Vitamin D - A Superstar for Winter Health Infection-Fighting Abilities For Colds and Flu


This well-known vitamin has recently become a “superstar” among our customers, their MDs and wellness experts alike.  Recent research has pushed the amazing impact that Vitamin D has on our everyday health into the limelight. 

A large and growing body of evidence is showing that this “sunshine vitamin” controls some 30,000 different genes in our bodies all of which play a crucial role in our health and well-being. (1)

This vitamin is naturally produced during the summertime when our skin is exposed to direct sunlight— a good reason not to overuse sunscreen. But in the northern latitudes in winter…well above the equator, where we live in Massachusetts, the rays that produce Vitamin D in our skin are long gone. In fact the sun’s rays are insufficient to produce ANY Vitamin D from October through May here in the Boston area.  We Northeasters have a very short summer 4-month window to utilize Vitamin D rays from the sun….leaving us to consider Vitamin D supplements for our best health solutions!

Vitamin D3, or cholecalciferol is the most effective form of this vitamin which is actually a group of fat-soluble prohormones produced in the body (1) through the sun exposure or naturally occurring in a very few foods: fatty fish such as mackerel, salmon, and tuna, and in small amounts in cheese, egg yolks, and beef liver (2).  Vitamin D is also added to foods such as milk, orange juice, and breakfast cereals.

Important for the “winter blues,” recent research at the University of Arizona College of Medicine highlighted an “enhanced the ability of the brain cells to produce serotonin by anywhere from double to 30 times as much.” (3)  Think better sleep and the ability to ward off viruses with an increase in serotonin (4, 5). 

According to an article in the New England Journal of Medicine, “When the immune system is fighting pathogens …. cytokines can assist in fighting off the flu …. they also deplete one’s serotonin levels …. depressive symptoms—can accompany or follow the flu. (6)

But serotonin research isn’t all that has been discovered in recent years.  Vitamin D also exhibits its infection-fighting abilities in the treatment of pneumonia, colds, and flu. Vitamin D has been shown to regulate the expression of the genes that influence our immune system to “rev up” and attack and destroy foreign bacteria and viruses that can cause us to become sick. (4,5)

Vitamin D can also help reduce the risk of other conditions as well, including type 2 diabetes, chronic inflammation, age-related macular degeneration (the leading cause of blindness), and Alzheimer’s disease.  (4,5)

Vitamin D also exhibits its infection-fighting abilities in the treatment of tuberculosis, pneumonia, colds, and flu. It can also improve seizure control in epileptics.  (4)

People with low levels of vitamin D (suggested in large population studies), appear to have a greater risk of developing heart disease, which includes heart attack, stroke, and heart failure.  In these studies the risk was compared to people with higher levels of vitamin D. (2)

Women who are taking at least 400 IU of vitamin D daily have been shown to lower their risk of developing Multiple Sclerosis (MS). (4)

Obesity and higher mortality also seem to be correlated with vitamin D levels in the body. (4)

The National Institutes of Health has set the maximum upper limit at 1,000 IU daily for infants 0 - 6 months, 1,500 IU daily for infants 6 months to one year, 2,500 IU daily for children 1 - 3 years, 3,000 IU daily for children 4 - 8 years, and 4,000 IU daily for anyone over 9. (2)


(1) National Institutes of Health /

(2) University of Maryland Medical Center /

(3) Jeremy C. Fox, Globe Correspondent, News Article, “Research Suggests Vitamin D Could Affect Brain Function”, Jan 5, 2015



(6) New England Journal of Medicine

* The information provided in this blog post is not to be used for the diagnosis or treatment of any medical condition. Please consult a licensed medical professional for diagnosis and treatment of health/medical conditions.