Considering all the good vitamin D can do for your health, it's no wonder the sunshine vitamin can cut your risk of succumbing to pancreatic cancer, one of the most fatal forms of cancer.

Unfortunately, the source of vitamin D touted in the study was not the sun but oral vitamin D. I've got to tell you that although there is clearly some benefit from oral vitamin D, it is very clearly not your best choice for vitamin D, as it is simply too darn easy to overdose.

I can tell you this from personal experience as I have overdosed on both too much cod liver oil and last year too much sun exposure. The only solution to overdose is to stop all vitamin D sources and let time run its course.

The difference between the two is that it takes about six months for levels to normalize with oral preparations and about two weeks from sunshine. Clearly your body is designed to have far tighter control when you receive the vitamin D from appropriate sun exposure.

So, rather than supplements, strive to get your vitamin D naturally from safe sunshine exposure. You need to be hyper cautious if you choose to use oral vitamin D preparations, and I would not do that unless you regularly have your blood levels of vitamin D monitored.

By the way, getting more than the RDA of vitamin D resulted in no extra benefits either, no surprise, as excess amounts in your blood are dangerous. There is very little risk overdosing on vitamin D, however, when your body generates it from safe sun exposure.

In general, it's also important to remember these other crucial points:

• Optimal vitamin D levels lie in a very small range. To be certain your levels are where they should be, have your doctor test your blood and supplement as needed in order to maintain that level.

• The darker your skin is, the farther away from the equator you are, and the further away you are from the summer months, the less likely it is that you will produce adequate vitamin D levels from sun exposure alone.

• It is always preferable to get your vitamin D from sun exposure, but for some of us that just isn't possible. In that case, the type of vitamin D you use as a supplement is absolutely crucial. Only vitamin D3 (cholecalciferol), the type of vitamin D found naturally in foods like eggs, organ meats, animal fat, cod liver oil and fish, is appropriate for supplementation.

One of the most challenging things about preventing cancer is that there can be any number of contributing factors involved, all of which seem to vary from person to person and cancer to cancer.

Optimizing your vitamin D levels certainly seems important considering that it is a potential factor in as many as 16 different types of cancer including not only pancreatic cancer, but also lung, breast, ovarian, prostate and colon cancers.