Eating a Mediterranean diet could help keep the mind sharp and reduce frailty in old age, researchers have found.
Retired adults in five countries followed either a diet rich in healthy fats and fruit and vegetables or continued their normal diet for one year.
Researchers analysed stool samples and found the Mediterranean-style diet boosted bacteria in the gut.
Some bacteria are linked to healthy ageing by staving off frailty and memory-loss, scientists say.
The study adds to mounting evidence finding the Mediterranean diet to be one of the healthiest in the world.
Eating a Mediterranean diet could keep the mind sharp and reduce frailty in old age, researchers have found. The traditional Mediterranean diet includes lots of vegetables, fruits, beans, and is abundant in healthy fats like olive oil (pictured)
The traditional Mediterranean diet includes lots of vegetables, fruits, beans, and wholegrains. It is also abundant in healthy fats like olive oil.
It contains moderate amounts of fish, white meat and some dairy, and very little sugar and red meat.
Experts from the UK, France, Italy, the Netherlands and Poland wanted to see if following a Mediterranean diet for a year could improve participants’ microbiome.
The composition of our gut is partly determined by our genes but can also be influenced by lifestyle factors.
Interest in, and knowledge about, the microbiota has recently exploded as we now recognise just how essential they are to our health, affecting everything from mood to the development of serious disease.
Last year, scientists at California Institute of Technology found the first ever link between the gut and Parkinson’s symptoms.
In the latest study, researchers asked half a group of 612 people aged between 65 and 79 to eat a Mediterranean diet.
The other half stuck to their existing diet which varied according to each country. British people in the study were the least likely to naturally follow a Mediterranean diet, while those in Italy and France were the most.
EXPLAINED: THE MEDITERRANEAN DIET
Consuming more fruit and fish, and fewer sugary drinks and snacks, are the most important aspects of a Mediterranean diet.
- Whole grains
- Fish and meat
- Monounsaturated fats, such as olive oil
- Saturated fats, like butter
- Red meat
- Processed foods, like juice and white bread
- A glass of red wine here and there is fine
How you can follow it:
- Eat more fish
- Squeeze more fruit & veg into every meal
- Swap your sunflower oil or butter for extra virgin olive oil
- Snack on nuts
- Eat fruit for dessert
The new diet was tailored to older people so it wasn’t difficult for them to stick to.
Participants were classed as frail, on the verge of frailty or not frail and seemingly healthy, according to the findings in the journal Gut.
Researchers analysed the gut microbiome with stool samples at the beginning and end of the 12-month diet period.
Sticking to the Mediterranean diet was linked with beneficial changes to the gut microbiome and stemming the loss of bacterial diversity.
Those who adhered to the diet the most experienced the greatest gain in desirable bacteria, while losing the most ‘bad’ bacteria. In other words, their microbiome was re-programmed.
The researchers observed an increase in the types of bacteria previously associated with indicators of reduced frailty, such as walking speed and hand grip strength.
A significant positive change was seen in the gut microbiome of those with reduced frailty. As a result, their condition was slowed, the researchers said.
In comparison, the group who didn’t change their usual diet had a steeper decline into frailty.
Some bacteria are linked with improved brain function, such as memory. In fact, the researchers saw a slower loss of cognitive function, such as memory, in the Mediterranean diet group.
Following the diet led to a reduction of potentially harmful inflammatory chemicals, namely C-reactive protein and interleukin-17.
They also found the microbiome changes were linked to a decrease in bacteria involved in producing some bile acids, which, when overproduced, are linked to an increased risk of bowel cancer, insulin resistance, fatty liver and cell damage.
In contrast, those who stuck to their normal diet had no significant changes in their gut bacteria diversity.
The researchers said the most striking finding was how strong the link was between an improved gut environment and markers of ageing.
They were also surprised to see the Mediterranean diet had an effect on all participants regardless of where they lived, and the same bacteria responded.
The changes were largely driven by an increase in dietary fibre, which would come from fruit and vegetables, the team said.
Vitamins and minerals – specifically, C, B6, B9, copper, potassium, iron, manganese, and magnesium – also played a large role.
The authors cautioned that a Mediterranean diet may be impractical for older people with dental problems or trouble swallowing.
Previous studies suggest a restrictive diet, common in older people, reduces the diversity of microbiome in the gut. But it may be difficult to get older people to eat a varied diet.