A new study claims fish oil pills slow biological ageing. Should we be taking them?

Over three years, the team reported, people on the omega-3 supplements slowed their clocks by about three months on average.

“This was a huge amount of work, really impressive stuff,” said Associate Professor Lindsay Wu, who studies biological ageing at the University of NSW.

“But the question is whether the readout used here is relevant to patient health.”

Something’s fishy

Interest in fish oil stems from the discovery that Greenland’s Inuit people, who eat a lot of whale blubber and seal fat, seem to be strongly protected from heart disease.

Whale blubber and seal fat are chock-full of omega-3 long-chain polyunsaturated fatty acids, which are important components of the outer walls of our cells.

Because of that role, they are in prime position to affect the signals cells send each other; omega-3s outcompete other fatty acids that can signal the body to increase inflammation levels, as well as altering the way the genes in our DNA turn on or off in a manner that reduces inflammation.

A hallmark 1999 Lancet study found omega-3 supplements for heart attack survivors cut the risk of them having a second one by about 15 per cent.

But other studies have come back with contradictory results, to the point where scientists remain confused and guidelines “fuzzy”, says University of Adelaide professor Robert Gibson, who has led clinical studies of omega-3 supplementation.

Case in point: in 2018, the Cochrane policy institute – generator of gold-standard scientific evidence – concluded after reviewing the evidence that omega-3 supplements did nothing to cut the risk of heart problems. But two years later the institute slightly modified this conclusion, finding there is potentially a small reduction in the risk of dying from coronary heart disease.

Australia’s Heart Foundation recommends two to three serves of oily fish a week for everyone but does not offer a direct recommendation on supplements.

“Omega-3s are generally cited as being ‘good’ for you,” says Gibson. “But evidence is lacking.”

Ticking clocks

So, fish oils might be good for your heart. What about ageing?

Our new study measures ageing by looking at a person’s “DNA methylation clock”.

Methyl groups can be attached to genes within our DNA, either enhancing or restricting their function; think of them as mark-ups on the blueprint of your life. As we age, our DNA typically loses more and more of these marks.

“All those marks are associated with health-related traits,” says Professor Nir Eynon, who works on methylation clocks at the Australian Regenerative Medicine Institute at Monash University.

“As we get older, we are losing muscle mass if we don’t train. Our VO2 max, aerobic capacity is diminished. A lot of those metabolic processes, muscle contraction processes, are being down-regulated.”

In Altos Labs’ study, participants taking omega-3 showed a slightly slower accumulation of DNA-marks than you’d expect.

Three points on this: One, it’s not clear why the clocks slowed – indeed, we don’t fully understand how ageing itself works, let alone how to slow it.

Two: three months is a small difference, right on the threshold of detection.

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And three: research is yet to conclusively link changes in these clocks to actual health outcomes people care about, like … dying.

Indeed, the same study that found omega-3s slowed the clock also found no effect on a range of real-world health parameters like physical and cognitive function.

“I’m not saying it’s bullshit. There is a real signal. But it’s still very diffuse. It’s like if you want to study far galaxies with binoculars,” says Professor Luigi Fontana, director of the Healthy Longevity Research and Clinical Program at the Charles Perkins Centre.

What health advice can we take away from this research?

The Altos Labs team members take a daily omega-3 supplement. The independent scientists I spoke to were far less convinced.

Eynon is far more enthusiastic about emerging data on exercise.

In studies of muscle samples and small groups of volunteers, he has shown aerobic exercise is associated with signs of a younger biological age.

And hey – even if you’re sceptical of methylation clocks, the evidence for exercise and healthy ageing is very strong.

Eynon practises what he preaches, training five days a week and trying to eat only between 1pm and 9pm. He does not take any supplements.

“Not yet. But I’m not saying I’m going to do that in a few years. If the evidence is striking … it might be something I will consider.”

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