Healthy food that can slow ageing: the new science

 
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Have you got premature ageing on your plate? Science is revealing a truth beyond calories: our food does more than simply sustain us—it can alter the rate at which our bodies grow older.

The bad news is that apparently innocent foods can push midlife bodies and brains into fast-track decrepitude. The good news? Simple changes could slow the sound of ticking substantially.

Making that shift looks increasingly vital, given the utterly depressing announcement earlier this year that forty and fifty-somethings are now, on average, in significantly worse physical shape than their counterparts were only a decade or two ago. The discovery means that age-related conditions such as obesity, heart disease, high blood pressure, diabetes and the dreaded dementia are likely to strike us earlier, warn investigators from University College London (UCL) who studied the health of more than 135,000 people.

We won’t necessarily die any sooner, though, adds their report in the journal Population Studies—we will just spend far longer wallowing in enfeebled misery. As George Ploubidis, the UCL professor who co-wrote the study predicts, we “are expected to live longer on average, but with more years of ill health”. It sounds as though we are all doomed.

But, of course, this health decline is not caused by evil comets or sorcery. It’s down to our lifestyle, and in particular what’s on the end of our forks.

So, what does science say we should be eating to bat off this dismal trend? The latest piece of helpful evidence emerged just recently, and it’s to do with a chemical in your bloodstream called trimethylamine N-oxide, or TMAO. To fans of red meat, those four letters may spell danger.

The compound is produced when we eat protein, but it is released at particularly high levels when we eat red meat. Bacteria in our gut break down meat proteins into a chemical called trimethyl­amine. The liver converts this into TMAO and sends it coursing through the bloodstream. Studies already show that people with higher levels of TMAO have a risk of heart attack or stroke more than double the average, even if they exercise and don’t smoke.

Until now scientists haven’t managed to explain the heightened risk, but the new research in the American Heart Association journal Hypertension shows that raised levels of TMAO in adults’ blood causes accelerated age-related tissue damage in the lining of blood vessels.

The researchers measured 101 older adults and 22 young adults and found that TMAO levels significantly rise with age and, in turn, cause increasing damage to arteries and hearts. When the researchers fed TMAO to young mice, their blood vessels aged rapidly. “It made them look old,” says Vienna Brunt, a physiologist at the University of Colorado Boulder who led the study. Twelve-month-old mice (equivalent to 35 in human years) looked more like 27-month-old mice (age 80 for people) after eating TMAO for several months, she says.

Brunt’s results also indicate that mice with high TMAO levels show problems with learning and memory, suggesting that diet-related blood-vessel damage may also bring on cognitive decline.

The study reinforces the emerging realisation that midlife diets can help to determine the rate and nature of our ageing. Other evidence for this emerged in July, thanks to researchers at the Karolinska Institute in Sweden who followed 2000 people from their mid-fifties to their mid-seventies. They reported in the journal Nutrients that the fifty-somethings who cut sugar and salt from their diets and ate more daily vegetables went on to enjoy significantly lower levels of dementia diagnoses in their eighth decade.

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Similarly, a French study in the Annals of Internal Medicine in 2013 of more than 10,000 women found that those whose diets closely matched healthy eating guidelines when in their fifties subsequently had significantly fewer chronic diseases, physical impairments and mental health problems in their seventies.

Neither study could link any single ingredient to better health. Overall diet quality made the difference. Why? In other research, investigators at King’s College London and the University of Miami suggest that we simply have to act more healthily once we hit midlife because our bodies are ceasing their life-protecting work.

It seems we can spend our younger adult years playing fast and loose with food, thanks to the fact that our bodies run myriad molecular systems that help to protect us from such self-inflicted damage, says the research in the journal Aging Cell last year. But when we hit midlife those “longevity-related molecular pathways” wither. As the report’s senior author, Claes Wahlestedt, a professor of therapeutic innovation at Miami University, says: “Humans appear to stop using these pathways from about 50 years of age onward.”

The hopeful news is that we may be able to keep these “get-out-of-jail- (relatively)-free” cards from expiring if we nourish our bodies’ systems properly. “How long and how ‘hard’ each person regulates these pathways may influence human lifespan,” Wahlestedt adds.

Even if we can’t keep these bodily defences going, we can at least stop wreaking dietary damage on ourselves. That means bidding goodbye to many components of the standard “western-type” diet (high intakes of fried and sweet food, processed food, red meat, refined grains and high-fat dairy products, such as butter). The Whitehall II study, which followed more than 5000 public servants across several decades, found that those who ate like this were less likely to experience “healthy ageing” 16 years later, in terms of physical and mental health—again, regardless of whether they exercised.

As for those consuming good-­quality fare, such as a Mediterranean diet rich in oily fish and fresh vegetables? A breakfast bowl of fresh berries instead of that fry-up? There just weren’t enough healthy-eating civil servants to provide a useful sample, according to the 2013 report in The American Journal of Medicine.

Instead, evidence for the benefits of eating well in midlife comes from the mice involved in the TMAO study. Brunt reports that in ageing rodents that ate a compound called dimethyl butanol—found in some olive oils, vinegar and red wine—the age-related damage to their blood vessels was halted, even repaired.

According to Brunt, previous studies have indicated that dimethyl butanol can prevent the body from producing artery-damaging levels of TMAO. Her team is now looking for other TMAO-blocking chemicals, but for now, she adds, a plant-based diet may be best to keep it at bay.

And when better to adopt these strategies than right now? A poll by King’s College London suggests that a third of us have consumed more food or eaten less healthily than normal during lockdown. It’s time to adopt a new regimen. This one’s for life—and a longer one at that. 

 

John Naish is a health and wellbeing journalist who writes regularly for the UK’s Daily Mail and the Times. He lives in Brighton, UK.

The original version of this article appeared in the Times and is used with permission under an arrangement with The Interview People.