Vitamin D is very important to keep the immune system working efficiently. Vitamin D deficiency increases the body’s susceptibility to infections. So you want to make sure to keep your Vitamin D 25 OH level between 40 to 60 ng/ml at all times. Use the following calculator to determine the estimated additional Vitamin D you will need to take to reach the target Vitamin D serum level above:

Although there are no conclusive studies about Vitamin D intake and influenza prevention, please consider these articles:
• Epidemic Influenza and Vitamin D
• Randomized trial of Vitamin D supplementation to prevent seasonal influenza A in schoolchildren.
• Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data
• Randomized trial of Vitamin D supplementation to prevent seasonal influenza A in schoolchildren

I also recommend that you give your infant 400 IU of Vitamin D3 daily. Give your baby who weighs 23 pounds or greater 800 IU daily; your child who weighs 28 to 54 pounds 1000 to 2000 IU a day; your child who weighs 57 pounds to 84 pounds 2000 to 3000 IU daily; your child who weighs 85 to 114 pounds 4000 IU daily; and you child who weighs 115 pounds or more 5000 IU daily. This is especially important during the winter months when colds and flu proliferate. These are moderate doses and should not cause any problems. However, after they have been on vitamin D3 for 6 months, they should get their Vitamin D levels checked, also.

If you have had portions of your intestines removed, or if you have had bariatric surgery, you may be at risk for vitamin D deficiency. Please make sure your doctor measures your vitamin D level and treats you with appropriate doses of Vitamin D3 to maintain optimal levels in order to protect you especially during this illness season.