Vitamin D and Coronavirus

Here is another guest post from my scientific advisor, Robert DeStefano, who also happens to be my younger brother. He is a master biologist who has kept up his interest in science and nature even after retiring from the teaching profession. He has been following the coronavirus since it first appeared and has helped me on many of my posts. Early in March he argued that longer days and increased sunlight would be the real antidote. In particular, he believed ultraviolet light from the Sun was necessary for a healthy immune system. It looks like he was right.

                                                                Vitamin D.


Most of us were taught in school that Vitamin D is essential for proper bone development.  However, Vitamin D is also proving to be a major factor associated with IMMUNITY, DIABETES, HEART DISEASE, CANCER and the EVOLUTION OF SKIN COLOR.  

Most of us were also taught that the human body can make Vitamin D by being exposed to sunlight; hence it has been called the Sunshine Vitamin.  However, few people realize that what causes the production of Vitamin D is Ultraviolet light, specifically UV B.  Unfortunately the Northern Hemisphere receives very little UV B during the winter months.  In fact, we only start to receive significant amounts of UV B as the days grow longer around April, peaking during the summer, and tapering off beginning in the fall. 

The UV B which reaches the Earth occurs mainly between 10 AM and 2 PM.  A person outside on a bright sunny day for about 15 to 30 minutes will produce a substantial amount of Vitamin D, and, since Vitamin D is a fat soluble vitamin, we store excess amounts of it.  The typical recommendation for Vitamin D is about 600 to 800 IU a day.  This can be achieved by being exposed to UV B when available, or by eating food rich in Vitamin D such as oily fish, or by eating foods supplemented with Vitamin D such as milk and certain cereals, or by taking a Vitamin D tablet or a Multivitamin containing Vitamin D.

There are a variety of factors which go into our ability to make Vitamin D from UV B radiation.  Age, skin color, and various medications can all limit Vitamin D production.  As we age our skin does not produce the same amount of Vitamin D as when we were young; therefore, elderly people are more at risk of not producing enough Vitamin D from the Sun.  The darker the skin, the less UV B is absorbed thus limiting the amount of Vitamin D produced.  A very dark skinned person will require probably 3 times the Sun exposure than a very light skinned person to produce an adequate amount of Vitamin D.  Medications such as anti inflammatories, anti hypertensions, antibiotics, endocrines, and anti epileptics all limit the amount of Vitamin D production.

The seasonality of the flu is still somewhat of a mystery; however, the role of Vitamin D has always been considered to be one factor in this regard.  The amount of UV B reaching the Earth is dependent on season and latitude.  In fact the Evolution of skin color is closely tied to Vitamin D production.  UV B is abundant at the equator but diminishes going north or south from the equator.   A person being dark at the equator will be protected from excess amount of UV radiation which could cause skin cancer and still be able to produce enough Vitamin D.  If we follow the evolution of Man from Africa to Europe, being lighter and lighter in color was genetically selected for in order to produce Vitamin D in UV B limited areas but at the same time people run the risk of skin disorders such as cancer.  Typically the flu strikes the hardest during winter time in the Northern Hemisphere and begins to taper off in mid spring and summer when we begin to have UV B and natural Vitamin D production increasing.  

The question now is, “Does Vitamin D play a significant immunological role?”  Research over the past few years seems to indicate that Vitamin D plays a major role.  Proper amounts of Vitamin D can cause the production of potent anti-viral molecules known as cathelicidins.   Cathelicidins work as part of our innate immune system to stop the virus from infecting cells and turning those cells into viral factories. 

Research has shown that immune cells such as macrophages, T-cells and B-cells all have DNA receptors for Vitamin D indicating that these cells will initiate production of a variety of anti microbial molecules once signaled by Vitamin D. Vitamin D is associated with over 200 human genes which indicates that Vitamin D must be involved in many reactions which occur in the body.  Over 2500 DNA binding sites have been discovered for Vitamin D with many of those sites associated with a variety of autoimmune disorders such as Lupus, Rheumatoid Arthritis, Leukemia and Crohn’s disease.   Before there were antibiotics, Vitamin D was used to treat Tuberculosis.  Vitamin D is used to treat upper respiratory disease and to maintain proper skeletal structure and function. Vitamin D deficiency has been linked to Multiple Sclerosis, Autoimmune Diabetes, Asthma, Cancer, and Osteoporosis.  

            How much Vitamin D do we need?  When a blood Vitamin D test is taken, the numbers in ng/ml (nanograms of 25-HydroxyVitamin D per milliliter of blood) show a wide range in people.  Currently less than 20 indicates deficiency, 20 to 30 insufficient and 40 to 50 being sufficient. However, some researchers believe these numbers are too high while others believe that the numbers are too low. Too high a level can be dangerous as excess Vitamin D is not eliminated from the body.

Using these numbers, it has been estimated that close to a billion humans currently fall into the range of deficient or insufficient.  Some doctors recommend getting Vitamin  D level checked prior to going into Fall and Winter as the stores of Vitamin D will start to diminish with less and less UV B reaching the Northern Hemisphere with the opposite true for the Southern Hemisphere which enters Spring and Summer. 

Vitamin needs are usually expressed with the term International Units (IU) rather than a microgram amount in order for a typical person to make sense of the numbers.  The recommended daily intake of Vitamin D usually is in the range of 700 to 1000 IU which is easily obtainable by spending about 30 minutes in the Sun around midday during mid spring and summer.  In certain situations some doctors use what is called a Vitamin D hammer which is a dose of 50,000 IUs which then is gradually tapered off.  For a person with severe deficiency, some doctors will prescribe 20,000 IUs for several weeks and then reduce to 10,000 IUs or until the individual is no longer Vitamin D deficient.  Keep in mind that being in the Sun for several hours on a weekend will produced about 200,000 IUs of Vitamin D naturally.  However, as the level of UV B declines entering fall and winter, sunlight will no longer provide the daily requirement of Vitamin D.  As mentioned before, humans do store the fat soluble Vitamin D but without ingesting Vitamin D from either food or supplements, the stored Vitamin D will eventually be depleted resulting in either deficient or insufficient Vitamin D especially among the elderly.  

            I have never had my Vitamin D level checked, but I now believe that checking Vitamin D blood level during a routine blood test is warranted.   Elderly, dark skinned, immunocompromised individuals, etc. would be served well by knowing their Vitamin D level especially as fall begins in the Northern Hemisphere.

Robert DeStefano

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