New research is suggesting that Vitamin D3 may be the largest thing to hit, literally, colds, flu and depression. In the past it has been thought that people get colds and flu in winter because it is cold. In this day and age though how cold do people get really? Most places are heated, most people have more than enough clothes and yet it is common for many to catch a cold or flu 3-4 times if not more.
Some studies are now suggesting that what may actually be the cause is a lack of sunlight. Sunlight is converted by the skin into vitamin D3 which is an important vitamin for regulating the immune system. In winter depending on where you live there is significantly less sun and given that most people are covered up in winter, far less sunlight is absorbed by the skin.
With Vitamin D3 what is important is increasing the blood levels of your body though it is a good idea to go to your doctor and get a blood test for your Vitamin D3 levels first. This is the most accurate way of knowing how much you should take of this vitamin. Besides the cold and flu this important vitamin will also help to ward off the types of depression that are known to be caused by lack of sunlight (Seasonal Affective Disorder).
If your Vitamin D3 levels are very low it can often take between 4-5 months to increase your blood levels to the point where you are at your optimum levels. Many online retailers sell this vitamin in higher dosages and in bulk amounts so it can be useful to shop around until you find the dosage that is right for you.