A new study shows that people with high blood levels have a 40% reduction in colorectal cancer risk. This is a very interesting study because it measured blood levels of vitamin D directly. This creates several questions; was it just the high levels of vitamin D or was it other factors related to vitamin D such as time outdoors in the sun, exercise, food sources of vitamin D such as fish that are high in other nutrients such as omega-3's.
Hopefully further research will shed light on these questions. In the meantime, get a vitamin D test. I'm surprised at how many of my patients who eat well and are out in the sun regularly have low levels of D. If you are low be sure that you are getiing exposed to sunlight on a regular basis, and supplement with a high quality vitamin D until your levels are normal. You may then want to supplement with 2,000IU per day periodically as a maintinance dose. I have an excellent vitamin D product available at my office.
Read the studyhere.