This chart is interesting! It shows that the effectiveness of vitamin D supplements in terms of actual rise in blood level of vitamin D depends on the starting level. For example, if your starting level is at 20 ng/mL, taking a 1000 IU per day supplement can raise your blood level by about 10 ng/mL. But the same 1000 IU per day increase your blood level by only 4 ng/mL if you are already at 60 ng/mL. And it practically does nothing if you are at 80 ng/mL.
This knowledge can help consumers and doctors decide an appropriate level of vitamin D supplementation.
Many people take vitamin D supplements, either on their own, or because they have been prescribed to them by their doctors. The media is full of news about vitamin D deficiency and a common response is to take a daily vitamin supplement. But does it work?
According to this chart, the answer is it depends! If you are in the 40 -60 ng/mL range, which most experts believe to be ideal, popping a pill because of the media frenzy about vitamin D deficiency is completely useless. You are better off watching your diet and lifestyle by consuming vitamin D rich foods (dairy, fortified juices, fatty fish and mushrooms) and getting limited sun exposure without sun screen. Your body creates a reserve of vitamin D in your fat cells, which can help you go through the winter months when you are not able to get much sun. The vitamin D calculator can help you estimate your vitamin D intake from food and sun exposure.
If you are clinically diagnosed as having insufficient or deficient levels of vitamin D, you should look at your baseline blood level of vitamin D and talk to your doctor about an appropriate amount of supplementation. Use the above chart as a starting point of discussion. Do not blindly accept a high dose of vitamin D supplement because it can cause toxicity. Your doctor will use a try-and-wait approach, but you need to ask questions and convince yourself that the prescribed treatment makes sense for you.
If you want to read more about the data behind this chart, click here for the complete research paper.