Winning the Cold War
A Review of Natural Remedies for the Common Cold
Influenza infection is a leading cause of morbidity, with 20-25 million doctor visits per year. Annually there are about 190 million lost school days due colds and flu. Conventional anti-inflammatory and anti-fever medications, as well as decongestants provide for relief of symptoms. Other modalities have been suggested to boost the immune system or curtail the annoying symptoms associated with colds and flu.
A number of companies sell enhanced foods and beverages, such as Fruit2O Immunity beverage, that supposedly boost or enhance the immune system. These products containing various herbal, vitamin, and mineral additives, do not function as their label claims. While zinc can block cold-causing rhinoviruses from adhering to the nasal lining, zinc lozenges or nasal sprays are an unreliable way to reduce cold symptoms.
Four decades ago, Linus Pauling claimed that 3 to 5 grams of vitamin C a day would prevent or cure the common cold. After 30 clinical trials involving over 11,000 participants, we can clearly say that vitamin C does not prevent colds. Research suggests that vitamin C slightly reduces the duration and severity of colds, but there is no benefit to exceeding 250 mg/day, a level easily obtained from consuming the recommended 9 servings a day of fruits and vegetables.
Cold-fx, a standardized extract of American ginseng root, is approved in Canada for the relief of cold symptoms. Healthy adults who took Cold-fx for 4 months had fewer colds, and symptoms were milder, while elderly people experienced fewer respiratory infections.
Flowers of European elder are known to reduce the severity and duration of cold and flu symptoms, while garlic, a wide spectrum antibiotic, is commonly taken to help fight the common cold and upper respiratory infections.
Echinacea preparations are widely used in Europe to boost the immune system and shorten the duration and severity of a cold. Unfortunately with herbal remedies, their effects are not always predictable since the purity and identity of the product may not be guaranteed, and the ideal dosage is often not known.
We should keep our immune system healthy by eating meals rich in fruits and vegetables, getting adequate sleep, managing stress appropriately, and getting regular exercise. When you exercise moderately, such as walking briskly, the natural killer cells and neutrophils start circulating at an increased level. These immune cells defend the body against invading bacteria and viruses, and stay elevated for about 3 hours after a 45-min walk. They then drop to normal levels until you exercise again, emphasizing the importance of regular exercise since the benefit from immune cells is short lived.
Author: Winston Craig, MPH, PhD, RD.
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