Fascinating study of twins reveals what happens to their brains when one eats healthy and the other doesn’t
From when you’re in school you’re told to eat a balanced meal every day, but what actually happens when you do? A new study on twins might be one of the best indicators yet at least when it comes to mental health.
Researchers tracked more than 1700 pairs of older twins over 11 years, examining their fruit and vegetable intake, health, body weight and their mental wellness.
The researchers found that those who ate less of the fresh food were more likely to be depressed. They didn’t measure other mental health conditions like anxiety, ADHD or psychosis.
This was the case even after researchers took into account other factors like age, sex, education level, their living situation and BMI.
Dr Annabel Matison, lead author of the study, said simple nutrition recommendations could help the 21million Americans with depression fight back against their condition, alongside counselling or medication.
‘The findings present another argument for increasing fruit and vegetable intake in adults over 45 years of age,’ she said.
Doctors consider twin studies the gold standard of research, because you have two participants with nearly identical DNA that you can study at once, Dr Karen Mather, who co-authored the research explained.
Like the fruit and vegetable study, a separate 2024 study showed the difference in twins who received very few Botox injections – image A – next to twin who got Botox regularly – image D
Dr Mather said: ‘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.’
This has been done to explore everything from intelligence to aging. A study released earlier this year looked at how using Botox as you age can prevent wrinkles, comparing identical twins to one another.
As such, the researchers from the University of New South Wales looked to twins for their study, and published their findings in the journal Scientific Reports.
It included data from four different international studies of twins.
They took place in the US, Denmark, Australia and Sweden. Each study included slightly different measures – some didn’t track weight over time, for example.
All 3,483 of the study participants were over 45 years old at baseline data, in an attempt to determine how nutrition affects people into later years, since most studies on the topic have focused on younger people.
They asked each group about their daily eating habits and sorted them into groups based on how often they ate fruits like bananas, oranges, apples and pears, and how often they ate salads, cooked vegetables and raw vegetables.
They included potato intake as a separate measure.
They also measured their depression symptoms, using the surveys conducted in each of the four different studies.
In every group included in the review, a higher intake of fruits and vegetables was associated with better mental health. They did not calculate a figure that explained how much fruit and vegetable intake had an effect on mental health.
They adjusted the data for factors like age, sex, education, partnership and BMI, when the studies included that measurement.
They found these factors had little impact on the data, and said: ‘the addition of BMI, physical health and cognitive ability to the model had minimal impact on results. This suggests the exclusion of participants is unlikely to have impacted the results.’
The researchers suggested that better nutrition has a number of benefits for brain health. For one, increasing vitamins and fiber helps nourish the whole body and keep a healthy supply of blood to the brain.
For another, eating fresh food can keep the bacteria in the gut healthy, they said, which could play a role in keeping the mind quelled.
Dr Matison said: ‘The importance of the gut microbiome and its potential influence on depression as a result of inflammation, both systemic and neuroinflammation, is becoming increasingly well understood.’
