When it comes to links between diet and health outcomes there is still a great deal that remains unknown or at the very least uncertain. The fact is that we know relatively little about what specifically causes many diseases and illnesses. Medicine experienced a Golden Age for much of the 20th century when a number of huge scientific and medical breakthroughs caused life expectancy to leap.
However, progress rather stalled towards the end of the second millennium and in some ways this has fuelled a desire for a magical “silver bullet” that could cure diseases, such as cancer. Many believe such a panacea, be it for cancer, heart disease or even – rather more generally – aging itself, may come through our diet and so stories about “super foods” and “miracle diets” abound.
Factors for Consideration
The growing rise in veganism has also led many people to wonder about the health benefits of a vegan diet, a topic that we consider in greater detail elsewhere.
No One Vegan Diet Is the Same
As we have said many times, there is no single entity or regime that constitutes a vegan diet; what one vegan eats may be so different to what another eats that the fact neither eating plan includes animal products may be all but irrelevant.
None the less, we can look at “the vegan diet” in general terms by looking at health outcomes for vegans as a population. In this way, we can try to assist those who are interested in how being vegan might affect one’s chances of getting cancer.
Luck & Genetics
In reality, luck and genetics play a far greater role in many illnesses than diet or lifestyle do. That’s why anecdotal stories of centenarians who put their longevity down to the fact they “smoked like chimneys” or “drank a bottle of brandy a week” exist.
Eating well, exercising regularly and avoiding negative factors like smoking, alcohol and other drugs, and pollution are important but they are only part of a bigger picture.
Increasingly, researchers are looking at stress, mental well-being and social connectedness too, so diet is very much just one small part of the jigsaw. What’s more, to extend that metaphor, it is a jigsaw from which several of the pieces are currently missing.
All that said, nobody argues that diet is not a piece of the puzzle, perhaps even a corner piece, so what role does being vegan have when it comes to one’s chances of developing cancer?
Do Vegans Get Cancer?
Before we look at vegan cancer rates, let us first consider if vegans even get cancer at all? This is a question that some people ask and, sadly, there is definitely no silver bullet when it comes to cancer or any other major disease. Which is to say that, yes, vegans do get cancer.
Cancer is the generic term for a group of diseases, of which there are more than 100, and it has existed for thousands of years. There is no group of people that is immune from this disease, with cancer affecting every section of the global population irrespective of age, diet, race or location (although prevalence varies, most notably according to age).
So, if vegans can and do get cancer, do they get it more or less frequently than non-vegans? Or is the incidence of cancer among vegans around the same as it is in other dietary groups?
Problems with Assessing Vegan Cancer Rates
For a long time, veganism was considered a very niche diet for lentil-munching hippies only (check out other vegan myths). This meant that it was not widely studied, partly because it was not easy to get enough vegans to create a worthwhile sample and also because it was not considered important due to the small number of people who followed what was perceived to be a very unusual and restrictive diet.
The vegetarian diet was studied more closely but over the past 30 years, and especially over the last decade, veganism has become increasingly mainstream and widespread. This has both facilitated and encouraged better research on the impact of a meat- and animal-free diet. A lot of the data still looks more at those who only eschew meat, rather than all animal products, but there are now at least some robust pieces of research that consider vegans specifically.
Types of Vegan Diets Not Accessed in Studies
Of course, such studies on diet are very difficult, with so many different variables and factors to consider and account for. Moreover they often rely on self-reporting and do not usually consider what type of diet, healthy or otherwise, each group is consuming, beyond the key characteristic of vegan or non-vegan (for example).
In the case of cancer, the situation is complicated further because this is not a single disease but a group of many similar, but distinct, diseases. So, whilst one type of diet may see more incidences of a specific type of cancer, it may see a lower number recorded for others.
Sensationalist News Stories
Finding media reports about the incidence of cancer among vegans and vegetarians is really easy. A feature in the Huff Post had the headline “A Vegan Diet (Hugely) Helpful Against Cancer”; an article in the Daily Express about “How To Live Longer” claimed that vegans have “lower overall cancer incidence”; and The Telegraph had a headline claiming, “Being a vegetarian can cut your risk of cancer by a half…”.
Some of these stories are more balanced than others, despite their often misleading, sensationalist headlines. And, whilst they often link to some form of scientific study, or at least mention one, the real message behind them doesn’t stand up to any sort of serious scrutiny.
NHS “Behind the Headlines”
Indeed, the very useful NHS “Behind the Headlines” feature looks specifically at one of the stories we mentioned above. They use the headline as a starting point and then look in great detail at the actual research upon which it is based, assessing the merit of the science, its limitations and to what degree the headline is valid.
The claim made by the Telegraph (and, in fairness, other news outlets, including the BBC that reported on this research) as discussed by the NHS, that ‘Vegetarians get less cancer’, was found wanting in a whole host of ways. Despite using two highly respected studies (the Oxford Vegetarian Study and EPIC-Oxford cohort research) as a starting point, the NHS Knowledge Service raised six major concerns.
This sort of picture is all too common and applies to just about any health and nutrition story you are likely to encounter in the media. Whether it is in relation to cancer and veganism, heart disease and the latest faddy South American berry, or dementia and some obscure exercise programme, finding the real truth behind the headline is sometimes a very tricky thing to do.
Short, simple headlines catch our attention and sell news (or make us click these days), whilst nuanced, balanced, cautious, yet scientific comment does not, and so really understanding the full picture about vegans and cancer is not easy, primarily because we just don’t know the full facts at this stage.
Cancer Rate Among Vegans: Looking at Scientific Studies as Evidence
All that said, we will do the best we can to help those wondering whether or not the vegan diet might be helpful from a cancer-prevention point of view. Despite all the issues, there is some data that is instructive to look at.
2012 Study: Cardiovascular Disease Mortality and Cancer Incidence in Vegetarians: A Meta-Analysis and Systematic Review
One worthwhile study was titled “Cardiovascular Disease Mortality and Cancer Incidence in Vegetarians: A Meta-Analysis and Systematic Review”. The title may not have been overly catchy (it certainly wouldn’t make a good newspaper headline!) but this 2012 meta-analysis delivered a captivating conclusion.
Looking at seven studies that they felt were sufficiently robust, encompassing over 124,000 people in the USA, Japan, UK, Germany and Netherlands, these researchers concluded that “vegetarians have a significantly lower … overall cancer incidence (18%) than non-vegetarians.”
2017 Study: Vegetarian, Vegan Diets and Multiple Health Outcomes: A Systematic Review With Meta-Analysis of Observational Studies
Another systematic review of various studies published in 2017 that did look specifically at vegans found similar results. It concluded that:
This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (-25%) and incidence from total cancer (-8%). Vegan diet conferred a significant reduced risk (-15%) of incidence from total cancer.
Incidentally, the reduction in heart disease was similar to that found by the first analysis we considered.
1999 Study: The Oxford Vegetarian Study: an overview
Another study that specifically considered the vegan diet is perhaps the most famous piece of research in this area and was mentioned earlier. The EPIC-Oxford was carried out at Oxford University as part of the European Prospective Investigation into Cancer and Nutrition (EPIC). This cohort study was carried out in a number of countries across Europe seeking to investigate the relationship between diet and cancer (and also other diseases).
More than half a million people were looked at with the UK recruiting more than any of the other nine nations. Oxford engaged almost 30,000 vegetarians and vegans and whilst the study is not without limitations, it found that, overall, non-meat eaters had a lower risk of at least some cancers.
2014 Study: Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans
A study that combined these findings with those from another important piece of research mentioned earlier, the Oxford Vegetarian Study, as well other similar ones, backed this up. Published in 2014, this research considered 2,246 vegans (out of a wider pool) and concluded that:
Total cancer incidence was 12% lower in fish eaters, 11% lower in vegetarians, and 19% lower in vegans compared with meat eaters.
Whilst there is some overlap between parts of the research we have detailed, as well as with many other similar meta-studies, taken together, these form a convincing argument that vegans are less likely to develop cancer than those on an omnivorous diet. In addition, there is lots of research that directly links meat, especially of the processed and red variety (as we shall discuss), to some cancers.
Bearing all of this in mind it seems safe to conclude that the vegan diet is highly compatible with reducing one’s risk of developing cancer in general and some specific cancers in particular.
Why Might Vegans Develop Fewer Cancers?
Most studies into cancer and veganism have looked at populations over a period of time. They have shown a correlation between being vegan and a lower incidence of cancer but not necessarily a causal relationship or explicit reasons that indicate how and why this might be the case.
That said, it would seem fairly obvious why this might be the case and we would say that Cancer Research UK sums things up pretty well when they say:
A well-planned vegetarian or vegan diet can be very healthy, as diets high in plant foods like fruit, veg, wholegrains and pulses and low in processed and red meat can help you to keep a healthy weight and reduce the risk of cancer. But your diet won’t automatically be healthier by cutting out meat and fish or all animal products.
That latter point is something we have talked about many times. A “vegan diet” isn’t healthy per se and the Cancer Research site goes on to say that vegans, and indeed everyone, should follow the normal, mainstream government guidelines around nutrition. These can be summarised as:
Following a Healthy Vegan Diet is Key
- Eat five or more servings of fruit and veg a day with the majority being veg
- Eat lots of wholegrains
- Limit fat, especially saturated fat
- Eat a wide range of plants
- Eat a portion of nuts a day
- Drink lots of water
- Limit food and drink that is high in salt or sugar
A vegan diet is naturally likely to tick many of the boxes a healthy diet should. It means you are more likely to be eating a wide range of fruit and veg, as well as nuts, seeds and legumes (all great sources of vegan protein) and it is also likely to be low in saturated fat as this is mainly found in animal products. Diets high in fibre are also strongly linked with being protective in terms of developing cancer, especially certain types, such as bowel cancer, and once again most vegan diets score well in this regard.
Red & Processed Meat Linked to Cancer
What’s more, a vegan diet will be 100% free of red meat and processed meat, with these types of animal product particularly linked to cancer. In addition, various studies have shown that vegans typically have a lower Body Mass Index. With obesity strongly linked to many cancers, this is also a factor, although many of the systematic reviews do try to allow for this.
All of these things combine to make the vegan diet, generally speaking, just about the best around when it comes to cancer, even if we can’t be 100% clear about how exactly this works.
Conclusion: A Healthy Vegan Diet Reduces Cancer Risk
The weight of evidence is growing to suggest that vegans experience a lower incidence of cancer than non-vegans. This is shown over many pieces of research and indeed in many systematic reviews that have looked at multiple studies.
These have tended to show correlation rather than cause and we do not know the precise mechanism of how a vegan diet may reduce cancer risk. However, it seems highly likely that increased consumption of fruit, vegetables and dietary fibre, and reduced intake of saturated fat are key. In addition, our certainty that red and processed meats are carcinogenic is high and these are not something any vegan will consume.