The Adventist Health Study-2 (AHS-2) is a large national cohort of 96,000 Seventh-day Adventists in the U.S. and Canada. The study is searching for associations between diet and risk of common and medium frequency cancers (breast, prostate, colorectal, lung, uterus, pancreas, melanoma of skin). This cohort is unusual in that about half are vegetarian, many eat soy at Asian levels, and many have very low or absent dairy intake while others eat normal amounts of dairy. Thus observations on these people, many of whom have contrasting dietary habits, may provide insights about diet and cancer, so supporting dietary changes that could be readily adopted by many.