Monday, August 27, 2012

PearsPears
What's New and Beneficial About Pears
  • For nutritional reasons, we're often advised to consume the skins of fruits. However, it's less often that research provides strong evidence in support of this advice. Recent studies have shown that the skin of pears contains at least three to four times as many phenolic phytonutrients as the flesh. These phytonutrients include antioxidant, anti-inflammatory flavonoids, and potentially anti-cancer phytonutrients like cinnamic acids. The skin of the pear has also been show to contain about half of the pear's total dietary fiber.
  • In recent studies measuring risk of type 2 diabetes in U.S. women, pears have earned very special recognition. Researchers now know that certain flavonoids in food can improve insulin sensitivity, and of special interest in this area have been three groups of flavonoids (flavonols, flavan-3-ols, and anthocyanins). All pears contain flavonoids falling within the first two groups, and red-skinned pears contain anthocyanins as well. Intake of these flavonoid groups has been associated with decreased risk of type 2 diabetes in both women and men. However, a new analysis of the Nurses' Health Study has shown that among all fruits and vegetables analyzed for their flavonoid content, the combination of apples/pears showed the most consistent ability to lower risk of type 2 diabetes. We believe that this special recognition given to pears as a fruit that can help lower risk of type 2 diabetes in women is likely to be followed by future studies showing this same benefit for men.
  • You've no doubt heard someone say that cloudy fruit juices containing fruit pulp provide better nourishment than clear fruit juices that have had their pulp removed through filtering. Scientists have now proven that statement to be correct with respect to pear juice. With their pulp removed, pear juices were determined to lose up to 40% of their total phenolic phytonutrients, and to have significantly reduced antioxidant capacity. "Cloudy" pear juices (technically referred to as "high turbidity" juices) emerged as the superior juice type in terms of nutrient content as well as antioxidant benefits.


Nutrients in
Pear
1.00 each (178.00 grams)
Nutrient%Daily Value

fiber22%

vitamin C12.4%

vitamin K10%

Calories (103)5%

This chart graphically details the %DV that a serving of Pears provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. 
Antioxidant and Anti-Inflammatory Support
While pears are not an unusual source of conventional antioxidant or anti-inflammatory nutrients (for example, vitamin E or omega-3 fatty acids), the phytonutrient category is where this fruit excels. For example, in the Baltimore Longitudinal Study of Aging (1,638 participants, average age range 62-69 years), the combination of apples/pears ranked as the second highest source of flavonols among all fruits and vegetables—partly due to the epicatechin richness of pears. Average flavonol intake in the study was about 14 milligrams per day, and one pear can provide about half of this amount all by itself. The list of phytonutrients found in pears has been of special interest to researchers, and the list below summarizes their findings about key phytonutrients provided by this fruit.
Hydroxybenzoic acids
  • chlorogenic acid
  • gentisic acid
  • syringic acid
  • vanillic acid
Hydroxycinnamic acids
  • coumaric acid
  • ferulic acid
  • 5-caffeoylquinic acid
Hydroxyquinones
  • arbutin
Flavanols, also known as Flavan-3-ols
  • catechin
  • epicatechin
Flavonols
  • isorhamnetin
  • quercetin
  • kaempferol
Anthocyanins (in red-skinned varieties, including Red Anjou, Red Bartlett, Comice, Seckel, and Starkrimson)
Carotenoids
  • beta-carotene
  • lutein
  • zeaxanthin
Virtually all of these phytonutrients have been shown to provide us with antioxidant as well as anti-inflammatory benefits. As a result, intake of pears has now been associated with decreased risk of several common chronic diseases that begin with chronic inflammation and excessive oxidative stress. These diseases include heart disease and type 2 diabetes.
Decreased Risk of Type 2 Diabetes and Heart Disease
As a very good source of dietary fiber, pears might logically be expected to help protect us from development of type 2 diabetes (or DM2, which stands for "diabetes mellitus type 2) as well heart disease. Adequate intake of dietary fiber is a long-established factor in reducing our risk of both diseases, and in the case of pears, this benefit may be even more pronounced due to the helpful combination of both soluble and insoluble fiber in this fruit. In addition to their fiber content, however, pears have other ways of helping to protect us against these diseases. In the case of DM2, scientists now know that pear flavonols (including isorhamnetin, quercetin, and kaempferol), flavan-3-ols (especially epicatechin), and the anthocyanins (found in red-skinned varieties including Red Anjou, Red Bartlett, Comice, Seckel, and Starkrimson) all help improve insulin sensitivity. (More and more research attention is being given to mechanisms of action in this area, including regulation of the enzyme NADPH oxidase.) In the case of heart disease, recent research has shown that pear fibers are able to bind together with bile acids in the intestine, lowering the pool of bile acids and decreasing the synthesis of cholesterol. In addition, the phytonutrients in pear may play a special role in these fiber-bile acid interactions. The ability of pear fibers (and other fruit fibers) to bind bile acids has actually been compared to the cholesterol-lowering drug cholestyramine, with pears showing about 5% of the ability of the drug to accomplish this result. (Among commonly eaten fruits, only bananas and pineapples showed more bile acid-binding ability at 9% and 6%, respectively.)
Reduced Cancer Risk
The health benefits of pear fiber also extend into the area of cancer risk. Fiber from pear can bind together not only with bile acids as a whole, but also with a special group of bile acids called secondary bile acids. Excessive amounts of secondary bile acids in the intestine can increase our risk of colorectal cancer (as well as other intestinal problems). By binding together with secondary bile acids, pear fibers can help decrease their concentration in the intestine and lower our risk of cancer development. In the case of stomach cancer (gastric cancer), intake of pears has also been shown to lower cancer risk. Here the key focus has not been on pear fiber, however, but on pear phytonutrients, especially cinnamic acids (including coumaric acid, ferulic acid, and 5-caffeoylquinic acid). In a recent study from Mexico City, it took approximately 2 total fruit servings per day and 4 daily vegetable servings to accomplish a decrease in gastric cancer risk. Pears and mangos were among the key foods determined to provide cinnamic acids in the study.
Esophageal cancer (specifically, esophageal squamous cell carcinoma, or ESCC) is a third cancer type for which pear intake helps lower risk. In a very large-scale study conducted by the National Institutes of Health and the American Association of Retired Persons (involving 490,802 participants), pears were found to be a key food associated with reduced risk of ESCC. Interestingly, numerous foods belonging the rose (Rosaceae) family were also found to lower risk of ESCC, including apples, plums, and strawberries.
Other Health Benefits
It's become fairly common to hear both laypersons and healthcare practitioners talking about pear as one of the more easily digested fruits. In fact, many practitioners recommend that pear be one of the first fruits considered when it comes time to introducing an infant to his or her first pureed fruits. Even though we have been unable to find large-scale human studies to support these digestibility claims, we don't question the fact that easier digestion has been experienced by many individuals in the context of pears versus other fruits. One factor that may come into play here is the low acid nature of pears, especially in comparison to widely enjoyed citrus fruits like lemons, grapefruits, and oranges.

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