Scientists say restricting ultra processed foods (UPFs) – which include everything from sausages to fizzy drinks and sliced bread – could reduce cancer cases
Eating more processed junk food has been linked to a 41% higher risk of cancer.
An international research team tracked the health and diet of more than 100,000 Americans with an average age of 63 and looked at their chances of developing lung cancer. Over an average of 12 years 1,706 people developed the disease. People who consumed the highest amounts of Ultra Processed Foods (UPFs) were 41% more likely to develop lung cancer compared with those who consumed the least. The findings were adjusted to factor in whether or not people smoked tobacco. A quarter of cases occur in non-smokers.
UPFs are food products that have undergone multiple industrial processes and contain ingredients not typically found in home cooking. Additives include preservatives, emulsifiers, artificial colours and flavours which are used to enhance taste, texture and prolong shelf life.
The types of UPFs consumed most were processed meats like sausages and burgers as well as soft drinks.
Author Dr Kanran Wang, of Chongqing University Cancer Hospital in China, said: “Although additional research in other populations and settings is warranted, these findings suggest the healthy benefits of limiting UPF. Limiting UPF intake globally could contribute to reducing the burden of lung cancer.”
Brits consume a greater proportion of UPFs than any nation apart from the US. Estimates suggest they make up more than half of the average UK citizen’s diet. However most have no idea what this internationally recognised food category includes.
Most supermarket sliced bread is a UPF as well as shop-bought sandwiches, wraps, pastries, instant noodles, crisps, formed ham, breakfast cereals, cheap yoghurts and ice cream.
UPFs have unhealthy artificial additives to boost flavour and shelf life including emulsifiers, sweeteners, stabilising gums, flavour compounds and colouring agents. These are typically not used in home cooking but can be cheaper in mass produced food than natural ingredients.
Previous research has suggested that people who eat more UPFs are 24% more likely to have a heart attack or stroke.
Lung cancer is the most common cancer in the world. And in 2020 alone there were an estimated 2.2 million new cases and 1.8 million deaths from the disease worldwide. The latest study drew on data from the US Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trials.
Researchers focused in particular on UPF that included sour cream, as well as cream cheese, ice cream, frozen yoghurt, fried foods, bread, baked goods, salted snacks, breakfast cereals, instant noodles, shop-bought soups and sauces, soft drinks, sweetened fruit drinks, hamburgers, hot dogs and pizza.
The average study participant had just under three servings of UPFs each day. Consumption ranged from half a portion a day in those who ate the least, up to six servings a day in those consuming the most UPFs.
The authors said that they did make adjustments to their findings based on whether or not people smoked but they did not make adjustments for smoking intensity, which may have an impact on findings.
It is an observational study so they point out that “causality cannot be determined”. The results are published in the journal Thorax.
Commenting, Prof Sam Hare, consultant radiologist at the Royal Free London NHS Trust, said: “A quarter of lung cancer cases occur in non-smokers so we do need research exploring whether other factors are associated with lung cancer. We also know immunity is linked to cancer biology so it is a good idea to do research into factors like diet. However further work is needed to establish direct causation between UPFs and lung cancer.”
Tom Sanders, Professor of Nutrition at King’s College London, said: “Unhealthy diets often go hand in hand with smoking habit and low socioeconomic status. There appears to be no plausible mechanism to explain why ultra processed food should affect risk of lung cancer.”