It isn’t a pretty fruit. Its skin looks like something that should be on the back of an alligator. It sometimes is actually called the “alligator pear.” And it has been shunned by some people because of its high fat content. Indeed, the avocado is laden with fat; a single specimen can harbour up to 30 grams, more than any other fruit. But, there is an important but. Not all fat is created the same. Oleic acid, the fat found in avocado, is of the mono-unsaturated variety, which is actually linked with a reduced risk of heart disease. The same fat is also found in olives and some provocative laboratory research has shown that it may alter the expression of certain genes associated with aggressive forms of breast cancer. Extracts of avocado have even been shown to inhibit the growth of prostate cancer cells, albeit only in the lab. The best candidates for this effect are carotenoids, a variety of fat soluble antioxidants found in avocados. Lutein, in particular, was examined because avocados are higher in lutein content than any other fruit. But in a laboratory study, lutein alone did not destroy cancer cells. It seems the whole mix of compounds found in avocados is necessary for this effect, including the fat content.
Indeed the fat content may be critical to the health benefits. Carotenoids are fat soluble and in the absence of fat are not readily absorbed into the bloodstream. This also means that adding avocados to vegetables that have a high carotenoid content can enhance the bioavailability of these nutrients. Researchers at Ohio State University examined this very possibility. They fed volunteers salads containing vegetables rich in lutein, beta-carotene and lycopene, with and without avocado. Then they measured the levels of the carotenoids in the volunteers’ bloodstream. The results were clear. Addition of avocado increased absorption in some cases as much as fifteen-fold. Salad dressings, which of course also contain fat, would likely have a similar effect but in general they contain far less desirable types of fat. On top of this, avocados are also a good source of potassium, an adequate intake of which can reduce the risk of high blood pressure and stroke. They are also rich in dietary fiber, as well as in folate, which has been linked with a reduced risk of heart disease. And then there is beta-sitosterol, the substance that has achieved cholesterol-lowering fame by being incorporated into margarines, such as Benacol. Well, avocados are an excellent source of beta-sitosterol. An Australian study reported a reduction in blood cholesterol in people eating an avocado a day for a month.
Is there a downside to avocados? A small one. People who are watching their weight have to remember that in spite of the fruit’s health benefits, a cup does contain about 235 calories. There is also a slight problem with allergies. People who are allergic to latex are often allergic to avocados as well. And one final point. The name “avocado” derives from the Aztec word “ahuacatl” meaning testicle. You see, avocados also have a supposed aphrodisiac effect. I’m putting some in my salad.