Natural Immunity Ingredient Reviews
Experts reviewed some popular natural remedies and ingredients that are thought to help shorten symptoms of – or possibly even ward off – the common cold and flu. Here are the ones that received a "thumbs up."
While echinacea, Airborne and other products didn't make the cut, evidence does support the following ingredients as having potential to support your immune system.
• Omega-3 Fatty Acids - Best known for their heart-healthy properties, omega-3 fatty acids are also powerful immune boosters. Omega-3s increase the activity of phagocytes-cells that fight flu by eating up bacteria-according to a study by Britain's Institute of Human Nutrition and School of Medicine. Other research shows that omega-3s increase airflow and protect lungs from colds and respiratory infections.
• Astragalus – This Chinese root is shown to stimulate the white blood cells that fight infection, says Andrew Weil, MD. A study published in 2007 found that astragalus appears to boost immunity in mice, and a pilot study suggests that the herb may have similar effects in people. Keep in mind that astragalus may take 6 to 8 weeks to reach its full effect.
• Vitamin D - This power nutrient may effectively boost immunity and help prevent colds, a Harvard study shows. People with the lowest vitamin D levels were 36% more likely to have upper respiratory infections, compared with those with the most D. (Asthma patients with low levels of D were nearly 6 times as likely to get sick as those with the greatest amounts.) Adequate amounts of D help produce cathelicidin, a protein with virus-killing qualities.
• American ginseng - This particular ginseng variety contains compounds that increase white blood cells and interleukins, proteins the immune system relies on. People who took this supplement caught half as many colds as a group taking a placebo, according to a study by the Center for Immunotherapy of Cancer and Infectious Diseases at the University of Connecticut. When they did get sick, their symptoms lasted less than half as long.
• Zinc – Taking this mineral at the very start of a cold may slow the multiplication of the virus in the nose and throat, appearing to shorten the duration of colds. But take too much; while even a slight deficiency in zinc, which is needed to produce white blood cells, can increase your risk of infection, more than 50 mg daily can suppress your immune system and block absorption of other essential minerals.
Based on a Prevention magazine research review.