Researchers at the University of California Riverside have identified a concerning correlation between high-fat diets and elevated risks for obesity, colon cancer, and irritable bowel diseases (IBD). The study also highlights adverse effects on the immune system, brain function, and an increased susceptibility to COVID-19 associated with such dietary patterns.
In a comprehensive study published in the journal Scientific Reports, the researchers fed mice three distinct high-fat diets over a 24-week period, with at least 40% of the calories derived from fat. The diets included saturated fat from coconut oil, monounsaturated modified soybean oil, and unmodified soybean oil high in polyunsaturated fat.
While acknowledging that mouse studies may not perfectly mirror human responses, researchers emphasized the shared 97% of working DNA between mice and humans. The study revealed concerning changes in gene expression in all four parts of the mice’s intestines when compared to a low-fat control diet.
Lead author Frances Sladek, a cell biology professor at UC Riverside, cautioned against the common belief that all plant-based diets are inherently healthier, asserting, “A diet high in fat, even from a plant, is one case where it’s just not true.”
The significance of the findings lies in the fact that soybean oil, a commonly consumed oil in the United States and other countries like China, India, and Brazil, showed particularly impactful changes. Researchers observed shifts in genes related to gut bacteria, fat metabolism, and surprising changes in genes regulating susceptibility to infectious diseases.
The study also unveiled an increase in the expression of ACE2 and other host proteins used by COVID-19 spike proteins to enter the body, adding an additional layer of concern regarding high-fat diets.
Notably, coconut oil demonstrated the greatest number of gene expression changes, followed by unmodified soybean oil. The differences between the two soybean oils suggested that polyunsaturated fatty acids in unmodified soybean oil, primarily linoleic acid, played a role in altering gene expression.
Medical professionals not involved in the study expressed concern over the impact of high-fat diets on the immune system, microbiome, and overall health. Dr. Anton Bilchik, a surgical oncologist, emphasized the negative effects on the immune system and the microbiome, leading to an increased risk of diseases such as inflammatory bowel disease and colon cancer.
Dr. Sudarsan Kollimuttathuillam, an oncologist and hematologist, emphasized the indirect impact of high-fat diets on DNA, stating that foods affect gene expression, playing a crucial role in increasing or decreasing the long-term risk of diseases.
Experts provided advice on dietary choices, recommending limiting intake of unhealthy fats, refined sugars, and highly processed foods. They suggested adopting a diet rich in plants, whole foods, healthy fats, and high-quality carbs to reduce the risk of common cancers.
Dr. Shiara Melissa Ortiz-Pujols, an obesity medicine specialist, encouraged small changes in diet, such as opting for olive oil over processed cooking oils, to promote positive changes in the microbiome and overall health. The emphasis was on sustainable lifestyle changes rather than short-term restrictive diets.