Here I look at how the herbs echinacea and elderberry may work on your immune system.
Hard evidence shows that echinacea definitely affects the immune system in many ways. It increases lymphocyte activity and the ability of white blood cells to ingest foreign invaders. However, despite years of clinical studies, there is controversy surrounding its effect or lack thereof on the common cold.
In studies that showed a positive effect, echinacea reduced the severity and duration of common cold symptoms up to 30% if a person started taking it at the first sign of a cold and continued taking it for the next seven to 10 days. Yet some studies did not show any beneficial effects. These conflicting results may be due to the fact that echinacea differs quite a bit in terms of its composition as a consequence of using a variety of plant material, extraction methods, and additives.
The best meta-analysis of the effect of echinacea on the common cold was published in 2006 by a group of German researchers. These researchers did a thorough search of the world literature from 1997 to 2005 .They selected only high-quality randomized placebo-controlled trials and excluded trials using combination of echinacea with other herbs. They identified 16 trials and the highlights of their findings include the following.
A variety of different echinacea preparations were used. Comparing echinacea to placebo, a significant positive effect was reported in several studies, a positive trend in one and no difference in six.
They concluded that some evidence shows that certain preparations of “Echinacea purpurea” might be effective for the early treatment of colds in adults. As well, beneficial effects of other echinacea preparations and for preventative purposes might exist, but have not been proven in solid studies.
Elderberry extract has been shown to possess both antiviral properties and effects in moderating the immune system. When given within 48 hours of influenza symptoms, syrup with elderberry juice (“Sambucol,” “Nature’s Way”) could reduce both the symptoms (by 56%) and duration of influenza. The full effect is usually seen within two to four days.
In a study conducted in Israel, 60 patients (aged 18-54 years) with influenza-like symptoms for 48 hours or less were randomized to receive one milliliter of elderberry or placebo syrup four times a day for five days. Results of this study showed that, not only were flu-like symptoms shortened by four days, but there was also less use of rescue medication in the elderberry-treated group.