Is veganism actually healthy?

The switch to veganism is usually fuelled by one of three motives: the environment, ethics or health.

While the later two motives appear well justified, the question of veganism and health is shrouded in mystery and mis-information.

Advocating a vegan, plant-based diet on the basis of health alone implies that all meat and dairy is, in some way, harmful, and that for optimal health one is best poised to give up these products entirely.

However, the idea that meat and dairy is “unhealthy” may be based on outdated nutritional science.

At the very least, there is insufficient evidence that meat and dairy are harmful to the human body, and plenty of evidence showing their nutritional value and the risk of nutritional deficiencies when these foods are avoided.

Those who have switched to a vegan diet exclusively for their health may have been misled.

Let me explain…

Two things to understand

Before you can consider the health implications of a vegan diet, there are two things you must understand.

First, that the study of nutrition is still young.

We’ve been able to fly planes longer than we’ve understood anything meaningful about nutrition.

The first vitamin, thiamine (or, B1), wasn’t “discovered” until 1926.

Since then, we’ve identified many vitamins and minerals, as well as their role in human health. But there are still many mysteries to be unraveled. In particular, we don’t really know how our diets contribute to long-term chronic disease, such as type-2 diabetes and heart disease.

Much of the “proven” science out there is, well, anything but proven.

How so?

This is the second point you must understand.

In nutrition, there are two kinds of research: epidemiological and randomised clinical trials (or, RCTs).

An epidemiological study is observational. Researchers study a large group of people over a long period of time as live their normal lives. They gather data, like what they eat, how much they exercise, and so on, and they correlate that data with the health conditions they develop over time.

For example, when attempting to find a correlation between meat consumption and risk of heart disease, a researcher will examine those who succumbed to heart disease and review their diets: did they eat a lot of meat? What kind of meat did they eat? How often? If, say, 90% of people who got heart disease ate red meat daily, that indicates a strong correlation between red meat consumption and heart disease.

However, it’s essential to understand that correlation does not prove causation.

For example, that same 90% of participants may also never exercise, smoke 20 cigarettes a day, and eat sugary and processed food alongside red meat. Any of these other correlations could also be responsible for heart disease.

That’s why observational studies can never prove an argument. They’re great for generating hypothesises — that is, educated assumptions — but they can never prove them.

To prove a hypothesis, the researcher must conduct a randomised clinical trial.

But that’s not easy to do. RCTs are exorbitantly expensive, time consuming and require large participation and dedication from those who do participate.

I mean, think about it. Let’s say you want to identify whether a given food causes a long-term disease, like type-2 diabetes.

First, you’d need to need a large enough dataset to provide meaningful insight — in other words, lots of people. You’d need to ensure half of the participants ate enough/avoided the item in question, and that the other half continued consuming their normal diet (serving as a control group to ensure that they wouldn’t/would have contracted the disease anyway). And you’d need to study them long enough to see the diseases develop — in some cases, this takes decades.

The difficulty in setting up a RCT, funding it, and running it long enough to provide useful data is immense. Even then, the data may not be conclusive.

This is why most of the research that we hear about, and most of the “science” that informs government nutritional guidelines in the UK, the US and elsewhere, is actually based on observational research.

But, we’ll revisit this later.

The health benefits a vegan diet

For now, let’s go back to the question: is a vegan diet actually healthy?

There’s a handful of observational studies, and even a few short and low-participated RCTs, that have explored the relationship between specific vegan diets and their impact on health and disease.

Some research suggests that a vegan diet may promote lower cholesterol, lower blood pressure, and increased weight loss, as well as other positive health markers.

But, exploring the outcome of specific vegan diets isn’t useful. These data simply can’t tell us whether veganism in general is actually healthy or not.

Wait… Why?

There is no “definitive” vegan diet

Consider these two hypothetical vegans: Donald and Rebecca.

Donald eats mainly “whole foods” — leafy greens, fruit, some root vegetables, whole grains, tofu and so on. Meat, cheese, milk, eggs and anything else from another living creature repulses him.

Rebecca feels the same way about animal products, but she’s equally repulsed by leafy greens and whole grains. Instead, she eats mainly processed food: vegan chicken nuggets, deep-fried tofu burgers, vegan cheese, crisps and chocolate.

The only parallel between Donald and Rebecca’s diet is the single element that ties together all vegans: the exclusion of animal products.

Veganism is not a diet of recommendation, but rather a diet of limitation.

We already know fruit and vegetables are healthy, and besides, there’s no reason an omnivore can’t eat just as many plant-based products as a vegan. Any health benefits a vegan derives from a plant-based diet are also accessible to an omnivore.

(A quick aside: this may be the reason that many people who switch to veganism, like those in documentaries such as Forks over Knives, find themselves to be generally healthier and even manage to reverse chronic disease. If you have only ate processed junk food your entire life, and you then switch to a whole-foods diet of fruit and vegetables, which are rich in vitamins and minerals, then naturally you’ll feel better. Often, this is attributed to giving up meat, but chances are this is simply the result of eating better food in general).

In any case, if we want to determine whether or not veganism is healthy, we shouldn’t consider what they do eat, but rather the implications of the things they don’t eat.

In other words, we need to identify the benefits and risks of giving up meat and dairy.

Benefits of giving up meat and dairy

The world is inundated with articles and documentaries promoting the various health benefits of a diet low in meat and dairy.

But what does the science say?

Let’s consider three of the most prominent and oft-cited claims.

The first is the World Health Organisation conclusion that red and processed meat may be carcinogenic.

In 2015, 22 researchers from 10 different countries met to evaluate 800 epidemiological studies and answer the question: does red and processed meat cause cancer?

The group concluded that:

• there is “limited evidence in human beings for the carcinogenicity of the consumption of red meat”
• “there is sufficient evidence in human beings for the carcinogenicity of the consumption of processed meat”

“Limited” hardly inspires confidence, and the evidence may be more limited than you might expect.

Dr. M Klurfeld, one of the researchers involved in the project, described it as “one of the most frustrating experiences of his professional career”.

The data, he explains, only indicates a higher risk of colon cancer specifically. The evidence supporting the increased risk of other cancers is non-existent or inconclusive.

Further still, only 14 of the 800 studies reviewed were based on red meat, and only 18 were based on processed meat. Only 7 of the 14 red meat studies, and only 12 of the 18 processed meat studies, indicated any increased risk of cancer.

In other words, 50% of the red meat studies and 66% of the processed meat studies found any correlation between red or processed meat and colon cancer.

And there’s that critical word again: correlation.

All of these studies were epidemiological — observational. An observational study by its very nature cannot prove causation.

Sure, red meat could cause colon cancer. But, it could also be that those who eat red meat also eat sugary processed foods over fruit and vegetables, to smoke cigarettes, and exercise less.

One of the studies also found a correlation between white meat consumption (that is, fish, chicken and so on) and lower rates of disease. Again, this is only correlation and other factors may be responsible.

The point is: we shouldn’t make decisions based on shaky science. A lot more research is needed before we can assert that red meat causes cancer, or that white meat reduces the risk of disease.

The second oft-cited resource is a book called The China Study by Dr. T Campbell.

The book is based on a 20-year epidemiological study that explored the correlation of chronic diseases across different counties in China and the dietary patterns of the people within those counties, identified through blood findings and dietary surveys.

And what did Dr. Campbell find?

Campbell’s research indicates that eating a whole-food, vegan diet can help people avoid, and even reverse, chronic diseases. In his view, any and all animal products are harmful and should be avoided. For example, he argues that animal protein be carcinogenic.

While his work is well-received in certain circles, his work is observational, and thus cannot be considered conclusive.

The China Study has also received a lot of flak online.

And when I say a lot, I mean a lot.

But why all the criticism?

Red Pen Reviews describe Campbell’s evidence indicating that a whole food, plant-based diet prevents or reverses chronic disease as “fairly compelling.”

The issue is the substantial claim that animal protein in general causes cancer.

Campbell’s animal protein hypothesis stems from his research that found that casein, a form of animal protein may be carcinogenic when consumed in isolation. Campbell then used this research as a basis to claim that all animal protein causes cancer, despite research indicating the exact opposite.

According to Red Pen Reviews, there is “little compelling evidence” to support the notion that animal protein in general causes cancer.

In fact, some of Campbell’s own earlier research indicates that some animal products may be healthy. He found, for example, that fish oil inhibited cancer development.

While The China Study presents some reasonable arguments, the conclusions regarding animal products are far from conclusive.

The China Study is popular, but its popularity pales in comparison to diet/heart hypothesis, which is arguably the most influential nutritional hypothesis in the world.

After the Second World War, the Western world experienced “epidemic” rates of heart disease — thousands of middle-aged people across the Western world were struck down by heart attacks daily, and nobody knew why. The world pined for an answer. They wanted some variable that they could change to control the situation.

Did people need to exercise more? Did they need more fresh air? To eat less sugar?

Enter American physiologist Ancel Keys. In 1955, he presented his theory to the WHO. He told them that saturated fat, which is found in almost all meat and dairy products, is the problem.

Eat less saturated fat, argued Keys, and we’ll see less cases of type-2 diabetes, heart disease, and every other chronic disease plaguing the Western world.

His ideas fell on keen ears.

The diet/heart hypothesis came from Keys’ epidemiological Seven Nations Study. The study explored the dietary habits of people from seven nations across the world, and found a correlation between chronic disease and meat consumption.

But, the study had several major issues:

• he intentionally omitted nations whose dietary habits failed to show a correlation between meat consumption and chronic disease
• he studied some nations during Lent, a time when few people would have consumed meat (thus showing an inaccurate correlation between meat consumption and chronic disease)
• all of the data is epidemiological, thus observational

In any case, his “evidence” coupled with his charisma took hold in the U.S., and even landed him a place on the cover of TIME magazine. Soon, the American Heart Association, and later the United States government itself, adopted the hypothesis as official policy.

In Dietary Goals, the United States made official recommendations that the entire U.S. population adopt a low-fat diet. (They pushed this despite the fact that Keys’ epidemiological research only focused on men, and did not consider the impact of a low-fat diet on women or children).

Although many in the research community proposed alternative hypothesises, they were brushed aside as the diet/heart hypothesis became enshrined as common sense within and outside of the scientific community.

The rest of the world followed the U.S, advocating a low-fat diet to their citizens, and forming a theoretical house of cards atop a hypothesis.

For that’s all the diet/heart hypothesis is: a theory. At this point, it had never been proven.

And what actually happened when researchers literally put the hypothesis on trial? In RCT after RCT, saturated fat has been exonerated. There has been no evidence to show that saturated fat is harmful.

Yet, the perception that saturated fat is dangerous continues. It’s ingrained in our collective mindset.

The diet/heart hypothesis is the reason doctors tell us to keep our cholesterol low, it’s the reason supermarkets are flooded with “low-fat” products, and its why other, potentially more dangerous products (sugar, for example) have gotten off the hook.

There are no doubt other arguments against meat, but many are based on these aforementioned points, or have equally little scientific justification.

In short: there appears to be little conclusive science vindicating the health risks of meat consumption.

But, is there any risk to giving up meat and dairy?

Risks of giving up meat and dairy

Though anthropologists debate whether our ancient ancestors ate meat or not, there is little doubt our recent ancestors, such as the Romans, ate meat and dairy alongside fruit and vegetables.

For instance, we know some Roman soldiers marched rye-dough pies stuffed with honey and goat’s cheese and that many of the ancient tribes that still thrive today — such as the Inuit and Maasai — ate, and still eat, meat exclusively.

And truth be told, they don’t look too bad.

Even in the Western world, there’s little doubt that meat has been a staple for a long while.

Spend a winter in the United Kingdom, and the need for meat becomes apparent.

As I write this essay, it’s 3 degrees Celsius outside in the seaside town of South Shields. The wind is harsh and it batters you relentlessly.

Vegetation would have to be particularly hardy to survive in these cold and harsh conditions. In reality, not much beyond brassicas (that is, cabbage, sprouts, kale, etc.) grows in this country at winter time — most of the fresh fruit and vegetables we have is imported from abroad, or had been frozen earlier in the year.

My British ancestors, however, had neither freights nor freezers. They may have traded with other Europeans, but only the rich Lords. It’s unlikely that the typical peasant enjoyed grapes and spinach from France or Spain.

Further still, before the Columbian Exchange that took place from the late 15th century onwards, when Columbus “discovered” the Americas, the vegetables available in Europe were much more limited. Most of the fruit and vegetables we enjoy today had never been seen by Europeans, Asians or Africans until Colobus brought them back with him.

All tomatoes, potatoes, corn, avocados, squash, peanuts, strawberries, and many other vegetables were completely unknown before the late 15th century. If you think it’s tough being a vegan now, imagine how they felt during winter in Medieval Europe.

No — during winter, it’s more likely that pulses and legumes that had been harvested in the summer and dried out made up the typical European fare. They’d have supplemented that with meat. “Every peasant had at least one pig,” says Colin Spencer in British Food, which would be slaughtered in November and salted down for the year.

The lack of vegetation in winter is also why cheese in particular is a useful foodstuff — peasants could milk the cows in summer and turn the milk into cheese that could be consumed in winter.

In short: meat and dairy has been a staple of the human diet in many societies across the world for generations. It would have been a challenge to survive the harsh winters of Northern Europe, for example, without dried legumes and pulses, but also processed meat (salted bacon, for example) and cheese.

But things have changed now. We do have freights and freezers. Does meat and dairy have a place in the modern, Western diet?

Although many plant-based food stuffs boast impressive nutritional value, some of the most nutrient dense foods on the planet come from animal products.

Consider liver, for example. Our livers store vitamins, glucose and iron, as well as other essential nutrients. So, naturally, this organ meat is particularly nutritious. Organ meat, or “offal”, is generally more nutritious than the muscle meat that we typically consume.

Cheese, milk and yogurt is generally written-off as “unhealthy”, but they’re all great sources of complete proteins (that is, they provide all the essential amino acids that a human needs to survive, whereas most plant sources do not), as well as almost every vitamin and mineral that the human body needs. Yogurt often contains live bacteria that has been shown to be great for digestive health (that being said, vegan yogurts also generally offer the same digestive health benefits).

But what about muscle meat?

The very same WHO report that categorised red and processed meat as potentially carcinogenic also noted that red meat is nutritious: it’s also a complete source of protein and contains many important micronutrients, such as B vitamins, iron and zinc.

When it comes to fish, the evidence is even more compelling.

In one study, five Korean scientists examined over 1,000 foods and assigned each food a “nutritional score” — the higher the score, the more likely the food is to meet, but not exceed, your daily nutritional needs.

26 of the top 100 foods were animal-based products, and most were fish. Pork fat, for instance, surprisingly had a “73” nutritional score, while Flat Fish and Ocean Perch scored “88” and “89” respectively.

Veganism insinuates, through its extreme exclusion of all products derived from animals, that animal products are all in some way harmful. But if we consider the situation exclusively from a health perspective, if we know that some animal products are more nutritious than most plant-based products, why would we give them up?

And yet, this is exactly the course of action that veganism prescribes.

Worse still, instead of replacing meat and dairy in the diet with natural plant-based products, such as legumes, pulses, grains and vegetables, many opt for “ersatz” foods that emulate meat and dairy.

Meat is swapped out for meat-like products made from soy, jackfruit (which is particularly nutritionally poor, containing virtually no protein), and whatever Quorn is.

Cheese is replaced by vegan substitutes which come in a variety of styles. While those made from vegetables or nuts are relatively nutritious, nearly all vegan cheese made in the UK, at least, is made from coconut oil mixed with starch.

(This is particularly ironic given that many people switch to a vegan diet based on the notion that saturated fat is harmful, while coconut oil actually contains double the saturated fat of beef dripping).

While companies have done a fantastic job emulating the experience of eating meat — that is, the aesthetic, the texture and the taste — these products are generally less nutritious. Most of the substitutes contain less vitamins and minerals, and vegan cheese in particular is mostly carbohydrates and fat.

It is also worth remembering that veganism itself is a relatively new concept. As discussed, humans have eaten meat for thousands of years, whereas veganism has been around for a few decades. These ersatz meat substitutes are equally new, and there’s been little research evaluating their long-term health effects. We simply do not know what happens to the human body after 20 years of eating Quorn chicken.

However, we do know that when someone gives up meat and dairy, they put themselves at great risk of nutritional deficiencies.

One scientific review found that vegans tended to have lower intakes of vitamins B2, B3, B12, D as well as iodine, zinc, calcium, potassium and selenium. Another study also indicated a lower intake of omega-3 fatty acids.

All of these vitamins and minerals are harder, albeit not impossible, to find in plant-based foods.

A vegan can avoid micronutrient deficiencies, but their diet must be rigorously planned. These nutrients and minerals can be found in fortified foods, such as nutritional yeast and some dairy-free milk and cereals, as well as supplements.

But is it enough?

Remember: the study of nutrition is young. We may not actually fully understand everything that the human brain and body need for healthy development. “There are so many unknowns,” says Nathan Cofnas, a co-author of a study exploring the impact of the vegan diet on health and the brain. There may be nutrients available in animal products that are essential to our health.

“When you deviate from the typical diet for your species, to one which has not been tested and properly established to be healthy or good for the brain, you are conducting an experiment and you are taking a risk.”

Moreover, there’s a difference between the nutrients you consume and what your body actually absorbs. For example, if you consume 10mg of iron, your body may only absorb 5mg of it.

As it turns out, the non-heam iron found in plant-based foods is not as easy for the body to absorb as the haem iron from animal products. So, if a vegan and omnivore consume equal proportions of vitamins and minerals, such as iron, the omnivore is likely to be absorbing more.

Micronutrient deficiency can have detrimental effects — from inhibited brain development and infertility to long-term fatigue, extreme weight loss and cognitive issues such as depression, poor memory or difficulty concentrating.

And these effects aren’t felt immediately.

The health risks associated with B12 and iron deficiency take years to appear.

In some cases, vegans may not feel the impact until their late 40s or 50s.

The risks of micronutrient deficiency may be especially problematic for developing children. One study exploring the topic concluded that “there are still many unknowns about the health effects of meatless diets in children.” This uncertainly led the Royal Academy of Medicine in Belgium to declare that a vegan diet is “unsuitable” for children.

At any rate, it is well understood that an unplanned vegan diet often leads to micronutrient deficiencies, but we don’t fully understand the long-term effects this has on both adults and children.

So, where does all of this leave us?

Conclusion

The information out in the wild is vast.

Have I trawled through every study on meat and dairy, and analysed the data? Of course not.

Have I read every book on plant-based nutrition. No chance.

Have I watched every documentary advocating or “debunking” veganism? No.

The truth is, I’m not a dietitian, I’m not a nutritional scientist, and I’m not a doctor. In fact, I have absolutely no connection to the world of nutrition whatsoever.

I write software for a living.

So, why should you listen to me? Well, you don’t have to. I’m not here to give diet advice or tell you how to live your life.

I’m simply presenting the science as I have found it.

And that science indicates that there is not enough evidence to conclude that animal products are harmful.

Much of what we’ve been led to believe — from the “health risks” of saturated fat to the “carcinogenic” nature of red and processed meat — is based on observational studies.

In the cases where RCTs have been conducted, the results have been either inconclusive or proved the opposite.

There have been a handful of RCTs on vegan diets specifically, though most conclude that more data is needed. Plus, these studies follow specific vegan diets. As we’ve established, veganism is a diet of limitation, not recommendation, thus only the impacts of giving up meat and dairy are relevant in the evaluation of the vegan diet.

Based on this, the idea of veganism as a healthy alternative to the omnivore diet implies that all animal-based products are harmful, which science indicates is far from true.

Many animal products, especially fish and offal, appear not only harmless in moderation, but highly nutritious.

Our bodies need vitamins and minerals, such as zinc, iron and B12, that are more readily available from these animal products than in plant-based foods.

A vegan diet must be carefully planned to ensure sufficient quantities of this stuff. A vegan shouldn’t just swap out meat for non-meat alternatives and call it a day. At the very least, vegans need to consider supplements and fortified foods.

Even still, nutrition is a young science, and we don’t fully understand what the human body needs. Perhaps there are certain nutrients in animal foods that aid in the development of the brain, for example.

“Science is not possession of the truth,” as Dr Klurfeld puts it, “but is the systematic, reproducible pursuit of the answers, and we should depend on reliable science for dietary recommendations.”

The current science criminalising meat and dairy is anything but reliable. Vastly more research is needed.

But, even if there isn’t enough research to incriminate meat and dairy, should we just assume it’s safe?

Probably not.

We, as a society, should continue to research the long-term impact of meat and dairy, as well as other food stuffs such as meat-free alternatives.

Even if we have ate meat for thousands of years, we shouldn’t continue to do so just because “that’s what we’ve always done”. Logic and science should dictate our diet, not tradition.

But, if we want to consider the food products that have caused the rise in chronic disease — type-2 diabetes, heart disease and all the rest of it — over the last hundred years, would logic not suggest that the most recent addition to our diet is the culprit?

If so, that culprit is not meat and dairy, which has been a staple food source in societies across the world for thousands of years.

No, the newest addition to the diet is sugar. Refined sugar has only been a large part of the human diet since the 17th century, and it’s continued to rise in popularity ever since. Nowadays, sugar is ubiquitous.

It seems clear to me that such a recent addition to the human diet, and one that is extraordinarily prolific, should be our first culprit. But, just like meat, more research is needed.

You might think this account has been particularly biased. And you’re right — I do have a bias. I’m actually bias towards veganism.

I wish there was evidence that meat and dairy was harmful, and that a person could not only survive, but thrive, when eating a plant-based diet.

Why? Because there are so many other good reasons to go vegan.

We know that methane gas produced by cows and animal manure, as well as major deforestation undertaken to provide land for herding cows, is a major contributor to climate change.

And while the ethics of eating meat is contentious, I believe most people would be hard-pressed to defend the factory farming approach that treats animals as products, sending them down a conveyor belt of slaughter.

Yes — I do wish that the third reason, our health, was a justifiable reason to make the switch. Unfortunately, I’m not so certain.

Like I said, I have no intention of giving dietary advice but, as it stands, it appears meat and dairy still have a place in a healthy diet, albeit one that is largely plant-based.