Avocados sure taste good, and they've got a lot of important nutrients. (One fellow I know who used to be a serious alcoholic told me that how he survived his worst times with this health largely intact was to eat an avocado a day, which is an interesting story but not a hypothesis I recommend testing.)
Several clinical trials have reported that diets that incorporate avocado may help lower levels of L.D.L., or “bad,” cholesterol, because the fruit contains plant sterols called phytosterols that compete with cholesterol for absorption in the intestines. One small clinical trial found that women with Type 2 diabetes who followed a diet rich in monounsaturated fats, including those from avocados, had lower triglyceride levels. Another small trial suggested avocados may improve vascular health and have anti-inflammatory effects. Some papers have reported that an extract made of avocado and soybean oils may alleviate pain from osteoarthritis, but a 2003 systematic review concluded that the data were mixed.
But one drawback to avocados is their high calorie count, about 250 calories per fruit, Dr. Kris-Etherton said. “So people have to be careful – they can’t just add an avocado a day to a bad diet and see health benefits.”