Flu: symptoms of vitamin D deficiency

One of the symptoms of vitamin D deficiency could well be the flu.

This is a relatively new medical theory. In the past, Vitamin D has mostly been associated with the bones and among the most well-known symptoms of vitamin D deficiency is the disease called rickets, which causes a softening of the bones in children.

In addition, vitamin D deficiency is said to play a major role in osteoporosis, a disease in which older people lose calcium in the bones, causing the bones to become brittle.

Since diseases like rickets became longer a serious problem, there has not been a lot of interest in Vitamin D for a long time.

Renewed interest

In recent years, however, interest in this "old vitamin" has been revived for two reasons:

1. There has been an increase in the incidents of rickets in countries like America, where the problem is supposed to have been long solved, especially among African-American children
   
   
2. A number of scientific studies have suggested that Vitamin D plays important roles in helping to prevent infectious diseases like the flu, as well as more serious immune-related diseases like cancer.

There are sound, logical reasons to believe that the flu is actually one of the symptoms of vitamin D deficiency. Vitamin D is formed naturally when a person is exposed to sunlight and, in temerate countries, the flu season occurs in winter - when there is not a lot of sunlight and also when people tend to stay indoors because of the cold.

This casual observation is now backed by scientific studies. In 2005, a group of scientists from UCLA reported in the prestigious journal, Nature, that Vitamin D increases the body's production of a class of proteins, called antimicrobial peptides. These antimicrobial peptides - of which about 200 are known - directly and rapidly destroy the cell walls of bacteria, fungi, and viruses, including the influenza virus, and play a key role in keeping the lungs free of infection.

Dr J J Carnell

Interestingly, it was a psychiatrist, Dr J J Carnell, who made some pertinent observations that suggest the flu could be one of the symptoms of vitamin D deficiency.

Dr Carnell had worked 10 years in a maximum security hospital "for the mentally insane" and during a flu outbreak in 2005, he observed that patients throughout the hospital were getting the flu, except for those in this ward. He wrote:

My patients had intermingled with patients from infected wards before the quarantines. The nurses on my unit cross-covered on infected wards. Surely, my patients were exposed to the influenza A virus. How did my patients escape infection from what some think is the most infectious of all the respiratory viruses? My patients were no younger, no healthier, and in no obvious way different from patients on other wards. Like other wards, my patients are mostly African Americans who came from the same prisons and jails as patients on the infected wards. They were prescribed a similar assortment of powerful psychotropic medications we use throughout the hospital to reduce the symptoms of psychosis, depression, and violent mood swings and to try to prevent patients from killing themselves or attacking other patients and the nursing staff. If my patients were similar to the patients on all the adjoining wards, why didn't even one of my patients catch the flu?

Dr Castell soon figured that the difference was that all his patients had been taking 2,000 units of Vitamin D daily for at least a few months. This was because Dr Castell had earlier researched Vitamin D and, upon testing, found that almost all his patients had low levels of the vitamin. So he started to give his patients Vitamin D daily.

Dr Castell's paper was published in 2006 in Epidemiology and Infection. While he emphasised that his paper was just a theory that has not yet been scientifically proven, he points out that treating the flu as one of the symptoms of vitamin D deficiency does explain a lot of observations, such as:

• Why the flu predictably occurs in winter, when vitamin D levels are at their lowest, and disappears in summer
• Why influenza is more common in the tropics during the rainy season
• Why the cold and rainy weather, which drives people indoors and lowers vitamin D blood levels, is associated with influenza
• Why cod liver oil (which contains vitamin D) reduces the incidence of viral respiratory infections
• Why the elderly who live in countries with high vitamin D consumption, like Norway, are less likely to die in the winter
• Why children with vitamin D deficiency and rickets suffer from frequent respiratory infections
• Why African Americans, with their low vitamin D blood levels (because dark skins require more sunlight exposure to produce vitamin D), are more likely to die from influenza and pneumonia than Whites.

Click here to read an article by Dr Castell, sharing about what led him to regard the flu as one of the symptoms of vitamin D deficiency.

Healthy dose?

When we talk about the symptoms of vitamin D deficiency, then the question arises - what is a healthy level of vitamin D?

The US Food and Nutrition Board puts the "Adequate Intakes" of Vitamin D at 200 IU daily for children and adults up to 50 years old, 400 IU for adults aged 50 to 70 and 600 IU for the elderly above 71 years old. However, just 20 minutes of exposure to sunlight can produce up to 20,000 IU of Vitamin D. Scientists like Dr Castell therefore believe that human requirements for Vitamin D is in the order of tens of thousands of IU per day, and not just a few hundred IU.

The best source of vitamin D is sunlight exposure. The best food source of vitamin D would be cod liver oil, which provides about 1,360 IU of Vitamin D per serving. Other fish, like salmon, tuna, makeral and sardines, provide between 200 and 360 IU per serving while other food sources like beef, egg, liver, etc provide just tens of IU,

Meanwhile, we learn from Dr Joseph Mercola, who runs a highly popular health website, that a lot more health conditions could also be symptoms of vitamin D deficiency. Dr Mercola has compiled a long list of medical journal articles about the role of Vitamin D in protecting use against cancer, infectious diseases, auto-immune diseases, heart disease as well as brain, skin and bone problems.

He aptly calls Vitamin D the "superstar" Vitamin.