Drinking milk and eating cheese doesn't cut it! Eating fish three times a day is better for Vit D.
Other studies have found that people who take Vit D supplements aren't as prone to catch flu.
I am taking 4,000 units per day, it is flu season. I take 2,000 the rest of the time. I can absolutely testify that the problems with colds and drainage and stuffiness disappeared.
The dosage seems to have not been settled. I at first took 2,000 units and bought 1,000 unit tabs from Walmart. I bought a big bottle. When they were gone, I found that Walmart was then selling 2,000 unit tabs. That means the demand is for 2,000 unit
I guess it will all settle out on some dosage. In the mean time, excess apparently doesn’t hurt and the cost is trivial. Better some than none