The Healthy Librarian at the Happy Healthy Long Life blog wrote about a small scientific study documenting an incredibly easy way to increase blood levels of vitamin D in people taking supplemental vitamin D:
Take the supplement with the largest meal of the day
Subjects of this research were taking vitamin D supplements—often a very high dose—for medical reasons, yet blood levels remained unacceptably low. Blood levels of vitamin D (25-hydroxyvitamin D) rose by 50% simply by taking the same dose with the largest daily meal.
Other people, including young healthy adults, may or may not respond the same way. Do you know?
As for me, I’ll be sure to take my vitamin D supplement with my largest meal.
Disclaimer: All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status. Always consult your personal physician before making any dietary, nutritional supplement, or exercise changes.
Diabetic Mediterranean Diet 
I’m always a bit skeptical of the physiological meaning of these studies. The relationship between pharmacokinetics and pharmacodynamics of a simple drug is a tricky thing at best. For an exogenous given hormone, it’s even more confusing. My first question would be – what happens to the vitamin D taken with a meal? Is it not absorbed. Is it degraded faster? Or, is taken up by the tissue faster? Ultimately, these doses need to be correlated to a physiological measurement or biomarker of some sort showing whether or not changes in dosing schedule makes a difference in function.
Good points, Isaac. I’m not sure anyone has hard and fast answers to your points yet.
-Steve
That was always a sticking point in drug development. One camp would dose to blood levels while the other would dose to effect. I belong to the latter.
Dietary vitamin D presumably should be transported via chylomicrons given that it’s backbone is cholesterol. Do you know how skin derived vitamin D is transported? I wonder if that affects the biological effects to some extent. Certainly the lipoprotein class affects where other fats are distributed (HDL goes to liver whereas LDL goes to periphery). It would seem that vitamin D would be no different.
I also wonder if those patients requiring very high doses to normalize the blood levels are resistant to the effects of sunlight raising blood levels? If so, then I would presume that their cellular vitamin D uptake is higher. Maybe something akin to the Milano mutation for ApoA?