High sugar intake is linked to increased odds of depression and anxiety in new study

A recent study published in the journal Health Science Reports has found that consuming high amounts of sugar and sugary drinks tends to be linked with a higher chance of experiencing depression and anxiety. By examining the dietary habits and mental health of adults, scientists found that specific types of sugar might play unique roles in mood disorders. The findings suggest that reducing sugar intake could be a modest but helpful step in supporting public mental health.

Sugar is a simple carbohydrate that the body uses for quick energy. It is found naturally in whole foods like fruits and milk, but it is also added in large quantities to processed foods and beverages. As global consumption of added sugars continues to rise, scientists are working to understand how this dietary trend affects human health.

Heavy sugar intake is already known to increase the risk of physical conditions like heart disease and diabetes. However, its direct connection to mental health conditions like depression and anxiety is less understood. Diet is a major lifestyle factor that can either protect against or contribute to various chronic diseases.

“Diet is one of the biggest risk factors for long-term health conditions, as acknowledged by the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), and researchers are now paying more attention to how it affects mental health because it’s something we can change,” said study author Piril Hepsomali, an associate professor at the University of Reading.

“In simple terms, healthier diets, rich in vegetables, fruit, nuts, legumes, and whole grains, are linked to lower chances of depression and anxiety. In contrast, less healthy diets, high in sugar, salt, and saturated fats, are linked to higher chances of these conditions. Studies also show that “Western-style” diets and ultra-processed foods are associated with poorer mental health.”

“One key factor across these unhealthy diets is high sugar intake. Around the world, people are consuming more sugar, especially through sugary drinks. These drinks are already known to increase the risk of conditions like obesity, heart disease, and type 2 diabetes. Evidence on sugar and mental health is still emerging with some mixed findings, but overall suggests harmful effects, despite some mixed findings.”

“However, while there is some emerging evidence linking diet—particularly sugar intake—to depression and anxiety, the Global Burden of Disease study does not yet provide clear estimates for these relationships,” Hepsomali continued. “To address this, we examined how total and specific sugar intake, sugary drink consumption, and other key dietary factors are associated with depression and anxiety. In this study, we followed the Global burden of disease Lifestyle And mental Disorder (GLAD) Project guidelines.”

The researchers analyzed data from a sample of 377 participants between the ages of 18 and 66. The group was predominantly made up of female university students. All participants completed an online survey that asked detailed questions about their typical eating habits and their current mental health. The scientists used a widely recognized food frequency questionnaire to estimate how much of specific foods each person consumed on a regular basis. This tool helped them calculate the daily intake of various nutrients.

The researchers examined total sugar, sugary drinks, and specific sugars like sucrose and fructose. Sucrose is the scientific name for common table sugar, while fructose is the natural sugar primarily found in fruit. The participants also filled out a standardized mental health questionnaire designed to identify recent symptoms of depression and anxiety.

The data revealed that 12.5 percent of the participants had symptom scores matching likely depression. Additionally, 16.4 percent of the sample had scores indicating likely anxiety. The researchers used statistical models to see if dietary habits predicted the presence of these mental health conditions.

To ensure accuracy, the scientists adjusted their calculations to account for age, sex, income, and body mass index. Body mass index is a calculation based on height and weight that is used to categorize a person’s physical size. Taking these variables into account helps isolate the specific effect of diet.

The analysis showed that higher intake of sugar-sweetened beverages was associated with an increased likelihood of experiencing both depression and anxiety. The researchers also found that total sugar consumption was linked to greater odds of these mood disorders. The effect sizes were small but statistically significant.

“Although the effects we observed were relatively small, this is common in studies like ours compared with clinical or case–control studies, where participants often have more extreme symptoms or take medications that can inflate effects,” Hepsomali told PsyPost. “This means sugar is just one piece of the puzzle. Even so, small effects can matter at the population level, so modest reductions in sugar intake could have real impacts on public mental health, even if the effect for any one person is limited. In short, sugar is a risk factor worth paying attention to, but it’s not the whole story.”

When looking at specific types of sugar, the scientists noticed a unique pattern. Higher consumption of sucrose was specifically associated with higher odds of anxiety, but not depression, which “raises questions about the underlying mechanisms and clearly warrants further investigation,” Hepsomali said. Other food groups, such as fruits, vegetables, red meat, and whole grains, were not linked to depression or anxiety in this particular sample.

“It’s possible that sugar is the dominant dietary factor influencing mental health in this sample, perhaps overshadowing the effects of other foods,” Hepsomali explained. “But of course, that doesn’t mean other aspects of diet aren’t important. There’s still a lot to explore, and future research will need to dig deeper into these relationships.”

There are several biological reasons why sugar might influence mood and brain function. High sugar consumption can lead to insulin resistance, a condition where the body stops responding properly to the hormone that regulates blood sugar. This condition can trigger low-grade inflammation throughout the entire body.

This bodily inflammation provides evidence of a biological link to altered brain chemistry. Inflammatory signals can disrupt the production and transport of important mood-regulating chemicals like dopamine and serotonin. Without proper levels of these chemicals, people are more susceptible to experiencing low mood and chronic worry.

Heavy sugar intake might also disrupt the balance of helpful bacteria living in the digestive tract. The gut environment is known to communicate directly with the brain and influence emotional regulation. Unhealthy changes in these bacteria can lead to the overproduction of stress-related compounds.

Social and behavioral factors might also play a role in the link between diet and mental health. People who consume high amounts of sugary drinks often experience physical weight gain, which can lead to social stigma and worsened mental well-being. Additionally, sugary drinks often contain other active ingredients, like caffeine or artificial sweeteners, that might independently affect anxiety levels.

While the study provides helpful insights, there are a few potential misinterpretations to keep in mind. Because the research relied on a one-time survey, it cannot prove that sugar actively causes depression or anxiety. It is entirely possible that people experiencing mental health challenges simply consume more sugary foods as a coping mechanism. This reverse relationship is often called emotional eating, where individuals seek out sweet foods to temporarily soothe distress.

The study sample was mostly made up of university students, and there were many more women than men. This specific demographic makeup means the findings might not apply to the broader, more diverse general population. Also, people filling out food questionnaires sometimes misremember or incorrectly report what they ate over the past months. These self-reported inaccuracies can obscure the true dietary habits of the participants.

“We found that people who consumed more sugar were more likely to experience depression and anxiety,” Hepsomali explained. “I would like to note that this doesn’t show that sugar or sugary drinks directly cause these conditions, but it highlights that how much sugar we consume is an important factor to consider for our mental health.”

Future research will need to track diverse groups of people over long periods to better understand the sequence of events between diet and mood. This approach would help clarify the direct impact of nutrition on brain health.

“Currently, I’m conducting a range of clinical trials investigating how different nutrients, or combinations of them, affect mental, cognitive, and sleep health across the lifespan,” Hepsomali said. “I pay particular attention to mechanisms such as inflammation, gut microbiome composition and diversity, and brain chemistry, structure, and function, all to advance research in nutritional psychiatry. While I don’t have immediate plans to directly follow up on the findings from this study, a logical next step would be an intervention reducing sugar intake and tracking depression and anxiety.”

The study, “Sugar Intake Is Associated With Increased Odds of Depression and Anxiety: Evidence From A Cross-Sectional Study,” was authored by Christle Coxon, Mira Rufeger, Grace Hollamby, Deborah N. Ashtree, Rebecca Orr, Melissa M. Lane, and Piril Hepsomali.