There is growing evidence that nutrition not only plays a role in disease prevention, it can also impact mental health. A recent study of more than 50,000 middle-aged and older adults (average age of 62) examined the relationship between fruit and vegetable consumption and psychological distress, or symptoms associated with depression and anxiety. This study looked at how reported fruit and vegetable consumption at baseline related to the likelihood of having high to very high levels of distress two to four years later.
The researchers found that whether considered separately or combined, levels of fruit and vegetable consumption at the start of the study were associated with significantly lower prevalence of psychological distress. These findings remained consistent even when demographic characteristics and psychological risk factors were taken into account. This association was markedly stronger for women than men.
At the time of follow-up, baseline fruit and vegetable consumption combined or separate was again associated with lower incidence of psychological distress. When adjusted to account for other factors that may have been contributing to psychological distress, medium levels of combined fruit and vegetable consumption (four to seven servings a day) and medium levels of vegetable consumption (two to four servings per day) remained significant, while medium levels of fruit consumption (one to two servings a day) approached significance. High levels of fruit and vegetable consumption did not remain significant. With respect to this finding, the authors write, “This may indicate that those who consume healthy amounts of fruit and vegetables are more likely to have favourable socioeconomic status and other lifestyle risk factors (eg, physical activity), which together contributed to lower psychological distress.” Again, at follow-up, women showed more benefit than men. As for how fruits and vegetables could be producing these effects, the researchers pointed to nutrients that could reduce inflammation and oxidative stress, and note that other research has associated B vitamin deficiency with depression.
Other factors that the researchers found to be associated with psychological distress at follow-up included not being married, being younger, smoking, lower education, lower income, lower BMI, lower alcohol intake, and low levels of physical activity.
Nguyen B, Ding D, and Mihrshahi S. Fruit and vegetable consumption and psychological distress: cross-sectional and longitudinal analyses based on a large Australian sample. BMJ Open. (2017). DOI: 10.1136/bmjopen-2016-014201