Actinidia / Kiwi
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
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
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).
Kiwi Fruit 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.
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.
Research reveals no data regarding the use of kiwi fruit as an antioxidant.
Research reveals no animal data regarding the use of kiwi fruit for performance enhancement.
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.
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
One kiwi fruit contains about 100 mg vitamin C (approximately the recommended US daily intake) and significant quantities of the carotenoids lutein and xanthine.
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).
Consumption of relatively large quantities of the fruit has resulted in hives and diarrhea in some subjects.
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.
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.
4. Varughese KI, Su Y, Cromwell D, Hasnain S, Xuong NH. Crystal structure of an actinidin-E-64 complex. Biochem . 1992;31:5172-5176.
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.
6. Podivinsky E, Forster R, Gardner RC. Nucleotide sequence of actinidin, a kiwi fruit protease. Nucleic Acids Res . 1989;17:8363.
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.
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.
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.
10. Wang H, Ng TB. Isolation of an antifungal thaumatin-like protein from kiwi fruits. Phytochemistry . 2002;61:1-6.
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.
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.
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.
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.
15. Shimizu T, Morikawa A. Anaphylaxis to kiwi fruit in a 12-year-old boy. J Asthma . 1995;32:159-160.
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.
17. Mancuso G, Berdondini RM. Oral allergy syndrome from kiwi fruit after a lover's kiss. Contact Dermatitis . 2001;45:41.
18. Rademaker M. Allergic contact dermatitis from kiwi fruit vine ( Actinidia chinensis ). Contact Dermatitis . 1996;34:221-222.
19. Veraldi S, Schianchi-Veraldi R. Contact urticaria from kiwi fruit. Contact Dermatitis . 1990;22:244.
20. Gastaminza G, Bernaola G, Camino ME. Acute pancreatitis caused by allergy to kiwi fruit. Allergy . 1998;53:1104-1109.
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.
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.
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.
Food as Medicine: Kiwifruit (Actinidia deliciosa, Actinidiaceae)
By Hannah Baumana and Rachel Powersb
Kiwifruit (Actinidia deliciosa, Actinidiaceae), also known by the less common name “Chinese gooseberry,” is one of 50 known species within the genus Actinidia.1 These species are climbing, woody vines with large, heart-shaped leaves and cream-colored flowers that bloom in the spring. The flowers are dioecious, withmale and female blossoms found in separate individuals. The kiwifruit matures in early winter and typically has brown fuzzy skin. Depending on the species, the flesh is either green or yellow, but all species are filled with small black, edible seeds.1 While A. deliciosa accounts for about 90% of kiwifruit in international trade, two other species are cultivated and sold commercially: A. chinensisand A. arguta.2 Actinidia deliciosa is the common green kiwifruit.3 The most common cultivar of A. chinensis is “Hort16A,” known by the brand name ZESPRI, or “gold kiwifruit.”4Actinidia arguta is referred to as “baby kiwi” or “grape kiwi” due to the small size of its fruits.2Actinidia species are native to southwestern China, but they are now cultivated in New Zealand, the United States, Italy, France, Chile, and Japan.5
Phytochemicals and Constituents
Kiwifruit provides fiber, potassium, folate, phosphorus, copper, and vitamins A, C, E, and K.3,6 In fact, one kiwifruit provides more than the Recommended Dietary Allowance (RDA) of vitamin C for adults and almost 35% of the RDA of vitamin K. Vitamin C has numerous health benefits, including anticarcinogenic and immune-regulating properties.3,7 In addition, it plays a role in the formation of collagen, a major component of connective tissue, skin, and bones. Vitamin C intake also has been shown to help mitigate a number of conditions, including cardiovascular disease and inflammation.8 Vitamin E is an antioxidant that stops the oxidation of low-density lipoprotein (LDL) cholesterol and protects cell membranes against damage caused by reactive oxygen species.9 Vitamin E also helps maintain the structure and function of skeletal, cardiac, and smooth muscles. Vitamin K regulates blood clotting, aids in the transfer of calcium through the body, and supports bone health, reducing the risk of osteoporosis and bone fractures due to age.10
Kiwifruit is also a good source of fiber, which contributes to its laxative effect. Additionally, the lignins in cellulose (a form of dietary fiber) are believed to have antimutagenic properties due to their ability to increase the adsorption of aromatic amines in the gut, thus preventing them from entering the blood stream. Aromatic amines can act as carcinogens after they have been metabolized by the liver.3
One of the interesting compounds present in kiwifruit is actinidin, an enzyme that helps to hydrolyze proteins. Due to the actinidin content of kiwifruit, other fruits and dairy products will soften or curdle upon
prolonged contact with the chopped fruit, so kiwifruit should be added at the last minute to fruit salads and other mixed preparations. Actinidin has been shown to improve digestion by assisting with protein digestion and digestive motility.11 Kiwifruit contains numerous other bioactive compounds, including organic acids, plant pigments, and polyphenols. The primary organic acid in kiwi is citric acid, but it also contains malic, quinic, gallic, and oxalic acids. Organic acids provide the fruits with significant antioxidant properties.Some of the plant pigments present in kiwifruit include carotenoids and chlorophylls, and some cultivars also contain anthocyanins.11 The carotenoids include beta-carotene, lutein, violaxanthin, and 9’-cis-neoxanthin.3 When compared with other commonly consumed fruits, kiwifruit is the richest source of lutein, which is a carotenoid that is highly concentrated in the macula of the eye and is associated with lowering risk of cataracts. All Actinidia species contain chlorophylls a and b, but levels are much lower in the gold kiwi variety. Some kiwifruits also contain anthocyanins, but they are not a significant component of the antioxidant capacity of the fruit. Glutathione is another important antioxidant present in kiwifruit, and it not only prevents oxidative damage of cells but also helps to keep vitamins C and E in their active form, regenerating their antioxidant capacities.11
Historical and Commercial Uses
Kiwifruit is featured in Chinese literature dating back to the 15th century.12 The kiwifruit was originally called mi hou tao, or “monkey peach,” because monkeys would eat the fruit in the wild.4 Traditionally, both the root and the fruit of A. chinensis were used in traditional Chinese medicine and are known as xiao yang tao. The root of A. chinensis contains antiangiogenic phytochemicals including triterpenes, polyphenols, and anthraquinones, and it has been noted in the Chinese pharmacopeia as being useful for treating many diseases, such as stomach, rectal, and breast cancers, as well as hepatitis viral infections.12-14 The fruit of A. chinensis was used as a juice to quench thirst, aid digestion, clear heat, and reduce irritability, inflammation, and vomiting.3,14
Other Actinidia species were used for their therapeutic effects as well. Historically, A. macrosperma was used to stimulate the immune system and A. polygama was used as an anti-inflammatory agent and to counteract allergies due to its anti-asthmatic effect.3,15
Clinical trials for kiwifruit primarily have focused on its effects on the digestive, immune, and cardiovascular systems. Preliminary research has also investigated the antioxidant properties of kiwifruit and its possible inhibitory effect on cancerous cell growth.
Clinically, kiwifruit has been shown to have a laxative effect. Daily consumption of the fruit improved the frequency and ease of bowel movements and improved stool bulk and softness in healthy older adults.3 In another study, researchers found that daily kiwifruit intake relieved symptoms in subjects suffering from chronic constipation, with no reports of adverse effects like diarrhea.3 Additionally, a trial in healthy subjects who were not experiencing constipation found no adverse gastrointestinal effects from daily consumption of kiwifruit.16
These gastrointestinal benefits are attributed to the lubricating effects of kiwifruit’s pectin and the enzyme actinidin, which combine with the enzymes in the stomach and the small intestine to improve digestion.4The pectin and fiber present in kiwifruits also function as prebiotics. Prebiotics help to modify the composition of the bacterial flora in the gut so that healthy bacteria are stimulated and harmful bacteria are suppressed. An in vitro study looked at the prebiotic effect of the pectin present in kiwifruit compared to other prebiotics like inulin, guar gum, and citrus pectin. The pectin in kiwifruit was more effective than these prebiotics in reducing the intestinal adhesion of harmful bacteria and increasing the adhesion of beneficial bacteria.17 In a mouse study on irritable bowel disease (IBD), extracts of both green and golden kiwifruit were administered, resulting in a potent anti-inflammatory effect. These results indicate that further research should be done exploring the medicinal properties of kiwifruits in the treatment of IBD.18
Antibacterial and Immunological Activity
In an in vitro study, essential oil from A. macrosperma produced inhibitory effects against a number of common bacteria, including Escherichia coli and Staphylococcus aureus, as well as three common fungal species.3 In a mouse study, kiwifruit extract was shown to alter innate and acquired immunity when the mice were injected with cholera and diphtheria/tetanus vaccines.15 This could have implications for improving immunity in vaccinated individuals, particularly children and other high-risk populations.
Other animal studies have shown that extracts of A. arguta may have anti-allergenic effects, implying a potential for the use of kiwi extracts as therapies for allergy conditions like bronchial asthma or eczema.3 A human trial observed the effects of daily intake of golden kiwifruit on both older adults (older than 65 years) and young children (ages 2-5) in relation to cold and flu-like illnesses. For the adults, those who ate four kiwifruits daily had symptoms for fewer days over the course of a cold than the adults who ate two bananas (Musa acuminata, Musaceae) daily. In the preschool children, the odds of getting a cold or the flu decreased by almost half in the children who ate two kiwifruits daily instead of one banana.4
There is some evidence that kiwifruit may have the ability to affect risk factors for cardiovascular disease, like blood pressure, plasma triglycerides, and platelet aggregation. A human study showed that eating two to three kiwifruits per day reduced triglyceride levels by 15% and reduced platelet aggregation response by18% compared to control.19Multiple studies have shown that daily kiwi consumption improves not only triglyceride levels, but also the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol. One clinical trial studied male smokers who ate three kiwis per day for eight weeks. The patients had significantly reduced blood pressure and angiotensin-converting enzyme (ACE) activity (a component of the blood pressure-regulation process), especially those with hypertension. A number of in vitro studies support the claim that kiwifruit reduces platelet aggregation, but clinical trials are conflicting and more human studies are needed to confirm this effect.4
Antioxidant and Cytotoxic Properties
The vitamin and phytochemical composition of kiwifruit give it powerful antioxidant properties. An in vivo study showed that kiwifruit juice ingestion increased plasma antioxidant capacity within 30 minutes and that these levels were sustained for up to 90 minutes. Though this was not a long-term study, this may have implications for kiwifruit’s ability to fight oxidative stress.3 Similar findings were established through two human studies in the United Kingdom, which showed that kiwifruit consumption improved antioxidant status of both the plasma and lymphocytes of participants. One of these studies also showed that kiwifruit seemed to stimulate DNA repair. A pilot study was performed to extrapolate on this possibility and the results showed that kiwi aided DNA repair for an average of 13 hours after ingestion.7
Though vitamin C is known for its antioxidant power, it also has a synergistic effect on iron absorption. In a study of young women with mild anemia (iron deficiency), participants who consumed two golden kiwifruits with an iron-fortified cereal daily had significantly improved iron levels compared to participants who ate the cereal with a banana. The vitamin C content, along with the carotenoids lutein and zeaxanthin present in kiwifruits, are likely responsible for this outcome.4
There is a great deal of investigation into the role of antioxidants and other phytochemicals in the prevention of cancerous cell growth, but despite kiwifruit’s history of use in traditional Chinese medicine, there are few clinical trials establishing the connection of the fruit and its constituents with cancer prevention or treatment. In vitro studies have shown that extracts of Actinidia species may be toxic to cancer cells. Additionally, mice studies have shown that kiwifruit juice inhibits growth of sarcoma cells.12Another mouse study showed that catechin in the stems of A. arguta and the juice of A. deliciosa increased bone marrow proliferation, which may have implications for reducing the adverse effects of chemotherapy treatments. There has also been evidence suggesting that the prebiotic effect of fiber found in foods may change the bacteria in the colon, providing protection against colon cancer.3
Though it is poorly understood, there is an allergy risk associated with the fruits of Actinidia species. Allergic reactions can range from mild itching of the throat, mouth, and lips, and swelling to anaphylaxis, though it is more common for reactions to be mild. The more severe reactions typically occur in children.4The prevalence of allergies to Actinidia fruits may vary geographically; in France, Finland, and Sweden, kiwifruit is one of the top ten most common allergens.16 Allergies to kiwifruit are often cross-reactive with other common allergens such as pollens, rye (Secale cereale, Poaceae), hazelnut (Corylus avellana, Betulaceae), chestnut (Castanea spp., Fagaceae), banana, and avocado (Persea americana, Lauraceae). Heat treatment and industrial homogenization have been shown to greatly reduce the allergic reactivity of green kiwi. These treatments are often performed on processed products like beverages and jams.20
Kiwifruit contains oxalate, which is from the salt of oxalic acid. Oxalates can cause oral irritation in some individuals, and they can be risky for individuals with a history of calcium oxalate-containing kidney stones. Oxalate in high concentrations can also reduce the bioavailability of calcium, magnesium, and iron in the body.3 Though kiwifruit contains more than 10 mg of oxalate per serving (enough to be considered high levels), it would require daily consumption of large quantities of kiwifruit for the levels of oxalates in the body to become dangerous. Additionally, oxalate content decreases during storage.16
Macronutrient Profile: (Per one fruit [approx. 69 grams])
0.8 g protein
10.1 g carbohydrate
0.4 g fat
Secondary Metabolites: (Per one fruit [approx. 69 grams])
Excellent source of:
Vitamin C: 64 mg (106.7% DV)
Vitamin K: 27.8 mcg (34.8% DV)
Good source of:
Dietary Fiber: 2.1 g (8.4% DV)
Potassium: 215 mg (6.1% DV)
Vitamin E: 1 mg (5% DV)
Folate: 17 mcg (4.3% DV)
Manganese: 0.07 mg (3.5% DV)
Magnesium: 12 mg (3% DV)
Calcium: 23 mg (2.3% DV)
Phosphorus: 23 mg (2.3% DV)
Vitamin B6: 0.04 mg (2% DV)
Thiamin: 0.02 mg (1.3% DV)
Niacin: 0.24 mg (1.2% DV)
Riboflavin: 0.02 mg (1.2% DV)
Vitamin A: 60 IU (1.2% DV)
Iron: 0.2 mg (1.1% DV)
DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.
Recipe: Kiwi, Lemon, and Rosemary Shrub
Courtesy of Jerry James Stone22
1 1/2 pounds kiwifruit
2 slices of lemon
1 sprig of rosemary
1 cup sugar
1 cup champagne vinegar
Peel and thinly slice the kiwifruit. Arrange a layer of kiwifruit in a quart-sized jar and sprinkle with sugar. Repeat the layering until all the sugar and fruit is in the jar. Seal and let stand for five hours.
Add the lemon, rosemary, and vinegar to the jar. Seal and shake to combine and dissolve the sugar, then let stand for 24 hours.
Strain the mixture through a sieve into a clean quart-sized jar. Seal and refrigerate. To serve, mix two tablespoons of the shrub with sparkling water in an ice-filled glass.
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Motohashi N, Shirataki Y, Kawase M, et al. Cancer prevention and therapy with kiwifruit in Chinese folklore medicine: A study of kiwifruit extracts. J Ethnopharmacol. 2002;81(3):357-364. doi:10.1016/S0378-8741(02)00125-3.
Zhu WJ, Yu DH, Zhao M, et al. Antiangiogenic triterpenes isolated from Chinese herbal medicine Actinidia chinensis Planch. Anti-Cancer Agents Med Hist. 2013;13(2):195-198. doi:10.2174/187152013804711146.
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Shu Q, Mendis De Silva U, Chen S, et al. Kiwifruit extract enhances markers of innate and acquired immunity in a murine model. Food Agric Immunol. 2008;19(2):149-161. doi:10.1080/09540100802117198.
Singletary K. Kiwifruit. Nutr Today. 2012;47(3):133-147. doi:10.1097/NT.0b013e31825744bc.
Parkar SG, Redgate EL, Wibisono R, Luo X, Koh ETH, Schröder R. Gut health benefits of kiwifruit pectins: Comparison with commercial functional polysaccharides. J Funct Foods. 2010;2(3):210-218. doi:10.1016/j.jff.2010.04.009.
Edmunds SJ, Roy NC, Love DR, Laing WA. Kiwifruit extracts inhibit cytokine production by lipopolysaccharide-activated macrophages, and intestinal epithelial cells isolated from IL10 gene deficient mice. Cell Immunol. 2011;270(1):70-79. doi:10.1016/j.cellimm.2011.04.004.
Park YS, Leontowicz H, Leontowicz M, et al. Comparison of the contents of bioactive compounds and the level of antioxidant activity in different kiwifruit cultivars. J Food Compos Anal. 2011;24(7):963-970. doi:10.1016/j.jfca.2010.08.010.
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Stone JJ. Kiwi, lemon & rosemary shrub (drinking vinegar). Jerry James Stone website. December 4, 2013. Available at: jerryjamesstone.com/recipe/kiwi-lemon-rosemary-shrub-drinking-vinegar/. Accessed June 22, 2017. [Editor’s note: The linked webpage contains profanity.]
BMC Vet Res. 2017 Mar 16;13(1):70. doi: 10.1186/s12917-017-0987-6.
Responsiveness of cats (Felidae) to silver vine (Actinidia polygama), Tatarian honeysuckle (Lonicera tatarica), valerian (Valeriana officinalis) and catnip (Nepeta cataria).
Bol S1, Caspers J2, Buckingham L3, Anderson-Shelton GD4, Ridgway C5, Buffington CA6, Schulz S2, Bunnik EM7.
Olfactory stimulation is an often overlooked method of environmental enrichment for cats in captivity. The best known example of olfactory enrichment is the use of catnip, a plant that can cause an apparently euphoric reaction in domestic cats and most of the Pantherinae. It has long been known that some domestic cats and most tigers do not respond to catnip. Although many anecdotes exist of other plants with similar effects, data are lacking about the number of cats that respond to these plants, and if cats that do not respond to catnip respond to any of them. Furthermore, much is still unknown about which chemicals in these plants cause this response.
We tested catnip, silver vine, Tatarian honeysuckle and valerian root on 100 domestic cats and observed their response. Each cat was offered all four plant materials and a control, multiple times. Catnip and silver vine also were offered to nine tigers. The plant materials were analyzed by gas chromatography coupled with mass spectrometry to quantify concentrations of compounds believed to exert stimulating effects on cats.
Nearly all domestic cats responded positively to olfactory enrichment. In agreement with previous studies, one out of every three cats did not respond to catnip. Almost 80% of the domestic cats responded to silver vine and about 50% to Tatarian honeysuckle and valerian root. Although cats predominantly responded to fruit galls of the silver vine plant, some also responded positively to its wood. Of the cats that did not respond to catnip, almost 75% did respond to silver vine and about one out of three to Tatarian honeysuckle. Unlike domestic cats, tigers were either not interested in silver vine or responded disapprovingly. The amount of nepetalactone was highest in catnip and only present at marginal levels in the other plants. Silver vine contained the highest concentrations of all other compounds tested.
Olfactory enrichment for cats may have great potential. Silver vine powder from dried fruit galls and catnip were most popular among domestic cats. Silver vine and Tatarian honeysuckle appear to be good alternatives to catnip for domestic cats that do not respond to catnip.