Nutritional science for mind health products
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The numbers of days suffering from a sore throat were cut from 5.4 to 2 days as a result of eating kiwifruit, compared to bananas, while the numbers of days of suffering from head congestion fell from 4.7 to 0.9 days, researchers report in the British Journal of Nutrition.
Consuming the kiwifruit led to increases in blood levels of vitamin C, but researchers from the New Zealand Institute for Plant and Food Research and Massey University.
“This study shows that the micronutrients provided by regular eating of gold kiwifruit appear to be important in reducing symptoms of colds and other upper respiratory infections,” said lead author Dr Denise Hunter.
“While we do not know what compounds produce these results, these findings suggest that eating gold kiwifruit on a regular basis throughout the winter period may reduce the severity of some cold symptoms.”
The study was funded by Zespri International Limited, and the company also provided the fresh and free-dried gold kiwifruit used in the study.
Cold stats
The common cold is one of the most widespread illnesses in the world. It is estimated that adults suffer from between two and four episodes annually, whilst children in school may have as many as 12 episodes per year.
A recent Cochrane review estimated that the total economic impact of cold-related work loss exceeds $20 billion per year. As a result, Americans spend around $2.9 billion on over-the-counter drugs (and another $400 million on prescription medicines) for symptomatic relief of cold.
Study details
If further data supports the findings of the new study, it could see kiwifruit added to a list of potential cold remedies. The researchers recruited 37 healthy over-65 year olds and asked them to eat four kiwifruit daily for four weeks then switch to two bananas per day (or vice versa) with a four week kiwifruit/banana-free period prior to each treatment period.
Results indicated a reduction in self-reported cold symptoms with gold kiwifruit compared to banana, with sore throat symptoms reducing from 5.4 to 2 days and head congestion from 4.7 to 0.9 days.
The researchers also reported an easing in the severity of symptoms of head congestion during the gold kiwifruit period.
Markers of immune health were not significantly affected by consumption of the kiwifruit or banana, they added.
Take home
“Regular consumption of gold kiwifruit by community-dwelling older people has a positive and significant influence on a number of plasma antioxidants, including vitamins C and E (a-tocopherol), and lutein/zeaxanthin, and significantly reduces cellular damage from oxidative stress, namely lipid peroxidation,” said the researchers.
“Furthermore, when participants consuming gold kiwifruit experienced symptoms of upper respiratory tract infections, many symptoms tended to be shorter in duration and less severe; this was significant for duration and severity of head congestion, and duration of sore throat.
“Although the mechanisms behind the influence of enhanced plasma antioxidants and dietary analytes on improved symptoms of upper respiratory tract infectionsafter consumption of gold kiwifruit remain speculative, the reduction in duration and severity of selected upper respiratory tract infections symptoms indicates that gold kiwifruit may provide an important and clinically relevant contribution to lessening the burden of respiratory infection in older individuals.”
Source: British Journal of Nutrition
Published online ahead of print, FirstView Articles, doi: 10.1017/S0007114511006659
“Consumption of gold kiwifruit reduces severity and duration of selected upper respiratory tract infection symptoms and increases plasma vitamin C concentration in healthy older adults”
Authors: D.C. Hunter, M.A. Skinner, F.M. Wolber, C.L. Booth, J.M.S. Loh, M. Wohlers, L.M. Stevenson, M.C. Kruger
4 comments (Comments are now closed)
To answer Chris...
There are more than 70 species of kiwifruit, in various sizes, shapes and colors. Much like breeding new varieties of apples, genetically different plants can be crossed to generate new fruit.
The Gold one was developed by naturally breeding from the living library of different kiwifruit vines at Plant & Food Research. Think of the difference as the same as a Granny Smith versus a Royal Gala
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Posted by Mike
09 January 2012 | 21h11
Kiwi Rules
Kiwi is a supernutritional food; any type...Kiwi has remarkable qualities; Vit. C; Potassium; BetaCarotene; Fiber; Vitamin E; Luetin...a True superfood ! Kiwi also has a great flavor to boot ! !
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Posted by Anne
07 January 2012 | 11h14
What about regular kiwifruit?
Gold kiwifruit is a different strain than the more affordable green kiwifruit. Moreover, gold kiwifruit production has been essentially destroyed in its native New Zealand by a widespread bacterial infection (http://www.nzherald.co.nz/business/news/article.cfm?c_id=3&objectid=10776531), which of course could come to affect production worldwide.
Thus, it is extremely unfortunate that this study used banana consumption as its one control group for beneficial effects. A further study, looking at comparative effects of green kiwifruit, and ideally other vitamin-rich fruits such as citrus, is a natural follow-up.
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Posted by Jon Yaffe
04 January 2012 | 15h03
Gold kiwifruit versus non Gold kiwifruit
What is the difference between gold and non gold kiwifruit.
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Posted by Chris
02 January 2012 | 22h07
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