While we may suspect that eating processed food is associated with a higher risk of cancer, a very large prospective study published in the British Medical Journal earlier this year looked for associations between eating processed food and risk of cancer. Other studies have suggested that there is a higher risk of obesity, hypertension, and lipid disorders when eating low nutrient dense foods and now this study suggests a higher risk of cancer too.
Nearly 105,000 people (78% women and 21% men) participated in this study examining self-reported food intake separated into four categories—Unprocessed or minimally processed foods, Processed culinary ingredients, Processed food, and Ultra-processed food (NOVA classification or see after the blog for a brief description). Those with a greater consumption of ultra-processed food had diets that were higher in energy, sugar, fat (especially saturated fat), and sodium and lower in fiber and micronutrients.
The researchers suggest hypotheses for why ultra-processed foods may be associated with cancer risk. They:
- Contain higher quantities of total fat, saturated fat, and added sugar and salt while containing few vitamins and little fiber
- May contain substances that are carcinogenic because of the heat treatment (eg, smoking, drying, frying, roasting, barbecuing) during processing
- Have food additives (eg, sodium nitrite in processed meat and others) which may cause cancer, but research in this area remains controversial
Packaging may also interact with or leave contaminants on the food that have an unknown cancer risk.
The foods, in this study, contributing the most to intake in the ultra-processed group were sugary products (26%), sugar sweetened beverages (20%), starchy foods and breakfast cereals (16%), and ultra-processed fruits and vegetables (15%).
Individuals who tended to consume more ultra-processed foods were younger, current smokers, less educated, with less family history of cancer, lower physical activity level, and lower alcohol intake.
A “10% increase in the proportion of ultra-processed foods in the diet was associated with significant increases in the risk of overall cancer (12%) and risk of breast cancer (11%).” The effect remained even after adjusting for body mass index.
Considerations for this study:
- Since it was a study designed to look for associations, rather than cause and effect, there could be other reasons for the increase in cancer.
- Because all of the participants were French citizens, it may not be generalizable to Americans.
- More of the participants were women, so these results may not be applicable to men.
While BIG members obviously want to eat to get stronger and perform well WODs, ultimately, the goal is to remain as healthy as possible. Fortunately, it looks like eating mostly foods with minimal processing and packaging is an approach to support all of these ends.
Happy and healthful eating,
Donna G. Pertel, MEd, RD, LDN
*In this study—
Ultra-processed food was defined as mass produced and packaged:
- Breads and buns; packaged snacks; confectionery and desserts
- Sugar sweetened beverages (SSB)
- Meat balls, poultry and fish nuggets, and “other reconstituted meat products transformed with addition of preservatives other than salt (for example, nitrites)”
- Instant noodles and soups
- Frozen or shelf stable ready meals
- “Food products made mostly or entirely from sugar, oils and fats, and other substances not commonly used in culinary preparations such as hydrogenated oils, modified starches, and protein isolates”
- Flavorings, colors, emulsifiers, nonnutritive sweeteners, and other additives are often added to these foods
This contrasts with—
- Minimally processed foods: “…Fresh, dried, ground, chilled, frozen, pasteurised, or fermented staple foods such as fruits, vegetables, pulses, rice, pasta, eggs, meat, fish, or milk.”
- Processed culinary ingredients: “…Salt, vegetable oils, butter, sugar, and other substances extracted from foods and used in kitchens to transform unprocessed or minimally processed foods into culinary preparations.”
- Processed foods: “…Canned vegetables with added salt, sugar coated dried fruits, meat products preserved only by salting, cheeses, freshly made unpackaged breads, and other products manufactured with the addition of salt, sugar, or other substances of the ‘processed culinary ingredients’ group.”