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Home > How to Stay Healthy
How to stay healthy during flu season
Chances are high that you will be exposed to seasonal and H1N1 influenza viruses this winter. If you have a chronic condition, you are more vulnerable to serious consequences. So what is the best way to protect yourself?
After a discussion with your physician, you may choose to get one or both vaccines. Hopefully you will be protected in a few weeks -- but some at-risk people do not mount an effective response to influenza vaccines. In a study of elderly persons, influenza antibody levels barely increased after immunization.1 Other high risk populations may also respond poorly.2,3
Research suggests several strategies to strengthen your defense against the influenza virus and boost your response to the influenza vaccine. Influenza infection leads to decreased levels of antioxidants in the lungs and liver.4,5 This oxidative stress can promote influenza infection.5 Antioxidants can have major benefits in fighting influenza.
An important study of 262 people found that 79% of people developed symptoms after being exposed to an H1N1 influenza strain. But only 25% of participants taking an antioxidant called N-acetylcysteine (NAC) developed symptoms after being exposed. An additional benefit was that the symptoms were less severe in the NAC-treated group.6 Two studies in mice showed that NAC also can synergize with antiviral medications. Mice treated with NAC and either Tamiflu7 or ribavirin8 were more likely to survive a lethal dose of influenza than mice treated with the antiviral alone.
Another antioxidant called Quercetin may be beneficial in fighting influenza. Quercetin is a bioflavonoid found in a variety of fruits and vegetables. Quercetin restored levels of many lung antioxidants in a mouse model of influenza infection.4 Quercetin also significantly protected mice from increased vulnerability to influenza caused by exercise stress.9 Acute lung injury due to influenza and other insults can be prevented by loss of a pathway called TLR4-TRIF.10 Quercetin is able to down-regulate this pathway.11
A study of nutrition and influenza found that nutritional deficiencies increased the risk of respiratory infections, including influenza.12 The most common deficiencies were Vitamins C, D, B-6, and B-12 and Folic Acid and Zinc. Deficiency of Vitamin D is surprisingly common. Although the optimal blood level for Vitamin D is 50 ng/ml according to many experts,13-15 only 23% of US adults have levels above 30 ng/ml.16 Regular exercise and using multivitamin supplements were independently associated with better antibody response to influenza vaccination among coronary artery disease patients.17 A study in elderly patients confirmed the increased antibody responses with exercise and found that a daily multivitamin increased the cellular immune response to influenza vaccination.18
Adequate levels of Vitamin D are important for the immune system, in addition to benefits for bones and teeth. Although Vitamin D supplementation may not lower the incidence of respiratory infections,19 it might help the body deal with secondary infections. Bacterial infections are found in about 30% of fatal cases of pandemic H1N1 influenza.20 With adequate Vitamin D, the body can produce cathelicidins that have been shown to fight bacteria and viruses,21-23 (including influenza 24-27) in laboratory studies. Some scientists believe that the wintertime dip in blood Vitamin D levels plays a role in the seasonal nature of influenza.28
Studies on the benefits of Vitamin C for respiratory infections have been contradictory. A possible explanation for the confusion is that Vitamin C doesn’t last very long in the body. For large doses, its half-life is only 30 minutes.29 This implies that small frequent doses may be more helpful. According to one study (reviewed in 29), hourly Vitamin C may be beneficial for influenza or colds.
Action plan
MasterYourIllness offers an excellent multivitamin, Immune Vitality that contains the antioxidants NAC and Quercetin. Depending on your age, intake of fatty fish and sunlight exposure, you may require additional Vitamin D. Multiple small doses of Vitamin C may be beneficial (consider oral lozenges).
References for this article
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