A NEW ANALYSIS SUGGESTS REPLACING even a small amount of ultra-processed foods (with an equal amount of minimally-processed ones) appears to drop cancer risk. Today, we explore the relationship between ultra-processed food and cancer.
Ultra-processed foods are heavily processed and contain many added ingredients, such as preservatives, artificial flavors, and sweeteners. Some examples of ultra-processed foods include:
- Sweetened breakfast cereals
- Soft drinks and energy drinks
- Processed meats, such as hot dogs and sausages
- Fast food burgers and fries
- Instant noodles and soups
- Snack foods, such as chips and crackers
- Candy and chocolate bars
- Frozen meals and pizzas
- Flavored yogurts and fruit juices
- Cake mixes and other baked goods with many artificial ingredients.
These foods are often high in calories, sugar, salt, and unhealthy fats and may contribute to various health problems if consumed excessively. Experts recommend limiting ultra-processed foods’ consumption and choosing whole, minimally processed foods whenever possible.
Colorectal cancer and diet basics
Evidence suggests that a high intake of ultra-processed foods might raise cancer risk. However, we need more research to understand the link between ultra-processed foods and cancer fully.
Colorectal cancer is the third most common cancer among men and women in the United States and the second leading cause of death from cancer worldwide.
Diet might be an important colorectal cancer risk factor. Today, ultra-processed foods contribute 57 percent of the total daily calories consumed by American adults. This proportion has been steadily increasing over the last two decades.
Ultra-processed foods are high in added sugar, oils, fats, and refined starch. These substances can impact the gut microbiome composition unfavorably. Moreover, processed foods increase weight gain and obesity risks, known risk factors for colorectal cancer.
Diets rich in ultra-processed foods are typically low in nutrients (calcium, fiber, and vitamin D) and bioactive compounds associated with lower colorectal cancer risk.
Other problematic ingredients in an ultra-processed food diet include food additives (including artificial sweeteners and dietary emulsifiers). These substances can increase the pro-inflammatory potential of the gut microbiome.
The processing of some meats that contain nitrosamines may produce cancer-promoting agents (carcinogens). Heating acrylamide-containing foods can produce carcinogens, too. Finally, dangerous chemicals — including bisphenol A — may leak out of the packaging of ultra-processed foods.
Here is what I previously wrote about ultra-processed foods:
Ultra-processed foods and cancer
A 2018 large study in the British Medical Journal found that a 10 percent increase in the proportion of ultra-processed foods in the diet was associated with a small (1.12 times) increase in the risk of overall cancer and a 1.1 times rise in breast cancer risk.
The study also found that ultra-processed foods are associated with higher levels of obesity, a known risk factor for many cancer types. However, I always bring some skepticism to observational studies (for example, people consuming tons of ultra-processed foods are more likely to have other poor health habits). With that in mind, here are the results:
Men in the highest fifth of consumption (compared with those in the lowest fifth) had a 1.3-fold increase in colorectal cancer incidence. This positive association appeared limited to the distal (far end, including the rectum) colon. Women overall did not have a food: colon cancer risk association.
The culprits? Sugar-sweetened beverages among men and ready-to-eat dishes among women increased risk. Yogurt and dairy-based desserts lowered risk among women.
In summary, total unprocessed food consumption is associated with colorectal cancer risk in men and certain subgroups of ultra-processed foods in men and women.
Take the results with a grain of salt.
Given that observational studies such as this one provide only very low-level evidence, the authors note that we need additional studies; the evidence on this topic is inconclusive.
Other studies have suggested that certain additives commonly found in ultra-processed foods, such as nitrates and nitrites, may be carcinogenic. However, the evidence on this topic is inconclusive.
A new study — Processed foods and cancer
A new study suggests that replacing even a small amount of processed and ultra-processed foods — with an equal amount of minimally-processed options — might reduce cancer risk.
The researchers analyzed data from 450,000 participants from the European Prospective Investigation into Cancer and Nutrition (EPIC) study and examined 25 anatomical sites.
None of the subjects had cancer diagnoses at study enrollment. Nearly 48,000 individuals had a cancer diagnosis at an average follow-up of 14.1 years. The average was 51 years at study entry, and the body mass index was 25.3.
The researchers classified the level of food processing with the NOVA system:
- Minimally or non-processed foods (NOVA 1)
- Processed culinary ingredients (NOVA 2)
- Processed foods (NOVA 3)
- Ultra-processed foods (NOVA 4).
The researchers highlighted comparisons between NOVA 1 and 3 and between NOVA 1 and 4.
Here are the study results:
Swapping out just 10 percent of processed foods (with minimally processed ones) lowered overall cancer risk by a small amount (a relative four percent). More impressively, the risk for esophagus squamous cell cancer dropped by more than one-third, liver cancer by nearly one-quarter, and head and neck cancer by one-fifth.
Rectal cancer risk dropped by one-tenth, and post-menopausal breast cancer risk by under one-tenth.
My take
The authors appropriately note several study limitations. Notably, the intake of ultra-processed foods contributed to about one-third of the total daily energy intake among study participants. Today, that percentage could be nearly double across European countries.
The overall results are in line with historical study results. Increased consumption of minimally processed and fresh foods appeared to be associated with reduced overall risk for cancer and risk for specific cancers. Increased processed and ultra-processed food consumption was associated with increased cancer risks.
The recent study is the largest to analyze the associations between food processing and cancer risk. We need more research to understand this relationship better. Still, I will choose whole, minimally processed foods to promote my overall health and try to dodge chronic diseases.
Do I aim for perfection? Nope. I just finished a wonderful dark chocolate-covered pretzel.
If you know someone with breast cancer, here is my comprehensive online course:
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider for medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
Thank you for reading “Ultra-processed Foods and Cancer: Small Changes Drop Risk.”
