Heart disease

The term heart disease is often used instead of cardiovascular disease (CVD) and describes a chronic disease of the heart and blood vessels.

The disease usually reduces blood flow to the heart, brain or body because of fat layers clogging the inside of your arteries (blood vessels), hardening and narrowing them (atherosclerosis). High cholesterol levels in your blood are the main problem, contributing building material for these fat layers, also called cholesterol plaques. Narrower arteries also mean higher blood pressure – that’s often the first sign that something’s wrong.

Heart attacks and strokes are mainly caused by blockages that cut off blood supply to the heart or the brain. A stroke can also be caused by a brain artery bursting.

A certain amount of cholesterol in the blood is essential for good health but your body makes all it needs. Butter, ghee, cream, whole milk, high-fat cheese, dairy desserts, as well as all meat, contain high amounts of saturated fat which raises cholesterol levels in the blood. If you eat these foods daily, your body may produce much more cholesterol than it needs.

In an experimental study where each group of people ate 50 grams of different fat daily – butter or vegetable oils – for four weeks, the participants who ate butter had the worst cholesterol results (Khaw et al., 2018). Their total and bad cholesterol levels shot up compared to the other group – if that happens after just four weeks, imagine what a lifetime of butter munching might do to your blood vessels!

A scientific team studied the effect of a diet high in red meat, white meat and no meat on people’s cholesterol levels and found that both types of meat increased them, while a meat-free diet did not (Bergeron et al., 2019). They also tested the effect of additional saturated fat by adding high-fat dairy products and butter to the participants’ diets – and it turned out that it increased cholesterol levels in all groups.

A Cochrane Review, highly respected by scientists, analysed 48 studies including over 65,000 participants and found that reducing saturated animal fat intake reduced the risk of heart attack and stroke by 14 per cent (Hooper et al., 2012). That was just by reducing saturated fat – not cutting out meat and dairy. The results could have been even more impressive if that had happened! A more recent Cochrane review (Hooper et al., 2020) suggested reducing saturated fat lowered the risk of cardiovascular events by 17 per cent. Practical ways to achieve reductions in saturated fat, they say, include reducing cakes, biscuits, pies and pastries, butter, ghee, lard, palm oil, sausages and cured meats, hard cheese, cream, ice cream, milkshakes and chocolate.

To lower your cholesterol levels and keep them down, it’s crucial to reduce your saturated fat intake – saturated fat is found mostly in meat, dairy, eggs, coconut and palm oil.

Animal products, including dairy, are one of the main sources of saturated fats in Western diets. Butter, high-fat cheese, whole milk, cream, milkshakes, creamy desserts, ice cream, whipped cream, etc contain high amounts of saturated fat which can contribute to heart disease. On top of that, animal protein as such – whether from dairy, meat or eggs – has also been linked to an increased risk of heart disease.

In 2010, the Nurses’ Health Study reported on the relationship between main protein sources and heart disease in women (Bernstein et al., 2010). Higher intakes of red meat and high-fat dairy products were linked with a higher risk of heart disease.

A large study of over 70,000 people looking at their animal and plant protein intake and heath found that those who ate the most plant protein and the least animal protein were 27 per cent less likely to die from heart disease in general, 28 per cent less likely to die from a heart attack and also 28 per cent less likely to die from stroke compared to people who ate the most animal protein (Budhathoki et al., 2019).

When it comes to fat, one major study focused just on dairy products and heart disease and found that replacing dairy fat with plant-based polyunsaturated fats and wholegrains could greatly reduce the risk of heart disease (Yu and Hu, 2018). Another study found that replacing butter with margarine* can reduce the risk of heart attack (Liu et al., 2017). And a study of people at risk of heart disease found that people who eat the most saturated fats had up to 80 per cent greater risk of heart disease compared to people who ate mostly unsaturated (plant) fats (Guasch-Ferré et al., 2015).

A study compiling data from three highly-respected studies that involved over 220,000 participants found that replacing dairy fat in the diet with non-dairy fats can seriously reduce your risk of heart disease. The results showed that replacing just five per cent of dairy fat with polyunsaturated fats may lower the risk by 24 per cent (Chen et al., 2016). Polyunsaturated fats are the omega-3 and -6 fats found in many plant foods – read more here.

In recent years, a number of studies have suggested that certain compounds in dairy foods, especially fermented ones such as yoghurt and cheese, (eg calcium, magnesium, potassium, probiotics, bioactive peptides etc) may counter the harmful effects of saturated fat meaning that dairy may have a neutral effect or even lower the risk of heart disease. Many of these studies received funding from the dairy industry and the study design of some may be questionable, at best.

Walter C. Willett, Professor of Epidemiology and Nutrition at Harvard TH Chan School of Public Health says it’s important to consider what you are replacing a food with when evaluating its health effects, as simply saying dairy is ‘neutral’ doesn’t account for what you might swap it with (Willett, 2017). Peanut butter, for example, would be considered a healthier choice compared to cheese or bologna – a processed meat sausage.

The American Heart Association (AHA) says that randomised controlled trials that lowered intake of saturated fat and replaced it with polyunsaturated vegetable oil reduced CVD by around 30 per cent similar to the reduction achieved by statin treatment (Sacks et al., 2017). They say: “no information from controlled studies supports the hypothesis that fermentation adds beneficial nutrients to cheese that counteract the harmful effects of its saturated fat.”

Lead author, Dr Frank Sacks, said: “We want to set the record straight on why well-conducted scientific research overwhelmingly supports limiting saturated fat in the diet.”

Vegans and people who eat predominantly wholefood plant-based diets have lower blood pressure and cholesterol levels than all other diet groups and a much lower risk of heart disease – 25 to 57 per cent (Bradbury et al., 2014; Le and Sabaté, 2014; Appleby and Key, 2016; Dinu et al., 2017; Benatar and Stewart, 2018; Kahleova et al., 2018; Korakas et al., 2018; Matsumoto et al., 2019).

*Margarine used to be made with hydrogenated fats, which is why it gained bad reputation, but that changed when scientists discovered that hydrogenated fats are bad for the heart and blood vessels. Nowadays, margarine is made with plant oils and fats and does not contain hydrogenated fats so is a healthier alternative to butter.

Going dairy-free is not just a healthy choice, it’s also an ethical and sustainable one. If you’re used to meals based around meat and dairy, the idea of a plant-based diet may be daunting but we’re here to help make it super easy!