All about avocados

My current obsession is avocados. I love guacamole, but sometimes I don't have tomatoes on hand and don't feel like making it, so I've been tossing chunks of avocado onto my tacos lately, and the leftovers I'll just eat plain. So, I thought I'd share some facts from The World's Healthiest Foods website.

Avocados

Although the creamy rich Hass avocados are generally available throughout the year, they are the most abundant and at their best during the spring and summer in California and in October in Florida. During the fall and winter months you can find Fuerto, Zutano and Bacon varieties.

The avocado is colloquially known as the Alligator Pear, reflecting its shape and the leather-like appearance of its skin. Avocado is derived from the Aztec word "ahuacatl".

This chart graphically details the %DV that a serving of Avocados provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Avocados can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Avocados, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

• Health Benefits
• Description
• History
• How to Select and Store
• How to Enjoy
• Safety
• Nutritional Profile
• References

Health Benefits

Promote Heart Health

Avocados contain oleic acid, a monounsaturated fat that may help to lower cholesterol. In one study of people with moderately high cholesterol levels, individuals who ate a diet high in avocados showed clear health improvements. After seven days on the diet that included avocados, they had significant decreases in total cholesterol and LDL cholesterol, along with an 11% increase in health promoting HDL cholesterol.

Avocados are a good source of potassium, a mineral that helps regulate blood pressure. Adequate intake of potassium can help to guard against circulatory diseases, like high blood pressure, heart disease or stroke. In fact, the U.S. Food and Drug Association has authorized a health claim that states: "Diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke."

One cup of avocado has 23% of the Daily Value for folate, a nutrient important for heart health. To determine the relationship between folate intake and heart disease, researchers followed over 80,000 women for 14 years using dietary questionnaires. They found that women who had higher intakes of dietary folate had a 55% lower risk of having heart attacks or fatal heart disease. Another study showed that individuals who consume folate-rich diets have a much lower risk of cardiovascular disease or stroke than those who do not consume as much of this vital nutrient.

Promote Optimal Health

Not only are avocados a rich source of monounsaturated fatty acids including oleic acid, which has recently been shown to offer significant protection against breast cancer, but it is also a very concentrated dietary source of the carotenoid lutein; it also contains measurable amounts of related carotenoids (zeaxanthin, alpha-carotene and beta-carotene) plus significant quantities of tocopherols (vitamin E).

In a laboratory study published in the Journal of Nutritional Biochemistry, an extract of avocado containing these carotenoids and tocopherols inhibited the growth of both androgen-dependent and androgen-independent prostate cancer cells.

But when researchers tried exposing the prostate cancer cells to lutein alone, the single carotenoid did not prevent cancer cell growth and replication. Not only was the whole matrix of carotenoids and tocopherols in avocado necessary for its ability to kill prostate cancer cells, but the researchers also noted that the significant amount of monounsaturated fat in avocado plays an important role. Carotenoids are lipid (fat)-soluble, which means fat must be present to ensure that these bioactive carotenoids will be absorbed into the bloodstream. Just as Nature intends, avocado delivers the whole heath-promoting package.

Increase Your Absorption of Carotenoids from Vegetables

Enjoying a few slices of avocado in your tossed salad, or mixing some chopped avocado into your favorite salsa will not only add a rich, creamy flavor, but will greatly increase your body's ability to absorb the health-promoting carotenoids that vegetables provide.

A study published in the March 2005 issue of the Journal of Nutrition tested the hypothesis that since carotenoids are lipophilic (literally, fat-loving, which means they are soluble in fat, not water), consuming carotenoid-rich foods along with monounsaturated-fat-rich avocado might enhance their bioavailability.

Not only did adding avocado to a salad of carrot, lettuce and baby spinach or to salsa greatly increase study participants' absorption of carotenoids from these foods, but the improvement in carotenoid availability occurred even when a very small amount-as little as 2 ounces-of avocado was added.

Adding avocado to salad increased absorption of alpha-carotene, beta-carotene and lutein 7.2, 15.3, and 5.1 times higher, respectively, than the average amount of these carotenoids absorbed when avocado-free salad was eaten.

Adding avocado to salsa increased lycopene and beta-carotene absorption 4.4 and 2.6 times higher, respectively, than the average amount of these nutrients absorbed from avocado-free salsa. Since avocados contain a large variety of nutrients including vitamins, minerals, as well as heart-healthy monounsaturated fat, eating a little avocado along with carotenoid-rich vegetables and fruits is an excellent way to improve your body's ability to absorb carotenoids while also receiving other nutritional-and taste-benefits.

Avocado Phytonutrients Combat Oral Cancer

Oral cancer is even more likely to result in death than breast, skin, or cervical cancer, with a mortality rate of about 50% due to late detection, according to Great Britain's Mouth Cancer Foundation. Avocados may offer a delicious dietary strategy for the prevention of oral cancer. Phytonutrients in Hass avocados, the most readily available of the more than 500 varieties of avocados grown worldwide, target multiple signaling pathways, increasing the amount of free radicals (reactive oxygen species) within pre-cancerous and cancerous human oral cell lines, that leads to their death, but cause no harm to normal cells. ? Semin Cancer Biol. 2007 May 17. Earlier research by UCLA scientists also indicates that Hass avocados may inhibit the growth of prostate cancer as well. When analyzed, Hass avocados were found to contain the highest content of lutein among commonly eaten fruits as well as measurable amounts of related carotenoids (zeaxanthin, alpha-carotene, and beta-carotene). Lutein accounted for 70% of the measured carotenoids, and the avocado also contained significant quantities of vitamin E. J Nutr Biochem. 2005 Jan;16(1):23-30.

Description

The avocado is colloquially known as the Alligator Pear, reflecting its shape and the leather-like appearance of its skin. Avocado is derived from the Aztec word "ahuacatl."

Avocados are the fruit from the Persea Americana, a tall evergreen tree that can grow up to 65 feet in height. There are dozens of varieties of avocadoes, which fall into three main categories-Mexican, Guatemalean, and West Indian-which differ in their size, appearance, quality and susceptibility to cold. The most popular type of avocado in the United States is the Hass variety, which has rugged, pebbly brown-black skin. Another common type of avocado is the Fuerte, which is larger than the Hass and has smooth, dark green skin and a more defined pear shape.

Avocados vary in weight from 8 ounces to 3 pounds depending upon the variety. The edible portion of the avocado is its yellow-green flesh, which has a luscious, buttery consistency and a subtle nutty flavor. The skin and pit are inedible.

History

Avocados are native to Central and South America and have been cultivated in these regions since 8,000 B.C. In the mid-17th century, they were introduced to Jamaica and spread through the Asian tropical regions in the mid-1800s. Cultivation in United States, specifically in Florida and California, began in the early 20th century. While avocados are now grown in most tropical and subtropical countries, the major commercial producers include the United States (Florida and California), Mexico, the Dominican Republic, Brazil and Colombia.

How to Select and Store

A ripe, ready to eat avocado is slightly soft but should have no dark sunken spots or cracks. If the avocado has a slight neck, rather than being rounded on top, it was probably tree ripened and will have better flavor. A firmer, less mature fruit can be ripened at home and will be less likely to have bruises. The Hass avocado weighs about 8 ounces on average and has a pebbled dark green or black skin, while the Fuerte avocado has smoother, brighter green skin. Avoid Fuertes with skin that is too light and bright. Florida avocados, which can be as large as 5 pounds, have less fat and calories, but their taste is not as rich as California varieties.

A firm avocado will ripen in a paper bag or in a fruit basket at room temperature within a few days. As the fruit ripens, the skin will turn darker. Avocados should not be refrigerated until they are ripe. Once ripe, they can be kept refrigerated for up to a week. If you are refrigerating a whole avocado, it is best to keep it whole and not slice it in order to avoid browning that occurs when the flesh is exposed to air.

If you have used a portion of a ripe avocado, it is best to store the remainder in the refrigerator. Store in a plastic bag, wrap with plastic wrap, or place on a plate and cover with plastic wrap. Sprinkling the exposed surface(s) with lemon juice will help to prevent the browning that can occur when the flesh comes in contact with oxygen in the air.

How to Enjoy

For some of our favorite recipes, click Recipes

Tips for preparing avocados:

Use a stainless steel knife to cut the avocado in half lengthwise. Gently twist the two halves in opposite direction if you find the flesh clinging to the pit. Remove the pit, either with a spoon or by spearing with the tip of a knife. Place the halves face down, then peel and slice. If the flesh is too soft to be sliced, just slide a spoon along the inside of the skin and scoop it out. You can prevent the natural darkening of the avocado flesh that occurs with exposure to air by sprinkling with a little lemon juice or vinegar.

A few quick serving ideas:

Use chopped avocados as a garnish for black bean soup.

Add avocado to your favorite creamy tofu-based dressing recipe to give it an extra richness and beautiful green color.

Mix chopped avocados, onions, tomatoes, cilantro, lime juice and seasonings for a rich-tasting twist on traditional guacamole.

Spread ripe avocados on bread as a healthy replacement for mayonnaise when making a sandwich.

For an exceptional salad, combine sliced avocado with fennel, oranges and fresh mint.

For a beautiful accompaniment to your favorite Mexican dish, top quartered avocado slices with corn relish and serve with a wedge of lime.

Safety

Avocados and Latex Allergy

Like bananas and chestnuts, avocados contain substances called chitinases that are associated with the latex-fruit allergy syndrome. There is strong evidence of the cross-reaction between latex and these foods. If you have a latex allergy, you may very likely be allergic to these foods as well. Processing the fruit with ethylene gas increases these enzymes; organic produce not treated with gas will have fewer allergy-causing compounds. In addition, cooking the food may deactivate the enzymes.

Nutritional Profile

Avocados are a good source of vitamin K, dietary fiber, vitamin B6, vitamin C, folate and copper. Avocados are also a good source of potassium: they are higher in potassium than a medium banana.

Although they are fruits, avocados have a high fat content of between 71 to 88% of their total calories - about 20 times the average for other fruits. A typical avocado contains 30 grams of fat, but 20 of these fat grams are health-promoting monounsaturated fats, especially oleic acid.

For an in-depth nutritional profile click here: Avocado.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Avocados is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Introduction to Food Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

Avocado, slices 1.00 cup 146.00 grams 235.06 calories
Nutrient	Amount	DV (%)	Nutrient Density	World's Healthiest Foods Rating
vitamin K	29.20 mcg	36.5	2.8	good
dietary fiber	7.30 g	29.2	2.2	good
potassium	874.54 mg	25.0	1.9	good
folate	90.37 mcg	22.6	1.7	good
vitamin B6 (pyridoxine)	0.41 mg	20.5	1.6	good
vitamin C	11.53 mg	19.2	1.5	good
copper	0.38 mg	19.0	1.5	good

World's Healthiest Foods Rating	Rule
excellent	DV>=75%	OR	Density>=7.6	AND	DV>=10%
very good	DV>=50%	OR	Density>=3.4	AND	DV>=5%
good	DV>=25%	OR	Density>=1.5	AND	DV>=2.5%