Dr Shireen Kassam and Dr Zahra Kassam | Contributors - Nourish plant-based living

Dr Shireen Kassam and Dr Zahra Kassam

Dr Zahra and Dr Shireen Kassam are sisters, cancer doctors, and board certified Lifestyle Medicine Physicians with a special interest in plant-based nutrition. Shireen is founder of Plant-Based Health Professionals UK, and Zahra is co-founder of Plant-Based Canada. Their first joint book, Eating Plant-Based: Scientific answers to your nutrition questions, was published in 2022.


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Eating up the world

There is a link between the climate crisis and what’s on our plates. The hard facts are astounding, as is the difference a plant-based change can make.

Greenhouse gas (GHG) emissions are contributing significantly to global warming and climate change. The Intergovernmental Panel on Climate Change (IPCC) has warned us about the dire consequences of the projected global warming of 1.5°C above pre-industrial levels, which could happen in the next decade. This includes extreme heat, increased and more frequent flooding and droughts, rising sea levels, species loss and extinction, and risks to human health, livelihoods, food security, water supply, and economic growth.

The IPCC report released in 2021 states that it is “unequivocal” that human activity has warmed the atmosphere, the ocean, and the land on a scale that is “unprecedented” over thousands of years. Already, human-induced climate change is resulting in many weather and climate extremes in every region across the globe. Many changes due to GHG emissions are already “irreversible” for centuries to millennia. GHG concentrations have continued to increase and are “attributed largely to human activities, mostly fossil fuel use, land use change, and agriculture”. Urgent action is needed. The goal of the Paris Agreement is to prevent this catastrophic rise in temperature, yet, in 2020, scientists warned that without a drastic change to our food system, we will not be able to keep within these temperature limits and that dietary change is the most important approach to meeting these climate-change targets.

Dietary change is the most important approach to meeting [our global] climate-change targets

THE EMISSIONS ON OUR PLATES

Half of the world’s habitable land is used for agriculture, with more than 80 percent of farmland globally used for meat and dairy farming, be it for grazing animals or growing food for animals. Even though estimates vary, the food system is responsible for over a quarter, if not a third, of the world’s GHG emissions, and the production and consumption of meat, dairy, and eggs accounts for more than 60 percent of these emissions.

A more recent paper presented the results of a Global Sensitivity Analysis and suggested that animal agriculture is in fact responsible for a whopping 87 percent of GHG emissions. Even the most sustainably produced animal foods generate more GHG emissions than any plant foods, regardless of the distance travelled to get to your plate. The emissions from animal agriculture are greater than those from all forms of transportation combined.

It is not just the carbon emissions from animal agriculture that are problematic but also the methane produced by wetland rice systems and ruminant animals, and nitrous oxide from fertiliser and manure. Methane is an even more potent GHG than carbon, by 25 times, trapping the sun’s heat and warming the Earth 86 times as much as the same mass of carbon dioxide over a 20-year period. Within animal farming, methane is generated from the burps of ruminant animals – principally, cows and sheep – and global emissions continue to rise dramatically, in part due to animal agriculture and farming. Raising ruminant animals for meat and dairy alone accounts for around half the GHG emissions from animal agriculture.

Some argue that because methane is relatively short-lived in the atmosphere – only 10 years compared with hundreds of years for carbon dioxide – it matters less. This does not mean we should continue producing methane. It means we have a chance in a shorter period to significantly reduce these emissions. In fact, it seems we have been vastly underestimating the contribution of methane from intensively raised animals to GHG emissions by as much as 90 percent, despite the prevailing narrative that factory farms use less land and are a more ‘efficient’ way to raise animals for food.

The United Nations is clear: we have to address methane emissions now in order to keep global warming below levels associated with irreversible and catastrophic consequences.

THE POLLUTION IN PRODUCTION

Nitrogen emissions from animal farming are also increasingly problematic. These emissions come from nitrogen present in synthetic and organic fertilisers and animal manure and urine, resulting in nitrous oxide generation, another potent GHG gas. Nitrous oxide is 300 times more potent than carbon dioxide, trapping more heat and remaining in the atmosphere for longer than methane – over 100 years. Animal agriculture contributes around a third of nitrogen emissions, with most of that coming from the production of animal feed.

The vast quantities of animal manure produced from farming not only emit nitrous oxide but also contaminate land and pollute our water systems. The safe management and disposal of this manure are becoming impossible tasks. The waste from animal farming is contributing to air pollution from gases such as ammonia, hydrogen sulphide, nitrous oxide, and methane. These gases have an adverse impact on human health, with farm workers and people living close to animal farming operations having an increased risk of asthma and other lung problems and cardiovascular diseases.

A first-of-a-kind study from the US determined how the production of various foods impacted air quality and consequent health outcomes. The study showed that 17,900 deaths a year were attributable to air pollution caused by agriculture, with ammonia emissions, farm animal waste, and fertiliser application accounting for most of these deaths. Altogether, 80 percent of these deaths were attributed to the production of animal-derived foods, with red meat the greatest contributor. The production of all plant foods considered was less polluting than any animal foods. The authors concluded that a shift to vegetarian and vegan diets would vastly improve air-quality-related health issues.

THE PLANT-BASED DIFFERENCE

There is a vast inefficiency in the current food system when you consider that animal farming produces only 18 percent of the calories and 37 percent of the protein consumed globally while using over 80 percent of farmland.

Farmed animals themselves also consume more calories and protein than they produce for human consumption. Conservative estimates show that farmed animals consume between six and 12.5 kilograms of plant protein to produce a single kilogram of animal protein. This means that we currently produce enough food to feed two planets. If we were all to transition to eating a meat- rich diet typical of the 20 most industrialised countries, we would need seven planets to produce enough food!

If we all adopted a 100 percent plant-based or vegan diet, we could reduce the land used for food production by 76 percent and GHG emissions from the food system by up to 50 percent. The land released would then be able to be used to capture significant amounts of carbon. Crops can also be produced in a manner which allows for carbon sequestration into the soil instead of contributing to emissions, with further reductions in fossil fuel use also possible.

Further studies have examined the impact of shifting towards plant-based diets on both human and environmental health and concluded definitively that it would provide combined benefits. Plant-based diets could reduce GHG emissions by 56 percent and other environmental impacts of the food system by six to 22 percent. At the same time, this improves the nutritional quality of our diet, significantly reducing the burden of chronic disease and reducing premature mortality by 22 percent. When considering protein sources, tofu, beans, nuts, and peas have the lowest carbon footprint compared with any source of animal protein, and their consumption has significant advantages for human health.


Eating Plant Based Cover This article is an edited extract from Eating Plant-Based: Scientific answers to your nutrition questions by Dr Shireen Kassam and Dr Zahra Kassam. Published by Hammersmith Books. Available in Australia via Booktopia.

Lead image: Cottonbro on Pexels


This article is an edited extract from Nourish plant-based living, Issue 74 • View magazine
Zahra and Shireen
Dr Shireen Kassam and Dr Zahra Kassam

Dr Zahra and Dr Shireen Kassam are sisters, cancer doctors, and board certified Lifestyle Medicine Physicians with a special interest in plant-based nutrition.

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Aren’t humans designed to eat meat and dairy? 

Humans for most of history have been gatherers rather than hunters, yet the myth persists that eating animals is natural and necessary. Doctors Shireen and Zahra Kassam set the record straight.

​​Humans are omnivores. We have a choice. We can choose to include meat, dairy and eggs in our diet, but these foods are not essential. There are no nutrients within animal-derived food that cannot be obtained from whole plant foods – the one exception being vitamin B12.

In fact, the opposite is true. Without sufficient plant foods, human health and wellbeing suffer. Plant foods are essential for vitamins and minerals such as vitamins C, E, K and folate, and of course fibre.

We evolved to be gatherers

Humans for most of history have been gatherers rather than hunters. Nutritional anthropologists have estimated that the nutrient intake of prehistoric humans included as much as 100 grams of fibre per day. That’s a lot of plant foods! Hunting animals for food is challenging for humans, and our anatomy and physiology are in fact more adapted to eating plants.

Just look at your canine teeth, for example. They are short and blunt, unlike animals that rely on meat like lions, whose canines are long, sharp and curved. Our canines would not be very effective at stabbing, tearing and killing prey.

Hunting animals for food is challenging for humans, and our anatomy and physiology are in fact more adapted to eating plants.

Most humans are lactose intolerant

The majority of the world’s population does not have the ability to digest lactose, the main sugar in dairy, beyond weaning. This is because the enzyme lactase does not persist in mammals once a mothers’ milk is unnecessary in the diet. Without the production of lactase in the gut, the consumption of dairy can lead to unpleasant symptoms such as nausea, diarrhoea and bloating. This is termed ‘lactose intolerance’.

Lactose intolerance ranges from up to 30 percent in Caucasian populations to up to 90 percent in Asian, Indian and African populations and, overall, this is the norm in 70 percent of the global population. The adaptation for digesting lactose – lactase persistence – arose around 5000-10,000 years ago, mainly in European populations in line with domestication of cows and the production of dairy. An evolutionary advantage for this adaptation does not seem to be apparent.

It is worth mentioning that no other species drinks milk beyond a young age, their own mother’s, or the milk of another species.

Overall, lactose intolerance is the norm in 70 percent of the global population.

The plant-powered way

Some of the healthiest and longest-lived populations on this planet, found in regions of the World termed Blue Zones, have in common a diet that is at least 85 percent plant-based, with some, such as vegans in Loma Linda, California, consuming no animal foods at all.

Regardless of our adaptations and ability to consume meat, dairy and eggs, the question we should be asking is ‘do we need to?’ The answer is a resounding NO.

My doctor told me I had to eat meat

What you have to understand about doctors in general, is that they will have received very little or no nutrition education during medical school. So, the nutrition advice you may receive from most doctors will not necessarily be based on the latest evidence, but will most likely reflect the preferences and biases of the doctor. Studies show that doctors who undertake regular physical activity, for example, are much more likely to promote the benefits of physical activity to their patients. In the same way, a doctor who continues to eat red and processed meat is likely to tell their patients that eating these foods in moderation is fine and that meat is necessary in the diet.

Our advice: Find a doctor, dietitian or nutritionist who is trained in nutrition and, in particular, plant-based nutrition.

Luckily, more nutrition and lifestyle training is gradually being incorporated into the medical school curricula and postgraduate education, but there will be an inevitable lag between implementing this education and the time when all doctors will be able to provide evidence-based nutrition counselling to their patients. Our advice: make sure you do your own research and acknowledge the limitations of your doctor who will be super-specialised in their own area but cannot be an expert in everything. Find a doctor, dietitian or nutritionist who is trained in nutrition and, in particular, plant-based nutrition.


Eating Plant Based Cover This article is an edited extract from Eating Plant-Based: Scientific answers to your nutrition questions by Dr Shireen Kassam and Dr Zahra Kassam. Published by Hammersmith Books. Available in Australia via Booktopia.

Lead image: Dmussman on Shutterstock


Zahra and Shireen
Dr Shireen Kassam and Dr Zahra Kassam

Dr Zahra and Dr Shireen Kassam are sisters, cancer doctors, and board certified Lifestyle Medicine Physicians with a special interest in plant-based nutrition.

Enjoying our inspiring stories? We always love to hear from you with suggestions for the content you want more of. Suggest a topic here.

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The connection between eating animals and pandemics

Drs Shireen and Zahra Kassam explain how animal farming has dramatically increased the risk of new infections with epidemic and pandemic potential.

Several pandemics that have occurred in the last century can be traced back to our farming practices and the use of animals as food. In fact, three out of four new and emerging infections are zoonoses – that is, diseases that arise in animals and then jump to humans. Here’s how our appetite for animals is driving the problem, and the plant-based solution that is at our fingertips.

A direct association

Industrialisation of animal farming, along with the wildlife trade and habitat destruction that goes with it, has created the perfect conditions for the emergence of new zoonotic infections – mostly viruses – that jump from animals to humans.

The conversion of wild habitats to farmland destroys the natural ecosystems and wipes out larger species, leaving behind smaller animals, such as rats and bats, which are more likely to carry infections that can be passed on to humans. These smaller animals are mobile and adaptable, and can produce lots of offspring rapidly.

In addition, the increasing industrialisation of animal agriculture means that most farmed animals are raised on factory farms, kept in cramped and squalid conditions, suffer from stress and disease and thus are more likely to succumb to infections. These infections can be passed on to other animals, mutate and eventually have the potential to be passed on to humans.

A matter of time

An even bigger threat than coronavirus for causing a future pandemic is a bird flu. Recent strains include H5N1, which was first detected in humans in 1997, causing a major outbreak in 2004, and H7N9, which was first detected in 2013. Both originated in wild birds and were transmitted to humans via poultry farming. Although transmission to humans is currently rare, when it does occur there is a 60 percent chance of dying from H5N1 and about 30 percent from H7N981.

It is only a matter of time before these viruses adapt and become more transmissible to humans and, when they do, the results could be catastrophic. In fact, it is already happening. In February 2021, the media reported the first case of H5N8 bird flu in humans. Many of us consider the COVID-19 pandemic a warning, with worse in store if farming practices do not change.

The plant-based solution

A global shift to a plant-based food system would free up 75 percent or more of agricultural land that is currently used for animal pasture and to grow crops to feed animals, while still being able to produce enough food for the global population. This land could instead be allowed to rewild, restore natural habitats and biodiversity, and act as a store of carbon – while dramatically reducing the risk of new pandemics emerging.

At the same time, efforts to promote healthful plant-based eating and other beneficial lifestyle changes will help to address the high prevalence of chronic non-communicable diseases in the world today, in turn building resilience against the ongoing COVID-19 pandemic, and future pandemics that are likely to arise.

***

It’s clear that transforming our food system can – and must – be part of the solution to restoring human and planetary health to a state of flourishing. The time for change is now!


Eating Plant Based Cover This article is an edited extract from Eating Plant-Based: Scientific answers to your nutrition questions by Dr Shireen Kassam and Dr Zahra Kassam. Published by Hammersmith Books. Available in Australia via Booktopia.

 

Lead image: Paul Shuang on Shutterstock


Zahra and Shireen
Dr Shireen Kassam and Dr Zahra Kassam

Dr Zahra and Dr Shireen Kassam are sisters, cancer doctors, and board certified Lifestyle Medicine Physicians with a special interest in plant-based nutrition.

Enjoying our inspiring stories? We always love to hear from you with suggestions for the content you want more of. Suggest a topic here.

Sign up to our newsletter and receive our latest editorial and offers directly in your inbox.

No meat, no problem

Don’t athletes require meat protein for muscle growth? Drs Shireen and Zahra Kassam put this common myth to bed.

Yes, protein intake is important for muscle growth, maintenance, and repair, but it comes down to choosing the best quality protein – and plant protein wins hands down over animal protein in this regard.

Plant protein is preferable

In part, this is because plant protein comes packaged with nutrients that are beneficial for preventing injury and enhancing recovery from exercise, such as antioxidant and anti-inflammatory compounds, which are mostly absent from animal sources of protein. In fact, animal protein causes inflammation in the body, which is certainly not an ideal situation for optimal athletic performance.

In addition, plant-based sources of protein are also high in healthy carbohydrates, including fibre, and healthy fats, which all help to keep our vital organs functioning to their best ability, clearly crucial for optimal performance. Beans, nuts and seeds can provide all the protein necessary for all types of athletic performance without reaching for protein powders.

Studies have examined whether plant sources of protein can help build muscle as effectively as animal protein. A meta-analysis showed soy protein was as effective as various sources of animal protein for building muscle mass and strength in response to resistance training, but of course without increasing the risk of heart disease and cancer.

Verified ‘vegains’

Small studies of short duration have also been conducted specifically in vegans. One study directly examined the heart function by echocardiography and maximum oxygen consumption of vegan and omnivore amateur runners, with 22 participants in each group, and reported better heart function and cardiorespiratory fitness and endurance, suggesting an advantage for the vegan group.

Another study in young, physically active women tested endurance and muscle strength in 28 vegans and 28 omnivores and reported better exercise performance in the vegan group with no disadvantage for muscle strength. A further small study investigated the impact of protein source on muscle mass and strength: 19 vegan and 19 omnivorous men undertook 12 weeks of supervised resistance training. Their protein intake was adjusted to obtain 1.6 grams per kilogram per day, including from protein supplements, either soy or whey. Various measures of muscle mass and strength, including muscle biopsies, were performed at the beginning and end of the study. The results showed that both groups had equal gains in muscle mass and strength, demonstrating that plant protein is not inferior to animal sources of protein.

The suggestion is that the higher carbohydrate intake in a vegan diet and resulting higher glycogen stores may be the reason for the better endurance and performance. Plant-based diets improve endothelial function and hence vascular function, helping to better oxygenate tissues and muscle. The lower blood viscosity due to the better blood lipid profile also enhances blood flow to the muscles.

Plant-based performance

For all athletes who want to achieve optimal performance, planning, knowledge and skills when it comes to nutrition are important regardless of the chosen diet pattern. The increasing number of elite athletes who have adopted a plant-based diet and demonstrated incredible athletic performance is proof in itself. To name just a few: Kate Strong, Fiona Oakes, Robert Cheeke, Lewis Hamilton, Morgan Mitchell, Kendrick Ferris and Derrick Morgan. Seba Johnson and Nimai Delgado have never eaten meat.


Eating Plant Based Cover This article is an edited extract from Eating Plant-Based: Scientific answers to your nutrition questions by Dr Shireen Kassam and Dr Zahra Kassam. Published by Hammersmith Books. Available in Australia via Booktopia.

 

Lead image: Cottonbro on Pexels


Zahra and Shireen
Dr Shireen Kassam and Dr Zahra Kassam

Dr Zahra and Dr Shireen Kassam are sisters, cancer doctors, and board certified Lifestyle Medicine Physicians with a special interest in plant-based nutrition.

Enjoying our inspiring stories? We always love to hear from you with suggestions for the content you want more of. Suggest a topic here.

Sign up to our newsletter and receive our latest editorial and offers directly in your inbox.

YOUR INPUT