A new scientific trial in Spain aims to settle the question, once and for all, of whether wine in moderation has health benefits. Felicity Carter reports.
Wine appears to play an important role in the Mediterranean Diet, consistently ranked as the world’s healthiest.
Yet the World Health Organisation has declared there is no safe level of alcohol.
This difference in opinion has prompted Spanish researchers to ask if it would be better or worse to remove wine from the Mediterranean Diet.
It’s a project that could also determine, once and for all, if there are any health benefits to drinking wine in moderation — or if it’s all an illusion.
A new dietary trial
In late December 2023, Professor Miguel Martinez-Gonzalez and his team launched UNATI (University of Navarra Alumni Trialist Initiative). It’s a randomised control trial, a type of study known as the gold standard in science.
Prof Martinez-Gonzalez — Professor of Public Health at the University of Navarra and Adjunct Professor of Nutrition at Harvard University — outlined the project in front of an audience of scientists and doctors at the Lifestyle, Diet, Wine & Health Congress, held in Rome in late March 2025.
UNATI, partly funded by the European Research Council, will be the most significant randomised control trial done on alcohol; a previous attempt in the US collapsed amid accusations of impropriety.
The conclusions will be released later this decade.
Clinical trials from Spain have concluded that wine is an important component of the Mediterranean diet. Felicity Carter spoke to the lead researcher.
What earlier studies said
A previous study, PREDIMED, coordinated by Prof Martinez-Gonzalez, looked at the impact of the Mediterranean Diet on cardiovascular disease.
Dietary studies are difficult. Researchers have to track people to make sure they stick to the diet, and then there are ‘confounding variables’ to deal with, like participants who turn out to have underlying diseases. As Prof Martinez-Gonzalez said, “you need many years of following up thousands of participants”.
The PREDIMED study began in 2003 with 7,447 patients, none of whom had heart problems at the start of the trial. The patients were divided into three groups. The first two were given Mediterranean diets, one supplemented with extra olive oil, and the other with nuts. The diet was rich in olive oil, fruit and vegetables, legumes and seafood, with some poultry. Both groups could have one glass of wine a day if they wanted.
The third group was stuck on a low-fat diet.
Prof Martinez-Gonzalez — Professor of Public Health at the University of Navarra and Adjunct Professor of Nutrition at Harvard University
The trial ended in 2010 and a follow-up showed that those on the Mediterranean diet had 30% lower rates of coronary heart disease, stroke or cardiovascular death compared to the group eating the low-fat diet.
“It was effective not only in bringing down the rates of major cardiovascular disease, but also peripheral artery disease,” said Prof Martinez-Gonzalez. “Also atrial fibrillation — only for the group provided with extra virgin olive oil — also diabetes.”
Wine still leads the way for EU alcohol exports
The group allocated to receive extra olive oil also seemed to have lower rates of breast cancer and improved cognition.
There is always the problem of knowing for certain whether participants followed the diet or not, so in a related study, 1,232 of the PREDIMED participants had their urine tested for tartaric acid, a marker for wine consumption. Published in January this year, that study demonstrated that “light to moderate wine consumption”, in association with the Mediterranean diet, was associated with lower cardiovascular disease in a population at high risk.
The team got plenty of great feedback.
“When you recommend the Mediterranean diet to people and you mention that it includes wine, people are happy,” said Prof Martinez-Gonzalez.
But these results, by themselves, are not conclusive enough to stop the “no safe level” narrative in its tracks.
The WHO’s mantra
In 2018, the Lancet medical journal published a study called the Global Burden of Diseases, Injuries and Risk Factors (GBD) 2016, a study covering 195 countries from 1990 to 2016.
The report landed like a bombshell, because it claimed that the harms done by alcohol were “larger than previously estimated”. And, it said, even if alcohol had a small positive effect on heart disease, it didn’t matter, because of alcohol’s associations with cancer.
Its conclusion was that there was “strong support” for the idea that there is “no safe level of alcohol consumption”.
Then in 2023, the WHO released a statement that there was no safe level of alcohol use.
But, said Prof Martinez-Gonzalez, the original GBD report was “21 pages full of numbers, graphs, estimations and complicated mathematical issues” and he’s not certain that anybody read it from beginning to end.
In any case, the GBD collaborators published an update four years later. This time the report was 51 pages — and contradicted the first report.
Depending on the level of cardiovascular risk in a population, there might be an ideal level of alcohol consumption. The WHO and other health bodies did not update their stance in line with the new report, however, because of alcohol’s association with cancer.
“They say that the healthiest level is not zero in populations where there is a higher [amount] of cardiovascular disease; small amounts of alcohol can get better outcomes,” said Prof. Martinez-Gonzalez.
In other words, depending on the level of cardiovascular risk in a population, there might be an ideal level of alcohol consumption.
The WHO and other health bodies did not update their stance in line with the new report, however, because of alcohol’s association with cancer.
The problem with all these declarations is that alcohol research is plagued by serious gaps. There are no studies, for example, that specifically compare the health effects of spirits, wine and beer. Nor do most studies take drinking patterns into account.
But “we have more and more evidence that the drinking pattern modifies the effect of the absolute amount of ethanol that we are drinking,” said Prof Martinez-Gonzalez.
In 2014, he was involved in a project which followed 18,394 Spaniards over 12 years. The researchers discovered that when people spread their alcohol intake over the week, drank red wine, consumed it with meals, and mostly avoided spirits, the death rate was lower when compared to other styles of drinking. This study was later replicated in both the UK and Italy, said Prof. Martinez-Gonzalez.
But would health outcomes be better if alcohol, including wine, was removed altogether?
A new Spanish study confirms that moderate wine drinking has cardiovascular benefits for at-risk people. Felicity Carter reports.
A group of researchers had already asked this question back in 2009. They’d published a study of 23,349 Greek men and women on the Mediterranean diet and concluded that moderate ethanol consumption was responsible for 23.5% of the diet’s benefit.
Other studies have shown similar results. But what’s needed is a study that looks specifically at alcohol, comparing drinkers with non-drinkers.
UNATI aims to answer the question of whether red wine has a potential health benefit — or an adverse one — once and for all. It involves 10,000 Spaniards over the age of 50, split into two groups. One group will be given an intervention to help them give up drinking altogether, while the other will drink a small amount of red wine with their meals.
“We will follow up with period teleconferences every three months — interventions with dieticians, psychologists and nurses that we have hired for four years,” he said. “We have 500 medical doctors all over Spain involved.”
Everyone will be followed until the end of 2028, with researchers watching for the emergence of heart disease, diabetes and cancer. Eventually, the outcomes of those who drank and those who abstained will be compared, finally answering the question of whether wine is good or bad for health.
UNATI is important for many reasons, not least because it may be the last big study ever done in this area. Later this year, the US Government is due to release its Dietary Guidelines of America (DGA), which will include recommendations about alcohol. The politicking around the DGAs has been intense, with two separate groups tasked with evaluating the evidence — and coming to opposite conclusions.
If the US Government were to adopt the line that there is no safe level of alcohol, it would have a chilling effect on future research. No ethics panel would ever give the green light to a study which required people to ingest a toxin.
So the wine world will have to wait until the end of 2028 for an answer. Given the noise around the question of alcohol and health, it’s going to be a long wait.
