A British study has found no conclusive evidence that large amounts of Vitamin D can combat cancer, heart disease, diabetes, multiple sclerosis and other chronic diseases.
The study rejects theories that large supplements of Vitamin D can fight off serious illnesses.
It found Vitamin D is essential for good bone health, but excessive quantities can actually make people's health worse.
The study says that for most people, sunlight is the most important source of Vitamin D, and it notes enough can be created long before people start to get sunburn.
It does not say how long people should go into the sun, but says for most, a few minutes in the middle of the day should be enough.