What they do: Omega-3s fight inflammation, now considered one of the top skin-agers, and they also help protect against sunburn, enhancing the effects of your SPF sunscreen.

Bacteria in our gut gobble up things like sugars and fatty acids, which they can break down either through respiration or fermentation. Respiration provides a bigger energy kick.

Research has linked omega-3 oil, available as an over-the-counter nutritional supplement, to cardiovascular health, and it also appears to improve mood and cognitive function.