Why butter, cheese and ice cream could help you live longer: Top epidemiologist shares stunning discovery that could change our view on saturated fats forever

Could a type of saturated fat in butter, cheese and ice cream improve your health?

It might sound absurd, given the health messages we’ve had for years about saturated fat being ‘bad’. Yet an increasing body of research suggests that a saturated fat, known as C15:0 (or pentadecanoic acid), might strengthen our cells, calm inflammation, lower cholesterol and even heal our livers.

As a result, it could stave off the diseases associated with old age, and help us live longer and healthier, according to Stephanie Venn-Watson, a US epidemiologist and author of a new book, The Longevity Nutrient: The Unexpected Fat That Holds The Key To Healthy Aging.

‘I didn’t intend to find a saturated fat that would dismantle 50 years of dietary recommendations,’ she told Good Health. ‘Yet a humble fat is becoming a top candidate on the human longevity leaderboard.’

C15:0 is mainly found in tiny amounts in whole-fat dairy products and certain fish. Scientists have known about it since 1955, when pentadecanoic acid was isolated from shark liver oil. However, they’ve only recently started to think it may have wide-reaching effects on our health.

Venn-Watson stumbled upon C15:0 in 2001 during her research on elderly bottlenose dolphins. Having previously worked for the Centers for Disease Control and Prevention in the US, and the World Health Organisation, she was recruited by the US Navy to improve the health of around 100 dolphins in San Diego Bay that the Navy had been responsible for.

She found dolphins suffer the same problems as humans as they age, including heart disease, metabolic syndrome (a cluster of conditions that includes raised cholesterol), fatty liver disease and even Alzheimer’s.

Yet not all the dolphins were developing these conditions. ‘The difference came down to diet,’ she says. ‘The healthier dolphins were eating more fish with C15:0.’

Navy dolphins are offered five different types of fish. Two – herring and mackerel – have C15:0, while the other types (such as capelin, which are sardine-like, and squid) had no detectable C15:0.

The idea that something similar could be happening with humans seemed unlikely.

Saturated fats have long been vilified for their association with cardiovascular disease.

However, it turns out not all saturated fats are equal. They are divided into two main categories: even-chain and odd-chain. Even-chain fatty acids, which have an even number of carbon atoms, are pro-inflammatory and harm the mitochondria (the energy powerhouses of cells); but odd-chain fatty acids, especially C15:0, are anti-inflammatory and repair mitochondria.

The message that ‘saturated fats are bad’ emerged in the late 1970s. It led to a shift towards low-fat milk and vegetable-based margarine. Yet, despite a four-fold drop in whole milk intake, the global prevalence of obesity, type 2 diabetes, metabolic syndrome and fatty liver disease has increased.

Could 50 years of avoiding dairy fat actually be part of the problem? Between 2015 and 2017, Venn-Watson’s team ran eight studies which suggested that C15:0 is not just any fatty acid, it’s an essential fatty acid. These are important for health but our bodies can’t make enough of them, so we need to get them from our diet.

‘C15:0 certainly has beneficial effects,’ says Dr Sandra Kaufmann, a cellular biologist and anti-ageing doctor based in Florida.

‘The most compelling’ is that red blood cells that are C15:0 deficient are more likely to become damaged and die, which in turn is linked to ageing and disease. C15:0 appears to play a protective role.

A study in the Journal of Nutrition in 2019 found that people who consumed higher amounts of even-chain saturated fatty acids were at greater risk of dying prematurely.

So how much C15:0 do we need? Research in the journal Nutrients suggests around 100-200mg a day.

‘This equates to about 2-3 oz of cheese from grass-fed ruminants (cows, goats, sheep) as they have higher C15:0 than corn-fed animals,’ says Venn-Watson. She cites pecorino, which has around 50 per cent more C15:0 than other cheeses.

The problem is that when we consume full-fat dairy we’re not just getting those odd-chain fatty acids, in particular C15:0, but also those health-sabotaging even-chain fatty acids.

So Venn-Watson and her team have developed a C15:0 supplement without the even-chain fats. In one of four human trials – reported in the Journal of Nutrition last year – people aged 18-24 who were overweight with raised liver enzymes (a sign of damage) took the supplement or a placebo every day.

After 12 weeks, the supplement group had significantly lower liver enzyme levels. ‘Questions remain, but our findings indicate that C15:0 may have a role in managing the underlying metabolic dysfunction common among some patients with liver disease, diabetes and cardiovascular disease,’ says Dr Jeffrey Schwimmer, a professor of paediatrics at the University of California San Diego who led the study.

Another of the trials, reported in the American Journal of Clinical Nutrition last year, found that women with fatty liver disease given a daily C15:0 supplement had lower LDL (‘bad’) cholesterol and improved gut microbes.

Professor David Weinkove, chair of the British Society for Research on Ageing, isn’t convinced. He says the first trial was small and carried out over a short time frame, while the women in the second trial had also changed their diet (to a Mediterranean-based regimen). ‘It didn’t look at supplementation alone,’ he says.

Stephanie Venn-Watson has now founded a company that produces C15:0 supplements (at £1.50 per pill). But do we need them?

‘C15:0 does have many positive attributes,’ says Dr Kaufmann. ‘Higher quantities in the body have been linked to improved health parameters. There’s also evidence that supplementation can help lower inflammation and elevated liver enzymes.’

‘But there are lots of other molecules that have similar, if not better, results,’ she says. Eating dairy may, however, be more tempting. ‘On the other hand, maybe it’s an excuse to eat more ice cream!’