More evidence against ultra-processed foods | Office of Science and Society

This article was first published Official Gazette of Montreal.

Super processed food! Hardly a day goes by without an article appearing about these dietary demons that are ruining our health. In fact, as I was putting the finishing touches on this article on these demons, yet another study came up asking for publication. The paper has the ominous title: “Integration of lipidomics with targeted single-cell and spatial transcriptomics defines an unresolved pro-inflammatory state in colon cancer.” This doesn't seem to hint at ultra-processed foods, but by the time media reports distorted this study, we weren't told that cooking oil, which is commonly found in ultra-processed foods, can cause cancer. I did.

First, let's understand what “ultra-processed foods” really are. It's hard to come up with a simple definition, so the word “try” is appropriate. First of all, ultra-processed foods are full of things you don't have in your cupboard, such as emulsifiers, artificial flavors, colors, sweeteners, preservatives, high fructose corn syrup, modified starches, hydrolyzed proteins, hydrogenated oils and xanthan gum. These are typically packaged in plastic, raising the additional concern that trace chemicals, including potential endocrine disruptors, can leach into the contents. Additionally, ultra-processed foods typically contain more fat, sugar, salt, and seed oil than home-cooked meals. All these ingredients work together to make ultra-processed foods tastier, cheaper, and therefore more marketable.

What does this have to do with “lipidomics” and colon cancer? “Lipid” is the technical term for fatty substances, and “lipidomics” is the study of the activity of fatty substances in biological systems, including cells. Fats include fatty acids found in corn oil, soybean oil, peanut oil, and sunflower oil. These fatty acids are commonly found in ultra-processed foods, which make up more than 50% of our food supply. These fatty acids mostly fall into the category of “omega-6 fats,” where the number 6 is the first carbon involved in a double bond counting from the last carbon in the chain of carbon atoms, or the “omega” carbon. refers to fatty acid. (Omega is the last letter of the Greek alphabet, hence the term.) In contrast, in “omega-3 fats,” the first double bond is located at the third carbon from the end of the molecule. I will. It turns out that the difference in biological activity between omega-3 and omega-6 fats is very important.

Cancer is caused by “mutations,” or changes in the sequence of nucleotides that combine to form DNA. Such changes can lead to tumor development, which is then recognized by the immune system as an invader and activates various immune cells. The signal for this activity comes from the release of arachidonic acid, which is produced from linoleic acid, the most common fatty acid found in seed oils. When immune cells become active, they release compounds that cause inflammation. This is the desired state when the body tries to fight off an intruder. If this action is successful, the tumor is nipped in the bud and the compounds that cause inflammation are eliminated by mediators produced from omega-3 fats. But without an adequate supply of omega-3 fats, inflammation can smolder. This chronic inflammation can damage tissues, making them more susceptible to cancer.

The study, reported in the Lipidomics paper, compared colon cancer tissue and normal colon tissue from the same patients. Samples were analyzed for omega-6 fat-derived pro-inflammatory compounds and omega-3 fat-derived anti-inflammatory mediators. While normal tissue contains a balance of molecules derived from both types of fat, tumor tissue contains far more inflammatory compounds derived from omega-6 fats. The authors suggest that the cause of this problem may be an imbalance in dietary intake of omega-3 and omega-6 fats, due to the prevalence of ultra-processed foods rich in omega-6s. Researchers propose that this disparity may be responsible for the increase in colorectal cancer diagnoses in young people.

Not that fast! There are no data to support this suggestion. The study did not attempt to examine the participants' diets, so we do not know whether cancer patients were consuming more omega-6 fats. Also, the actual increase in colorectal cancer among young people is very small. Nevertheless, many news outlets touted this study as if it proved that cooking oil causes cancer. An act of sheer fear-mongering.

That being said, many studies support the benefits of increasing your intake of omega-3 fats compared to omega-6 fats. The best source of omega-3s is fish, but you can also get them from nuts, flaxseeds, and chia seeds. Still, the most effective solution is to reduce the foods with the worst ratio of omega-3 to omega-6: ultra-processed foods.

In recent years, large-scale epidemiological studies such as France's NutriNet-Santé and the UK's Biobank have followed thousands of people and monitored their diet and health over decades. They point to links between eating ultra-processed foods and heart disease, cancer, early death, and even psoriasis. Other studies have linked these foods to cognitive decline, insomnia, and depression, along with an increased risk of stroke and inflammatory bowel disease. Admittedly, these studies only show an association and cannot prove causation, but they all point in the same direction, which certainly raises concerns.

Then there is the scourge of obesity. In one of the most widely cited studies on the effects of ultra-processed foods, Dr. Kevin Hall and his team at the National Institutes of Health enrolled 20 adults who agreed to live in a clinical research unit for four weeks. Ta. They were randomly divided into two groups, with one group receiving ultra-processed foods and the other group receiving mostly unprocessed foods. Meals were adjusted for calories, fat, protein, sugar, sodium, and fiber, and participants were instructed to eat more or less of either meal, depending on their preference. After two weeks, the group switched to the alternative diet. The results were amazing! On the ultra-processed diet, participants ate approximately 500 more calories per day, and this intake was reflected in a 1-kilogram weight gain during the ultra-processed phase. Granted, this was a short-term study, but it still adds weight to the “beware of ultra-processed foods” argument.

So how should we be careful? Sugary breakfast cereals, potato chips, baking mixes, instant noodles, chicken nuggets, fish sticks, frozen pizza, soft drinks, hot dogs, fast food hamburgers and fries, cold cuts, cheese, candy bars, flavored yogurt, Ice cream, prepackaged soups, energy bars, white bread, TV dinners, and even plant-based meat substitutes all fall into the ultra-processed category.

So what's for dinner? How about a homemade chicken soup packed with vegetables, a salad of kale, tomatoes, cucumbers and onions with olive oil and vinegar dressing, or pasta with crushed tomatoes and tomato sauce seasoned with olive oil, salt and garlic?Dessert? Apple strudel. Yeah! Humans do not survive only on unprocessed food.

@JoeSchwarcz