Kiwifruit Kiwifruit

Kiwifruit Kiwifruit

Packed with more vitamin C than an equivalent amount of orange, the bright green flesh of the kiwifruit speckled with tiny black seeds adds a dramatic tropical flair to any fruit salad. California kiwifruit is available November through May, while the New Zealand crop hits the market June through October making fresh kiwis available year round.

The kiwifruit is a small fruit approximately 3 inches long and weighing about four ounces. Its green flesh is almost creamy in consistency with an invigorating taste reminiscent of strawberries, melons and bananas, yet with its own unique sweet flavor.

Food Chart
This chart graphically details the %DV that a serving of Kiwifruit 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 Kiwifruit can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Kiwifruit, 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
Individual Concerns
Nutritional Profile
References

Health Benefits

Kiwifruit can offer a great deal more than an exotic tropical flair in your fruit salad. These emerald delights contain numerous phytonutrients as well as well known vitamins and minerals that promote your health.

Kiwi's Phytonutrients Protect DNA

In the world of phytonutrient research, kiwifruit has fascinated researchers for its ability to protect DNA in the nucleus of human cells from oxygen-related damage. Researchers are not yet certain which compounds in kiwi give it this protective antioxidant capacity, but they are sure that this healing property is not limited to those nutrients most commonly associated with kiwifruit, including its vitamin C or beta-carotene content. Since kiwi contains a variety of flavonoids and carotenoids that have demonstrated antioxidant activity, these phytonutrients in kiwi may be responsible for this DNA protection.

The protective properties of kiwi have been demonstrated in a study with 6- and 7-year-old children in northern and central Italy. The more kiwi or citrus fruit these children consumed, the less likely they were to have respiratory-related health problems including wheezing, shortness of breath, or night coughing. These same antioxidant protective properties may have been involved in providing protection for these children.

Premier Antioxidant Protection

Kiwifruit emerged from our food ranking system as an excellent source of vitamin C. This nutrient is the primary water-soluble antioxidant in the body, neutralizing free radicals that can cause damage to cells and lead to problems such as inflammation and cancer. In fact, adequate intake of vitamin C has been shown to be helpful in reducing the severity of conditions like osteoarthritis, rheumatoid arthritis, and asthma, and for preventing conditions such as colon cancer, atherosclerosis, and diabetic heart disease. And since vitamin C is necessary for the healthy function of the immune system, it may be useful for preventing recurrent ear infections in people who suffer from them. Owing to the multitude of vitamin C's health benefits, it is not surprising that research has shown that consumption of vegetables and fruits high in this nutrient is associated with a reduced risk of death from all causes including heart disease, stroke and cancer.

Kiwifruit is also a good source of the important fat-soluble antioxidant, vitamin E. This combination of both fat- and water-soluble antioxidants makes kiwi able to provide free radical protection on all fronts.

Fiber for Blood Sugar Control Plus Cardiovascular and Colon Health

Our food ranking system also qualified kiwifruit as a very good source of dietary fiber. The fiber in kiwifruit has also been shown to be useful for a number of conditions. Researchers have found that diets that contain plenty of fiber can reduce high cholesterol levels, which may reduce the risk of heart disease and heart attack. Fiber is also good for binding and removing toxins from the colon, which is helpful for preventing colon cancer. In addition, fiber-rich foods, like kiwifruit, are good for keeping the blood sugar levels of diabetic patients under control.

Kiwifruit also passed our food ranking test as a good source of the minerals potassium, magnesium, copper and phosphorus.

Protection against Asthma

Eating vitamin C-rich fruit such as kiwi may confer a significant protective effect against respiratory symptoms associated with asthma such as wheezing.

A study published in Thorax that followed over 18,000 children aged 6-7 years living in Central and Northern Italy found that those eating the most citrus and kiwifruit (5-7 servings per week) had 44% less incidence of wheezing compared to children eating the least (less than once a week). Shortness of breath was reduced by 32%, severe wheeze by 41%, night time cough by 27%, chronic cough by 25%, and runny nose by 28%.

Children who had asthma when the study began appeared to benefit the most, and protective effects were evident even among children who ate fruit only once or twice a week.

Protection against Macular Degeneration

Your mother may have told you carrots would keep your eyes bright as a child, but as an adult, it looks like fruit is even more important for keeping your sight. Data reported in a study published in the Archives of Opthamology indicates that eating 3 or more servings of fruit per day may lower your risk of age-related macular degeneration (ARMD), the primary cause of vision loss in older adults, by 36%, compared to persons who consume less than 1.5 servings of fruit daily.

In this study, which involved over 110,000 women and men, researchers evaluated the effect of study participants' consumption of fruits; vegetables; the antioxidant vitamins A, C, and E; and carotenoids on the development of early ARMD or neovascular ARMD, a more severe form of the illness associated with vision loss. Food intake information was collected periodically for up to 18 years for women and 12 years for men. While, surprisingly, intakes of vegetables, antioxidant vitamins and carotenoids were not strongly related to incidence of either form of ARM, fruit intake was definitely protective against the severe form of this vision-destroying disease. Three servings of fruit may sound like a lot to eat each day, but kiwifruit can help you reach this goal. Slice kiwi over your morning cereal, lunch time yogurt or green salads. For a more elegant meal, decorate any fish dish or fruit salad with kiwi slices.

A Delicious Way to Enjoy Cardiovascular Health

Enjoying just a couple of kiwifruit each day may significantly lower your risk for blood clots and reduce the amount of fats (triglycerides) in your blood, therefore helping to protect cardiovascular health.

Unlike aspirin, which also helps to reduce blood clotting but has side effects such as inflammation and bleeding in the intestinal tract, the effects of regular kiwi consumption are all beneficial. Kiwifruit is an excellent source of vitamin C, and polyphenols, and a good source of vitamin E, magnesium, potassium, and copper, all of which may function individually or in concert to protect the blood vessels and heart. In one study, human volunteers who ate 2 to 3 kiwifruit per day for 28 days reduced their platelet aggregation response (potential for blood clot formation) by 18% compared to controls eating no kiwi. In addition, kiwi eaters' triglycerides (blood fats) dropped by 15% compared to controls.

Description

The kiwifruit is a little fruit holding great surprises. The most common species of kiwifruit is Actinidia deliciosa, commonly known as Hayward kiwi. Inside of this small, oval-shaped fruit featuring brown fuzzy skin resides a brilliant, semi-translucent emerald green flesh speckled with a few concentrically arranged white veins and small black seeds. Its flesh is almost creamy in consistency with an invigorating taste reminiscent of a mixture of strawberries and bananas, yet with its own unique sweet flavor.

With the growing interest in kiwifruit, other species are now becoming more widely available. These include the hardy kiwi and the silvervine kiwi, two smooth-skinned varieties that are the size of cherries and whose flesh has a golden yellow-green hue.

History

The kiwifruit is a fruit with a very interesting history and whose recent rise in popularity reflects a combination of an appreciation for its taste, nutritional value, unique appearance and, surprisingly, its changing name.

Native to China, kiwifruits were originally known as Yang Tao. They were brought to New Zealand from China by missionaries in the early 20th century with the first commercial plantings occurring several decades later. In 1960, they were renamed Chinese Gooseberries.

In 1961, Chinese Gooseberries made their first appearance at a restaurant in the United States and were subsequently "discovered" by an American produce distributor who felt that the U.S. market would be very receptive to this uniquely exotic fruit. She initiated the import of these fruits into the United States in 1962, but to meet what was felt to be burgeoning demand, changed its name from Chinese Gooseberry to kiwifruit, in honor of the native bird of New Zealand, the kiwi, whose brown fuzzy coat resembled the skin of this unique fruit. Currently, Italy, New Zealand, Chile, France, Japan and the United States are among the leading commercial producers of kiwifruit.

How to Select and Store

When selecting kiwifruits, hold them between your thumb and forefinger and gently apply pressure; those that have the sweetest taste will yield gently to pressure. Avoid those that are very soft, shriveled or have bruised or damp spots. As size is not related to the fruit's quality, choose a kiwifruit based upon your personal preference or recipe need. Kiwifruits are usually available throughout most of the year.

If kiwifruits do not yield when you gently apply pressure with your thumb and forefinger, they are not yet ready to be consumed since they will not have reached the peak of their sweetness. Kiwifruits can be left to ripen for a few days to a week at room temperature, away from exposure to sunlight or heat. Placing the fruits in a paper bag with an apple, banana or pear will help to speed their ripening process. Ripe kiwifruits can be stored either at room temperature or in the refrigerator.

For the most antioxidants, consume fully ripened kiwifruit:

Research conducted at the University of Innsbruck in Austria suggests that as fruits fully ripen, almost to the point of spoilage, their antioxidant levels actually increase.

Key to the process is the change in color that occurs as fruits ripen, a similar process to that seen in the fall when leaves turn from green to red to yellow to brown—a color change caused by the breakdown and disappearance of chlorophyll, which gives leaves and fruits their green color.

Until now, no one really knew what happened to chlorophyll during this process, but lead researcher, Bernard Kräutler, and his team, working together with botanists over the past several years, has identified the first decomposition products in leaves: colorless, polar NCCs (nonfluorescing chlorophyll catabolytes), that contain four pyrrole rings - like chlorophyll and heme.

After examining apples and pears, the scientists discovered that NCCs replace the chlorophyll not only in the leaves of fruit trees, but in their very ripe fruits, especially in the peel and flesh immediately below it.

"When chlorophyll is released from its protein complexes in the decomposition process, it has a phototoxic effect: when irradiated with light, it absorbs energy and can transfer it to other substances. For example, it can transform oxygen into a highly reactive, destructive form," report the researchers. However, NCCs have just the opposite effect. Extremely powerful antioxidants, they play an important protective role for the plant, and when consumed as part of the human diet, NCCs deliver the same potent antioxidant protection within our bodies. . Angew Chem Int Ed Engl. 2007 Nov 19;46(45):8699-8702.

How to Enjoy

For some of our favorite recipes, click Recipes.

Tips for Preparing Kiwifruit:

Kiwifruits are so delicious that they can be eaten as is. They can be peeled with a paring knife and then sliced or you can cut them in half and scoop the flesh out with a spoon. You can also enjoy the skins which are very thin like a Bosc pear and are full of nutrients and fiber; the peachlike fuzz can be rubbed off before eating.

Kiwifruits should not be eaten too long after cutting since they contain enzymes (actinic and bromic acids) that act as a food tenderizer, with the ability to further tenderize the kiwifruit itself and make it overly soft. Consequently, if you are adding kiwifruit to fruit salad, you should do so at the last minute so as to prevent the other fruits from becoming too soggy.

While sliced kiwi fruit may soften other fruits when combined in fruit salad, a study published in the June 2006 issue of the Journal of Agricultural and Food Chemistry has found that minimal processing of kiwi and other fruits—cutting, packaging and chilling—does not significantly affect their nutritional content even after 6, and up to 9, days.

Researchers cut up kiwi fruit, pineapples, mangoes, cantaloupes, watermelons, and strawberries. The freshly cut fruits were then rinsed in water, dried, packaged in clamshells (not gastight) and stored at 41 degrees Fahrenheit.

After 6 days, losses in vitamin C were less than 5% in mango, strawberry, and watermelon pieces, 10% in pineapple pieces, 12% in kiwifruit slices, and 25% in cantaloupe cubes.

No losses in carotenoids were found in kiwifruit slices and watermelon cubes. Pineapples lost 25%, followed by 10-15% in cantaloupe, mango, and strawberry pieces.

No significant losses in phenolic phytonutrients were found in any of the fresh-cut fruit products.

"Contrary to expectations, it was clear that minimal processing had almost no effect on the main antioxidant constituents. The changes in nutrient antioxidants observed during nine days at five degrees Celsius would not significantly affect the nutrient quality of fresh cut fruit. In general, fresh-cut fruits visually spoil before any significant nutrient loss occurs," wrote lead researcher Maria Gil.

In practical terms, this means that you can prepare a large bowl of fruit salad on the weekend, store it in the refrigerator, and enjoy it all week, receiving almost all the nutritional benefits of just prepared fruit salad. To ensure kiwi fruit does not "tenderize" the other fruits in your salad, store sliced kiwi in a separate air-tight container and add to the rest of the fruit salad just before serving.

A Few Quick Serving Ideas:

Kiwifruit are so delicious, they can be eaten as is. One of our favorite ways to do so is to peel with a paring knife and slice.

Add kiwifruit to tossed green salads.

Serve sliced kiwifruit and strawberries, fruits whose flavors are naturally complementary, topped with yogurt.

Mix sliced kiwifruit, orange and pineapple together to make chutney that can be served as an accompaniment to chicken or fish.

Blend kiwifruit and cantaloupe in a food processor to make a chilled soup. For a creamier consistency, blend yogurt in with the fruit mixture.

Kiwifruit have a wonderful flavor and appearance for use in fruit tarts.

Individual Concerns

Kiwifruit and Oxalates

Kiwifruit are among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating kiwifruit. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we've seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits—including absorption of calcium—from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content.For more on this subject, please see "Can you tell me what oxalates are and in which foods they can be found?"

Kiwifruit and Latex Allergy

Like avocados and bananas, kiwifruit contain substances called compounds 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 deactivates the enzymes.

Nutritional Profile

Kiwifruit is an excellent source of vitamin C and a very good source of dietary fiber. It is also a good source of the minerals potassium, magnesium, and copper. In addition, kiwifruit is a good source of the antioxidant vitamin E.

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

In-Depth Nutritional Profile
In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Kiwifruit 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.

Kiwifruit
1.00 each
76.00 grams
46.36 calories
Nutrient Amount DV
(%) Nutrient
Density World's Healthiest
Foods Rating
vitamin C 57.00 mg 95.0 36.9 excellent
dietary fiber 2.58 g 10.3 4.0 very good
potassium 252.32 mg 7.2 2.8 good
copper 0.12 mg 6.0 2.3 good
magnesium 22.80 mg 5.7 2.2 good
vitamin E 0.85 mg 4.2 1.7 good
manganese 0.08 mg 4.0 1.6 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%

In-Depth Nutritional Profile for Kiwifruit

References

Cho E, Seddon JM, Rosner B, Willett WC, Hankinson SE. Prospective study of intake of fruits, vegetables, vitamins, and carotenoids and risk of age-related maculopathy. Arch Ophthalmol. 2004 Jun;122(6):883-92. 2004. PMID:15197064.
Collins BH, Horska A, Hotten PM, et al. Kiwifruit protects against oxidative DNA damage in human cells and in vitro. Nutr Cancer 2001;39(1):148-53 2001. PMID:13330.
Duttaroy A, Jørgensen A. Effects of kiwi fruit consumption on platelet aggregation and plasma lipids in healthy human volunteers. Platelets 2004 Aug;15(5):287-292. 2004. PMID:15370099.
Ensminger AH, Ensminger, ME, Kondale JE, Robson JRK. Foods & Nutriton Encyclopedia. Pegus Press, Clovis, California 1983.
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Forastiere F, Pistelli R, Sestini P, et al. Consumption of fresh fruit rich in vitamin C and wheezing symptoms in children. SIDRIA Collaborative Group, Italy (Italian Studies on Respiratory Disorders in Children and the Environment). Thorax 2000 Apr;55(4):283-8 2000. PMID:13360.
Fortin, Francois, Editorial Director. The Visual Foods Encyclopedia. Macmillan, New York 1996.
Gil MI, Aguayo E, Kader AA. Quality changes and nutrient retention in fresh-cut versus whole fruits during storage. J Agric Food Chem. 2006 Jun 14;54(12):4284-96. 2006. PMID:16756358.
Ikken Y, Morales P, Martinez A, et al. Antimutagenic effect of fruit and vegetable ethanolic extracts against N-nitrosamines evaluated by the Ames test. J Agric Food Chem 1999 Aug;47(:3257-64 1999. PMID:13350.
Khaw KT, Bingham S, Welch A, et al. Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study. European Prospective Investigation into Cancer and Nutrition. Lancet. 2001 Mar 3;357(9257):657-63 2001.
Kurl S, Tuomainen TP, Laukkanen JA et al. Plasma vitamin C modifies the association between hypertension and risk of stroke. Stroke 2002 Jun;33(6):1568-73 2002.
Maillar C. [The kiwi, rich in vitamins C and E and also in potassium]. Servir 1998 May-1998 Jun 30;46(3):160 1998. PMID:13380.
Sommerburg O, Keunen JE, Bird AC, van Kuijk FJ. Fruits and vegetables that are sources for lutein and zeaxanthin: the macular pigment in human eyes. Br J Ophthalmol 1998 Aug;82(:907-10 1998. PMID:13370.
Wood, Rebecca. The Whole Foods Encyclopedia. New York, NY: Prentice-Hall Press; 1988 1988. PMID:15220.