It's winter - for most of us. The sun is as low as it can be and doing little to help us maintain Vitamin D.
Any wonder we (not me) tend to get sick with colds and flu in the winter:
As the graph in the article shows, blood vitamin D levels drop significantly during winter to a point where immune action against virus' are at their weakest. Another reason to take vitamin D3 supplements and test your blood vitamin D level.
And because we have CML - all the more reason to make sure our vitamin D levels do not fall to levels shown in the graph. There is a similarity in the biology of virus and biology of cancer. Both require immune system activation to defend against. Low vitamin D is like leaving the lock on the gates to the army when your land is invaded. Vitamin D unlocks the gate.
Testing twice a year until you have a good feel for how much vitamin D3 you need to be taking will help you know you are in the sweet spot.
(for our Australian friends - just slide the X-axis so January is July ... it's an inference, but probably an accurate one)