Say it over and over to yourself: Don't eat highly processed foods, don't eat foods with additives (e.g., emulsifiers, colors), don't eat foods/beverages with high fructose corn syrup, don't eat lots of pre-packaged foods or fast foods.
Why? This kind of high fat, low-fiber Western diet (which most of us eat), is linked to lots of health problems and also an unhealthy gut microbiome. Cancer, diabetes, heart disease!
Instead, eat a Mediterranean style diet - a diet rich in fruits and vegetables, whole grains, seeds, nuts, whole grains, legumes. Also, lots of olive oil. This is a high fiber diet linked to good health and a healthy gut microbiome.
Research finds harms (e.g., harmful alterations of the gut microbiome or intestinal lining, cancer) from ingredients added to highly processed foods, such as emulsifiers, carrageenan, artificial sweeteners, maltodextrin, carboxymethyl cellulose, polysorbate-80, artificial colors and flavors, high fructose corn syrup, etc. Bottom line: Try to avoid any ingredient that's not normally in your kitchen! Read ingredient lists on labels.
Excerpts from a commentary (transcript of podcast) by Dr. D. Johnson from Medscape: Forget Fad Diets, Here's the One You Need
Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia. Welcome back to another GI Common Concerns.
All of us routinely see diet recommendations on the Internet — like TikTok — or in new books. Every possible diet seems to receive this promotional push, although the evidence behind them is often lacking.
So what do we mean when we talk about a "healthy diet"?
The Western diet has really cannibalized the health of the United States and Western civilizations.
This diet is typically characterized by high intakes of processed and prepacked food items, red meat, dairy, and grains, consisting of high-fat, high-protein, and low-fiber components. These food items have become diets of convenience as opposed to diets potentially promoting health.
They've led to an associated increase in so-called "diseases of civilization," including cardiovascular disease, obesity, and a variety of metabolic diseases and cancers.
Western diets have been also associated with a variety of microbial and gut integrity changes, which in turn, are associated with an assortment of bad outcomes. Specifically, they're associated with decreases in microbial diversity in the gut; upregulation of proinflammatory mediators, cytokines, and chemokines; and several changes to gut integrity, immunity, and pathways that are derivatives toward diseases and even promoting translocation of gut bacteria.
In contradistinction, we have the Mediterranean diet, which is often proffered as the good or healthy diet for most patients. This comprises a diet that's high in fiber and low in animal protein and saturated fat, and is characterized by a higher ingestion of vegetables, fruits, and healthy fat and a lower intake of red meat and dairy. The Dietary Guidelines for Americans recommend a Mediterranean diet for promoting health and minimizing disease.
The high fiber content of Mediterranean diets is a key reason behind that recommendation. Fiber comes in soluble and insoluble forms. Soluble fiber gets digested, whereas insoluble fiber moves through the gastrointestinal tract, bringing components of water absorption and promoting gut motility, particularly in the colon.
Insoluble fiber has a variety of ascribed benefits, particularly related to the changes in the gut production of short-chain fatty acids, which are incredibly important for optimizing intestinal function.
We know that short-chain fatty acids increase secretion of immunoglobulins, induce regulatory T-cell tissue repair, promote antimicrobial peptides and mucus production, and basically optimize intestinal function and the intestinal barrier integrity. This is all critically important in promoting health.
Some things commonly added to diets have been shown in animal models to have a significant impact in changing gut integrity. In particular, this is observed in prepacked foods that are often found in the Western diet, which incorporate things such as emulsifiers and food additives with a goal toward enhanced aesthetics and taste.
Some that we see routinely in popular food items are carboxymethyl cellulose and polysorbate-80. These are derivatives in a variety of dairy products. Interestingly, they decelerate the melting of ice cream. That may be good for your kids eating an ice cream cone in the backseat in the summer, but not so good potentially for the intestine. The same is true as it relates to maltodextrin, which is a very common thickener and sweetener, but again decreases the mucosal layer thickness and increases gut permeability.
Carrageenan, which is made from red seaweed, is added to increase texture, primarily in dairy products and sauces. It also decreases gut integrity and permeability changes and antigenic translocation.
Another common food additive is high-fructose corn syrup, something we're seeing more and more data about. Its use in sugary beverages was once implied to have, and now clearly is associated with, an increased risk for nonalcoholic fatty liver disease, early colon cancer, and a variety of other cancer pathways. Recent animal model data have shown mechanistically how it contributes to colon cancer. It was also most recently associated with liver cancer in postmenopausal women ingesting one sugary beverage a day.
Almost all sugary beverages have shifted from using cane sugar to high-fructose corn syrup because it's cheaper and sweeter.
When it comes to artificial sweeteners, the top three that have been studied to date are aspartame, saccharin, and sucralose (Splenda). They are not absorbed but rather are fermentable sugars that get to the gut and change the gut microbiome. In animal models, they have been shown to promote obesity and diabetes, which is very much paradoxical to what their advertised intent is. Again, this has only been studied for these three agents, and we also don't have data in lower-threshold exposures.
I think it's common sense to minimize the use of these things and instead ask patients to use natural sugars, consume water, and incorporate other strategies; that's what I discuss with my own patients.
I tell my patients to be a good, conscientious thinker, look at your food, minimize the processed foods, and build your meals. The Western diet needs to go. The more we can use the Mediterranean diet, the better off we are. You can still have your occasional cheeseburger and French fries but use common sense.
David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology.