 It all started about 15 million years ago. It was the Miocene epoch. Things seemed to be going pretty good until it seems two flaming meteorites smashed into what's now Germany with the estimated power of a couple million Hiroshima's. The crater looks quaint now, but at the time there was a mass extinction event wiping many animals out, but not the common ancestor of the Great Apes, of which we are one, who developed a mutation that may have allowed them to thrive. They lost the ability to detoxify uric acid. Why is that a good thing? Uric acid is naturally produced by the body and may help us hold on to fat, which is good when there's not a lot of food around, with pesky asteroids and all. Also helps us retain sodium, which is good if there aren't a lot of salt shakers out on the savanna, and it helps act chemically as an antioxidant, which is good since green tea hadn't been invented yet. The problem is it's a tightrope. You don't want to have too much in your blood, which may be why other animals retained an enzyme to get rid of the stuff. Fast forward 15 million years. When salt and calories abound, the last thing we need is more sodium and fat retention. But the antioxidant part we like, unfortunately not all antioxidant compounds are necessarily good for us. For example, the preservative BHA works by preventing the oxidation of foods, but is reasonably anticipated to be a human carcinogen. Similarly, uric acid is chemically an antioxidant, but when you have too much in your blood, it can crystallize into your joints, a disease called gout, and a high uric acid level may also put us at risk for high blood pressure, stroke, heart disease, diabetes, and death. So, keeping one's uric acid levels low is an important dietary goal, and we'll explore how tomorrow.