Twin study reveals shocking results after one ate less vegetables than the other

A small change to your diet could have positive benefits to your mental health, a study has found.

Twins are often used in this kind of research as they share 50 to 100 percent of their genetic background, making them ideal candidates for comparative studies.

For example, identical twins Ross and Hugo Turner went on separate meat and vegan diets to see how their bodies reacted over a 12-week period with some surprising results.

Now the results of a new study involving over 3,000 twins have been released.

The research looked at longitudinal associations between fruit and vegetable intakes and depressive symptoms in middle-aged and older adults specifically.

As of 2023, it was found that 29 percent of US adults had been diagnosed with depression at some point in their lives, GALLUP reported at the time.

This marked a 10 percent increase in comparison to 2015.

For the new twin study, participants all hailed from four countries: Australia, Denmark, Sweden and the US and also ranged from 45–90 years in age.

Twins are often used for scientific studies (Getty Stock Images)

Over an 11-year period, researchers at UNSW Sydney’s Centre for Healthy Brain Ageing (CHeBA) assessed the associations between fruit and vegetable intake and depressive symptoms in the study participants.

The landmark research went on to conclude that the twins that ate more fruit and vegetables had less depressive symptoms.

"The findings present another argument for increasing fruit and vegetable intake in adults over 45 years of age." lead author and Post Doctoral Fellow Dr Annabel Matison said.

The study further explains: "Our meta-analyses of four observational studies in adults 45 + years found higher intakes of both fruit and vegetables were associated with lower risk of incident depression (15% and 9% respectively).

"There are, however, limitations to this evidence; for example, few studies to date have focused on older adults, and the associations detected may be due to residual confounding."

In particular, the fruit and vegetable consumption was found to be low in the two Scandinavian studies, with Dr Matison adding: "The average for both being less than half the World Health Organisation recommended intake of at least 5 serves per day.

"We are unclear what the reduction in depression scores would be if intakes were increased to recommended levels."

The study concluded that eating more fruit and vegetables can help with depression (Getty Stock Images)

While there may be some limitations to the study, twin studies are often raved about in the science community.

Discussing the benefits of twin research, co-author on the research and Leader of CHeBA’s Genomics and Epigenomics Group, Dr Karen Mather, said: "Twin pairs share 50-100% of their genetic background and when raised together share the same family environment.

"One of the advantages of the twin design is that it can help address the issue of unwanted factors, such as socioeconomic status early in life, influencing the results."