Recent research published in journals health science report found that people who consumed large amounts of sugar and sugary drinks tended to be more likely to experience depression and anxiety. By examining the dietary habits and mental health of adults, scientists have discovered that certain types of sugar may play a unique role in mood disorders. The findings suggest that reducing sugar intake could be a modest but beneficial step in supporting the public’s mental health.
Sugar is a simple carbohydrate that the body uses to get instant energy. It occurs naturally in whole foods such as fruit and milk, but it is also added in large amounts to processed foods and drinks. As added sugar consumption continues to increase worldwide, scientists are working to understand how this dietary trend affects human health.
Consuming too much sugar is already known to increase the risk of physical diseases such as heart disease and diabetes. However, its direct relationship with mental health conditions such as depression and anxiety is less understood. Diet is a major lifestyle factor that can prevent or contribute to a variety of chronic diseases.
Study author Piril Hepsomali, Associate Professor at the University of Reading, said: “As recognized by the Global Disease, Injury and Risk Factors Study (GBD), diet is one of the biggest risk factors for long-term health conditions, and researchers are now paying more attention to how diet affects mental health, because it’s something that can be changed.”
“Simply put, a healthy diet rich in vegetables, fruits, nuts, legumes, and whole grains is associated with a lower likelihood of depression and anxiety. In contrast, an unhealthy diet high in sugar, salt, and saturated fat is associated with a higher likelihood of these symptoms. Research also shows that ‘Western’ diets and ultra-processed foods are associated with poorer mental health.
“One of the key factors in 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 diseases such as obesity, heart disease and type 2 diabetes. The evidence on sugar and mental health is not yet clear, but despite some mixed findings, the overall effect suggests harmful effects.”
“However, while there is some emerging evidence of an association between diet, particularly sugar intake, and depression and anxiety, the Global Burden of Disease Study does not yet provide clear estimates of these relationships,” continued Hepsomalli. “To address this, we investigated how total and specific sugar intake, sugary drink intake, and other key dietary factors are associated with depression and anxiety. In this study, we followed guidelines from the Global Burden of Disease, Lifestyle and Mental Disorders (GLAD) project.”
Researchers analyzed data from a sample of 377 participants between the ages of 18 and 66. This group was mainly composed of female university students. All participants completed an online survey that asked detailed questions about their typical eating habits and current mental health. Scientists used a widely known food frequency questionnaire to estimate how much of a particular food each person regularly consumed. This tool helped me calculate my daily intake of various nutrients.
Researchers looked at total sugar, sugary drinks, and specific sugars like sucrose and fructose. Sucrose is the scientific name for common table sugar, and fructose is a natural sugar found primarily in fruits. Participants also completed a standardized mental health questionnaire designed to identify recent symptoms of depression and anxiety.
Data revealed that 12.5% of participants had symptom scores consistent with possible depression. In addition, 16.4 percent of the sample had scores indicating possible anxiety. The researchers used a statistical model to see if dietary habits predicted the presence of these mental health conditions.
To ensure accuracy, scientists adjusted the calculations to account for age, gender, income, and BMI. BMI is calculated based on height and weight and is used to classify a person’s physical size. Taking these variables into account can help identify specific effects of diet.
The analysis showed that the more sugary drinks you consumed, the more likely you were to experience both depression and anxiety. Researchers also found that total sugar intake was associated with increased odds of developing these mood disorders. The effect size was small but statistically significant.
“Although the effects we observed were relatively small, this is common in studies like ours when compared to clinical studies or case-control studies, where participants often have more extreme symptoms or take drugs that may exaggerate the effects,” Hepsomari told PsyPost. “This means that sugar is just one piece of the puzzle. Still, small effects can matter at a population level, so modest reductions in sugar intake can have a real impact on the public’s mental health, even if the impact on a particular person is limited. So sugar is a risk factor worth paying attention to, but it’s not the whole story.”
When looking at certain types of sugar, scientists noticed a unique pattern. High sucrose intake is particularly associated with increased odds of anxiety, but not depression. This “raises questions about the underlying mechanisms and clearly requires further investigation,” Hepsomali said. In this particular sample, other food groups such as fruits, vegetables, red meat, and whole grains were not associated with depression or anxiety.
“Sugar was the main dietary factor influencing mental health in this sample, possibly masking the effects of other foods,” Hepsomali explained. “But, of course, that doesn’t mean other aspects of diet aren’t important. There’s still much to explore, and future research should dig deeper into these relationships.”
There are several biological reasons why sugar affects mood and brain function. Consuming large amounts of sugar can cause insulin resistance, which means your body doesn’t respond properly to the hormones that regulate blood sugar levels. This condition can cause mild inflammation throughout the body.
This body inflammation provides evidence of a biological link with changes in brain chemistry. Inflammatory signals can interfere with the production and transport of important mood-regulating chemicals such as dopamine and serotonin. When these chemicals are not ingested at appropriate levels, people are more likely to experience low mood and chronic anxiety.
Consuming large amounts of sugar can disrupt the balance of beneficial bacteria that live in your 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 overproduction of stress-related compounds.
Social and behavioral factors may also play a role in the association between diet and mental health. People who consume large amounts of sugary drinks often experience weight gain, which can lead to social stigma and poor mental health. Additionally, sugary drinks often contain other active ingredients, such as caffeine and artificial sweeteners, that can independently affect anxiety levels.
Although this study provides useful insights, there are some potential misconceptions to keep in mind. Because this study is based on a one-time study, it cannot prove that sugar actively causes depression or anxiety. It’s entirely possible that people with mental health issues are simply consuming more sugary foods as a coping mechanism. This inverse relationship is often referred to as emotional eating, where we seek out sweet foods to temporarily relieve pain.
The study sample consisted primarily of university students, with significantly more women than men. This particular demographic means that the findings may not apply to the broader, more diverse general population. Also, people filling out food questionnaires may misremember or misreport what they ate in the past few months. These self-report inaccuracies can obscure participants’ true eating habits.
“We found that people who consumed more sugar were more likely to experience depression and anxiety,” Hepsomali explained. “We would like to note that while this does not show that sugar or sugary drinks directly cause these symptoms, it does highlight that the amount of sugar we consume is an important factor to consider for mental health.”
Future research will need to follow diverse groups of people over time to better understand the sequence of events between eating and mood. This approach helps uncover the direct effects of nutrition on brain health.
“Currently, I’m conducting various clinical trials investigating how different nutrients, or combinations of them, affect mental, cognitive and sleep health across the lifespan,” Hepsomali said. “I am paying particular attention to mechanisms such as inflammation, gut microbiome composition and diversity, and brain chemistry, structure, and function to advance research in nutritional psychiatry. Although there are no immediate plans to directly follow up on the results of this research, a logical next step would be interventions to reduce sugar intake and track 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 Krisl Coxon, Mila Rufeger, Grace Hollamby, Deborah N. Ashtree, Rebecca Orr, Melissa M. Lane, and Piril Hepsomali.
