and fat content of the meat as the satiety is higher with a diet containing high protein content and leads to less energy intake; an important strategy to weight loss.[10] This needs to be balanced with the evidence that a non-meat diet can help prevent becoming overweight and obese and promotes weight loss.[11] People who do not consume meat tend to be underweight, underweight women are more likely to develop osteoporosis (reduces bone mass and makes bones brittle) or becoming more susceptible to developing an eating disorder leading to mental health issues. For example, Bulimia is positively related to symptoms of depression, and low self-esteem[12].

Is Meat Required to Maintain Optimum Health? 

Throughout the life cycle of human beings, a balanced and nutritious diet is essential. Meat, especially lean red meat, provides essential nutrients and energy to maintain optimum health without the need for supplements. Modern science has consolidated the evidence that meat consumption is part of a balanced, healthy diet and increases energy and protein levels.[13] Adequate protein, intake as part of a balanced diet is required to support brain development, cognitive function, stronger muscles, and bone maintenance. This is particularly important for improving strength and daily functioning. In the aging population, bone and muscle health is vital to prevent the risk of falls, fractures, and physical disability.[14] The optimum human existence of a long life, high-reproductive rate and maintaining relatively large and demanding brains requires meat to be the part of a healthy, balanced, and optimum diet.

Is Meat Required to Maintain Mental Health?         

The most recent systemic review[15] of 160, 257 participants aged between 11-96 years (54% females and 46% males), including more than 8000 meat-abstainers demonstrated that those individuals who avoided meat consumption had significantly higher rates/risk of depression, anxiety and self-harm behaviours. A study of more than 4000 patients from Germany found that a vegetarian diet is associated with an elevated risk of mental disorders such as anxiety, depression, eating disorder and hypochondriasis.[16] Pellagra is protein-calorie-malnutrition that was known as the ‘lazy’ disease with emotional, cognitive, and physical stunting alongside many degenerative diseases leading to brain atrophy and subsequent low IQ/dementia and poor social behaviour.

Another issue linked to the controversies surrounding meat consumption is the stereotypes and stigma surrounding it. For example, it is frequently reported as a gender issue, with eating meat being categorised as being more ‘masculine'[17], which may make someone more subconsciously inclined to eat meat or refrain from it. However, on the contrary, the Gamechangers (2018) documentary helps eradicate this common stereotype that eating meat is somehow more ‘masculine’ and depicts how society, (particularly in America) suggests that men often require meat to be strong.

Does Eating Meat Lead to Chronic Diseases?    

Despite all the health benefits of meat-based nutrition, there has been increasing concern regarding a range of chronic diseases that are associated with the excessive consumption of meat, such as cardiovascular disease, type 2 diabetes and certain cancers, particularly colon cancer.[18] This needs to be viewed in the context of current lifestyle choices. A significant part of the diet of our hunter-gatherer ancestors was meat-based and these diseases were unknown in that population. The current average UK consumption of red and processed meat remains high, 86 g/d among men and 56 g/d among women (recommended 70 g/d) of red meat), but with the modern transport, household appliances and working practices, physical activity of modern humans is significantly lower[19]. Most of these health-hazards of meat consumption are associated with excessive intake of red and processed meats. The exact mechanism by which meat may lead to an increase in these chronic diseases is not fully understood, but the chemicals in processed and smoked meat may be a contributory factor. It must be noted that the moderate consumption of lean meat is not associated with an increase in chronic diseases.[20] It is suggested that excessive meat intake at the cost of plant-based nutrients, and unhealthy lifestyles lead to the development of chronic diseases.[21]  Elderly people who follow a vegan or vegetarian diet report lower incidences of high blood pressure, diabetes, obesity and heart disease. Although, even following these diets the elderly need to be receiving the right quantities of protein, calcium, and calories.[22]

Is a Meat-Free Diet Harmful to Health?  

A diet poor in meat can lead to several nutritional deficiencies such as general malnutrition, micronutrient deficiencies, and pellagra. Pellagra is a deficiency disease which is often associated with the over-dependence on maize as a staple food.[23] Goldberger demonstrated that pellagra was dietary in origin and due to a lack of meat and milk and can be treated with adequate dietary proteins.[24]

The implications of a meat-free diet on vulnerable groups such as infants, adolescents, pregnant and lactating mothers, and elderly need special attention. Meat has always played an important role as part of a balanced diet in these groups and there is no robust evidence that replacing vital nutrients with supplements can safeguard the health of these vulnerable groups.[25]

Though many meat alternatives are available and affordable for the population in the rich Western regions, so that they can attain adequate nutrition from non-meat sources. However, in many parts of the world, where food availability is limited, meat provides a vital source of a highly nutritious diet.[26] We argue that meat is widely available from land and sea sources; therefore, fresh meat can be made accessible to people in most parts of the world in every season. Regular access to meat, which is an excellent source of high-quality proteins and nutrients has the potential to alleviate malnutrition worldwide. Whereas a diet which is totally meat-free can be detrimental to human health.

Does Meat Consumption Cause Harm to the Environment?

It is argued that meat production is placing a substantial burden on global finite resources and contributes to global warming and climate change. Meat consumption is associated with the emission of greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, which is around 10 percent of all greenhouse gas emissions. Continued meat production at the current rate for the next 100 years will lead to less than 0.10C increase in global warming.[27] Prof Scollan argues that the nutrient density of food, defined as the degree of health and well-being that food contributes, could be an important factor to take into consideration to address the environmental impact of food consumption.[28]

It must not be ignored that cows and sheep act as bio-converters and convert inedible plant-material such as grass into high value, high-nutrient proteins, and essential micronutrients, such as iron and zinc. Intensive and battery farming for overproduction of meat adversely impacts the environment. It is argued that these climate effects can be effectively mitigated by moderate consumption of meat, careful management of grassland systems, improved efficiency and waste reduction. Research has indicated that eating less meat can reduce greenhouse gas emissions while also providing sufficient dietary requirements for health. [29]

Is Meat Consumption a Wise Choice?

Cultural and traditional influences are likely to affect an individual’s willingness to eat or not eat meat. Previous research on meat consumption habits has suggested that there is a paradox of attitudes towards the impact of meat on health, animal welfare and the environmental aspects. It was found that people who are concerned with animal life were often unwilling to change their dietary habits[30]. This suggests that disconnecting animals from meat is a strategy to prevent feeling guilty about eating meat and appreciating that ‘a living being has to die for you to eat meat’ (2011). However, hypothetically speaking, if the world became vegetarian or vegan, it would put substantial pressure on farmers, especially with the crop that is imported or traded from other countries. The economy would also inevitably be affected, for example, butchers would lose their jobs and many restaurants would have to find alternatives for several of their menus. Importing exotic food as meat alternatives from faraway places may add to the burden of environmental damage. 

In conclusion, meat is an important part of a healthy and balanced diet. Moderate meat consumption has many health benefits and eliminating meat from the diet can pose several health risks and an excess of meat consumption leads to negative consequences on the health, environment, and climate. Indeed, the answer to the question about the meat consumption has been given in the Holy Qur’an centuries ago; ‘eat and drink but do not be immoderate.’ [31]

Professor Amtul Razzaq Carmichael MD, M Ed, FRCS (Gen Surg.), MBBS, is a consultant. She qualified in 1987 with gold medals for academic Excellence and undertook her surgical training at major teaching hospitals in London, Edinburgh and Philadelphia. She has authored many articles for major peer-reviewed scientific journals. She is a senior member of The Review of Religions Editorial Board as well as Assistant Manager.

Aroosa Mahmood is a Psychology Undergraduate student in Sheffield and has a keen interest in research relating to food and animal welfare. 


ENDNOTES

[1] https://pubmed.ncbi.nlm.nih.gov/29945745/

[2] https://www.sciencedirect.com/science/article/abs/pii/S0309174018301712

[3] http://www.fao.org/nutrition/education/food-dietary-guidelines/regions/countries/united-kingdom/en/

[4] https://pubmed.ncbi.nlm.nih.gov/26043666/

[5] https://europepmc.org/article/med/30209430

[6] Pereira P.M.C.C. & Vicente A.F.R.B. (2013). – Meat nutritional composition and nutritive role in the human diet. Meat Sci., 93 (3), 586–592.

[7] https://betterhealthwhileaging.net/podcast/bhwa/vitamin-b12-deficiency-risks-diagnosis-treatment/

[8] Gilsing, A.M., Crowe, F.L., Lloyd-Wright, Z., Sanders, T.A., Appleby, P.N., Allen, N.E. and Key, T.J., 2010. Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study. European journal of clinical nutrition64 (9), p.933

[9] https://pediatrics.aappublications.org/content/123/3/917?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=mills&searchid=1&FIRSTINDEX=0&sortspec=date&resourcetype=HWCIT

[10] https://pubmed.ncbi.nlm.nih.gov/16002798/

[11] https://pubmed.ncbi.nlm.nih.gov/28630616/

[12] Willcox, M. and Sattler, D.N., 1996. The relationship between eating disorders and depression. The Journal of social psychology136(2), pp.269-271.

[13] https://www.researchgate.net/publication/315047406_Meat_and_Nicotinamide_their_causal_role_in_our_evolution_history_and_demographics

[14] https://pubmed.ncbi.nlm.nih.gov/25041653/

[15] https://www.tandfonline.com/doi/full/10.1080/10408398.2020.1741505

[16] https://ijbnpa.biomedcentral.com/articles/10.1186/1479-5868-9-67

[17] https://www.tandfonline.com/doi/full/10.1080/10408398.2020.1741505

[18] Wok A. (2016). – Potential health hazards of eating red meat. J. Intern. Med., 281 (2), 106–122. doi:10.1111/joim.12543.

[19] Bates A, Lennox A, Prentice A et al. (2014) National Diet and Nutrition Survey Results from Years 1, 2, 3 and 4 (Combined) of the Rolling Programme (2008/2009–2011/ 2012). London: Public Health England

[20] Mann NJ. Dietary lean red meat and human evolution. Eur JNutr 2000; 39: 71–9.

[21] https://pubmed.ncbi.nlm.nih.gov/31486336/

[22] https://caringpeopleinc.com/blog/vegan-diet-seniors/

[23] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5417583/pdf/10.1177_

[24] Goldberger J, Wheeler GA: Experimental pellagra in the human subject brought about by a restricted diet. Public Health Rep 1915; 30:3336-3339

[25] https://pubmed.ncbi.nlm.nih.gov/26643369/

[26] Smith J., Sones K., Grace D., MacMillan S., Tarawali S. & Herrero M. (2013). – Beyond milk, meat, and eggs: role of livestock in food and nutrition security. Anim. Front., 3 (1), 6–13. doi:10.2527/af.2013-0002

[27] https://pubmed.ncbi.nlm.nih.gov/30026199/

[28] https://www.bbc.co.uk/food/articles/meat_environment

[29] Macdiarmid, J.I., Douglas, F. and Campbell, J., 2016. Eating like there’s no tomorrow: Public awareness of the environmental impact of food and reluctance to eat less meat as part of a sustainable diet. Appetite96, pp.487-493.

[30] Bastian, B., 2011. The meat paradox: How we can love some animals and eat others. The conversation.

[31] The Holy Qur’an, Chapter: 7, Verse: 32