 Avocados have been described as a major dietary source of antioxidants. And this may be true compared to much of the stuff people eat, but compared to other common fruits, avocados are not necessarily anything to write home about. They do, however, contain those two carotenoid eye nutrients found in dark green leafy vegetables, lutein and zeaxanthin, which may explain why Mexican-Americans tend to beat out other ethnicities. The critical carotenoids are concentrated in the darkest green flesh close to the peel. And because of this, consumers should be advised to use the Nick and Peel method to obtain the nutrient-rich outer section of the avocado. The Tufts Nutrition and Health Letter detailed what that means. You cut in half-lengthwise around the seed, rotated quarter-turned, cut lengthwise again to make quarter-avocado segments, then you separate the quarters and remove the seed. And finally, starting from the tip, Nick and carefully peel so as to not to lose that nutrient-rich darkest green flesh immediately under the skin. Avocados can also boost the absorption of the carotenoid phytonutrients in other vegetables, because carotenoids like beta-carotene are fat soluble. However, many of our best foods for obtaining carotenoids like sweet potatoes, carrots, greens contain very little fat. So if you eat them straight, without any source of fat in your stomach, you may end up flushing a lot of that nutrition down the toilet. Remember, it's not what you eat, it's what you absorb. Here's the amount of beta-carotene that ends up in your bloodstream. Two, three, four, five, six hours after eating a little over a cup of salsa. There's a little bump. And the same thing with the red pigment lycopene. Okay, but now here's that same amount of salsa with an avocado added, tripling the absorption. And if you eat tomatoes without some source of fat at the same meal, avocados, or nuts and seeds, most of that bright red beautiful lycopene will end up in the toilet bowl rather than your bloodstream. Same thing eating a salad composed of lettuce, spinach, and carrots, with a fat-free dressing, hardly any beta-carotene makes it into your body. But add an avocado, and 15 times more beta-carotene ends up circulating throughout your body. Do you have to use a whole avocado, though? What about half an avocado? Pretty much the same effect, works just as well. What about a quarter of an avocado? We don't know the minimum amount of dietary fat required for optimum carotenoid absorption. It may just be a few grams per meal, though, in which case an eighth of an avocado would fit the bill, or just one or two walnuts. Interestingly, avocado consumption may not just enhance absorption of carotenoids, but then also enhance their subsequent conversion inside the body into vitamin A. People were given baby carrots, with and without guacamole. And same thing we saw before, way more beta-carotene in the bloodstream, the hours following the meal, with the guacamole added, compared to the same amount of carrots alone—in fact, over six times more. And since beta-carotene is turned into vitamin A in the body, there should be six times more vitamin A, too, right? No, they ended up with over 12 times more vitamin A. There was also a big increase in vitamin K levels and other fat-soluble vitamins, though that's partially because avocado contains vitamin K itself. Not too much, though, claims this avocado industry-sponsored review that people on the anticoagulant medication kumbadin have to worry. But that's not true. We've known for decades now that even though there's not an inordinate amount of vitamin K in avocados, it still interferes with the drug kumbadin, also known as warfarin. Though we're not exactly sure why. It may boost your liver's detoxifying enzymes or prevent absorption of the drug, but either way, those on the blood-thinner kumbadin may want to put walnuts on their salad instead.