Kiwis help you to get rid of common colds faster (and lessen the symptoms)
If people over 65 eat 4 kiwis a day, they can still get a cold - but their cold will be over faster. In addition, they will suffer less from some symptoms.
Researchers at the New Zealand Institute for Plant and Food Research Limited gave 32 people over the age of 65 4 kiwis every day for 4 weeks. More precisely, the researchers gave the subjects 4 yellow kiwis every day. The kiwis were marketed by Zespri. [zespri.com] Zespri funded the research.
On another occasion, the subjects were given 2 bananas every day for 4 weeks.
The table below shows the difference in the nutritional value of yellow kiwis and bananas.
During the study, the subjects completed a daily questionnaire, which doctors used to determine the symptoms and severity of colds.
There was no difference between the kiwi and banana phases when it came to catching a cold or not. But it did seem that the cold symptoms in the kiwi group passed faster during the kiwi phase.
If the subjects caught a cold while eating 2 bananas every day, they suffered from head congestion for an average of 5 days and a sore throat for 5 days. If they ate 4 kiwis every day, this would be 1 and 2 days respectively. The extent to which the subjects suffered from head congestion was also significantly less during the kiwi phase.
Click on the tables below for a larger version.
The researchers found no evidence of an effect of kiwi consumption on the immune system. They did discover, however, that if the subjects ate kiwis, more vitamin C and especially more lutein or zeaxanthin [the two are difficult to distinguish] were present in their blood. In addition, there was somewhat less free radical activity during the kiwi phase.
The researchers suspect that antioxidants in kiwifruit protect cells against viruses.
"The reduction in duration and severity of selected upper respiratory tract infection symptoms indicates that gold kiwifruit may provide an important and clinically relevant contribution to lessening the burden of respiratory infection in older individuals", the researchers summarize.
Br J Nutr. 2012 Oct;108(7):1235-45.
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