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Thursday, February 27, 2014

Onions - The World's Healthiest Foods


What's New and Beneficial About Onions

  • The flavonoids in onion tend to be more concentrated in the outer layers of the flesh. To maximize your health benefits, peel off as little of the fleshy, edible portion as possible when removing the onion's outermost paper layer. Even a small amount of "overpeeling" can result in unwanted loss of flavonoids. For example, a red onion can lose about 20% of its quercetin and almost 75% of its anthocyanins if it is "overpeeled."
  • The total polyphenol content of onions is much higher than many people expect. (Polyphenols are one of the largest categories of phytonutrients in food. This category includes all flavonoids as well as tannins.) The total polyphenol content of onion is not only higher than its fellow allium vegetables, garlic and leeks, but also higher than tomatoes, carrots, and red bell pepper. In the French diet, only six vegetables (artichoke heart, parsley, Brussels sprouts, shallot, broccoli, and celery) have a higher polyphenol content than onion. Since the French diet has been of special interest to researchers in terms of disease prevention, onion's strong polyphenol contribution will very likely lead to follow-up studies that pay closer attention to this unique allium vegetable.
  • Within the polyphenol category, onions are also surprisingly high in flavonoids. For example, on an ounce-for-ounce basis, onions rank in the top 10 of commonly eaten vegetables in their quercetin content. The flavonoid content of onions can vary widely, depending on the exact variety and growing conditions. Although the average onion is likely to contain less than 100 milligrams of quercetin per 3-1/2 ounces, some onions do provide this amount. And while 100 milligrams may not sound like a lot, in the United States, moderate vegetable eaters average only twice this amount for all flavonoids (not just quercetin) from all vegetables per day.
  • When onions are simmered to make soup, their quercetin does not get degraded. It simply gets transferred into the water part of the soup. By using a low-heat method for preparing onion soup, you can preserve the health benefits of onion that are associated with this key flavonoid.
  • When we get quercetin by eating an onion-rather than consuming the quercetin in purified, supplement form-we may end up getting better protection from oxidative stress. That's exactly what happened in an animal study where some animals had yellow onion added to their diet in a way that would provide the same amount of quercetin provided to other animals in the form of purified quercetin extracts. The best protection came from the onion version of this flavonoid, rather than the supplement form.
  • Several servings of onion each week are sufficient to statistically lower your risk of some types of cancer. For colorectal, laryngeal, and ovarian cancer, between 1-7 servings of onion has been shown to provide risk reduction. But for decreased risk of oral and esophageal cancer, you'll need to consume one onion serving per day (approximately 1/2 cup).

WHFoods Recommendations

With their unique combination of flavonoids and sulfur-containing nutrients, the allium vegetables—such as onions—belong in your diet on a regular basis. There's research evidence for including at least one serving of an allium vegetable—such as onions—in your meal plan every day.
When onion is your allium vegetable of choice, try to consume at least one-half of a medium onion on that day, and use this guideline to adjust your recipes accordingly. For example, if you are following a recipe that yields 4 servings, include at least 2 medium onions in the recipe so that each of your 4 servings will contain at least one half medium onion.
To bring out the sweet flavor of onions we recommend using our Healthy Saute method of cooking onions for just 7 minutes. Cut onions into slices of equal 1/4-inch thickness to help them cook more evenly. The thinner you slice the onions the more quickly they will cook. Let them sit for at least 5 minutes to enhance their health-promoting properties. For more details see the Healthiest Way of Cooking Onions in the How to Enjoy section below.

Onions, chopped, cooked
1.00 cup
(210.00 grams)
Calories: 92
GI: low




 vitamin B615.8%


 vitamin C14.5%





 vitamin B17.5%

This chart graphically details the %DV that a serving of Onions 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 Onions can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Onions, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

Health Benefits

Onions, like garlic, are members of the Allium family, and both are rich in sulfur-containing compounds that are responsible for their pungent odors and for many of their health-promoting effects. A wide variety of allyl sulfides are found in onion, including the four major diallyl sulfides: DMS (diallyl monosulfide), DDS (diallyl disulfide), DTS (diallyl trisulfide), and DTTS (diallyl tetrasulfide). Also present are a wide variety of sulfoxides, including (+) S-methyl-L-cysteine sulfoxide (MCSO), (+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO), S-methyl-l-cysteine sulfoxide, S-propyl-l-cysteine sulfoxide, and S-propenyl-l-cysteine sulfoxide. Onions are an outstanding source of polyphenols, including the flavonoid polyphenols. Within this flavonoid category, onions are a standout source of quercetin.

Cardiovascular Benefits

Unlike the research on garlic and its cardiovascular benefits, research specifically focused on onion has mostly been conducted on animals rather than humans. In animal studies, there is evidence that onion's sulfur compounds may work in an anti-clotting capacity and help prevent the unwanted clumping together of blood platelet cells. There is also evidence showing that sulfur compounds in onion can lower blood levels of cholesterol and triglycerides, and also improve cell membrane function in red blood cells.
In human studies, most of the cardiovascular benefits have been demonstrated in the form of overall diet. Multiple studies show onion to be a food that provides protection for the heart and blood vessels when consumed in a diet that is rich in other vegetables and fruits—especially flavonoid-containing vegetables and fruits. The benefits of onion in this overall dietary context extend to prevention of heart attack. In virtually all of these diet-based studies, participants with the greatest intake of vegetables (including onions) gain the most protection. The outstanding flavonoid content of onions supports these research findings. It's also interesting to note that onion is most commonly consumed in relatively small amounts along with other foods rather than by itself. For this reason, it can be more difficult to study in large-scale dietary research studies that involve thousands of participants and rely on diet diaries to determine onion consumption.

Support for Bone and Connective Tissue

Human studies have shown that onion can help increase our bone density and may be of special benefit to women of menopausal age who are experiencing loss of bone density. In addition, there is evidence that women who have passed the age of menopause may be able to lower their risk of hip fracture through frequent consumption of onions. "Frequent" in this context means onion consumption on a daily basis! In this research on bone density in older women, very sporadic eating of onion (once a month or less) did not provide much benefit. That finding, of course, was very expected. But less expected was the finding that it took daily consumption of onion to show robust benefits for bone density. Just as in the cancer-related onion research, the take-away message here is clear: you don't want to skimp on onions when you are incorporating them into your meal plan.
In and of itself, the high sulfur content of onions may provide direct benefits to our connective tissue. Many of our connective tissue components require sulfur for their formation. For example, with the exception of hyaluronic acid, all glycosaminoglycans (GAGS) are sulfated. (GAGS are the premiere family of molecules found in the ground substance of our connective tissue.)

Anti-Inflammatory Benefits

While onion is not as well researched as garlic in terms of specific inflammatory health problems like rheumatoid arthritis or allergic airway inflammation, this allium vegetable has nevertheless been shown to provide important anti-inflammatory benefits. Onionin A—a unique sulfur molecule in onion that is found in the bulb portion of the plant—has been shown to inhibit the activity of macrophages, specialized white blood cells that play a key role in our body's immune defense system, and one of their defense activities involves the triggering of large-scale inflammatory responses. While macrophage activity is typically a good thing, inhibition of their activity can sometimes be critical in getting chronic unwanted inflammation under control.
Onion's antioxidants—including its hallmark flavonoid antioxidant, quercetin—also provide us with anti-inflammatory benefits. These antioxidants help prevent the oxidation of fatty acids in our body. When we have lower levels of oxidized fatty acids, our body produces fewer pro-inflammatory messaging molecules, and our level of inflammation is kept in check.

Cancer Protection

Onion has repeatedly been shown to lower our risk of several cancers, even when we consume it in only moderate amounts. "Moderate" generally means 1-2 times per week, even though in some studies it has been used to mean up to 5-6 times per week. Colorectal cancer, laryngeal cancer, and ovarian cancer are the cancer types for which risk is reduced along with moderate amounts of dietary onion. For other cancer types, however, moderate intake of onion has not been enough to show significant risk reduction. For these cancer types—including esophageal cancer and cancers of the mouth—daily intake of onion is required before research results show significant risk reduction.
Many factors may play a role in these different research findings for different cancer types. However, the overall take-away from this research seems clear: you do not want to err on the side of small onion servings or infrequent onion intake if you want to obtain the full cancer-related benefits of onion. A few slivers of sliced onion on a tossed salad are a good thing—but probably not enough to provide you with the cancer-related onion benefits that you are seeking. In recipes that already call for onion, try to include at least 1 whole onion (medium size) in the recipe. In recipes that do not already call for onion, consider the addition of 1 medium size onion (if you think onion might fit into the recipe and still provide a tasty outcome). In terms of individual portion sizes when you sit down to eat a meal, try to consume the equivalent of 1/2 onion.

Other Health Benefits

In animal studies, onions have shown potential for improvement of blood sugar balance, even though it is not yet clear about the carry over of these benefits for humans who are seeking better blood sugar balance from their diet. Most of the animal studies have been conducted on rats, and most have used onion juice or onion extract as the form of onion tested. Future research is needed to clarify onion's potential for helping lower blood sugar and improving blood sugar control, especially in persons with blood sugar problems.
While not as well researched as garlic in terms of antibacterial benefits, onion has nevertheless been shown to help prevent bacterial infection. Along with its sulfur-containing compounds, the flavonoid quercetin contained in onion helps provide these antibacterial benefits. We've seen studies showing antibacterial activity of onion in relationship to the bacteria Streptococcus mutans and Streptococcus sobrinus. (These bacteria are commonly involved in the production of tooth cavities). Antibacterial benefits have also been shown in the area of gum (periodontal) disease bacteria, including Porphyromonas gingivalis and Prevotella intermedia. Interestingly, in one study, fresh, chopped, uncooked onion had antibacterial effects on these potentially unwanted gum bacteria, but non-fresh, uncooked onion (raw onion that was chopped and then left to sit for 2 days at room temperature) did not demonstrate these same antibacterial properties nor did fresh onion that was grated and then steamed for 10 minutes. While it is not possible to draw broad conclusions from a single lab study, these findings suggest that length of storage (for onion that has been chopped but not cooked) and duration of heat exposure (in this case involving exposure to steam for 10 full minutes) can affect some of onion's health benefits. For these reasons, special care may be needed in the storage, handling, and cooking of this allium vegetable.


What would a kitchen be without the distinctively pungent smell and taste of onions filling out the flavors of almost every type of cuisine imaginable? Fortunately, yellow storage onions are available throughout the year although sweet varieties have a much more limited growing season and are available only a few months out of the year.
While onions may bring a tear to your eye and a pungency to your breath they will also certainly bring delight to your taste buds. The onion, known scientifically as Allium cepa, is, on the surface, a humble brown, white or red, paper-thin skinned bulb; yet, despite its plain looks, it has an intense flavor and is a beloved part of the cuisine of almost every region of the world.
The word onion comes from the Latin word unio, which means "single," or "one"—reflecting of the onion plant producing a single bulb, unlike its cousin, the garlic, that produces many small bulbs. The name also describes the onion bulb when cut down the middle; it is a union (also from unio) of many separate, concentrically arranged layers.
Onions range in size, color, and taste depending upon their variety. There are generally two types of large, globe-shaped onions, classified as spring/summer or storage onions. The former class includes those that are grown in warm weather climates and have characteristic mild or sweet tastes. Included in this group are the Maui Sweet Onion (in season April through June), Vidalia (in season May through June) and Walla Walla (in season July and August). Storage onions are grown in colder weather climates and, after harvesting, are dried out for a period of several months, which allows them to attain dry, crisp skins. They generally have a more pungent flavor and are usually named by their color: white, yellow or red. Spanish onions fall into this classification. In addition to these large onions, there are also smaller varieties such as the green onion, or scallion, and the pearl onion.
Onions are a major source of polyphenols in general, and also of flavonoids (a very important subdivision of polyphenols). They can also vary greatly in their polyphenol and flavonoid content. In general, red onions are higher in total flavonoids than white onions, (with yellow onions falling somewhere in between).


Onions are native to Asia and the Middle East and have been cultivated for over five thousand years. Onions were highly regarded by the Egyptians. Not only did they use them as currency to pay the workers who built the pyramids, but they also placed them in the tombs of kings, such as Tutankhamen, so that they could carry these gifts bestowed with spiritual significance with them to the afterlife.
Onions have been revered throughout time not only for their culinary use, but also for their therapeutic properties. As early as the 6th century, onions were used as a medicine in India. While they were popular with the ancient Greeks and Romans, they were oftentimes dressed with extra seasonings since many people did not find them spicy enough. Yet, it was their pungency that made onions popular among poor people throughout the world who could freely use this inexpensive vegetable to spark up their meals. Onions were an indispensable vegetable in the cuisines of many European countries during the Middle Ages and later even served as a classic healthy breakfast food. Christopher Columbus brought onions to the West Indies; their cultivation spread from there throughout the Western Hemisphere. Today China, India, the United States, Russian, and Spain are among the leading producers of onions.

How to Select and Store

Choose onions that are clean, well shaped, have no opening at the neck, and feature crisp, dry outer skins. Avoid those that are sprouting or have signs of mold. In addition, onions of inferior quality often have soft spots, moisture at their neck, and dark patches, which may all be indications of decay. As conventionally grown onions are often irradiated to prevent them from sprouting, purchase organically grown varieties whenever possible to avoid onions that have undergone this process. When purchasing scallions, look for those that have green, fresh-looking tops that appear crisp yet tender. The base should be whitish in color for two or three inches. Avoid those that have wilted or yellowed tops.
Onions should be stored in a well ventilated space at room temperature, away from heat and bright light. With the exception of green onions, do not refrigerate onions. Place them in a wire hanging basket or a perforated bowl with a raised base so that air can circulate underneath. The length of storage varies with the type of onion. Those that are more pungent in flavor, such as yellow onions, should keep for about a month if stored properly. They will keep longer than those with a sweeter taste, such as white onions, since the compounds that confer their sharp taste help to preserve them. Scallions should be stored in a plastic bag in the refrigerator where they will keep for about one week. All onions should be stored away from potatoes, as they will absorb their moisture and ethylene gas, causing them to spoil more readily.
Store cut onions by placing in a sealed container; use them within a day or two since they tend to oxidize and lose their nutrient content rather quickly. Cooked onions will best maintain their taste in an airtight container where they can be kept for a few days; they should never be placed in a metal storage container as this may cause them to discolor. Although peeled and chopped onions can be frozen (without first being blanched), this process will cause them to lose some of their flavor.

Tips for Preparing and Cooking

Tips for Preparing Onions

Cut onions into 1/4-inch slices to cook them evenly and quickly. Let them sit for at least 5 minutes to help enhance their health-promoting benefits.
While many people love to eat onions, most dread cutting them since this process usually brings a tear or two to the eyes. The substance that causes the eyes to burn is a special gas that has been named lachrymatory factor (LF). (The full chemical name for this gas is propanthial S-oxide, and it is made from a naturally occurring compound in onion called 1-propenyl-L-cysteine sulphoxide.) Recent research has shown that LF gas is not produced through activity of onion's alliinase enzyme, but rather through the activity of a special enzyme named lachrymatory-factor synthase. Interestingly, even though lachrymatory-factor synthase is the enzyme responsible for production of LF gas, the alliinase enzyme must still be present in order for LF gas production to occur.
Of course, no sooner had this new tear-producing enzyme been discovered than researchers began looking for ways to switch off the gene that served as the blueprint for this enzyme. However, "silencing" the gene without compromising the health benefits of the onion turned out to be a difficult task. Even though researchers in Japan succeeded in shutting down the gene and preventing production of lachrymatory-factor enzyme (thereby paving the way for a genetically engineered onion that would not produce LF gas and cause tearing), they also determined that the shutdown of the gene caused significant (and mostly unwanted) changes in the overall mixture of sulfur-containing molecules in onion.
If cutting onions irritates your eyes, there are a few tricks that you can employ. Use a very sharp knife and always cut the onions while standing; that way your eyes will be as far away as possible. Consider cutting onions by an open window. If cutting onions really makes you cry, consider wearing glasses or goggles. Chill the onions for an hour or so before cutting; this practice can slow down the onion's metabolism and thereby lessen the rate of LF gas production. Cutting onions under cold, running water is a method that is often used to cut back on eye irritation, but it's a method we view as a second-best choice since some of the nutrients found in onion can be lost into the flow of water.

The Healthiest Way of Cooking Onions

Although onions are most often used as a seasoning, we want to share with you how to enjoy them as a healthy side dish. For great flavor and nutrition we recommend Heatlhy Sautéeing sliced onions. Heat 2 TBS vegetable or chicken broth over medium heat in a stainless steel skillet. When broth begins to steam, add onions and cover for 3 minutes. The onions will release a small amount of liquid. Uncover, add another 2 TBS broth, and continue to stir for 4 minutes, leaving the lid off. Toss with our Mediterranean Dressing and top with your favorite optional ingredients. For details see, 7-Minute Healthy Sautéed Onions

How to Enjoy

A Few Quick Serving Ideas

  • Combine chopped onions, tomatoes, avocado, and jalapeno for an all-in-one guacamole salsa dip.
  • To perk up plain rice, top with green onions (scallions) and sesame seeds.
  • Healthy Sauteed chopped onions can enhance the flavor or almost any vegetable dish.
  • Enjoy a classic Italian salad—sliced onions, tomatoes, and mozzarella cheese drizzled with olive oil.

WHFoods Recipes that Feature Onions

Individual Concerns

Onions are not a commonly allergenic food, are not known to contain measurable amounts of oxalates or purines and are also not included in the Environmental Working Group's 2010 report "Shopper's Guide to Pesticides" as one of the 12 foods most frequently containing pesticide residues.

Nutritional Profile

The outstanding polyphenol content of onions (including their rich concentration of flavonoid polyphenols) is probably the most overlooked nutrient content of these allium vegetable. Among the flavonoids, onions also provide a particularly large amount of quercetin. A wide variety of allyl sulfides are found in onion, including the four major diallyl sulfides: DMS (diallyl monosulfide), DDS (diallyl disulfide), DTS (diallyl trisulfide), and DTTS (diallyl tetrasulfide). Also present are a wide variety of sulfoxides, including (+) S-methyl-L-cysteine sulfoxide (MCSO), (+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO), S-methyl-l-cysteine sulfoxide, S-propyl-l-cysteine sulfoxide, and S-propenyl-l-cysteine sulfoxide.
Onions are a very good source of biotin. They are also a good source of manganese, vitamin B6, copper, vitamin C, dietary fiber, phosphorus, potassium, folate, and vitamin B1. For an in-depth nutritional profile click here: Onions.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Onions 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.
Onions, chopped, cooked
1.00 cup
210.00 grams
Calories: 92
GI: low
World's Healthiest
Foods Rating
biotin7.98 mcg26.65.2very good
manganese0.32 mg16.03.1good
vitamin B60.27 mg15.93.1good
copper0.14 mg15.63.0good
vitamin C10.92 mg14.62.8good
fiber2.94 g11.82.3good
phosphorus73.50 mg10.52.0good
potassium348.60 mg10.01.9good
folate31.50 mcg7.91.5good
vitamin B10.09 mg7.51.5good
World's Healthiest
Foods Rating
excellent DRI/DV>=75% OR
Density>=7.6 AND DRI/DV>=10%
very good DRI/DV>=50% OR
Density>=3.4 AND DRI/DV>=5%
good DRI/DV>=25% OR
Density>=1.5 AND DRI/DV>=2.5%
In-Depth Nutritional Profile for Onions


  • Ali M, Thomson M, Afzal M. Garlic and onions: their effect on eicosanoid metabolism and its clinical relevance. Prostaglandins Leukot Essent Fatty Acids. 2000 Feb;62(2):55-73. Review. 2000.
  • Azuma K, Minami Y, Ippoushi K et al. Lowering effects of onion intake on oxidative stress biomarkers in streptozotocin-induced diabetic rats. J Clin Biochem Nutr. 2007 Mar;40(2):131-40. 2007.
  • Borjihan B, Ogita A, Fujita KI et al. The Cyclic Organosulfur Compound Zwiebelane A from Onion (Allium cepa) Functions as an Enhancer of Polymyxin B in Fungal Vacuole Disruption. Planta Med. 2010 May 19. [Epub ahead of print]. 2010.
  • Brat P, George S, Bellamy A, et al. Daily Polyphenol Intake in France from Fruit and Vegetables. J. Nutr. 136:2368-2373, September 2006. 2006.
  • Chun OK, Chung SJ, and Song WO. Estimated dietary flavonoid intake and major food sources of U.S. adults. J Nutr. 2007 May;137(5):1244-52. 2007.
  • Dorant E, van den Brandt PA, Goldbohm RA. A prospective cohort study on the relationship between onion and leek consumption, garlic supplement use and the risk of colorectal carcinoma in The Netherlands. Carcinogenesis 1996 Mar;17(3):477-84. 1996. PMID:13660.
  • Eady CC, Kamoi T, Kato M et al. Silencing onion lachrymatory factor synthase causes a significant change in the sulfur secondary metabolite profile. Plant Physiol. 2008 Aug;147(4):2096-106. 2008.
  • El-Aasr M, Fujiwara Y, Takeya M et al. Onionin A from Allium cepa inhibits macrophage activation. J Nat Prod. 2010 Jul 23;73(7):1306-8. 2010.
  • Fukushima S, Takada N, Hori T, Wanibuchi H. Cancer prevention by organosulfur compounds from garlic and onion. J Cell Biochem Suppl 1997;27:100-5. 1997. PMID:13650.
  • Galeone C, Pelucchi C, Levi F, Negri E, Franceschi S, Talamini R, Giacosa A, La Vecchia C. Onion and garlic use and human cancer. Am J Clin Nutr. 2006 Nov;84(5):1027-32. 2006. PMID:17093154.
  • Galeone C, Pelucchi C, Talamini R et al. Onion and garlic intake and the odds of benign prostatic hyperplasia. Urology. 2007 Oct;70(4):672-6. 2007.
  • Galeone C, Tavani A, Pelucchi C, et al. Allium vegetable intake and risk of acute myocardial infarction in Italy. Eur J Nutr. 2009 Mar;48(2):120-3. 2009.
  • Gates MA, Tworoger SS, Hecht JL, De Vivo I, Rosner B, Hankinson SE. A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer. Int J Cancer. 2007 Apr 30; [Epub ahead of print]. 2007. PMID:17471564.
  • Gautam S, Platel K and Srinivasan K. Higher bioaccessibility of iron and zinc from food grains in the presence of garlic and onion. J Agric Food Chem. 2010 Jul 28;58(14):8426-9. 2010.
  • Imai S, Tsuge N, Tomotake M et al. Plant biochemistry: an onion enzyme that makes the eyes water. Nature. London: Oct 17, 2002. Vol. 419, Iss. 6908; p. 685. 2002.
  • Kim JH. Anti-bacterial action of onion (Allium cepa L.) extracts against oral pathogenic bacteria. J Nihon Univ Sch Dent. 1997 Sep;39(3):136-41. 1997.
  • Kook S, Kim GH and Choi K. The antidiabetic effect of onion and garlic in experimental diabetic rats: meta-analysis. J Med Food. 2009 Jun;12(3):552-60. 2009.
  • Matheson EM, Mainous AG 3rd and Carnemolla MA. The association between onion consumption and bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older. Menopause. 2009 Jul-Aug;16(4):756-9. 2009.
  • Melino S, Sabelli R and Paci M. Allyl sulfur compounds and cellular detoxification system: effects and perspectives in cancer therapy. Amino Acids. 2010 Mar 6. [Epub ahead of print]. 2010.
  • Moon JH, Nakata R, Oshima S, et al. Accumulation of quercetin conjugates in blood plasma after the short-term ingestion of onion by women. Am J Physiol Regul Integr Comp Physiol. 2000 Aug;279(2):R461-7. 2000.
  • Nemeth K and Piskula MK. Food content, processing, absorption and metabolism of onion flavonoids. Crit Rev Food Sci Nutr. 2007;47(4):397-409. 2007.
  • Nimni ME, Han B and Cordoba F. Are we getting enough sulfur in our diet?. Nutr Metab (Lond). 2007 Nov 6;4:24-36. 2007.
  • Phillips KM, Rasor AS, Ruggio DM, et al. Folate content of different edible portions of vegetables and fruits. Nutrition & Food Science 2008, 38(2):175-181. 2008.
  • Ramos FA, Takaishi Y, Shirotori M et al. Antibacterial and antioxidant activities of quercetin oxidation products from yellow onion (Allium cepa) skin. J Agric Food Chem. 2006 May 17;54(10):3551-7. . 2006.
  • Slimestad R, Fossen T and Vågen IM. Onions: a source of unique dietary flavonoids. J Agric Food Chem. 2007 Dec 12;55(25):10067-80. 2007.
  • Somerset SM and Johannot L. Dietary flavonoid sources in Australian adults. Nutr Cancer. 2008;60(4):442-9. 2008.
  • Wagner H, Dorsch W, Bayer T, et al. Antiasthmatic effects of onions: inhibition of 5-lipoxygenase and cyclooxygenase in vitro by thiosulfinates and "Cepaenes". Prostaglandins Leukot Essent Fatty Acids. 1990 Jan;39(1):59-62. 1990.
  • Wang L, Lee IM, Zhang SM, et al. Dietary intake of selected flavonols, flavones, and flavonoid-rich foods and risk of cancer in middle-aged and older women. Am J Clin Nutr. 2009 Mar;89(3):905-12. 2009.
  • Wetli HA, Brenneisen R, Tschudi I, Langos M, Bigler P, Sprang T, Schurch S, Muhlbauer RC. A gamma-Glutamyl Peptide Isolated from Onion (Allium cepa L.) by Bioassay-Guided Fractionation Inhibits Resorption Activity of Osteoclasts. J Agric Food Chem. 2005 May 4;53(9):3408-3414. 2005. PMID:15853380.
  • Wilson EA and Demmig-Adams B. Antioxidant, anti-inflammatory, and antimicrobial properties of garlic and onions. Nutrition & Food Science 2007, Vol. 37 Iss: 3, pp.178 ' 183. 2007.
  • Yang J, Meyers KJ, van der Heide J, Liu RH. Varietal Differences in Phenolic Content and Antioxidant and Antiproliferative Activities of Onions. J Agric Food Chem. 2004 Nov 3;52(22):6787-6793. 2004. PMID:15506817. 
Credits to: http://www.whfoods.com

Thursday, October 4, 2012

Keep the heart healthy by eating apples daily: Study;

A small-scale study funded by the apple industry claims that an apple a day can, indeed, keep the cardiologist at bay.

Published in the Journal of Functional Foods, the research found that healthy, middle-aged adults who ate one apple every day for four weeks succeeded in lowering levels of ‘bad’ cholesterol by 40 percent -- a substance which has been linked to the hardening of the arteries.
To carry out their study, researchers from Ohio State University recruited 16 healthy adults between the ages of 40 and 60 who weren’t regular apple eaters – less than twice a month. Participants were instructed to eat either a Red or a Golden Delicious apple every day for four weeks.
Another 17 participants took oral capsules containing 194 mg of polyphenols for four weeks, and a third group of 18 people took a placebo.
While the polyphenol capsules also yielded measurable results, they weren’t as strong as consuming whole apples, researchers said.
“That could either be because there are other things in the apple that could contribute to the effect, or, in some cases, these bioactive compounds seem to get absorbed better when they're consumed in foods,” hypothesized lead researcher Robert DiSilvestro.
When oxidized LDL or low-density lipoprotein --also known as ‘bad cholesterol’ -- oxidizes after meeting free radicals, the cholesterol is more likely to promote inflammation and cause tissue damage, researchers explain.
DiSilvestro also claims that eating whole apples daily was found to be more effective in this particular capacity -- lowering bad cholesterol levels -- than other antioxidant-rich foods he’s studied separately, including turmeric, green tea and tomato extract.
The latest study builds on previous research vaunting the health benefits of apples. A Florida State University study likewise proved that eating an apple daily lowered ‘bad cholesterol’ levels by 23 percent while also increasing good cholesterol levels by 4 percent. Female participants also lost an average of 1.5 kg (3.3 lbs) during the year-long experiment.

Monday, October 1, 2012

10 Common Allergy Triggers

Uncover your allergy triggers

Nearly 20% of Americans suffer from allergies. Allergies are an abnormal response of the immune system where the body's defenses react to a usually harmless substance in the environment, such as pollen, animal dander, or food. Almost anything can trigger an allergic reaction, which can range from mild and annoying to sudden and life-threatening. Here are 10 of the most common triggers.


Exposure to pollen from trees, grasses, and weeds can trigger hay fever or seasonal allergies. Symptoms include sneezing, runny nose, nasal congestion, and itchy, watery eyes. Treatments include over-the-counter products, prescription drugs, and allergy shots. Prevent symptoms by staying indoors on windy days when pollen counts are high, closing windows, and running the air conditioning.

Animal Dander

Proteins secreted by oil glands in an animal's skin and present in their saliva can cause allergic reactions for some. The allergy can take two or more years to develop and symptoms may not subside until months after ending contact with the animal. If your pet is causing allergies, make your bedroom a pet-free zone, avoid carpets, and wash the animal regularly. A HEPA filter and frequent vacuuming may also help. Allergy shots may be beneficial.

Dust Mites

Dust mites are microscopic organisms that live in house dust. They thrive in areas of high humidity and feed on the dead skin cells of humans and their pets, as well as on pollen, bacteria, and fungi. Help prevent dust mite allergies by covering mattresses, pillows, and box springs, using hypoallergenic pillows, washing sheets weekly in hot water, and keeping the house free of dust collecting-items such as stuffed animals, curtains, and carpet.

Insect Stings

People who are allergic to stings can have a severe or even life-threatening reaction. Symptoms include extensive swelling and redness from the sting or bite that may last a week or more, nausea, fatigue, and low-grade fever. Rarely, insect stings may cause anaphylaxis, with symptoms including difficulty breathing, hives, swelling of the face, throat, or mouth, rapid pulse, dizziness, or a sharp drop in blood pressure. For those severely allergic, epinephrine should be administered immediately after a sting; allergy shots are recommended to prevent anaphylaxis with future stings.


Molds produce allergens, irritants, and in some cases, potentially toxic substances. Inhaling or touching mold (magnified here) or mold spores may cause allergic reactions in sensitive individuals. There are many types of mold; all need moisture to grow. They can be found in damp areas such as basements or bathrooms, as well as in grass or mulch. Avoid activities that trigger symptoms, such as raking leaves. Ventilate moist areas in the home.


Milk, shellfish, nuts and wheat are among the most common foods that cause allergies. An allergic reaction usually occurs within minutes of eating the offending food. Symptoms, which can include asthma, hives, vomiting, diarrhea, and swelling around the mouth, can be severe. Avoid offending foods altogether; but if exposed, treatment with antihistamines or steroids is recommended. In life-threatening situations, an epinephrine injection is needed.


Latex in gloves, condoms, and certain medical devices can trigger latex allergy. Symptoms include skin rash, eye irritation, runny nose, sneezing, wheezing, and itching of the skin or nose. Allergic reactions can range from skin redness and itching to anaphylaxis, a serious reaction which can cause difficulty breathing, hives. Those allergic should wear a MedicAlert bracelet and carry an epinephrine kit.


Symptoms of allergies to medications, such as penicillin or aspirin, can range from mild to life-threatening and can include hives, itchy eyes, congestion, and swelling in the mouth and throat. It's best to avoid the drug altogether; however, if exposed, treatment with antihistamines or steroids is recommended. For coughing and lung congestion, bronchodilators may be prescribed. For severe symptoms, epinephrine may be needed.


Fragrances found in products including perfumes, scented candles, laundry detergent, and cosmetics can have mild to severe health consequences. For most people, symptoms abate once the scent is out of range. For some, repeated exposures cause an increase in symptoms that occur more often and last longer. There's some debate as to whether fragrance reactions are a true allergy or simply a response to an irritant.


Ick! Not only are cockroaches creepy, but a protein in their droppings can be a troublesome allergen. It can be difficult to eradicate cockroaches from your home, especially in a warm climate, or if you live in an apartment building where bugs can pass back and forth to a neighboring unit. Treat for roaches by using pesticides, keeping a clean kitchen, and repairing cracks and holes in floors, walls, and windows to prevent their entry into the home.

Air Pollution and Allergies: A Connection?

Does the "air we breathe" have an impact on the rising incidence of allergies and asthma? Hay feverwas rare in Japan before World War II. However, pollen allergy is now common and mostly affects those living in Japanese cities and near highways. Allergic disease is also more common in highly developed countries in North America and Europe and less common in Third World countries. This suggests that there must be something about modern, urban life that promotes allergy. Let us examine the impact of air pollution.
By far the most important indoor pollutant is tobaccosmoke, which is strongly associated with allergic sensitization, asthma, and other respiratory illnesses. Exposure to smoke results in the body's enhanced ability to produce IgE(the allergy antibody) that attaches to allergens (e.g. pollen, dust mites and dander). The IgE response is a key trigger of allergic reactions.
Parental smoking increases the risk of their children having many respiratory illnesses, including bronchitis, chronic cough, and asthma. Smoking during pregnancy and breastfeeding results in a higher risk for the children to develop allergic eczema (atopic dermatitis). The rate of asthma in an infant of a smoking mother is double that of a non-smoking mother. This is very important, since in North America, 25% of mothers smoke during pregnancy and 40% have a smoker in the home.

The increased rates of allergy and asthma in city environments and in those living close to highways has drawn attention to the role of outdoor pollution. Common air pollutants, such as ozone, sulfur dioxide, and nitrogen dioxide probably act more as irritants than as promoters of sensitization. These pollutants have been shown to be hazardous to adults and children with asthma. Recent studies suggest that prematurely born children are more sensitive to the respiratory effects of outdoor pollution. There may also be an association with diesel exhaust particles and the worldwide increase in respiratory allergies. Diesel exhaust has been shown to enhance the ability to make the allergy antibody, IgE, in response to exposure to allergens.
What is the bottom line? Tobacco smoke is by far the worst and most important air pollutant and it clearly promotes both allergy and asthma. Diesel fumes likely promote allergy, whereas other outdoor air pollutants act more as irritants that can aggravate allergies and asthma, rather than as true promoters of allergy or asthma.

Medical Author: Alan Szeftel, MD, FCCP
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Monday, August 20, 2012

Top 5 lifestyle changes to reduce cholesterol

Lifestyle changes can help reduce cholesterol, keep you off cholesterol-lowering medications or enhance the effect of your medications. Here are five lifestyle changes to get you started. 


High cholesterol increases your risk of heart disease and heart attacks. You can reduce cholesterol with medications, but if you'd rather make lifestyle changes to reduce cholesterol, you can try these five healthy lifestyle changes. If you're already taking medications, these changes can also improve their cholesterol-lowering effect.

1. Lose weight

Carrying some extra pounds — even just a few — contributes to high cholesterol. So losing as little as 5 to 10 pounds (about 2 to 5 kilograms) can help reduce cholesterol levels.
Start by taking an honest look at your eating habits and daily routine. Consider your challenges to weight loss — and ways to overcome them.
If you eat when you're bored or frustrated, take a walk instead. If you pick up fast food for lunch every day, pack something healthier from home. If you're sitting in front of the television, try munching on carrot sticks instead of potato chips as you watch. And, look for ways to incorporate more activity into your daily routine, such as using the stairs instead of taking the elevator. Take stock of what you currently eat and your physical activity level, and slowly work changes in.

2. Eat heart-healthy foods

Even if you have years of unhealthy eating under your belt, making a few changes in your diet can reduce cholesterol and improve your heart health.
  • Choose healthier fats. Saturated fats, found in red meat and dairy products, raise your total cholesterol and low-density lipoprotein (LDL) cholesterol, the "bad" cholesterol. As a general rule, you should get no more than 10 percent of your daily calories from saturated fat. Instead, choose leaner cuts of meat, low-fat dairy and monounsaturated fats — found in olive, peanut and canola oils — for a healthier option.
  • Eliminate trans fats. Trans fat can be found in fried foods and many commercial baked products, such as cookies, crackers and snack cakes. But don't rely on packages that are labeled "trans fat-free." In the United States, if a food contains less than 0.5 grams of trans fat per serving, it can be labeled "trans fat-free." Even though those amounts seem small, they can add up quickly if you eat a lot of foods that have a small amount of trans fat in them. Instead, read the ingredients list. You can tell if a food has trans fat in it if it contains partially hydrogenated oil.
  • Limit the cholesterol in your food. Aim for no more than 300 milligrams (mg) of cholesterol a day — less than 200 mg if you have heart disease. The most concentrated sources of cholesterol include organ meats, egg yolks and whole milk products. Use lean cuts of meat, egg substitutes and skim milk instead.
  • Select whole grains. Various nutrients found in whole grains promote heart health. Choose whole-grain breads, whole-wheat pasta, whole-wheat flour and brown rice.
  • Stock up on fruits and vegetables. Fruits and vegetables are rich in dietary fiber, which can help lower cholesterol. Snack on seasonal fruits. Experiment with veggie-based casseroles, soups and stir-fries. If you prefer dried fruit to fresh fruit, limit yourself to no more than a handful (about an ounce or two). Dried fruit tends to have more calories than does fresh fruit.
  • Eat foods rich in omega-3 fatty acids. Omega-3 fatty acids can help lower your LDL ("bad") cholesterol. Some types of fish — such as salmon, mackerel and herring — are rich in omega-3 fatty acids. Other good sources of omega-3 fatty acids include walnuts, almonds and ground flaxseeds.

3. Exercise on most days of the week

Whether you're overweight or not, exercise can reduce cholesterol. Better yet, moderate physical activity can help raise high-density lipoprotein (HDL) cholesterol, the "good" cholesterol. With your doctor's OK, work up to 30 to 60 minutes of exercise a day. Remember that adding physical activity, even in 10-minute intervals several times a day, can help you begin to lose weight. Just be sure that you can keep up the changes you decide to make. Consider:
  • Taking a brisk daily walk during your lunch hour
  • Riding your bike to work
  • Swimming laps
  • Playing a favorite sport
To stay motivated, find an exercise buddy or join an exercise group. And remember, any activity is helpful. Even taking the stairs instead of the elevator or doing a few sit-ups while watching television can make a difference.

4. Quit smoking

If you smoke, stop. Quitting can improve your HDL cholesterol level. And the benefits don't end there. Just 20 minutes after quitting, your blood pressure decreases. Within 24 hours, your risk of a heart attack decreases. Within one year, your risk of heart disease is half that of a smoker. Within 15 years, your risk of heart disease is similar to someone who never smoked.

5. Drink alcohol only in moderation

Moderate use of alcohol has been linked with higher levels of HDL cholesterol — but the benefits aren't strong enough to recommend alcohol for anyone who doesn't already drink. If you choose to drink, do so in moderation. This means no more than one drink a day for women, and one to two drinks a day for men. Drinking too much alcohol can lead to serious health problems, including high blood pressure, heart failure and stroke.

If lifestyle changes aren't enough ...

Sometimes healthy lifestyle changes aren't enough to lower cholesterol levels. Make sure the changes you choose to make are ones that you can continue, and don't be disappointed if you don't see results immediately. If your doctor recommends medication to help lower your cholesterol, take it as prescribed, but continue your lifestyle changes.

Credit : Mayo Clinic Staff

Top 5 foods to lower your Cholesterol

Diet can play an important role in lowering your cholesterol. Here are five foods that can lower your cholesterol and protect your heart. 

Can a bowl of oatmeal help lower your cholesterol? How about a handful of walnuts or even a baked potato topped with some heart-healthy margarine? A few simple tweaks to your diet — like these, along with exercise and other heart-healthy habits — may be helpful in lowering your cholesterol.

1. Oatmeal, oat bran and high-fiber foods

Oatmeal contains soluble fiber, which reduces your low-density lipoprotein (LDL), the "bad," cholesterol. Soluble fiber is also found in such foods as kidney beans, apples, pears, barley and prunes.
Soluble fiber can reduce the absorption of cholesterol into your bloodstream. Five to 10 grams or more of soluble fiber a day decreases your total and LDL cholesterol. Eating 1 1/2 cups of cooked oatmeal provides 6 grams of fiber. If you add fruit, such as bananas, you'll add about 4 more grams of fiber. To mix it up a little, try steel-cut oatmeal or cold cereal made with oatmeal or oat bran.

2. Fish and omega-3 fatty acids

Eating fatty fish can be heart healthy because of its high levels of omega-3 fatty acids, which can reduce your blood pressure and risk of developing blood clots. In people who have already had heart attacks, fish oil — or omega-3 fatty acids — reduces the risk of sudden death.
The American Heart Association recommends eating at least two servings of fish a week. The highest levels of omega-3 fatty acids are in:
  • Mackerel
  • Lake trout
  • Herring
  • Sardines
  • Albacore tuna
  • Salmon
  • Halibut
You should bake or grill the fish to avoid adding unhealthy fats. If you don't like fish, you can also get small amounts of omega-3 fatty acids from foods like ground flaxseed or canola oil.
You can take an omega-3 or fish oil supplement to get some of the benefits, but you won't get other nutrients in fish, such as selenium. If you decide to take a supplement, just remember to watch your diet and eat lean meat or vegetables in place of fish.

3. Walnuts, almonds and other nuts

Walnuts, almonds and other nuts can reduce blood cholesterol. Rich in polyunsaturated fatty acids, walnuts also help keep blood vessels healthy.
Eating about a handful (1.5 ounces, or 42.5 grams) a day of most nuts, such as almonds, hazelnuts, peanuts, pecans, some pine nuts, pistachio nuts and walnuts, may reduce your risk of heart disease. Just make sure the nuts you eat aren't salted or coated with sugar.
All nuts are high in calories, so a handful will do. To avoid eating too many nuts and gaining weight, replace foods high in saturated fat with nuts. For example, instead of using cheese, meat or croutons in your salad, add a handful of walnuts or almonds.

4. Olive oil

Olive oil contains a potent mix of antioxidants that can lower your "bad" (LDL) cholesterol but leave your "good" (HDL) cholesterol untouched.
Try using about 2 tablespoons (23 grams) of olive oil a day in place of other fats in your diet to get its heart-healthy benefits. To add olive oil to your diet, you can saute vegetables in it, add it to a marinade or mix it with vinegar as a salad dressing. You can also use olive oil as a substitute for butter when basting meat or as a dip for bread. Olive oil is high in calories, so don't eat more than the recommended amount.
The cholesterol-lowering effects of olive oil are even greater if you choose extra-virgin olive oil, meaning the oil is less processed and contains more heart-healthy antioxidants. But keep in mind that "light" olive oils are usually more processed than extra-virgin or virgin olive oils and are lighter in color, not fat or calories.

5. Foods with added plant sterols or stanols

Foods are now available that have been fortified with sterols or stanols — substances found in plants that help block the absorption of cholesterol.
Margarines, orange juice and yogurt drinks with added plant sterols can help reduce LDL cholesterol by more than 10 percent. The amount of daily plant sterols needed for results is at least 2 grams — which equals about two 8-ounce (237-milliliter) servings of plant sterol-fortified orange juice a day.
Plant sterols or stanols in fortified foods don't appear to affect levels of triglycerides or of high-density lipoprotein (HDL), the "good" cholesterol.

Other changes to your diet

For any of these foods to provide their benefit, you need to make other changes to your diet and lifestyle.
Cut back on the cholesterol and total fat — especially saturated and trans fats — that you eat. Saturated fats, like those in meat, full-fat dairy products and some oils, raise your total cholesterol. Trans fats, which are sometimes found in margarines and store-bought cookies, crackers and cakes, are particularly bad for your cholesterol levels. Trans fats raise low-density lipoprotein (LDL), the "bad," cholesterol, and lower high-density lipoprotein (HDL), the "good," cholesterol.
In addition to changing your diet, keep in mind that making additional heart-healthy lifestyle changes are key to lowering your cholesterol. Talk to your doctor about exercising, quitting smoking and maintaining a healthy weight to help keep your cholesterol level low.

Credit: Mayo Clinic Staff

Brain Foods

Want to keep your mind sharp and nourished? Here are 10 highly effective brain foods that improve memory, mood, concentration, and overall clarity.

1.    Blueberries—Blueberries serve a wide range of functions for improving mental function. Most notably, regular blueberry consumption has been shown to improve memory function. Furthermore, blueberries are rich in antioxidants, helping to prevent free radical damage. Still not convinced? Research has found that blueberries can also reverse age related declines in motor function, balance, and coordination.
2.    Salmon—Rich in Omega-3 fatty acids, salmon helps your brain develop tissue for increasing your brain power. Furthermore, salmon also plays a key role in fighting Alzheimer’s and other age-related cognitive disorders.
3.    Flax seeds—Flax seeds are crammed with ALA- a healthy fat that aids the cerebral cortex in functioning better. This is the portion of the brain responsible for processing sensory information. Keeping it sharp is vital.
4.    Coffee—Regular coffee drinking has been shown to reduce the risk of Alzheimer’s, Dementia, and other mental disorders. That’s because caffeine is good for the brain (in moderation), and it contains antioxidants. The important thing to note is you shouldn’t add in all the other junk to your coffee (the ridiculous Starbucks drinks crammed with sweeteners and fatty products).

5.    Mixed nuts—
Peanuts, walnuts, pecans, and other nuts contain properties that help with everything from fighting insomnia to promoting mental clarity and strong memory. Walnuts are rich in Omega-3 fatty acids while almonds contain natural mood-enhancing neurotransmitters.
6.    Avocados—Don’t let the avocado’s fat content fool you. It’s a healthy fat that promotes blood flow, keeping your mind functioning at its peak. That’s not all: Avocados have also been shown to reduce blood pressure.
7.    Eggs—Egg yolks are rich in choline, an essential nutrient to improving memory function.
8.    Whole grains—From oatmeal to whole grain bread, whole grains are excellent brain foods as they improve circulation and contain essential fibers, vitamins, and even some Omega-3. Just make your sandwiches from whole grain breads to enjoy the benefits.
9.    Chocolate—For me, this is the yummiest brain food of all. Dark chocolate is antioxidant-rich, and it also improves focus and concentration. Milk chocolate, on the other hand, improves memory and reaction time.
10.    Broccoli—Broccoli has been shown to improve memory function as well as slow the aging process. This means a broccoli-rich diet will keep you young and sharp.

Which brain foods do you enjoy?

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