Using data from a twin study conducted over many years, researchers found a link between levels of depression and the amount of fruits and vegetables people eat each day.
Twin studies are a powerful tool for elucidating the role that genetics and environment play in a variety of traits, behaviors, and conditions. Identical twins essentially share 100% of their genes, and fraternal twins share an average of 50%, so most of the differences between them are due to the experiences that one twin has had. The other twin is something that is not.
In a new international study led by the Center for Healthy Brain and Aging (CHeBA) at the University of New South Wales (UNSW) Sydney, researchers found a link between fruit and vegetable intake and symptoms of depression in twins aged over 45. I looked into gender.
“Pairs of twins share 50-100% of their genetic background and, when raised together, share the same family environment,” said CHeBA’s Genomics and Epigenomics Group Leader and senior author of the study. said Dr. Karen Mather. “One advantage of the twin design is that it addresses the issue of undesirable factors that influence outcomes, such as socio-economic status early in life.”
What identical twins separated at birth can tell us about genetics – BBC REEL
“Eat more fruits and vegetables!” has been the refrain of parents for decades. This is something that has been confirmed by science, unlike more dubious parental claims, such as that eating bread ears will make your hair curl. There is growing evidence about the impact of diet on mental health, including depression, but few studies have focused specifically on how fruit and vegetable intake affects depression in people over 45. . Fewer people are still taking advantage of the unique opportunity that twin studies offer to reduce the influence of genetic and environmental confounding variables.
In this study, researchers examined the association between baseline fruit and vegetable intake and depressive symptoms in 3,483 twins aged 45 and older. They are Australia, Denmark, Sweden and America.
Self-reported fruit and vegetable intake was collected and categorized as “low,” “moderate,” or “high” for both fruits and vegetables. For fruit, low intakes averaged 0.3 serves per day and high intakes averaged 2.1 serves per day. For vegetables, low intake was 0.5 servings per day and high intake was 2.0 servings per day. Participants’ depressive symptoms were measured at baseline and followed up using a validated scale to assess depression.
High fruit and vegetable intake was associated with reduced long-term depressive symptoms compared to low intake. Moderate consumption of vegetables, but not fruits, was also associated with lower depressive symptoms compared to lower intake.
“The results of this study present a new argument for increasing fruit and vegetable intake in adults over 45,” said Dr. Annabelle Mattison, postdoctoral researcher and lead author of the study. .
However, the researchers noted that “high” intakes of fruits and vegetables are still significantly below the recommended dietary intakes in most countries. They wondered what the results would be if people ate at least more than their daily recommended intake.
“Two large Scandinavian studies found that fruit and vegetable intakes were particularly low, with both averages less than half the World Health Organization’s recommended intake of at least five servings per day.” said Mattison. “It is unclear how much depression scores will decrease if intake is increased to recommended levels.”
Researchers suggest that the effect of fruits and vegetables on depression is at least partially related to the microbiome, which has been the focus of many recent studies.
“The importance of the gut microbiome and its potential impact on depression as a result of inflammation, both systemic and neuroinflammation, is becoming increasingly well understood,” Mathison said.
This study had limitations. Researchers were unable to adjust for physical activity because data were not available across all studies. Another is that the study used various self-report questionnaires to record dietary intake. Another is that clinical diagnosis is the final criterion for evaluating depression, whereas symptoms of depression are self-reported. In contrast, a particular strength of the twin design is that it reduces the influence of a variety of potential confounders, such as socioeconomic status, physical activity, and chronic health conditions.
Future research should address these limitations by using comprehensive, standardized tools to collect data on fruit and vegetable intake in addition to clinical assessment of depressive symptoms. there is.
The researchers say that based on their findings, health care providers should consider monitoring the fruit and vegetable intake of their patients, especially those with symptoms of depression.
The study was published in the scientific journal Scientific Reports.
Source: CHeBA