Yep, D3, which is the form that is very safe with low toxicity.
Deficiency in vit D is high, and it comes at a high cost. The vitamin is super cheap and safe. I think we have more to learn on the benefits of this vitamin, even though there are mountains of research already. I am truly surprised at how little coverage D3 gets. I currently get 1600iu from my multi and vit d supplement. I live in texas.
From PMID: 16251641
Vitamin D deficiency is now recognized as an epidemic in the United States. ...There is mounting scientific evidence that implicates vitamin D deficiency with an increased risk of type I diabetes, multiple sclerosis, rheumatoid arthritis, hypertension, cardiovascular heart disease, and many common deadly cancers. Vigilance of one's vitamin D status by the yearly measurement of 25-hydroxyvitamin D should be part of an annual physical examination.
They defined vitamin D insufficiency as a serum 25(OH)D of ≤20 µg/L (50 nmol/L), and divided their subjects into 4 age groups, 18–29 y, 30–39 y, 40–49 y, and ≥50 y. Serum 25(OH)D was measured in 142 subjects at the end of summer and in 165 subjects at the end of winter. A high incidence of vitamin D insufficiency was found (Table 2). A significant (P < 0.001) difference was demonstrated between measures of 25(OH)D after summer (35 ± 10 µg/L) and after winter (30 ± 10 µg/L). Vitamin D insufficiency was more prevalent in all age groups after winter and averaged 30% after winter and 11% after summer. Somewhat surprisingly, the eldest group was least likely of the groups to have insufficiency and the authors felt this is likely explained by subjects’ use of a multivitamin containing 400 IU of Vitamin D. Multivitamin use was significantly inversely associated with vitamin D insufficiency in the after summer and the after winter groups.
The data show that for every 40 IU of vitamin D intake, circulating 25(OH)D increases by 0.70 nmol/L (0.28 µg/L) over 5 mo on a given regimen. A steady state appears to be achieved after ~90 d on each dose tested (23,38). Thus, doses of 400, 1000, 5000, and 10,000 IU/d for 5 mo will result in theoretical increases in circulating concentrations of 7, 17.5, 70, and 175 nmol 25(OH)D, respectively. Again, no adverse events were noted.
Edited by Athanasios, 21 June 2010 - 12:37 AM.