Welcome back to “Dr. William Grant on Bolstering Health Through Sunlight and Vitamin D, Part 1 of 3.” In the latter part of the 20th century, American researchers discovered that the colon cancer mortality rate for Americans was much higher for those in the Northeastern US compared to the Southwestern US, a hotter climate where there is much more Sun. In our interview, Dr. Grant stated there is overwhelming evidence that vitamin D created by Ultraviolet B ray exposure can prevent, and reduce the death rate from, certain cancers.