Kiwi Fruit
Actinidia chinensis Planchon. Family: Actinidiaceae
Kiwi fruit , Chinese gooseberry , China gooseberry
 
Clinical Overview
Uses
Kiwi fruit is used as food, meat tenderizer and basis of a sports drink.

Dosing
One kiwi fruit contains about 100 mg vitamin C (approximately the recommended US daily intake) and significant quantities of the carotenoids lutein and xanthine.

Contraindications
Contraindications have not yet been identified.

Pregnancy/Lactation
Generally recognized as safe or used as food. Safety and efficacy for dosages above those in foods unproven and should be avoided.

Interactions
None well documented.

Adverse Reactions
Allergic reactions may occur in sensitive individuals. Cross-sensitivity with various pollens, latex, bananas, and avocado is possible.

Toxicology
Hives and diarrhea have been reported following consumption of large quantities of the fruit.

 
Botany
The kiwi fruit is native to China and Taiwan, but today, cultivation is widespread throughout the world. Major producers of kiwi fruit include New Zealand, California, and Italy, but a significant harvest is obtained from several other countries including France, Israel, and Spain. The Hayward variety is the most commonly grown commercial cultivar because of its superior hardiness and long shelf life, but several other varieties, including one bearing a yellow-fleshed fruit, are now in production. The plant is a vigorous, deciduous climber that grows to about 9 meters in height, tolerating full sun or semi-shade. The scented flowers are insect pollinated and appear in summer. Individual flowers are dioecious (either male or female, but only one sex is found on any one plant, so both male and female plants are required for fruit production). The egg-shaped fruit has a furry, brown skin and firm, translucent, emerald green flesh with numerous small, edible, black seeds at the center. When ripe, it is very juicy with a refreshing acid flavor, often described as a mixture of strawberry and pineapple. 1
 
History
The fruit was originally known as the Chinese gooseberry, but after aggressive marketing by New Zealand fruit growers, became known as the kiwi fruit (partly because of the resemblance of the fruit to the appearance of the kiwi, a small, brown, flightless bird). It has been used in China as the basis for a flavorful wine and has a long tradition of use as a fruit beverage. Kiwi fruit juice has been used in some cultures as a traditional meat tenderizer. Other reported traditional uses include treatment of urinary calculi, and as a diuretic, febrifuge, and sedative. 1
 
Chemistry
The main protein component of kiwi fruit is actinidin, an enzyme belonging to the class of thiol-proteases. It accounts for about 50% of the soluble protein content of the fruit and has been identified as its major allergen. 2 , 3 The gene for actinidin has been sequenced. 4 , 5 , 6 The proteolytic activity of actinidin is similar, but not identical, to that of papain. A glycoprotein inhibitor specific for pectin methylesterase has been isolated from the fruit 7 ; it is ineffective against other polysaccharide-degrading enzymes such as polygalacturonase and amylase.
The aroma profile and the aroma-active components of kiwi fruit have been extensively investigated. 8 Over 80 compounds have been identified in the volatile fraction of kiwi fruit; about 35 components appear to contribute to the aroma of kiwi fruit puree. The composition of the volatile fraction changes rapidly as the fruit matures from fresh, mature, to overripe, with a decrease in C6 compounds such as hexanal, hexenol, and ethyl butyrate, and an increase in terpene esters. The major compounds isolated from fresh puree include 3-methyl-2-butanone, 3-hydroxy-2-butanone, ( E )-2-hexenal, ethyl 3-hydroxybutyrate, phenylethyl alcohol, α-terpineol, and geraniol. It has been noted that the volatile components are commonly found in other fruits; there appear to be no flavor compounds specific to kiwi fruit.
Several antimicrobial compounds have been isolated from kiwi fruit. Seven phytoalexins were isolated from a methanol extract of the unripe fruit previously wounded and inoculated with fungus. 9 The isolated antimicrobial agents included a previously undescribed triterpene phytoalexin named actinidic acid, arjunolic acid, asiatic acid, and 23-hydroxytormentic acid. A single chain, antifungal, thaumatin-like protein also has been identified in kiwi fruit. 10 This is thought to be the only defense protein present in kiwi fruit at a level high enough to be isolated.
Kiwi fruit also has high concentrations of ascorbic acid and carotenoids (see Pharmacology).
 
Uses and Pharmacology
Kiwi fruit has no inherent pharmacologic activity. However, epidemiologic evidence linking high intake of fruit and vegetables to improved health status has stimulated research into the biological activity of the fruit.
Antioxidant activity   Kiwi fruit contained the highest proportion of ascorbic acid in an in vitro investigation into the antioxidant power of a group of commonly eaten fruits and vegetables. 11 The contribution of ascorbic acid to total antioxidant power was 73% for kiwi fruit compared with 54%, 46%, and 40% for grapefruit, lemon, and orange, respectively. One kiwi fruit contains about 100 mg vitamin C, or approximately the recommended US daily intake. The bioavailability of ascorbic acid from different food sources has not been fully elucidated.
A high daily intake of carotenoids has been associated with a significantly reduced risk for age-related macular degeneration. Traditionally, dark green, leafy vegetables have been recommended as the best source. A study comparing the carotenoid contents of a range of foodstuffs showed a higher proportion of lutein plus zeaxanthin (the major carotenoids in the human eye) in kiwi fruit than in spinach (54 and 47 mole%, respectively). 12 Kiwi fruit only ranked lower than egg yolk and corn (89 and 86 mole%, respectively) in the products tested.
Animal/Clinical data   Research reveals no data regarding the use of kiwi fruit as an antioxidant.
Performance enhancement
Animal data   Research reveals no animal data regarding the use of kiwi fruit for performance enhancement.
Clinical data   The effects of a kiwi fruit-based drink supplement given to athletes training in hot environments has been investigated. 13 In athletes riding a Monark ergometer, the mean work time to exhaustion was longer (149 min) compared with placebo (120 min) and the work load was larger (947KJ vs 833KJ, P < 0.001). The kiwi-based drink supplement resulted in an expansion of blood volume; hematocrit increased significantly after exercise in athletes taking placebo but did not change significantly in those consuming the supplement. Furthermore, based on the urinary excretion of vitamin C, it appeared that the vitamin C status of supplemented athletes improved compared with placebo. The drink was found to be “fragrant, tasty, refreshing and thirst quenching,” and did not appear to have any side effects.
Other uses   A thaumatin-like antifungal protein isolated from kiwi fruit showed modest activity against Botrytis cinerea and a weaker inhibitory activity against Mycosphaerella arachidicola , Coprinus comatus , and Physalospora piricola . 10
 
Administration & Dosage
One kiwi fruit contains about 100 mg vitamin C (approximately the recommended US daily intake) and significant quantities of the carotenoids lutein and xanthine.
 
Pregnancy/Lactation
Generally recognized as safe or used as food. Safety and efficacy for dosages above those in foods unproven and should be avoided.
 
Interactions
None well documented.
 
Adverse Reactions
The serotonin concentration of the fruit is approximately twice that of tomatoes and one third that of bananas. 14 Therefore, ingestion of kiwi fruit can increase urinary excretion of 5-hydroxyindoleacetic acid and may interfere with laboratory analyses for this serotonin by-product. Allergy to kiwi fruit is well documented in the literature, and several cases of anaphylaxis have been reported. 15 , 16 Trace amounts of kiwi fruit have been responsible for some of these reactions, including a reaction to kiwi fruit left on a knife subsequently used to prepare strawberries 16 and a reaction from the kiss of a partner immediately after he had eaten a fresh kiwi fruit. 17 Successful sublingual swallow allergen immunotherapy (SLIT) has been reported in a severely allergic patient. 16
Kiwi fruit has frequently been associated with oral allergy syndrome. This is characterized by an immediate hypersensitivity reaction beginning within a few minutes of the fruit coming into contact with the orolabial mucosa. Allergy in the form of contact dermatitis also has been documented, 18 , 19 usually associated with handling the fruit. However, a case report has been published of a kiwi fruit orchardist who had no reaction to the fruit but developed hand and face dermatitis from contact with the vine. 18 Although acute pancreatitis in the course of an allergic reaction to a food substance is rare, a case report describes a patient with repeated attacks of acute pancreatitis secondary to kiwi fruit ingestion. 20 Cross-reactivity of kiwi fruit with several other allergens has been reported. Most notable are the pollens including timothy, 3 birch, 3 , 21 and meadow fescue, 22 but cross-sensitivity with agents such as latex, avocado, and banana also have been reported. 23 IgE-immunoblot inhibition tests have demonstrated allergens with molecular weights ranging from 64 to 12 kd 3 ; the major allergen appears to be the proteolytic enzyme, actinidin, with a molecular weight of 30 kd (see Chemistry).
 
Toxicology
Consumption of relatively large quantities of the fruit has resulted in hives and diarrhea in some subjects.
 
References
 

1. Kiwi Fruit. Available online at: http://www.e2121.com/food_db/viewherb.php3 . Accessed May 2, 2004.

 

2. Pastorello EA, Conti A, Pravettoni V, et al. Identification of actinidin as the major allergen of kiwi fruit. J Allergy Clin Immunol . 1998;101:531-537.  PubMed

 

3. Pastorello EA, Pravettoni V, Ispano M, et al. Identification of the allergenic components of kiwi fruit and evaluation of their cross-reactivity with timothy and birch pollens. J Allergy Clin Immunol . 1996;98:601-610.  PubMed

 

4. Varughese KI, Su Y, Cromwell D, Hasnain S, Xuong NH. Crystal structure of an actinidin-E-64 complex. Biochem . 1992;31:5172-5176.  PubMed

 

5. Naylor S, Ang SG, Williams DH, Moore CH, Walsh K. Rapid determination of sequence variations in actinidin isolated from Actinidia chinesis (var. Hayward) using fast atom bombardment mapping mass spectrometry and gas phase microsequencing. Biomed Environ Mass Spectrom . 1989;18:424-428.  PubMed

 

6. Podivinsky E, Forster R, Gardner RC. Nucleotide sequence of actinidin, a kiwi fruit protease. Nucleic Acids Res . 1989;17:8363.  PubMed

 

7. Balestrieri C, Castaldo D, Giovane A, Quagliuolo L, Servillo L. A glycoprotein inhibitor of pectin methylesterase in kiwi fruit ( Actinidia chinesis ). Eur J Biochem . 1990;193:183-187.  PubMed

 

8. Jordán MJ, Margaría CA, Shaw PE, Goodner KL. Aroma active components in aqueous kiwi fruit essence and kiwi fruit puree by GC-MS and multidimensional GC/CG-O. J Agric Food Chem . 2002;50:5386-5390.  PubMed

 

9. Lahlou EH, Hirai N, Kamo T, Tsuda M, Ohigashi H. Actinidic acid, a new triterpene phytoalexin from unripe kiwi fruit. Biosci Biotechnol Biochem . 2001;65:480-483.  PubMed

 

10. Wang H, Ng TB. Isolation of an antifungal thaumatin-like protein from kiwi fruits. Phytochemistry . 2002;61:1-6.  PubMed

 

11. Szeto YT, Tomlinson B, Benzie IF. Total antioxidant and ascorbic acid content of fresh fruits and vegetables: implications for dietary planning and food preservation. Br J Nutr . 2002;87:55-59.  PubMed

 

12. 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;82:907-910.  PubMed

 

13. Chen JD, Yang ZY, Ma SH, Zhen YC. The effects of Actinidia sinensis planch (kiwi) drink supplementation on athletes training in hot environments. J Sports Med Phys Fitness . 1990;30:181-184.  PubMed

 

14. Feldman JM, Lee EM. Serotonin content of foods: effect on urinary excretion of 5-hydroxyindoleacetic acid. Am J Clin Nutr . 1985;42:639-643.  PubMed

 

15. Shimizu T, Morikawa A. Anaphylaxis to kiwi fruit in a 12-year-old boy. J Asthma . 1995;32:159-160.  PubMed

 

16. Mempel M, Rakoski J, Ring J, Ollert M. Severe anaphylaxis to kiwi fruit: immunologic changes related to successful sublingual allergen immunotherapy. J Allergy Clin Immunol . 2003;111:1406-1409.  PubMed

 

17. Mancuso G, Berdondini RM. Oral allergy syndrome from kiwi fruit after a lover's kiss. Contact Dermatitis . 2001;45:41.  PubMed

 

18. Rademaker M. Allergic contact dermatitis from kiwi fruit vine ( Actinidia chinensis ). Contact Dermatitis . 1996;34:221-222.  PubMed

 

19. Veraldi S, Schianchi-Veraldi R. Contact urticaria from kiwi fruit. Contact Dermatitis . 1990;22:244.  PubMed

 

20. Gastaminza G, Bernaola G, Camino ME. Acute pancreatitis caused by allergy to kiwi fruit. Allergy . 1998;53:1104-1109.  PubMed

 

21. Voitenko V, Poulsen LK, Nielsen L, Norgaard A, Bindslev-Jensen C, Skov PS. Allergenic properties of kiwi-fruit extract: cross-reactivity between kiwi-fruit and birch-pollen allergens. Allergy . 1997;52:136-143.  PubMed

 

22. Gavrovic-Jankulovic M, Cirkovic T, Burazer L, Vuckovic O, Jankov RM. IgE cross-reactivity between meadow fescue pollen and kiwi fruit in patients' sera with sensitivity to both extracts. J Investig Allergol Clin Immunol . 2002;12:279-286.  PubMed

 

23. Möller M, Kayma M, Vieluf D, Paschke A, Steinhart H. Determination and characterization of cross-reacting allergens in latex, avocado, banana, and kiwi fruit. Allergy . 1998;53:289-296.  PubMed