Avocado 101

In his book "Prime-Time Health", Dr. William Sears lists avocado as one of the foods that can lengthen our prime time (i.e., the second half of our lives or a time when the "want to dos" can start to replace the "must dos.")  Once reserved for royalty, today avocados are eaten more often than apple pie.  Historians tell us that avocados were first cultivated in southern Mexico, in 1519, Aztec emperor Montezuma II presented them as prized offerings to Spanish explorer Hernando Cortes.

There are more than 100 varieties of avocados, but just two main types:

  • California
  • Florida
You'll able to find California avocados year-round, while the Sunshine State's avocados are usually available from June through March.
 
The reasons why avocados are awesome:
  • Avocados contain antiangiogenic compounds such as lutein that are being studied for their cancer-fighting abilities[4].
    • In a Japanese study, lutein was found to be far more cancer-protective compared to other carotenoids such as alpha- and beta-carotene despite their stronger antioxidant activity. A likely explanation for this enhanced protection comes from lutein’s ability to prevent the formation of new blood vessels (angiogenesis).
  • Avocados are the most nutrient-dense fruit (ounce for ounce, top the charts among all fruits for folate, potassium, vitamin E, and magnesium):
    • Vitamin A
    • Vitamin B
    • Vitamin E
    • Folate (or folic acid), a vital nutrient for preserving neurotransmitter function
    • Heart-healthy monounsaturated fats
      • The only other fruit with a comparable amount of monounsaturated fat is the olive.
      • Research suggests that exercise burns monounsaturated fat more rapidly than saturated fat.
      • Monounsaturated fats lower LDL and raise HDL levels in the blood.
    • Magnesium, a mineral that can decrease your bad LDL cholesterol and triglyceride levels
      • Ounce for ounce, avocados provide more magnesium than the 20 most commonly eaten fruits, with the banana, kiwi, and strawberry in second, third, and fourth place, respectively.
    • Glutathione
      • Avocados offer about 28 mg of glutatione in 3 1/2 ounces, while many other fruits, such as watermelon (7 mg), pears (5 mg), and bananas (4 mg), contribute considerably less.
      • Glutathione (GSH) is a compound in the liver that helps keep everything in check. Not only does GSH detoxify things like drugs, but it's also essential for liver regeneration.
      • Glutathione has been shown to be effective for preventing cataracts
      • Studies suggest that glutathione helps prevent cancers of the mouth and pharynx, as well as heart disease
    • Beta-sitosterol
      • Researchers at the University of California, Los Angeles, found that avocados boast 76 mg of beta-sitosterol per 3 1/2 ounces
      • Animal studies have shown that beta-sitosterol inhibits the growth of cancerous tumors
      • Beta-sitosterol can inhibit the absorption of cholesterol from your intestines so you'll have less in your bloodstream, reducing your risk of heart disease
    • Fiber
  • They're versatile food (i.e., ingredients in many food recipes)
  • They have a a high satiety value and help fight obesity.
    • It's a perfect partnership of healthy fats, proteins, fiber, and healthy carbs.
  • They are powerful nutrient booster
    • Adding them to a salad or a salsa increases the absorption of antioxidants, carotenoids, lycopene, and lutein.
    • Their cholesterol-free fat helps your body absorb more of the nurtients in other foods, including lycopene in tomatoes.
  • They have the highest levels of the eye-enhancing nutrients lutein and zeaxanthin of any fruit.
    • Taking avocado can decrease BPH and decrease prostate growth
      • BPH occurs in the inner part of the prostate gland
      • BPH is noncancerous growth that happens with age.
    • When researchers used lutein alone, the prostate cancer cells were not affected.  However, an extract of avocado containing carotenoids and tocopherols inhibited the growth of cancer cells.
    • In other research[4], lutein was used to prevent the proliferation of blood vessels in the eyes of mice. This may eventually prove valuable in preventing eye diseases spurred by uncontrolled blood vessel growth, a process that can ultimately cause blindness.
  • They are a top baby food.
    • Avocado works in a similar fashion to blueberries in promoting brain health.
  • They are powerful potassium foods-- 1/2 medium size provides 500 mg K
  • Their extract may help with symptoms of osteoarthritis
  • Their consumption  is associated with improved overall diet quality, nutrient intake, and reduced risk of metabolic syndrome. [6]
Hass Avocado
 
Pebble-skinned Hass avocados are richest in healthy fat.  The famous Hass avocado was developed in the 1930s in La Habra Heights, California, where the "mother tree" was planted and tendered by postman Rudolph Hass.  Hass' pride and joy today accounts for about 95% of the commercial crop.  By the 1970s, the one-time cottage industry had morphed into a large-scale affair, and today California leads the nation in production.  Most commercially grown domestic avocados come from a part of the California state stretching from San Luis Obispo to the Mexican Border.
 
Ripe to Perfection
 
Avocados ripen only after picking.  Unripe avocados are said to be toxic.  So, ripen your avocados before eating them. 
 
It's a snap to ripen avocados.  Pop them in a brown paper bag, be patient for 2 to 5 days, and voila, they're ripe, yielding to gentle pressure.  If you're in a hurry, add an apple or banana to the bag.  Store ripe avocados in the refrigerator and wash the skin before peeling.

Based on a study from the University of California Los Angeles, the amount of carotenoids such as lutein found in California-grown avocados was highest in fruits that had been ripened for less than 10 days after their initial harvesting[5]. Furthermore, avocados harvested at the beginning of January contained on average only one-third to one-half the amount of total carotenoids as avocados harvested later in September, suggesting that fruits harvested later in the growing season had greater carotenoid content.
 
Among the 20 most commonly eaten fruits, avocado ranks #1 for vitamin E, lutein, glutathione, and beta-sitosterol (or phytosterol, a plant equivalent of cholesterol in animals).  Avocados are versatile, healthful, and low in pesticides.  Add them to your daily diets!
 
References
  1. "Prime-Time Health" by Willian Sears, MD with Martha Sears, RN
  2. Costco Connection, April 2010, vol 25, no 4.
  3. "The New Healing Foods" by Colleen Pierre, M.S., R.D.
  4. Avocados Contain Natural Antiangiogenic Compounds Beneficial for Cancer Protection and Eye Health
  5. Lu QY, Zhang Y, Wang Y, Wang D, Lee RP, Gao K, Byrns R, Heber D.  California Hass avocado: profiling of carotenoids, tocopherol, fatty acid, and fat content during maturation and from different growing areas. J Agric Food Chem. 2009 Nov 11;57(21):10408-13.
  6. Avocado consumption is associated with better diet quality and nutrient intake, and lower metabolic syndrome risk in US adults: Results from the National Health and Nutrition Examination Survey (NHANES) 2001--2008
  7. Guac-Humm-Mole (Avocado recipe)
  8. The incredible cholesterol-lowering benefits of the Avocado



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