Even a small amount of processed meat increases health risks, study finds

Globe and Mail

21-07-2025

There's abundant evidence that eating lots of processed meat is linked to an increased risk of heart disease, Type 2 diabetes and, most notably, colorectal cancer.
According to the World Cancer Research Fund, there is no intake level of processed meat that does not pose a colorectal cancer risk.
Now, findings from a large review of research add to the increasing body of evidence that underscores the harmful health effects of processed meat.
Here's what to know about the latest research, plus why you don't have to completely abandon your summer hot dog.
Processed meat refers to meat – red meat and poultry – that has been preserved by smoking, curing, salting or the addition of chemical preservatives.
Ham, bacon, pastrami, salami, deli meats, beef jerky, sausages and hot dogs, for example, are processed meats.
Commercially produced burgers can also fall into the processed meat category if they're preserved with chemicals.
For the study, published June 30 in the journal Nature Medicine, researchers analyzed dozens of previous studies that investigated the relationship between processed meat and risk of colorectal cancer, Type 2 diabetes and coronary heart disease.
To assess the connection between processed meat consumption and colorectal cancer, 18 studies involving 2,678,052 participants were reviewed.
All studies controlled for age and sex and most adjusted for other risk factors including body mass index, smoking, alcohol intake, calorie intake and physical activity.
On average, eating 50 grams of processed meat a day – versus none – was tied to a 26 per cent increased risk of developing colorectal cancer.
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For perspective, 50 g of processed meat is equivalent to roughly four slices of cooked bacon, three slices of packaged deli ham or two-thirds of a jumbo-sized hot dog (75 g). A standard-sized hot dog typically weighs 38 g.
To examine processed meat intake and Type 2 diabetes risk, 16 studies with a total of 1,115,885 participants were reviewed. The studies accounted for other influences such as age, sex, body mass index and dietary factors.
The risk of developing Type 2 diabetes was, on average, 30 per cent higher for a daily intake of 50 g of processed meat compared to none.
The researchers also conservatively estimated that consuming processed meat within the range of 0.6 to 57 g per day, compared to consuming none, was associated with, on average, at least a 7 per cent higher risk of colorectal cancer and an 11 per cent higher risk of Type 2 diabetes.
The risk of colorectal cancer and Type 2 diabetes rose as consumption increased.
Notably, health risks increased the fastest at low intake levels, suggesting there is no 'safe' amount of processed meat with respect to colorectal cancer or Type 2 diabetes risk.
A regular intake of processed meat was also tied to an increased risk of coronary heart disease. This finding, however, wasn't statistically significant, meaning it could have occurred by chance.
A high intake of processed meat is thought to increase visceral fat (deep abdominal fat) and inflammation.
Processed meat is also typically high in sodium and saturated fat.
As well, chemical compounds in cooked processed meat called heterocyclic amines and polycyclic aromatic hydrocarbons have been shown to induce tumours in experimental studies.
Heme iron in processed red meat may promote colon tumours by stimulating the formation of carcinogenic N-nitroso compounds. Processed meat can also contain nitrate additives, which can contribute to the formation of N-nitroso compounds in the body.
The new study also analyzed previous studies that examined the link between chronic disease risk and sugar-sweetened beverages (SSB), which include pop, iced tea, lemonade, sports drinks, energy drinks and sugary coffee drinks.
Consuming 250 g (eight ounces) of SSB per day, compared to none, was associated with a 20 per cent higher risk of developing Type 2 diabetes and a 7 per cent greater risk of developing coronary heart disease.
A high intake of added sugars, especially in liquid form, contributes to elevated inflammatory markers in the bloodstream and accumulation of harmful visceral fat.
The analysis included studies that were observational and, as such, found associations between diet and chronic disease. The findings don't prove there is a causal relationship.
As well, participants self-reported their dietary intake. Memory errors can occur when trying to recall long-term food intake.
Despites these limitations, the new findings are very consistent with prior research.
They reinforce recommendations to avoid or minimize the consumption of processed meat and sugar-sweetened drinks to improve health.
If processed meat and/or sugary drinks are a regular part of your diet, it's wise to cut back.
Remember, too, it's your overall dietary pattern that matters when it comes to health.
A diet that's plentiful in vegetables, fruits, whole grains, nuts and pulses can, if you like, include the occasional hot dog.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD