How much vitamin D3 should we supplement is one of the most difficult questions to answer. With recommendations all over the board by the experts, the average person’s head is spinning. The thing to remember, there is no harm in your serum level in the range of people in a sunny country. That is your serum 25(OH)D should range between 50 ng/ml to 90 ng/ml when supplementing with vitamin D3. It is also extremely important if you chose to supplement or your doctor suggest that you take vitamin D that you take vitamin D3 only.
Dr. Heaney at Creighton University has shown that the average healthy person uses about 75 IU of D3 per kg of body weight per day. However, very few people in the population are average. The best approach if you have not been supplementing with vitamin D3 is to take about 1000 IU of D3 per twenty five pounds of body weight per day for three months and then have your serum tested. You goal should be to have a serum level that stabilizes in the 60 to 80 ng/ml range. A rule of thumb for adjusting your intake is that 1000 IU of D3 should move your serum level about 10 ng/ml – again depending of lots factors. Everyone is different in how much vitamin D they need to achieve a sunny country level. This is because of disease states that require more D3, genetics, cofactors taken, and other activities that include tanning, exercise, and sun exposure.
Use common sense when you supplement. If you have lots of sun exposure on a given day with few clothes on, do not supplement on that day with vitamin D. If you go regularly into the sun and most likely for the three to four months of summer, reduce your supplementation by half to allow for casual sun exposure.
Dr. William Davis writes the Heart Scan Blog. He states that two of his patients of similar age and body weight had to take 2,000 IU versus 12,000 IU of vitamin D to achieve approximately the same serum level. Here is the article: The Folly of an RDA for Vitamin D
If you are taking vitamin D and are not getting the results you expected, have your serum tested. The best thing you can do for your health is to have your serum vitamin D tested once per year and maintain it at the level of a sunny country. – Pandemic Survivor