Twins Show That Eating More Fruits and Vegetables Leads to Fewer Depression Symptoms

A study revealed that twins who consumed more fruits and vegetables experienced fewer symptoms of depression compared to their siblings.

Researchers from the Centre for Healthy Brain Ageing (CHeBA) at the University of New South Wales in Australia published these findings in the international journal Scientific Reports on the 29th of last month.

The study analyzed data from four longitudinal twin studies conducted in Australia, Denmark, Sweden, and the United States to evaluate the relationship between fruit and vegetable consumption and depression symptoms over 11 years.

The research included 3,483 participants aged 45 and older at baseline, with available data on fruit and vegetable intake and depression-related information.

While previous research has linked fruit and vegetable consumption to depression risk, studies focusing on adults over 45 have been limited.

Dr. Karen Mather, co-author of the study and leader of the Genomics and Epigenomics Group at CHeBA, explained that twins share 50-100% of their genetic makeup and grow up in the same household, which allows researchers to control for factors like early-life socioeconomic status that might otherwise skew the results.

The researchers used food frequency questionnaires across all studies to assess fruit and vegetable intake. They examined 13 types of fruits, including bananas, citrus fruits, apples, and pears, and collected data on vegetable consumption regardless of preparation methods. Potato intake was excluded from the main analysis because cooking information was unavailable.

In the study, the low-fruit intake group consumed an average of 0.3 servings per day, while the high-intake group averaged 2.1 servings. For vegetables, the low-intake group averaged 0.5 servings daily, compared to 2.0 servings for the high-intake group.

Depression symptoms were evaluated by asking participants how often they experienced various emotions over the past week.

The analysis showed that being a twin had no impact on the relationship between vegetable consumption and depression symptoms. Among twin pairs, the siblings who ate more vegetables experienced fewer depression symptoms over time.

Overall, the study found that groups with higher fruit and vegetable intake showed fewer depression symptoms compared to those with lower intake. However, no clear correlation was found between fruit consumption alone and depression symptoms.

Researchers suggested that the high dietary fiber, vitamins, and micronutrients in fruits and vegetables may have contributed to these findings.

They also noted that fruit and vegetable intake positively influenced gut microbiota composition and might have prevented oxidative brain damage.

In this study, even participants who consumed relatively high amounts of fruits and vegetables did not meet the recommended intake levels in many countries. The World Health Organization (WHO) recommends a daily intake of 400 grams of fruits and vegetables, while some countries, like South Korea, recommend over 500 grams.

The research team cautioned that they could not precisely predict how much depression symptoms might decrease if fruit and vegetable intake were increased to recommended levels. They emphasized the need for future studies to use more comprehensive and standardized tools to collect dietary data and utilize clinical assessments of depression symptoms for more accurate results.