Arthritis Research UK said it was vital that people took advantage of sunlight to absorb the vitamin as a deficiency can cause bone loss, muscle function problems and rickets.
It has also been linked to multiple sclerosis and Scotland's high rate of that condition is thought to be linked to low levels of vitamin D. The chief medical officer for Scotland recommends pregnant woman and children take vitamin D supplements.
Arthritis Research UK medical director Alan Silman said: "Our advice to people is to step outside as this is the best way to get vitamin D.
"Don't allow your skin to go red, and take care not to burn, particularly in strong sunshine and if you have fair or sensitive skin. From June to August, just 15 minutes is generally enough time."