By Liam Mannix
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G’day, Liam Mannix here. Welcome to Examine.
We don’t often look at supplements here, because the evidence is either lacking or broadly suggests they don’t work.
We’re making an exception today to talk about omega-3 supplements, for two reasons: a) there’s a really interesting new study out; and b) omega-3 supplements have been recommended for certain people by the American Heart Association to cut the risk of heart disease.
Time to pick up the fish oil capsules?Credit: iStock
So, should we be taking them?
Let’s start with the new study, published in top journal Nature Aging by a team led by Steve Horvath from Altos Labs (a Silicon Valley anti-ageing start-up with links to Jeff Bezos).
The study is a re-analysis of data from a larger European randomised controlled trial that enrolled 2157 healthy, active people over 70 and followed them for three years.
That trial tested three interventions: a one-gram daily omega-3 supplement, a vitamin D supplement, or a simple home exercise program. The researchers were looking at a battery of outcomes: infection rates, blood pressure, falls, fractures, even physical and mental performance.
Those metrics all measure visible signs of ageing. Horvath’s sub-study measured the invisible: the tick of our cells’ biological clocks.
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,” says 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.”
Should we be turning to fish oil?Credit: Damian White
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 study published in the Lancet 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, the number of mark-ups on our DNA changes.
“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 loss 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.
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.
Professor Nir Eynon, at Body Fit Training’s Victoria Market studio on Tuesday.Credit: Wayne Taylor
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 not going to do that in a few years. If the evidence is striking … it might be something I will consider.”
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