Study: High-Fat Diet May Increase Anxiety

Select comfort foods wisely. While stress-eating might provide temporary relief, a recent study indicates that some high-fat foods can exacerbate anxiety over time.

The study found that a high-fat diet, particularly one rich in saturated fats from animal sources, disrupted the gut microbiome of lab rats and altered their behavior. These rats exhibited increased gene expression related to neurotransmitter activity, notably affecting serotonin in ways known to heighten anxiety.

Beyond the usual risks like obesity or heart disease, these results suggest that significant intake of saturated fats may also have mental health repercussions, according to lead author Christopher Lowry, a professor of integrative physiology at the University of Colorado Boulder.

“While it’s well-known that these are unhealthy foods, we often think of them only in terms of weight gain,” Lowry explains. “Understanding that they can also affect your brain and promote anxiety raises the stakes.“

Prevalence and Impact of Anxiety Disorders

Although occasional intense worry is common, some people endure more severe, persistent anxiety that can disrupt daily life. Anxiety disorders, affecting approximately 300 million people worldwide, are the most prevalent mental disorders according to the World Health Organization.

Anxiety is a multifaceted and variable emotion influenced by numerous factors, with dietary impacts not fully understood. However, prior studies have similarly linked high-fat diets to increased anxiety in rats, and there are indications of a comparable connection in humans.

Investigating the Role of Saturated Fats in Anxiety

In their recent study, Lowry and his team aimed to further explore the connection between saturated fats and anxiety. They divided adolescent male rats into two groups, each receiving different diets over a period of nine weeks.

One group was given a standard lab-rat diet consisting of about 11 percent fat, while the other group received a diet containing approximately 45 percent fat, primarily saturated fats from animal products.

Throughout the nine-week study, the researchers monitored the rats’ microbiomes using fecal samples and conducted behavioral tests at the end.

Rats on the high-fat diet not only gained weight but also showed significantly reduced gut bacteria diversity compared to the control group.

Additionally, these rats had more bacteria from the phylum Firmicutes and fewer from Bacteroidetes. In humans, this ratio is linked to obesity and a diet high in refined grains, processed meats, and fried foods.

The high-fat diet group also exhibited elevated expression of three genes: tph2, htr1a, and slc6a4. These genes are involved in the production and signaling of serotonin, a neurotransmitter crucial for various functions.

Investigating the Role of Saturated Fats in Anxiety

While serotonin is often associated with mood enhancement, it also plays roles in vomiting, wound healing, and digestion. The researchers note that serotonin’s influence on depression is complex, and certain serotonin-producing neurons can induce anxiety-like behaviors in animals when activated.

In this new study, increased expression of the three genes was especially notable in the dorsal raphe nucleus cDRD—a brainstem region associated with stress and anxiety, where most of the brain’s serotonin is produced.

The researchers note that previous studies in humans have linked higher tph2 expression in the cDRD with mood disorders.

“It’s extraordinary to find that a high-fat diet could alter gene expression in the brain,” says Lowry. “The high-fat group essentially displayed the molecular signature of a high-anxiety state in their brain.”

The study’s authors emphasize that not all fats are the same. Certain fats, such as those found in fish oil and olive oil, provide anti-inflammatory and cognitive benefits.

However, saturated fats from animal sources are different. Lowry’s research suggests that a diet high in these fats can increase both short-term and long-term anxiety, particularly in younger individuals.

Read the original article on: Science Alert

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