Supermarkets in Orkney and Shetland have seen "a run on bags of ice" during the motor neurone disease fundraiser, the island MP said.
Mr Carmichael was doused in iced sea water before jumping into the North Sea from Tingwall Pier in Orkney on behalf of MND sufferer Gordon Aikman.
Mr Aikman, director of research at the pro-UK Better Together campaign, launched the Gordon's Fightback campaign for more funding and support for MND sufferers after he was diagnosed with the condition earlier this year and warned he could be in a wheelchair by Christmas.
Mr Carmichael said: "People who are aware of Gordon Aikman's campaign to raise awareness and funds for MND Scotland cannot fail to be impressed by his bravery and enthusiasm in hugely challenging circumstances.
"I was delighted to take part in the ice bucket challenge and am pleased to report that the feeling has now returned to my fingers and toes.
"Ice is not usually in short supply across the Northern Isles but the ice bucket challenge has seen something of a run on bags of ice in Orkney and Shetland recently.
"I think that it is right that those profiting from these extra sales should give something back. I nominate the major supermarket chains to get involved and back this campaign."
Mr Carmichael's ice bucket challenge video is now available to view on YouTube, and donations to MND Scotland can be made through http://gordonsfightback.com.