Two-thirds of Scotland's sporting stars have been found to be deficient in the "sunshine" vitamin D. Lack of the vitamin infamously causes rickets.
Dr Brian Walker, the head of sports medicine at the sportscotland Institute of Sport, revealed the statistic as he outlined the measures being taken to make Scotland the "best prepared team ever" for Glasgow 2014.
This has included testing the athletes for levels of vitamin D - which is mainly produced by the body when the skin is exposed to sunlight - amid fears low levels could have an impact on their immunity and ability to fight of infections such as a cold.
Speaking at the A Summer Of Sport conference, Walker revealed they found 66% of Scottish sporting athletes were vitamin D deficient - with around 10% having "very low levels indeed".
He said supplements meant they were now on track to keep a pledge that "every Scottish athlete going into Glasgow will be have normal vitamin D levels".
Walker said: "Colds and so on can be an absolute disaster and sometimes performing with a viral infection can be a total disaster. So if we can reduce that significantly, then we can give them more training and they will perform better."
He revealed some of the challenges that faced Team Scotland at the start of the last Commonwealth Games in Delhi in 2010.
An advance party of seven sent out by the sportscotland Institute found an array of health and safety hazards, ranging from animal prints on the athletes' beds to exposed wiring. He told how the team was nicknamed Marigold Seven - after the gloves - for scrubbing the athletes' base clean.
He said one of the biggest fears - the athletes catching the notorious "Delhi belly" - had not materialised, with only around 10% of athletes and staff suffering diarrhoea and vomiting compared to the expected figure of around 30-40%.
Walker said vomiting bugs were still a threat for athletes in Glasgow and the team would be issued with anti-bacterial foam for handwashing. He added: "One of our big challenges is to keep the same discipline that you would have in Delhi in Glasgow."