Researchers have discovered that food antigens like milk proteins help keep tumors from growing in our guts, specifically in the small intestines. These experiments revealed how these proteins trigger the intestinal immune system, allowing it to effectively stop the birth of new tumors.
Researchers at the RIKEN Center for Integrative medical sciences (IMS) in Japan have discovered that food antigens (like milk proteins) help keep tumors from growing in our guts, specifically the small intestines. The study was published in the scientific journal Frontiers in Immunology on Sep. 18.
Food antigens get a lot of negative press because they are the source of allergic reactions to foods such as peanuts, shellfish, eggs, and milk. Even when they don't lead to allergic reactions, these antigens -- along with the many others found in plants and beans -- are still considered foreign objects that need to be checked out by the immune system.
Research has reported that food antigens activate immune cells in the small intestines, but not the large intestines. At the same time, some immune cells activated by gut bacteria are known to suppress tumors in the gut. In the new study, the researchers brought these two lines of thought together and tested whether food antigens suppress tumors in the small intestines.
Tumor suppression was directly related to the presence of antigen, not the nutritional value of the food or any specific antigen.
The diet also affected immune cells, specifically T cells, in the small intestines. In this study, mice that received the "antigen-free" diet had many fewer T cells than those that received the normal food with milk protein. Further experiments revealed the biological process that makes this possible.
These findings have clinical implications. Similar to antigen-free diets, clinical elemental diets include simple amino acids, but not proteins. This reduces digestive work and can help people with severe gastrointestinal conditions, such as Crohn's disease or irritable bowel syndrome. According to the researchers, "small intestinal tumors are much rarer than those in the colon, but the risk is higher in cases of familial adenomatous polyposis, and therefore the clinical use of elemental diets to treat inflammatory bowel disease or other gastrointestinal conditions in these patients should be considered very carefully."
Elemental diets are sometimes adopted by people without severe gastrointestinal conditions or allergies as a healthy way to lose weight or reduce bloating and inflammation. The new findings suggest that this could be risky and emphasizes that these kinds of diets should not be used without a doctor's recommendation.
Previous research has found that the milk protein α-casein functions as a tumor suppressor via activation of STAT1 signaling, effectively preventing breast cancer tumor growth and metastasis.
Got Milk?
Milk is naturally packed with essential nutrients in a convenient and accessible form. Drinking milk is particularly important for children, however nutrition content varies. Milk from grass-fed or pastured cows provides more beneficial fats and higher amounts of some vitamins.
Fat-free? 1%? 2%? - Importantly, they all have the same amounts of other nutrients, so if you choose a lower-fat variety, you’re not missing out on any of the good stuff. I typically suggest consuming lower-fat versions of dairy, including milk, yogurt and cheese. The exception is children under age 2. Young children need the fat found in whole milk for brain growth and development.
Does organic matter?
Yep. Organic milk comes from cows that aren’t treated with antibiotics or growth hormones, and the cows that produce it must spend at least 30% of their time at pasture.
Organic milk avoids the hormones and other unnecessary additives to dairy that we’re trying to avoid. Here’s a nutritional bonus: Grass-fed cows are thought to make milk that is higher in omega-3 fatty acids, which support heart, brain and eye health, along with the health of your digestive and immune systems.
Possible risks
Milk consumption has been associated with an increased risk of some cancers, like prostate and endometrial, possibly from the growth hormones. "When we look at cancer risk, we’re really looking at the fat in dairy, which contains estrogenic hormones” These hormones have been associated with an increased risk of prostate and endometrial cancer but with a lower risk of colorectal cancer.
On the other hand, prostate, endometrial and colorectal cancer risk may be increased by the use of synthetic growth hormones often given to cows. Cows that are given these hormones have an increased risk for infection, so they’re more commonly given antibiotics. The best way to avoid these risks is to buy organically raised dairy products, as they come from cows that aren’t treated with hormones and antibiotics.
Increased risk of heart disease
Whole milk and 2% milk, in particular, are high in saturated fat. Consuming a lot of saturated fat leads to more plaque (cholesterol and fat) building up in the lining of your arteries, which makes it harder for blood to flow through your body. This increases your risk of heart disease. We know that saturated fat can increase your level of LDL, or ‘bad cholesterol,’ so if you’re consuming these kinds of milk in large amounts, it really adds up.
Cheese is another contributor to increased LDL, so it’s important to consider not just how much milk you’re drinking, but also how much dairy you’re consuming in general — including whole-milk cheeses, butter and cream. They’re all high in saturated fat.
I personally eat plain, non-fat, Greek yogurt almost daily. This can be a good dietary swap, especially if you choose a version that’s plain and low in fat. It’s full of probiotics and healthy bacteria that can feed your gut.
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