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Cancer rates could rise due to growing intake of highly processed food

10% increase in amount of ultra-processed foods in diet linked to 12% higher risk of cancer

Adrian O'Dowd

Thursday, 15 February 2018

The growing trend of people consuming highly processed food could lead to rising numbers of cancer cases in the future, suggests a study* published today in The BMJ.

An international team of researchers found a possible association between intake of highly processed food in the diet and cancer, but have called for further exploration of their findings.

Ultra-processed foods such as packaged baked goods and snacks, fizzy drinks, sugary cereals, ready meals and reconstituted meat products often contain high levels of sugar, fat and salt, but lack vitamins and fibre.

Some previous studies have linked ultra-processed foods to higher risks of obesity, high blood pressure and cholesterol levels, but there is still little firm evidence to link intake to risk of disease.

Therefore, a team of researchers based in France and Brazil set out to evaluate potential associations between ultra-processed food intake and risk of overall cancer, as well as that of breast, prostate, and colorectal cancers.

They studied data from the NutriNet-Santé cohort study on 104,980 healthy French adults with an average age of 43 years who completed at least two 24-hour online dietary questionnaires, designed to measure usual intake of 3,300 different food items.

Foods were grouped according to degree of processing and cases of cancer were identified from participants' declarations validated by medical records and national databases over an average of five years.

Various well-known risk factors for cancer, such as age, sex, educational level, family history of cancer, smoking status and physical activity levels, were taken into account.

The results showed that a 10% increase in the proportion of ultra-processed foods in a person’s diet was associated with increases of 12% in the risk of overall cancer and 11% in the risk of breast cancer.

No significant association was found for prostate and colorectal cancers.

Further testing found no significant association between less processed foods (such as canned vegetables, cheeses and fresh bread) and risk of cancer, while consumption of fresh or minimally processed foods (fruits, vegetables, pulses, eggs, meat, fish and milk) was associated with lower risks of overall cancer and breast cancer.

Given that this was an observational study, no firm conclusions can be drawn about cause and effect, but nevertheless, the authors said: “To our knowledge, this study is the first to investigate and highlight an increase in the risk of overall - and specifically breast - cancer associated with ultra-processed food intake.”

They called for further exploration to confirm their findings and to better understand the effects of the various stages of processing but added: “If confirmed in other populations and settings, these results suggest that the rapidly increasing consumption of ultra-processed foods may drive an increasing burden of cancer in the next decades.”

They suggested a need for policies targeting product reformulation, taxation, and marketing restrictions on ultra-processed products and promotion of fresh or minimally processed foods.

In a linked editorial**, Martin Lajous and Adriana Monge based at the National Institute of Public Health in Mexico, said: “Fiolet and colleagues provide an initial insight into a possible link between ultra-processed foods and cancer.

“We are a long way from understanding the full implications of food processing for health and wellbeing.”

*Fiolet, T, Srour, B, et al. Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort. BMJ 2018;360:k322. DOI:10.1136/bmj.k322
**Monge, A and Lajous, M. Editorial: Ultra-processed foods and cancer. BMJ 2018;360:k599. DOI:10.1136/bmj.k599

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