Health Benefits of Kiwi Fruit 1


For centuries, the kiwi was used as a medicine rather than as a fruit. Known in Traditional Chinese Medicine as Xiao Yang Tao, kiwi fruit and kiwi root were boiled up into herbal teas for sweating, arthritis, and what we would now call obesity. Missionaries returning to New Zealand from China brought back the fruit, where it became known as Chinese gooseberries. Only in 1961 did the fruit arrive in the United States, where an enterprising grocery distributor decided she preferred the name “kiwi” fruit, honouring its preservation in New Zealand.

Packing more vitamin C than an orange, the hairy kiwi fruit, with the bright green flesh and the tiny black seeds, adds a creamy texture and exquisite taste to any tropical fruit salad. Harvested in California from November through to May, and in New Zealand from June through to October, kiwis are available fresh throughout stores the year round. Kiwi fruit also provides us with some exceptional nutritional benefits.

What Are the Key Nutritional Benefits of Kiwis?

A single kiwi provides 120% of an adult's daily requirement of vitamin C. It is also a good source of both potassium and fibre.

What Health Conditions Are Especially Responsive to Kiwi Consumption?

Phytonutrients unique to the kiwi, not limited to vitamin C or beta-carotene, are known to protect DNA from oxidative damage. And as an addition to any healthy diet, researchers have found that kiwi fruit also has these added health benefits:

The fruit relieves symptoms of asthma, allergies, and runny noses in six- and seven year-old children. A study of 18,000 children in northern Italy, in which elementary school children were given a serving of kiwi or citrus fruit every day, found that eating more fruit result in fewer asthma attacks, less coughing at night, and fewer bouts of wheezing. Even one or two servings a week made a difference, but in those children who ate five to seven helpings of citrus or kiwi every week, the incidents of wheezing fell by 44% percent, severe wheezing by 41%, shortness of breath by 32%, runny nose by 28%, night-time coughing by 27%, and chronic cough by 25%. Kiwi didn't cure asthma or allergies, but it definitely helped relieve the symptoms a great deal.

Kiwi fruit is thought to reduce symptoms of asthma and rheumatoid arthritis in adults, and may contribute to the prevention of cancer and diabetic heart disease, due to its vitamin C content.

It feeds healthy bacteria in the gut. The fibre in kiwi fruit can't be broken down by human digestive enzymes, but serves as a prebiotic food for the probiotic bacteria in the small intestine and colon. These bacteria, in turn, fight disease-causing bacteria and convert fibre into fatty acids that they share with their human hosts.

Kiwi fruit prevents age-related macular degeneration, the most common cause of blindness in people over the age of 60. A study of 110,000 men and women reported in the ‘Archives of Ophthalmology' that senior citizens who ate three servings of fruit per day were 36% less likely to develop “wet” macular degeneration (a form of the disease that causes rapid loss of sight) compared to those who consumed an average of 1-1/2 servings per day.

Kiwis may also be useful in supporting the recovery process from heart disease. Many people who have had heart attacks or ischemic stroke take anticoagulants, “blood thinners,” to prevent recurrence of the disease. Often, the side effects, or the cost of the medication, are so great that it has to be discontinued, though the need for cardiovascular protection continues.

One study found that volunteers who ate two or three kiwis a day for four weeks reduced their platelet aggregation responses (one measure of how strongly the blood tends to form blood clots) by 15%. This means that you probably shouldn't be eating large amounts of kiwi fruit if you are on a blood thinning medication that reduces platelet activating factor activity, such as aspirin. And in any case, ask your doctor whether the effects of kiwi would complement or counteract other drugs you are taking for heart health, making sure to mention it has aspirin-like anti-platelet activity. If drugs are not working for you, however, kiwis might help.

Are There Any People Who Need to Avoid Kiwi Fruit?

Kiwis are among the very few plant foods that contain appreciable quantities of oxalates; chemicals that can contribute to the formation of kidney stones and gallstones. If your doctor or your nutritionist has said that you need to avoid other fruits, vegetables, and various plant foods that contain large amounts of oxalates, such as spinach, beet greens, Swiss chard (silverbeet), collards, parsley, leeks, okra, quinoa, celery, green beans, rutabagas, summer squash, almonds, coffee, and tea, then you probably also need to avoid kiwi fruit.

Like many other tropical fruits, kiwis contain latex in their peels. If you are allergic to latex, or if you are allergic to avocados or bananas (which likewise contain latex in their peels), then you should probably avoid kiwi too.

Where Do Kiwis Fit in the Families of Fruit?

The most common kind of kiwi is the Hayward kiwi, also known as Actinidia deliciosa. The kiwi is a member of the Chinese Gooseberry Family, a group of about 300 plants that mostly bear hairy, berry-like fruit. Some varieties of kiwi produce cherry-size, yellowish-green fruit.

What Is the Best Way to Eat Kiwis Raw?

Enjoying your kiwi starts with picking the best fruit at the market, and to do that you need to know what to look out for. Avoid kiwis that have soft spots or bruises, and don't buy any that are shrivelled or that are very soft. You can tell when a kiwi is ripe enough to eat by applying light pressure on the surface. If the skin springs back into place, then it's ripe and ready. If the kiwi is hard, it may need up to a week to ripen. Place the kiwi(s) in a paper bag with an apple or banana inside. The other fruit will give off an ethylene gas that hastens the ripening of the kiwi fruit. The antioxidant content of the fruit actually increases as it ripens, especially if the fruit is exposed to light. Fully ripened kiwi fruit can be stored in the refrigerator, but unripe kiwis should be allowed to ripen at room temperature before refrigerating.

Most people prefer to peel kiwi fruit before eating it, but if you just rub the fuzz off, the peel is actually edible too. Some people prefer to cut the kiwi in half and scoop out the tender green flesh with a spoon. It's important not to slice the kiwi until just before eating it, because the actinic and bromic acids in the fruit act as tenderizers and can make the flesh of the fruit (or the flesh of other fruits in a salad) soft and then mushy. Kiwis don't usually soften strawberries, however.

Even though kiwis lose their texture once they have been sliced, they do not lose much of their antioxidant power. One study found that kiwis lose just 10% of their vitamin C content and none of their beta-carotene or alpha-carotene content when stored in the refrigerator for 6 days. You can make a big bowl of fruit salad a couple of days ahead of time without any significant loss of the nutritional content of kiwi fruit, although pineapple, mango, and strawberries lose about 25% of their antioxidant content once they are cut.

What Is the Best Way to Use Kiwis in Salads?

Kiwis are typically combined with pineapple, strawberries, or mango. They can be added to green salads, or they can be combined with strawberries to sweeten yogurt. Kiwi is an interesting addition to chutney served with meat or fish (just add kiwi to pineapple and mango and hot peppers, if you like them, or just use the fruit).

What Is the Best Way to Cook Kiwis?

Kiwis make colourful and flavourful fruit tarts.

What Are Some Ways to Make Kiwi Juice More Interesting?

Kiwi juice is great all by itself. Since kiwi already tastes like berries, melons, and bananas, don't combine it with those fruits. If you do want a fruit cocktail, then try adding celery, apple, and cucumber instead.

How Do I Get Kids to Like Kiwis?

Children usually like kiwis. Cutting out shapes from kiwi slices with a cookie cutter makes them even more appealing to the young ones.

How Long Do Kiwis Keep?

Don't keep whole kiwis in the refrigerator for more than a week, and use sliced kiwis as quickly as possible, preferably immediately, but certainly within 48 hours.

Tips for Frugal Use of Kiwis

The only way kiwis go to waste is if they are forgotten, so be sure to eat them as soon as they are ripe!

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.

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.

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(8): 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.

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(8): 907-10. 1998. PMID: 13370.


About Andy Williams

Andy Williams has a Ph.D. in biology and a strong interest in health and nutrition. The Paleo Gut web site was created to explore the health benefits of the Paleo diet and see how it is changing lives. Also, get our free daily Paleo Gut newspaper delivered to your inbox. Please feel free to contact me and let me know about your Paleo experiences or favorite recipes.


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