That is, unfortunately!, not how these things work. But it allows people to do more targeted studies, and (many years of research later) perhaps find a drug that can have some impact.

Or sometimes we get really lucky and just find a food or spice that upregulates/downregulates the right gene or affects the right enzyme (e.g. ginger contains compounds that suppress the inflammation triggering enzyme COX-2 without affecting the related COX-1 enzyme, which is actually beneficial. Most inflammation-reducing drugs affect both).

Although I'm sure we'd have noticed it by now if a food item targeted these genes (assuming they do significantly affect how healthily people age).

Thanks for the ginger example, it was tangential but gave me some ideas :-)