In October 2010, I began taking a Vitamin D supplement http://www.vitacost.com/Source-Naturals-Vitamin-D-400-IU-100-Tablets dosage of 400 IU three times a day for a month after hearing the symptoms for Vitamin D deficiency included low energy, fatigue, crankiness. I was more low energy than cranky, but figured I might need it. The blood test results for my “Vitamin D, 25 hydroxy” score was low at 28. And that was after taking it three times a day for a month before the test! It says the optimum level is 30-80 ng/mL.
In December I doubled my dosage after reading more about it, and am now taking two 400 IU tabs three times a day, after eating. That’s 2400 IU a day. People with higher rates of vitamin D in their blood have lower rates of disease and lower death rate, wind up with fewer bone fractures and fewer falls. I can’t remember when I last had a cold, and my bones are strong.