Monday, January 25, 2016

Avocado Healthy Fruit


The avocado native to Mexico and Central America, classified in the flowering plant family Lauraceae along with cinnamon, camphor and bay laurel
    Many of healthy foods provide with carotenoids. These orange-yellow pigments offer outstanding health benefits—but only if they are absorbed up into the cells. Intake of fat along with carotenoids greatly helps to improve their absorption. However, many of our best foods for obtaining carotenoids—for example, sweet potatoes, carrots, and leafy greens—contain very little fat (less than 1 gram per serving). As a special step for improving carotenoid absorption from carotenoid-rich foods, researchers have experimented with the addition of avocado to meal choices including salads, side servings of leafy greens, side servings of carrots, or tomato sauce. The amount of avocado added has varied from study to study but averages approximately 1 cup or 1 small/medium avocado providing 20-25 grams of total fat. As expected, this added avocado has been shown to increase carotenoid absorption from all of the foods listed above. Anywhere from two to six times as much absorption was found to occur with the added avocado! But in addition to this increased absorption was a much less anticipated result in a recent study: not only did avocado improve carotenoid absorption, but it also improved conversion of specific carotenoids (most importantly, beta-carotene) into active vitamin A.
    Avocados do contain carotenoids, in and of themselves. And thanks to their fat content, we can get good absorption of the carotenoids that they contain. However, if we happen to be consuming an avocado-free meal or snack that contains very little fat yet rich amounts of carotenoids, some added avocado might go a long way in improving your carotenoid absorption and vitamin A nourishment. Salad greens—including romaine lettuce—and mixed greens like kale, chard, and spinach are great examples of very low fat, carotenoid-rich foods that might be eaten alone but would have more of their carotenoid-richness transferred over into our body with the help of some added avocado.
    The method we use to peel an avocado might make a difference to our health. Research on avocado shows that the greatest phytonutrient concentrations occur in portions of the food that we do not typically eat, namely, the peel and the seed (or "pit.") The pulp of the avocado is actually much lower in phytonutrients than these other portions of the food. However, while lower in their overall phytonutrient richness, all portions of the pulp are not identical in their phytonutrient concentrations and the areas of the pulp that are closest to the peel are higher in certain phytonutrients than more interior portions of the pulp. For this reason, we don't want to slice into that outermost, dark green portion of the pulp any more than necessary when we are peeling an avocado. Accordingly, the best method is what the California Avocado Commission has called the "nick and peel" method. In this method, we actually end up peeling the avocado with your hands in the same way that we would peel a banana. The first step in the nick-and-peel method is to cut into the avocado lengthwise, producing two long avocado halves that are still connected in the middle by the seed. Next we take hold of both halves and twist them in opposite directions until they naturally separate. At this point, remove the seed and cut each of the halves lengthwise to produce long quartered sections of the avocado. we can use our thumb and index finger to grip the edge of the skin on each quarter and peel it off, just as we would do with a banana skin. The final result is a peeled avocado that contains most of that dark green outermost flesh, which provides you with the best possible phytonutrient richness from the pulp portion of the avocado.
    Recent research on avocado and heart disease risk has revealed some important health benefits that may be unique to this food. Avocado's reputation as a high-fat food is entirely accurate. Our 1-cup website serving provides 22 grams of fat, and those 22 grams account for 82% of avocado's total calories. And they do not necessarily provide a favorable ratio of omega-3 to omega-6 fat; we get less than 1/4 gram of omega-3s from one serving of avocado and 2.5 grams of omega-6s, for a ratio of 10:1 in favor of omega-6s. However, despite these characteristics, the addition of avocado to already well-balanced diets has been shown to lower risk of heart disease, improve blood levels of LDL, and lower levels of oxidative stress in the bloodstream following consumption of food. In one particular research study, participants in two groups all consumed a diet with the same overall balance, including 34% fat in both groups. But one avocado per day was included in the meal plan of only one group, and that was the group with the best heart-related results in terms of blood fat levels.

    Most researchers are agreed that the high levels of monounsaturated fat in avocado—especially oleic acid—play a role in these heart-related benefits. Nearly 15 out of the 22 grams of fat (68%) found in one cup of avocado come from monounsaturated fat. (And by contrast, less than 3 grams come from the category of polyunsaturated fat, which includes both omega-6s and omega-3s.) This high level of monounsaturates puts avocado in a similar category with olives, which provide about 14 grams of fat per cup and approximately 73% of those grams as monounsaturates. In addition to its high percentage of monounsaturated fat, however, avocado offers some other unique fat qualities. It provides us with phytosterols including beta-sitosterol, campesterol, and stigmasterol. This special group of fats has been shown to provide important anti-inflammatory benefits to our body systems, including our cardiovascular system. Not as clear from a dietary standpoint are the polyhydroxylated fatty alcohols, or PFAs, found in avocado. PFAs are a group of fat-related compounds more commonly found in sea plants than in land plants, making the avocado tree unusual in this regard. However, the studies that we have seen on PFAs and avocado have extracted these PFAs from the seed (or pit) of the fruit, rather than the pulp. Since we typically do not consume this part of the avocado, the practical role of these PFAs from a dietary standpoint is less clear than the role of monounsaturates and phytosterols described above.

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