Quote Originally Posted by Biciclista View Post
how much Vit D are you taking? what are your Vit D levels? (there's a test your doctor can do)
Yep, get your D-hydroxy levels tested. Also, consider that the most absorbable form of vitamin D is the animal form (D3 - cholecalciferol) from cod liver and other sources. Plant-based vitamin D (D2 - ergocalciferol) is not as well utilized by the body. I take these D Drops by Carlson's, which come from cod-liver. (I also take cod liver oil for the EFA benefits, but a serving of that usually has less than 1,000IU of D per dose.)

Keep in mind that the current RDA for vitamin D is quite low and on the verge of being drastically revised within the next year. The amounts you can get from normal dietary sources (even enriched with D) are generally not enough to avoid or correct a state of deficiency. Most people living above the 40th parallel (NorCal to NY, approximately) are deficient unless they get significant sun exposure all summer long.

Many healthcare providers and nutritionists advocate against taking too much vitamin D (and the other fat soluble vitamins like A & E) because it is fat soluble. The upper tolerated limit of D is suspected to be 10,000IU per day. If you are exposed to bright sunlight in summer, your body does not manufacture more than this amount.

My physician recommends 4,000-6,000IU in winter time, bumping that up to 8,000-10,000IU if I'm fighting off a cold/flu. In summertime I still take about 2,000IU daily because I work indoors and tend to avoid excessive sun exposure.