When scientists look at studies about vitamin D preventing colds and flu, it seems like some smaller studies showing vitamin D doesn't work might be missing. This could make vitamin D look more helpful than it really is.

Taking vitamin D every day might help lower your chances of getting colds or other breathing infections, but it doesn't always work the same way for everyone and scientists aren't totally sure yet.

Taking vitamin D supplements doesn't really help prevent common colds or similar infections for most people, based on a big review of studies.

Taking vitamin D might help kids between 1 and 15 years old get fewer colds and lung infections, but scientists aren't totally sure yet.

Taking vitamin D supplements doesn't really change your chance of having serious side effects, and it's considered safe for helping prevent colds and other breathing infections.

Taking a small daily dose of vitamin D might help lower your chances of getting colds or other breathing infections, but taking more doesn't seem to help extra, and scientists aren't totally sure about this yet.