How well wine can protect against diseases such as Alzheimer's could all be down to maintaining a healthy diet, reveals new research.
It has long been known that moderate intake of wine can protect against neurodegenerative conditions such as Parkinson's and dementia.
But now scientists have discovered that the degree of protection is down to how the wine is broken down in the gut - and that is where a healthy diet of fruit and veg helps.
Researchers from the Institute of Food Science Research in Madrid, Spain, selected some of these metabolites based on their presence in the urine and faeces of people consuming wine on a regular and moderate basis.
They looked at the metabolites, compounds left in the gut after the wine has passed through.
They added them to human cells under stress that normally leads to neuronal cell dysfunction and death, mimicking the initial stages of some neurodegenerative disorders.
They found that the metabolites protected the cells from death due to the stress conditions.
However they also discovered that the metabolites are active at different points in the cell death process.
The exact composition of the wine metabolites, known as wine-derived human gut metabolites, is therefore important in the protective neuronal effect.
And this composition depends on your gut microbiota composition, as the intestinal flora breaks down the wine into the different metabolites.
Lead author Dr Adelaida Esteban-Fernandez said: "In other words, differences in our gut microbiota are leading to the different metabolites, which underpins the idea that humans benefit from food in different ways.
"It is very important to understand that certain food compounds are responsible for this health benefit in protecting against the onset of neurodegenerative diseases as no medication was involved.
"This individual difference is a factor not to be neglected to understand the health effects of certain foods.
"We are now need to advance our understanding of the effect of diet in the promotion of normal brain function."
The study was published in the journal Frontiers in Nutrition, but the researchers emphasised that the benefits of moderate intake of wine are wiped out if you over-indulge.
Dr Esteban-Fernández added: "I am not advocating to replace medicines by diet, but I want to raise more awareness how your diet is helping to prevent diseases or reduces the risk of getting sick.
"It is more than feasible to go to the supermarket and buy vegetables and fruit. It depends only on the individuals to maintain a balanced diet.
"I am really aware about the importance of a healthy diet enriched in vegetables, fruits, and reduced industrial saturated fats.
"Although I try to maintain my dietary habits as good as possible, I think it is also important to not get too obsessed.
"Society is nowadays full of false myths about diet, and it is the role of both science and media to avoid the spread of these rumours, as well as make people aware of the importance of diet for your health."