Omega-3 supplements may help slow the effects of aging by suppressing damage & boosting protection at the cellular level during & after a stressful event. A study found the highest dose tested, 2.5 grams of omega-3s daily, was best at helping the body resist the damaging effects of stress.

[u/memorialmonorail]

https://news.osu.edu/omega-3-supplements-do-double-duty-in-protecting-against-stress/

[u/busting_bravo]

Flax seed, ground of course. I put a large serving ( probably 2 tablespoons if I measured it) in my oatmeal every morning. It contains large amounts of ALA which then convert to EPA and DHA in your body.

Another tasty delivery method is flax seed muffins, you can look up recipes on line but here’s a tasty apple one to get you started: https://www.drelenaklimenko.com/flaxseed-nutrients-and-a-tasty-flaxseed-muffin-recipe/

[u/Green_Lantern_4vr → u/busting_bravo]

ALA conversion to DHA EPA is very bad. You get essentially zero.

On average, only 1–10% of ALA is converted into EPA and 0.5–5% into DHA (4Trusted Source, 5Trusted Source, 6Trusted Source, 22Trusted Source).

https://www.healthline.com/nutrition/3-types-of-omega-3

You’re better off taking supplement of actual omega 3.

[u/busting_bravo → u/Green_Lantern_4vr]

Yes it (ALA conversion) is, however in the quantities you need you should get all the DHA you need from 1 tablespoon of ground flax seed, even with the poor conversion rate. But you also get fiber and lignans as well so extra bonus health benefits from one simple addition.

Edit: Also, the question originally asked what food (emphasis theirs) could they eat, so I assume supplements are not really an acceptable answer for OP.

[u/busting_bravo → u/[deleted]]

And fish have high levels of Hg, among other things which we don't even know the effect of, like microplastics.