"Red wine can 'help fight the ageing process' – but how much would you have to drink?," is the question posed by The Sun, after a US study suggested resveratrol, a substance found in the skin of red grapes, may help keep our muscles and nerves healthy as we get older.
But the story might also ask "and are you a mouse?" as the research was carried out in rodents, not people.
Researchers gave mice food containing resveratrol for a year, then compared the muscle and nerve cells of those mice to cells from mice the same age who'd had a normal diet. In the mice who'd had the resveratrol-enriched diet, they found less evidence of age-related changes.
Although red wine contains resveratrol, the amount varies widely, from around 0.2mg to 12.6mg per litre. That's nothing like enough to get the amounts consumed in this study.
The mice were fed 400mg of resveratrol per kilogram of body weight each day. An average weight woman in the UK (around 70kg) would need 28g of resveratrol a day for the same effect – or more than 2,000 litres of the most resveratrol-rich wine. An average weight man would need even more.
The researchers also looked at another chemical, metformin, but found it had less effect. However, they did find that a low-calorie diet seems to slow age-related changes in muscles and nerves. Previous studies have shown that exercise may help.
So eating less and exercising more is certainly a better bet than trying to drink your way to agelessness.
Where did the story come from?
The study was carried out by researchers from Virginia Tech, Roanoke College and the National Institute on Aging, all in the US, and was funded by the National Institutes of Health. The study was published in the peer-reviewed Journals of Gerontology: Biological Sciences and is open-access, meaning it's free to read online.
While The Sun's headline might have been a bit misleading, the story did make clear that the researchers don't recommend anyone tries "blasting their bodies with resveratrol in any form" to try to replicate the findings seen in mice.
Oddly, The Independent says the study showed resveratrol could keep the brain young. But the research looked at junctions between muscles and nerves in the leg, so it's unclear where this came from.
Interestingly, the media focused on the link with red wine rather than the findings of a calorie-controlled diet.
What kind of research was this?
This was experimental research on animals. The researchers were interested in determining the effect of resveratrol, metformin and calorie restriction on ageing.
Resveratrol occurs naturally in the skins of some red fruits, including some grapes, blueberries and mulberries. Metformin is a drug used to lower blood sugar for people with type 2 diabetes. Both have been linked to speeding up the repair of nerve endings.
While animal research can suggest areas for human research, there's a big difference between humans and mice, so we can't be sure the results apply to anything other than mice.
What did the research involve?
Researchers divided laboratory-bred mice into four groups and fed them either:
- a normal diet
- a lower calorie diet from four months of age
- a diet enriched with resveratrol from one year of age
- a diet enriched with metformin from one year of age
When the mice were aged two years, they looked at their muscle and nerves, at the meeting point of the two (the neuromuscular junction, or NMJ) in a leg muscle. They also looked at the NMJs of three-month-old mice to see how they compared to the older mice.
They used tissue staining and powerful microscopes to examine the tissues. Four mice were examined for each age group and each diet condition.
To check whether the substances had a direct effect on muscle cells, the researchers also did studies where they grew cells from the mice in the laboratory and fed them with either standard nutrient mix, or a nutrient mix enriched with resveratrol or metformin.
They compared the cell cultures for differences in structure and muscle fibre size.
What were the basic results?
Compared with mice fed a regular diet, those who'd been given resveratrol or who'd had a calorie-restricted diet showed:
- less fragmentation of tissue at the neuromuscular junction
- fewer areas where the nerve cells had degenerated, which would have meant that the muscle no longer had input from nerves
The two-year-old mice which had calorie-restricted diets had neuromuscular junctions that were most similar to the three-month-old mice. Metformin had little effect in this experiment.
Looking at the cell cultures, the researchers found that metformin, resveratrol and calorie restriction had an effect on the cross-sectional size of the muscle fibres. The majority of the muscle fibres were small. Mice fed the calorie-restricted diet had a greater proportion of small muscle fibres.
The researchers say that this indicates less ageing as muscle fibres increase in size with ageing.
How did the researchers interpret the results?
The researchers said their findings suggest that "resveratrol preserves motor function [movement] in part by protecting NMJs [neuromuscular junctions] and muscle fibres". They point out that it was "less effective compared with a CR [calorie restricted] diet" in preventing age-related changes.
However, they say, mice were started on the calorie-restricted diet at four months of age, while resveratrol was only started at 12 months of age. They suggest introducing resveratrol earlier might increase the effect.
They said it was "surprising" that metformin had little effect and speculated that this might have been because of the dose used.
Resveratrol has been of interest to anti-ageing scientists for many years and researchers have previously shown it may be linked to a slowing of the decline in thinking and movement, at least in rodents. This study suggests a possible way this might happen.
But the results don't tell us anything about what happens in humans. They suggest this substance may be useful for further research in humans at some point. They certainly don't provide a reason to drink gallons of red wine, in the hope of seeing an anti-ageing effect.
Drinking too much alcohol is a sure-fire way to speed up deterioration of thinking skills, and can cause brain damage. Too much alcohol in the long term is linked to several cancers, heart disease, stroke and liver disease.