New research shows that enjoying a meat dinner as small as the palm of your hand and a side of fries could increase stress and increase the risk of anxiety.
Researchers at the University of Colorado tested mice that were fed an average diet or a diet in which almost half of the daily calories came from fats found in junk food.
They found that the latter group had more active genes known to alter levels of the “feel-good” neurotransmitter serotonin, which had a direct influence on the mice’s greater anxiety.
Those who ate a high-fat diet also had less diversity in their gut bacteria, which aids in digestion, nutrient absorption, and is known to benefit overall health.
The fat found in hamburgers, steaks and French fries is known to increase the risk of obesity, as well as damage to the blood vessels that supply the heart, and has been strongly linked to a variety of health problems, including heart disease, digestive problems and diabetes. .
High-fat diets are known to increase the risk of obesity, heart disease and type 2 diabetes.
The mice were followed for nine weeks and divided into two groups: One group consumed a diet consisting of 11 percent fat, while the other consumed a diet containing 45 percent fat, primarily saturated fats, such as found in red meat.
The researchers collected fecal samples and, after nine weeks, investigated how the diets affected the mice’s behavior, leaving them in a maze from which they had to escape, placing them in a box separated by bright light and darkness; more time spent in the dark suggested more anxiety. behavior – and an open field for measuring exploratory behavior and responses to a new environment.
The researchers then injected the mice with a short strand of DNA that complements a certain genetic sequence to better understand how genes involved in serotonin levels are activated.
Measuring that level of gene expression allows researchers to know how the changes affect serotonin function.
The group that consumed a high-fat diet not only gained more weight, but showed higher expression of three genes (tph2, htr1a and slc6a4), all of which are involved in the production and signaling of the neurotransmitter serotonin, which plays a role in both anxiety and depression.
These genes are particularly active in a brainstem region associated with stress and anxiety, indicating that greater expression could be associated with higher levels of those emotions.
The average American diet is made up of about 36 percent fat, which would consist of about 80 to 120 grams of fat per day. Much of that daily amount of fat could come from eating a large serving of French fries and an eight-ounce rib eye steak.
The recommended intake of 2,000 to 3,000 calories for the average American man, who weighs about 200 pounds, should come from macronutrients that include 45 to 65 percent carbohydrates, 10 to 35 percent protein, and 20 and 35 percent fat.
For an average American woman weighing about 170 pounds, it is recommended to eat about 2,000 calories per day with a similar breakdown of macronutrients.
The fat intake recommendation is lower than the average diet and the 45 percent fat diet given to the mice.
Dr. Christopher Lowry, professor of integrative physiology at CU Boulder, said, “To think that just a high-fat diet could alter the expression of these genes in the brain is extraordinary.”
“The high-fat group essentially had the molecular signature of a high-anxiety state in their brain.”
While scientists don’t fully understand how a high-fat diet affects anxiety-related behaviors, changes in the connection between the gut and the brain are thought to be important.
The brain’s serotonin system is crucial for regulating emotions, including anxiety. The dorsal raphe nucleus (DR) is the brain’s main source of serotonin and its serotonin pathways influence various emotional behaviors and thought processes.
When serotonin-producing neurons in specific parts of the Dominican Republic are activated, anxiety-like responses can increase.
The findings, published in the journal Biological researchsuggest that the high-fat diet influenced gut microbiome diversity and community composition during the nine weeks of dietary treatment.
The gut microbiome plays a key role in health and disease, including anxiety, both in experimental models and in humans.
Dr Lowry said: “Everyone knows these are not healthy foods, but we tend to think of them strictly in terms of a small amount of weight gain.”
“If you understand that they also affect your brain in a way that can promote anxiety, the stakes are even higher.”
The gut microbiome is dominated by two types of bacteria: Firmicutes and Bacteroidetes. The results of the study showed an increase in the Firmicutes/Bacteroidetes (F/B) ratio in mice fed a high-fat diet.
A higher ratio of firmicute to bacteriodete has been associated with the typical Western diet and higher rates of obesity.
Firmicute growth outpacing that of bacteriodetes leads to less efficient extractions of nutrients from food, leading to weight gain.
A high ratio also influences metabolism and the way food is stored as fat, causing more fat to accumulate in the body.