Why You Need Extra Vitamin D during the Flu Season

Tuesday, December 02, 2008 by: Helmut Beierbeck
Tags: vitamin D, health news, Natural News

(NewsTarget) The flu season is upon us and you may be wondering whether or not you should get vaccinated. Recent evidence would suggest that flu shots aren′t very effective, especially for those most at risk - the elderly. These are the people most likely to come down with the flu, followed by complications like pneumonia. Flu shots also don′t seem to do a very good job at protecting young children.

So what can you do? There is good evidence that vitamin D wards off the flu and common cold. If you live far from the equator, you simply won′t get enough sun at this time of the year to make all the vitamin D you need. Given the importance of the sunshine vitamin for all aspects of your health, supplementation with vitamin D makes sense whether or not you decide to get the flu shot.

Influenza vaccination

"Flu Shots For The Elderly Are Ineffective". That′s the headline of an Oct. 23, 2008 release from the Orthomolecular Medicine News Service (1). The article picks up on a Sep. 2, 2008 report in the NY Times which claimed that "Doubts Grow Over Flu Vaccine in Elderly" (2).

"A growing number of immunologists and epidemiologists say the vaccine probably does not work very well for people over 70, the group that accounts for three-fourth of all flu deaths." (2)

The evidence for and against the flu shot′s effectiveness

Flu shots are effective if you believe the results of dozens of observational studies carried out over the last forty years or so. These studies seemed to show that flu shots cut the risk of dying in winter from any cause by almost 50% and reduced the need for hospitalization by nearly 30%. It should be pointed out that unambiguous evidence is hard to come by in this field, since doctors rarely confirm influenza with lab tests.

The only randomized placebo-controlled trial to date, a study published by a Dutch group in 1994, found that the vaccine prevented the flu in about 57% of patients in their sixties. For patients past seventy the rate dropped to just 23%.

A 2005 article, on the other hand, painted quite a different picture. That paper pointed out that, even though the percentage of elderly getting an annual flu shot more than tripled from 1980 to 2001, there was no corresponding drop in the death rate. The authors concluded that the flu probably causes just 5 - 10% of all winter deaths in the elderly.

Vaccination doesn′t appear to protect small children very well either, judging by the experience with the 2003 - 2004 and 2004 - 2005 vaccines. Investigators looked at laboratory-confirmed influenza cases in children 6 to 59 months of age, their vaccination status, and their influenza-related inpatient/outpatient visits to emergency departments and outpatient clinics. Here are the authors′ conclusions: (3)

"In 2 seasons with suboptimal antigenic match between vaccines and circulating strains, we could not demonstrate [vaccine effectiveness] in preventing influenza-related inpatient/[emergency department] or outpatient visits in children younger than 5 years. Further study is needed during years with good vaccine match."

A new 2008 Lancet article questions earlier findings that flu shots are effective (4). The authors of that paper suggest that the very decision to get vaccinated simply sets healthy seniors apart from the sick and frail. They theorize that healthier and more health-conscious patients are more likely to take the initiative to get a flu shot. Seniors who may have trouble taking care of themselves might simply not get to a doctor′s office for the vaccine. In other words, lower influenza rates in the vaccinated may have little to do with the vaccine′s effectiveness; seniors who get vaccinated may simply be healthier to begin with.

Needless to say, this view isn′t universally shared by the health care community. Proponents of immunization maintain that any reduction in the number of influenza cases has to be welcome, even if there is no sound evidence that this reduction is due to the flu shot. Doubters, on the other hand, simply see this attitude as a triumph of marketing over science.

Why would flu shots be ineffective?

First, there are some 200 to 300 different influenza virus strains, but the vaccine usually contains antigens of only a few. Preparing vaccines for the coming flu season is an annual guessing game. More often than not the vaccine doesn′t contain antigens of the most virulent strains.

Secondly, our immune system weakens with age; older adults do not respond as well as younger people to vaccines. For example, elderly patients may need as much as four times the amount of antigen for the same immune response as people under forty.

Thirdly, flu shots and other vaccines have harmful side effects. The Vaccine Adverse Effect Reporting System (VAERS) of the U.S. Food & Drug Administration (FDA) receives around 11,000 serious adverse reaction reports per year. Serious reactions are defined as death, life-threatening illness, hospitalization, or disability resulting from a vaccine. The FDA admits that in all probability only about 10% of adverse reactions are actually reported. The U.S. National Vaccine Information Center puts that ratio at only 3%.

In addition, the elderly take more medications than younger people. Combined with an already weakened immune system and potential vaccine side effects, the risk of adverse reactions can only grow with age.

What can you do to protect yourself?

Whether or not you decide to get the flu shot, you should do everything you can to strengthen your immune system. As the article from the Orthomolecular Medicine News Service puts it:

"Is there an available alternative? Yes, there may be: give the elderly more nutrients, rather than more needles. Older people often have inadequate diets. With ageing and illness, their bodies′ need for vital nutrients goes up, yet frequently their intake actually goes down." (1)

and

"Over-reliance on vaccinating the elderly ignores their fundamental problems of poor diet and vitamin/mineral deficiencies. These are underlying reasons for a susceptible immune system. Supplemental nutrition is the "other" immune system booster. It is time to use it." (1)

The authors point out that high doses of vitamin C have been shown to reduce the frequency and severity of influenza. Vitamin D and the minerals selenium and zinc have also been found effective.

The nutritional approach shouldn′t just be seen as a replacement for immunization. Even an effective vaccine still requires a functioning immune system. A vaccine presents the patient′s immune system with a weakened or dead virus. The immune system responds to that viral preparation in exactly the same way as it would to the real thing. By trial and error, the adaptive immune response develops antibodies and memory B and T cells against the viral strains it encountered; this process can take days if not weeks.

The difference between the live virus and the vaccine - and the idea behind vaccination - is that during that delay the live virus multiplies rapidly and may overwhelm the patient, whereas the weakened or dead viral strains cannot. If the vaccination worked, the patient′s adaptive immune system is prepared to respond immediately when it encounters the live virus.

Over-reliance on vaccinating the elderly, as the article from the Orthomolecular Medicine News Service puts it, also ignores another potent component of the host defenses - the innate immune system. Strengthening innate immunity may well pay larger dividends than the focus on adaptive immunity.

This is where vitamin D comes in.

Influenza and vitamin D

The new influenza model

One of the unusual aspects of influenza outbreaks is their seasonality; in temperate climates winter is flu season. The connection between the amount of sunlight and the disease was obvious enough, but the reason for this connection has only recently been understood (5). Vitamin D is essential to innate immunity, and most of our vitamin D is made by exposure to UV-B radiation from the sun; there simply are no significant dietary sources of vitamin D. Unless we supplement in the winter, our innate immunity will be compromised.

It is now believed (5) that much of the population carries various strains of the influenza virus year-round. During the summer months vitamin D is plentiful - unless one avoids the sun - and innate immunity can keep the virus in check. As winter approaches, vitamin D stores drop and the virus gains the upper hand.

That is when people get the flu and spread it. However, it seems that only a minority of influenza carriers are efficient transmitters of the virus. They will infect and sicken those that they come in contact with, but most of the newly infected will not pass the virus on; the epidemic is usually self-limiting.

Vitamin D′s mode of action

The adaptive immune system creates taylor-made antibodies to pathogens by trial and error. It is a match for any pathogen, but that process takes time. The innate immune system, on the other hand, produces antimicrobial peptides (AMPs) with broad-spectrum antimicrobial effects against intact microbes and "Pathogen-Associated Molecular Patterns (PAMPs)". These AMPs will not be a match for every pathogen, but when they are the innate immune system springs into action immediately.

The influenza virus is spread by coughing and sneezing, and inhaled. The epithelia in the upper airways are surrounded by a thin aqueous layer of AMPs covered by mucus. This double layer of antimicrobiol peptides and mucus creates an antimicrobial shield that rapidly and irreversibly damages the membranes of virus particles that penetrate it.

Viruses that somehow make it through that shield to the endothelium induce endothelial cells to emit a burst of new antimicrobial peptides. These inducible AMPs bind to the carbohydrate portion of a viral glycoprotein, hemagglutinin A, thereby blocking the fusion between virion (virus particle) and endothelial cell; the virion can no longer penetrate the endothelium. The inducible AMPs also recruit macrophages and other white blood cells to limit further damage and clean up the debris.

Where does vitamin D come into the picture? When microbes like the influenza virus end up in the upper airways, they stimulate the production of an enzyme that converts 25(OH)D, the circulating inactive form of vitamin D, into the hormonally active 1,25(OH)₂D (1,25-dihydroxyvitamin D). 1,25(OH)₂D is required to turn on the genes that code for antimicrobial peptides. Without vitamin D there is no innate immunity.

There is convincing evidence that supplementation with a sufficient amount of vitamin D can prevent the onset of a flu or cold. An analysis of a randomized controlled trial showed that post-menopausal African American women taking 800 IU/day of vitamin D were three times less likely to come down with the flu or cold than those receiving placebo. 2000 IU/day essentially eliminated cold and flu cases altogether (5).

Vitamin D recommendations

The amount of 2000 IU/day is considerably higher than the current recommendations from the Food and Nutrition Board of the U.S. Institute of Medicine: 200 IU/day from birth to age 50, 400 IU/day fom 50 to 70, and 600 IU/day for anyone over 70.

These values were originally chosen because they were found to prevent osteomalacia (bone softening) and rickets. It is now recognized that vitamin D has many additional physiological functions, for which these levels are totally inadequate. A number of scientists are therefore calling for the Food and Nutrition Board in the U.S. and its counterparts abroad to reassess their current recommendations (6).

Experts in the field now believe that 25(OH)D blood concentrations should at least be 50 ng/ml (nanograms per milliliter), the level normally reached by sun exposure during the summer months. In the flu season, when there simply isn′t enough sunlight, supplementation with at least 2000 IU/day is needed to get to that level. You′ll get that from 2 tbsp of cod liver oil. That amount is considered perfectly safe. A recent risk assessment put the safe tolerable upper intake level (UL) of vitamin D at 10,000 IU/day, i.e. five times the amount now believed necessary.

Summary

Don′t just rely on vaccination to get you through the flu season; flu shots simply don′t seem to be very effective, especially for the most vulnerable groups in society - the very young and the elderly. There are a number of possible reasons for this. The vaccine may not target the most virulent influenza strains, the patient′s immune system may already be too weak to mount an immune response, or the vaccine may have side effects.

Vaccines containing weakened or dead viruses are meant to prepare the adaptive branch of the immune system for the onslaught of the live virus. When everything works, the adaptive immune system is capable of matching any pathogen, but the process takes time. The innate branch of the immune system, on the other hand, has a fixed repertoire of peptides that match the most common pathogen-asociated molecular patterns. There may not always be a match, but when there is then innate immunity is ready immediately.

The proper functioning of the innate branch of the immune system depends on the patient′s stores of vitamin D. If you live in a temperate zone, you simply cannot get enough sun exposure in the winter to reach the necessary vitamin D levels; you need to supplement, for example by taking cod liver oil. Given all its other health benefits, such as improvements in bone strength, insulin regulation, muscle strength, cardiovascular function, and a decrease in the risk of certain cancers, the decision to supplement with vitamin D should be a no-brainer.

Sources:

1. Flu Shots For The Elderly Are Ineffective. Orthomolecular Medicine News Service, Oct. 23, 2008.



2. Doubts Grow Over Flu Vaccine in Elderly. Goodman B. NY Times Sep. 2, 2008.



3. Szilagyi PG et al. Influenza vaccine effectiveness among children 6 to 59 months of age during 2 influenza seasons: a case-cohort study. Arch Pediatr Adolesc Med 2008;162(10):943-951.
   http://archpedi.highwire.org/cgi/content/abstract/162/10/943



4. Jackson ML et al. Influenza vaccination and risk of community-acquired pneumonia in immunocompetent elderly people: a population-based, nested case-controlled study. The Lancet 2008;372:398-405.
   http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(08)61160-5/abstract



5. Cannell JJ, Zasloff M, Garland CF, Scragg R, Giovannucci E. On the epidemiology of influenza. Virol J 2008;5:29
   http://www.virologyj.com/content/pdf/1743-422X-5-29.pdf



6. Vieth R et al. The urgent need to recommend an intake of vitamin D that is effective. Am J Clin Nutr 2007;85:649-650.
   http://www.ajcn.org/cgi/reprint/85/3/649<.li>
   
   

About the author

Helmut Beierbeck has a science background and a strong interest in all scientific aspects of health, nutrition, medicine, weight loss, or any other topic related to wellness. You can follow his ruminations on his blog http://healthcomments.info and leave comments on this or any other health-related topic.