New research led by University of New South Wales scientists supports a role for fruit — but not vegetable — intake in protecting against depression.
Higher intakes of fruit are associated with a reduced risk of incident depression.
Depression is a major public health concern. The global impact of depressive disorders is estimated to be over 50 million years lived with disability, making depression the largest contributor to non-fatal burden of disease.
More than 80 % of this burden is accounted for by low- and middle-income countries.
Compared with depression in younger adults, depression in older adults has a greater impact on physical performance and cognition and is associated with lower quality of life and higher all-cause mortality.
A growing body of evidence suggests that dietary behaviors — in particular higher consumption of fruit and vegetables — may be important in reducing the risk of depression.
“Our aim with the new study was to examine the associations between fruit and vegetable intake and depression in adults 45 years and older,” said Dr. Annabel Matison, a researcher at the University of New South Wales.
The study involved 7,801 community-based adults without depression from multiple regions across six continents, including the United States, Sweden, Brazil, Nigeria, Malaysia and Australia.
It revealed a beneficial association between higher fruit intake and lower risk of depression over the nine year period.
“This interesting finding of a protective association between fruit intake and risk of depression demonstrates a need to give a greater emphasis to diet in healthcare,” Dr. Matison said.
Although the results suggested a benefit for the intake of vegetables, they were not statistically significant.
“The reason we found a beneficial relationship for fruit, but not vegetable intake, may be that vegetables are typically consumed cooked, which may impact their nutrient content, whereas fruit is generally consumed raw,” Dr. Matison said.
“Fruit and vegetable intake was self-reported via comprehensive food frequency questionnaire, short food questionnaire or diet history.”
“Depressive symptoms were assessed using validated measures and depression defined applying validated cut-offs.”
“The associations between baseline fruit and vegetable intakes and incident depression over a follow-up period of three to nine years were examined using the Cox regression method.”
It has been suggested that the high levels of antioxidants, dietary fiber and vitamins contained in fruit and vegetables may exert a beneficial influence on depression through numerous mechanisms such as their role in inflammation, oxidative stress and the gut microbiota.
As fruits and vegetables contain varying nutrients, it also seems likely that different types of fruit and vegetables may have differing impacts on the risk of depression.
The evidence for citrus fruits and green leafy vegetables being associated with lower risk of depression is particularly strong.
“Future research considering the consumption of different types of fruit and vegetables using standardized measures and focusing on larger numbers of older adults is definitely warranted, particularly for low- and middle-income countries,” said University of New South Wales’s Professor Henry Brodaty.
“The extension of current research being conducted into the genes associated with dietary intake provides a promising avenue to influence the intakes of fruit and vegetables.”
“We should also consider the types of fruit and vegetables consumed to better understand the relationships involved and studies should be designed to provide more comparability across cohorts.”
The study was published in the Journal of Affective Disorders.
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Annabel P. Matison et al. 2024. Associations between fruit and vegetable intakes and incident depression in middle-aged and older adults from 10 diverse international longitudinal cohorts. Journal of Affective Disorders 359: 373-381; doi: 10.1016/j.jad.2024.05.096