Study suggests possible link between highly processed foods and cancer

February 14, 2018, British Medical Journal
fast food
Credit: Maliz Ong/public domain

A study published by The BMJ today reports a possible association between intake of highly processed ("ultra-processed") food in the diet and cancer.

Further exploration is needed, but these results suggest that the rapidly increasing consumption of ultra-processed foods "may drive an increasing burden of cancer in the next decades," warn the researchers.

Ultra-processed foods include packaged baked goods and snacks, fizzy drinks, sugary cereals, ready meals and reconstituted meat products—often containing high levels of sugar, fat, and salt, but lacking in vitamins and fibre. They are thought to account for up to 50% of total daily energy intake in several developed countries.

A few studies have linked ultra-processed foods to higher risks of obesity, and cholesterol levels. But firm evidence linking intake to risk of disease is still scarce.

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

Their findings are based on 104,980 healthy French adults (22% men; 78% women) 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 (NutriNet-Santé cohort study).

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.

Several 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 show that a 10% increase in the proportion of ultra-processed foods in the 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 freshly made unpackaged bread) and risk of cancer, while consumption of fresh or minimally processed foods (fruits, vegetables, pulses, rice, pasta, eggs, meat, fish and milk) was associated with lower risks of overall cancer and .

This is an observational study, so no firm conclusions can be drawn about cause and effect, and the researchers point to some limitations. For example, they cannot rule out some misclassification of foods or guarantee detection of every new cancer case. Nevertheless, the study sample was large and they were able to adjust for a range of potentially influential factors.

"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," write the authors.

They stress that further work is needed to better understand the effects of the various stages of processing, but suggest policies targeting product reformulation, taxation, and marketing restrictions on ultra-processed products and promotion of fresh or minimally processed foods may contribute to primary cancer prevention.

In a linked editorial, Martin Lajous and Adriana Monge based at the National Institute of Public Health in Mexico, say this study provides "an initial insight into a possible link between ultra processed foods and cancer" but "we are a long way from understanding the full implications of food processing for health and wellbeing."

They point to several challenges, such as identifying the precise elements in ultra-processed foods that could lead to , and the potential impact of other unmeasured factors on the results.

As such, they conclude: "Care should be taken to transmit the strengths and limitations of this latest analysis to the general public and to increase the public's understanding of the complexity associated with nutritional research in free living populations."

Explore further: Consumption of processed meat may increase the risk of breast cancer, according to a new study.

More information: Consumption of ultra-processed foods and cancer risk: results from NutriNet-Sante? prospective cohort, BMJ (2018). www.bmj.com/content/360/bmj.k322

Editorial: Ultra-processed foods and cancer, BMJ (2018). www.bmj.com/content/360/bmj.k599

Related Stories

Consumption of processed meat may increase the risk of breast cancer, according to a new study.

January 4, 2018
Consumption of processed meat may increase the risk of breast cancer, according to a new study.

'Ultra-processed' foods make up more than half of all calories in US diet

March 9, 2016
'Ultra-processed' foods make up more than half of all calories consumed in the US diet, and contribute nearly 90% of all added sugar intake, finds research published in the online journal BMJ Open.

Can eating sugar cause cancer?

January 8, 2018
A recent study published by Belgian biologists found a relationship between glucose (sugar) and the activation of a gene that stimulates the growth of cancer cells. This led to public fear that everything with sugar should ...

Report: Whole grains decrease colorectal cancer risk, processed meats increase the risk

September 7, 2017
Eating whole grains daily, such as brown rice or whole-wheat bread, reduces colorectal cancer risk, with the more you eat the lower the risk, finds a new report by the American Institute for Cancer Research (AICR) and the ...

Study calculates contribution of risk factors to cancer in the US

November 21, 2017
A new American Cancer Society study calculates the contribution of several modifiable risk factors to cancer occurrence, expanding and clarifying the role of known risk factors, from smoking to low consumption of fruits and ...

Eating red and processed meat—what do scientists say

March 6, 2014
Recent reports warn about a link between eating red and processed meat and the risk of developing cancer in the gut. These reports have resulted in new nutritional recommendations that advise people to limit their intake ...

Recommended for you

Low-fat or low-carb? It's a draw, study finds

February 20, 2018
New evidence from a study at the Stanford University School of Medicine might dismay those who have chosen sides in the low-fat versus low-carb diet debate.

Tobacco kills, no matter how it's smoked: study

February 20, 2018
(HealthDay)—Smokers who think cigars or pipes are somehow safer than cigarettes may want to think again, new research indicates.

Just a few minutes of light intensity exercise linked to lower death risk in older men

February 19, 2018
Clocking up just a few minutes at a time of any level of physical activity, including of light intensity, is linked to a lower risk of death in older men, suggests research published online in the British Journal of Sports ...

Women who clean at home or work face increased lung function decline

February 16, 2018
Women who work as cleaners or regularly use cleaning sprays or other cleaning products at home appear to experience a greater decline in lung function over time than women who do not clean, according to new research published ...

Calcium and Vitamin D supplements are not associated with risk of heart attacks

February 16, 2018
New research from the University of Southampton has found no association between the use of calcium or vitamin D supplementation and cardiovascular events such as heart attacks.

Study shows options to decrease risk of motor vehicle crashes for adolescent drivers

February 16, 2018
Adolescents who receive comprehensive and challenging on-road driving assessments prior to taking the license test might be protected from future motor vehicle crashes, according to a University of Alabama at Birmingham study ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

JustAnotherFool
not rated yet Feb 17, 2018
It is what's missing from the processed food that is doing the damage...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.