The Humble Pear Is Packed With Phytonutrients Providing Antioxidant Protection Against Several Diseases
Pears are a powerhouse of phytonutrients called flavonols. While pears are not an unusual source of conventional antioxidant or anti-inflammatory nutrients, the phytonutrient category is where this fruit excels. In one study, pears received one of the highest scores when it came to these health-promoting nutrients, which provide antioxidant protection against a variety of diseases.
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.
In addition, one study has suggested that pears help protect the lungs due to their high flavonoid content, according to investigators led by Cora Tabak of the National Institute of Public Health and the Environment in Bilthoven. The investigators found that people with higher catechin intakes had a lower risk of chronic cough and breathlessness, even after smoking, age, body mass and other factors were considered. Two other groups of flavonoids--flavonols and flavones--were associated with a lower risk of chronic cough only.
The skin of a pear comprises even more phenolic phytonutrients as its flesh. These include antioxidants and anti-inflammatory flavonoids, apart from anti-cancer phytonutrients such as cinnamic acids. Also, rich with fibre, pear skins should always be consumed.
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.
Researchers have noted that flavonoids, which have three groups -- flavonols, flavan-3-ols, and anthocyaninsin -- are abundantly found in pears. This is especially beneficial for those who have type 2 diabetes.
The low acidic nature of pears makes it easy to digest and they are also known as being a hypoallergenic food, which means that the chances of one getting an allergy from a pear are very rare. The dietary fibre in pears makes them a good source of immune-supportive vitamin C and bone-building vitamin K.
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.
Flavanols, also known as Flavan-3-ols
Anthocyanins (in red-skinned varieties, including Red Anjou, Red Bartlett, Comice, Seckel, and Starkrimson)
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.
How to Select Your Pears
Pears come in different colours -- green, red, yellow and brown. They're perishable once they get ripe, so while buying pears, look for those which are firm but not very hard. Ensure that the skin is smooth and that there are are no bruises. Don't buy pears, which have dark spots.
If you want to speed up the ripening process, place the pears in a paper bag, in normal room temperature and keep turning them regularly.
The list below describes some of the more commonly enjoyed varieties of pears:
Bartlett: best known of the pear varieties in the U.S., and most often the variety found in cans. Bartletts are yellow/green and speckled, and sometimes called Williams pears
Bosc: cinnamon brown-skinned pears with long tapered necks with a honey-like but complex flavor
Comice: round, short pears with either green and red coloring, or sometimes almost completely red with especially soft and juicy flesh
Concorde: tall, skinny, and golden/green pears with flesh that is firmer and more dense than many other varieties
Forelle: red/green and speckled like a trout, and thus the name, meaning "trout" in German. A small-sized pear that yellows as it ripens.
Green Anjou: a widely available, compact, and short-necked pear. It doesn't change color much while ripening, so you'll need to use the stem test described in our How to Select and Store section.
Red Anjou: very much like its green counterpart, except a rich reddish maroon in color and higher in anthocyanins (which is the main reason for its rich red color)
Red Bartlett: very much like its yellow/green counterpart, except with an all-round bright red skin, they sometimes feature light vertical striping, and like Red Anjou, they are rich in anthocyanins
Seckel: smallest of the commonly eaten pears, usually yellow/green or olive green in color, and mixed with broad patches of red
Starkrimson: bright crimson red color, more narrow-necked that Red Anjou, but equally rich in anthocyanins and especially gorgeous in a salad
As with all of the world's healthiest foods, you should purchase certified organic pears to lower your risk of exposure to unwanted pesticides, sewage sludge contaminants, and any potential risks associated with irradiation or genetic engineering. Fortunately, over 250 certified organic farms in the U.S. now produce over 20,000 tons of organic pears, and so these delicious fruits are getting easier to find in organic form.
Karen Foster is a holistic nutritionist, avid blogger, with five kids and an active lifestyle that keeps her in pursuit of the healthiest path towards a life of balance.