Do kiwi skins contain poison?

Garden Experts
Dear Mr. Kötter, I have two mini kiwi plants (of the variety ‘Weiki’? the fruits have hairy skins as on a normal kiwi and are as large as a walnut), from which I was able to harvest 6 kg of fruit this year. I have made jam from normal kiwis several times (mixed with banana). Now I have tried to make jam using my own kiwis. In preparation, I washed the kiwis, topped and tailed them and scraped the hairs off as well as I could before cutting them up finely, pureeing them with their skins in the mixer and cooking them with a banana and jam sugar. Unfortunately, I have twice experienced gastric problems after eating the jam. My question is: Does the skin contain any (possibly poisonous) substances which are released during cooking, or does the banana react to these kiwis? – Many thanks for your answer.

The GARDENA gardening expert

Dear Mr. G., taking the skin off these kiwis would certainly prove too much work. I do not know of any incompatible substances being contained in the skin – whether in combination with banana or not.
Taste and adverse effects with regard to digestibility are only known to me from the use of kiwis together with yoghurt or curd: This is because the actinides contained in kiwis turns milk proteins into bitter substances. However, there are indications from another source: In natural medicine, it is well-known that kiwis assist digestion. It is possible that the jam (in comparison with the raw fruit) may contain high concentrations of kiwi substances which have caused your reaction. It is possible that you only react to these higher concentrations.
However, I cannot provide you with a final and binding answer to your question. Yet I do have one piece of practical information for you: If you have a hairy kiwi fruit in your garden, this is definitely not the ‘Weiki’ variety! Kiwi fruits featuring hairy skins only grow on the Actinidia deliciosa (synonym A. chinensis). If you replace these with A. arguta, you will only be able to harvest fruits the size of gooseberries, but these grow in huge quantities and only have smooth skins. The skin of the A. arguta is not peeled off for consumption, as with the Actinidia deliciosa. Should therefore the skin of the fruit have played a role in your indigestion, this kiwi should provide the solution you require. ‘Weiki’, by the way, is also an A. arguta variety.

Image: Heribert Wettels