Life Extension Magazine November 2006
Naturally Boosting Immunity During Cold Season
By Dale Kiefer
Consumers spend billions of dollars each year on over-the-counter cold and flu remedies, yet none of these drugs addresses the underlying factors that make people so susceptible to the viral infections that cause colds and flu.
While over-the-counter drugs help treat cold symptoms, people remain sick until their bodies’ natural immune systems rally to overwhelm the infection. Healthy immune function is not only critical to rapid recovery from common viral infections, but also determines how resistant people are to contracting these illnesses.
Further compounding the problem is that millions of doctors erroneously prescribe antibiotics to patients seeking relief for their cold symptoms. The inherent danger in this approach is that persistent misuse of antibiotics further weakens an already compromised immune system and may contribute to the development of antibiotic-resistant pathogens.
When the immune system functions optimally, people are less likely to be infected by the countless bacteria and viruses to which they are exposed each day. In fact, proper immune function is essential to mounting an antibody response to the flu vaccine, which conventional doctors recommend to elderly patients to help protect against common strains of the influenza virus.
Although Life Extension members achieve considerable immune support through their daily intake of high-potency antioxidants and hormones like DHEA, exciting new studies indicate that a combination of novel, natural agents works to strengthen critical immune components in the body, thus providing even greater protection against the onslaught of seasonal viral infections.
Normal Aging Diminishes Immune Function
Immune function declines precipitously with normal aging, as demonstrated by the large numbers of people over the age of 60 who succumb to influenza infections or suffer outbreaks of shingles (which occur when dormant herpes zoster viruses emerge due to depressed immune function).
Although considered “routine,” colds and flu can quickly lead to dangerous and even fatal upper-respiratory complications such as pneumonia. In 2002, influenza and pneumonia were the fifth leading cause of death among US men and women aged 65 and older, accounting for nearly 59,000 deaths in this age group alone. Among all ages and sexes, pneumonia and influenza were the seventh leading cause of death in 2002.1,2 Two years later, pneumonia and influenza slipped a notch, to the eighth leading cause of death among all Americans, supplanted by Alzheimer’s disease, which had formerly occupied that spot. Nevertheless, deaths from influenza and pneumonia still exceeded 61,000 in 2004.2,3
While the body’s age-related decline in immune function brings with it an increased susceptibility to infections,4,5 conventional medicine offers little to offset this decline. Despite mass immunizations of the elderly against influenza each year, lethal cases of flu and secondary pneumonia take a heavy toll on this age group. With advancing age, critical immune system cells called T-lymphocytes are less able to replicate, and their numbers diminish. Moreover, as these aging cells become “decrepit,” they may actually suppress immunity, further contributing to an aging person’s inability to fight off microscopic invaders.6,7
Immune function may also be weakened by factors ranging from chronic stress and poor nutrition to previous illnesses. When the immune system is compromised, a simple cold can quickly progress to full-blown pneumonia. This threat is especially significant for the elderly and is a leading cause of death for all Americans, regardless of age.
Acquired Immunity vs. Innate Immunity
For a large portion of the population, an annual flu shot may be the best defense against influenza infection. Flu shots work by exposing the immune system to very specific strains of flu virus that scientists believe are likely to cause an outbreak of flu in the coming year. After the body has been “primed” with specific (non-infective) viruses in the form of a vaccine, an optimally functioning immune system can then make antibodies that protect the body against future infection with these specific viruses. This ability to make antibodies in response to the flu vaccine is called acquired immunity. Acquired immunity is specific to the non-infective viruses contained within the vaccine. Thus, while it is highly effective against these particular viral strains, acquired immunity is of no value against the many other pathogens that people may encounter during cold and flu season. For this reason, the efficacy of a given vaccine is variable and usually limited.8,9
Fortunately, the body has a sophisticated primary defense system known as innate immunity. This system is designed to defend against all microbial invaders through the activation of large white blood cells called macrophages, which simply engulf their prey. However, their success depends on their ability to communicate effectively with other immune defense cells known as neutrophils, which make up most of the innate immune defense network. To neutralize an infection, it is critical that macrophages enlist the support of neutrophils in any battle against invading pathogens. Neutrophils are important types of white blood cells, critical for protecting your body against bacterial infection. Infection with the influenza type A virus has been found to deactivate neutrophils,10 which helps explain why people are at risk for bacterial illness during infection with the flu virus. Without the aid of neutrophils, the chances of succumbing to infection increase. Scientists have long known that macrophages must be “turned on” before they actively consume invaders ranging from bacteria and viruses to fungi and parasites.
Immune-Boosting Power of Beta-Glucan
Activating the communication and microbe-killing capabilities of macrophages is of paramount importance when confronting viral invaders, which may change their molecular “identities” in an effort to evade the body’s natural immune protection system. Numerous substances, including polysaccharides, lymphokines, and peptides, activate the defensive properties of macrophages. A polysaccharide called beta-glucan not only enhances macrophages’ ability to recognize and subdue microbial invaders, but also increases their ability to communicate with other cellular defenders of the immune system. These defenders, the immune “T cells,” subsequently initiate communications among a variety of immune system components, culminating in a cascade of events that amplify the immune response and ultimately overcome microbial invaders.
Korean researchers have demonstrated a direct anti-viral effect of beta-glucan against the influenza virus. Scientists exposed two groups of newborn pigs to the swine flu virus. Capable of infecting humans, it was a type of swine flu that notoriously prompted the US government to attempt the first nationwide flu vaccination program 30 years ago. This dramatic effort was spurred in part by the realization that another strain of swine flu may well have been responsible for the global devastation of the great flu pandemic of 1918, in which millions of people perished.
In this important experiment, one group of piglets received beta-glucan for three days before being infected with swine flu, while the other group received only a placebo for three days before infection with live virus. Objective evidence of swine flu infection in the lungs of piglets that had been infected, but not given beta-glucan, was significantly more severe than in the infected animals that had been pre-treated with beta-glucan.11
Furthermore, pigs that had been pre-treated with beta-glucan had significantly higher concentrations of natural disease-fighting substances, including interferon-gamma, in fluid obtained from the lungs within a week of infection. The researchers concluded that beta-glucan reduced signs of lung disease and the viral replication rate in the test subjects. These findings support the potential application of beta-glucan to prevent or treat influenza virus infection.11
In another experiment, scientists investigated the effects of beta-glucan against another viral challenge. Young piglets were exposed to porcine reproductive and respiratory syndrome virus, and then disease-fighting white blood cells were removed and exposed to varying concentrations of beta-glucan. Beta-glucan increased the production of interferon-gamma in a dose-dependent manner, leading the scientists to conclude that soluble beta-glucan may enhance innate antiviral immunity.12
These experiments demonstrate beta-glucan’s ability to dramatically improve innate immunity, particularly against potentially deadly viral infections.
While beta-glucan is found in several traditional folk remedies (including some Chinese mushrooms) that have been used for centuries to enhance immunity,13-16 these sources provide only limited amounts of the specific beta-glucan now known to provide powerful immune support. An old pharmaceutical preparation, Zymosan, was known to stimulate immunity as far back as the 1940s. Researchers at the Tulane University School of Medicine conducted dozens of studies of this substance, eventually isolating beta-glucan as its active ingredient. After the researchers modified this ingredient for ready ingestion, experimental evidence began to mount showing that beta-glucan is a highly effective immune system stimulator, activating defenses against both bacterial and viral organisms.17-21
Although beta-glucan is one of the most powerful biological response modifiers currently available in supplement form, not all beta-glucan supplements are created equal. As-yet-unpublished research, conducted at the University of Louisville in Kentucky, shows that a specially modified, yeast-derived form of beta-glucan dubbed beta-1,3-D-glucan is orally bioavailable and stimulates production of white blood cells in human bone marrow and spleen. Additionally, this proprietary form of beta-glucan has demonstrated superior ability to activate macrophages, neutrophils, and natural killer cells, effectively boosting immune function to confront threats ranging from radiation poisoning to tumors and infection.