What does the research say about processed meats and cancer?
In 2015, the International Agency for Research on Cancer, an independent agency of the World Health Organisation (WHO), reported that processed meat is carcinogenic to humans. This is based on an expert review article, which is summarised in the scientific journal Lancet Oncology.
WHO defines processed meats as products that have undergone salting, curing, fermentation or smoking to enhance flavour or improve preservation. This includes products like bacon, salami, hot dogs, ham and corned beef. WHO found that eating 50g of processed meats a day would increase the risk of developing bowel cancer by 18% over a lifetime – a statistic that increases with the amount of processed meat eaten. In fact, recent research found that people eating around 76g of red and processed meats a day had an increased risk of developing bowel cancer compared to those who ate only about 21g a day.
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A more recent study of almost 29,000 participants over seven years found a higher intake of red and processed meats is associated with a higher risk of colorectal cancer, but that there's little evidence that meat intake is associated with the risk for other cancers.
As a consequence, the current NHS recommendations suggest limiting your intake of red and processed meats to 70g per day, which is the average daily consumption in the UK, although you may choose to eat less.
What are nitrates and what do they do?
Nitrates are compounds that are found naturally in the human body and may be added to some foods by manufacturers to improve the look, colour and texture of products like bacon and other processed meats. They are sometimes included for food safety reasons to protect against microbes like botulism.
Are nitrates bad for you?
Nitrates are found naturally in some foods like green leafy vegetables, fennel and radishes. They are also added to meat by manufacturers to preserve them. So, nitrates themselves aren’t bad, unless they are converted to compounds called nitrosamines. This happens when bacon is cooked at a high temperature and the nitrates combine with amino acids that naturally occur in pork protein. This creates nitrosamines, which are known carcinogens. This means they are capable of causing cancer.
Vitamin C can be helpful because it may inhibit nitrosamine formation in the stomach – consuming high levels of fruit, such as citrus, or having plenty of green leafy veg or salad with your bacon may help reduce the risk of gastric cancer. There's also some evidence that having enough vitamin E may have a similar impact on nitrosamines. Vitamin E-rich foods include almonds, spinach, pumpkin and red peppers.
Is it better to buy nitrate-free bacon and other processed meats?
The evidence is pretty strong that a higher consumption of processed meat is associated with increased cancer risk. However, opting for nitrate-free bacon or other meats doesn’t mean it’s any better for you, either. Instead of using artificial nitrates during manufacturing, nitrate-free bacon is cured with celery juice or powder, which is also high in natural nitrates, so ‘no nitrates added’ on a food label is a little misleading.
Celery juice or powder does not contain the levels of vitamin C that a fresh celery stick would, so the vitamin C argument doesn’t stack up here either. Nitrate-free bacon carries the same risks as ‘normal’ bacon when it comes to nitrosamines and the risks of cancer.
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How much bacon is safe to eat?
The current advice from the NHS recommends that if you currently eat more than 90g (cooked weight) of red and processed meats a day, you should cut it down to 70g a day. This is equivalent to two or three rashers of bacon or a little over two slices of roast lamb, beef or pork (with each about the size of half a slice of bread). In light of the more recent evidence, it's best to reduce your intake of all processed meats to once every couple of weeks. Therefore, keeping your bacon intake to a minimum is recommended – eating it every couple of weeks is best.
Read more: How much red meat is safe to eat?
How can I minimise the risk of eating red meat and bacon?
1. Enjoy your bacon with peppers, avocado, spinach or a salad.
2. When you cook bacon, cook it at lower temperatures.
3. Buy meat less frequently, but ensure it's the best quality you can afford.
4. Try bacon alternatives, like turkey rashers, smoky flavoured tofu or tempeh rashers.
5. Add strong-flavoured smoked salmon or trout to your meal instead.
6. Replace the meat with ‘meaty’ veg, like portobello and porcini mushrooms.
7. Add spices, like paprika and chipotle peppers, to replicate bacon's smoky flavour and add extra depth.
8. Swap bacon for lentils, chickpeas, kidney beans, peas, butter beans, baked beans or haricot beans.
Now read:
Classic recipes minus the meat
What is a flexitarian diet?
Our favourite healthy vegetarian recipes
This article was last reviewed on 28 February 2022 by Kerry Torrens.
Kerry Torrens is a qualified nutritionist (MBANT) with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Applied Nutrition and Nutritional Therapy (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.
Emer Delaney BSc (Hons), RD has an honours degree in Human Nutrition and Dietetics from the University of Ulster. She has worked as a dietitian in some of London's top teaching hospitals and is currently based in Chelsea.
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