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 Echinacea: Fact and Fiction, Part Three By Kerry Bone, BSc (hons.), Dip. Phyto Editor's note: Click here to read part two of Dr. Bone's article. The Myth About Long-Term Use On the topic of the supposed detrimental effect of long-term use of echinacea, it should be pointed out that the original concerns arose out of a mistranslation/ misunderstanding of German clinical research published in 1989. Jurcic and coworkers tested the effect of an E. purpurea tincture on the phagocytic activity of human granulocytes following intravenous or oral administration.33 This clinical study has been subjected to considerable misinterpretation or over-interpretation, which has led some writers to suggest that echinacea depletes the immune system when used continuously for periods longer than several days. The reason behind the misunderstanding was that the test dose of echinacea was only given for the first five days, but phagocytic response was tested for 11 days. A cursory examination of the results might lead to the conclusion that echinacea "wears out" the immune system, since phagocytic activity peaks at five days and then begins to fall away. But this was only after the echinacea was stopped and activity only fell back to normal levels. So the study, in fact, demonstrates that phagocytic activity is higher than normal while echinacea is given and when echinacea is stopped, phagocytic activity remains well above normal for a few days. This suggests that far from causing depletion, there is a residual stimulating effect when echinacea is stopped. Moreover, phagocytic activity only returned to normal; that is, there was no depleting effect found, where activity would drop to less than normal. Echinacea and Autoimmune Disease There is considerable controversy over the safety and value of echinacea in autoimmune disease. Given the great variety of disorders that come under this classification, and the associated complexity of immune imbalances, it seems unreasonable to suggest there might be no circumstances when the herb is safe and useful. On the other hand, echinacea might not suit all patients with autoimmune disease. On this point, the few documented cases where it might have been associated with a patient's deterioration have been taken as a proof that it is contraindicated in autoimmune disease. However, this ignores the countless cases where echinacea has been safely prescribed in this context. There is growing evidence from individual cases and experimental models that autoimmune disease is often associated with a defective functioning of some aspect of the immune response, especially involving NK cells. NK cells are part of innate immunity and hence, this aspect of immunity can be deficient in autoimmune disease. In contrast, some aspects of T- and B-cell responses, which form the acquired immune response, usually are overactive in these disorders. The NK cell deficiencies probably vary across the range of different autoimmune diseases, but also might vary for individual patients expressing a particular disorder. (This latter point might explain why a handful of patients with autoimmune disease do not respond well to echinacea.) For example, patients with systemic lupus erythematosus often are deficient in NK cell function34 and the role of NK cells in inhibiting autoimmunity in general has been well-established from experimental models.35,36 Natural killer cell dysfunction also is a distinguishing feature of systemic onset juvenile rheumatoid arthritis37 and circulating NK cells are reduced in psoriasis and rheumatoid arthritis.38 A particular focus has been on NKT cells, which are a subset of T-cells that share properties of NK cells and conventional T-cells.39 NKT cells are potent producers of immunoregularity cytokines that can control an overactive immune response. A survey of patients with different autoimmune diseases found around half had reduced numbers of NKT cells.40 Given the above, the findings noted previously by Sandra Miller that E. purpurea root boosts NK cell numbers and function in experimental models are particularly relevant. Dr. Miller and colleague Danielle Delorme also have examined the effects of echinacea root consumption in non-obese diabetic (NOD) mice, a model of human type 1 diabetes. NKT cells are believed to be implicated in type 1 diabetes and their functional and/or numerical deficiency is thought to be largely responsible for the development of this disease in NOD mice.41 When NOD mice were fed echinacea for varying times. there was a substantial and significant increase in NK cell numbers. This was the only type of immune cell influenced by the echinacea in these mice. The authors concluded: "The observations of the present study have, at least in the animal model of human type 1 diabetes, led to 2 conclusions. First, daily consumption of Echinacea by animals afflicted with this particular autoimmune disease, leads to no negative repercussions, and indeed, may provide all the advantages, in vivo, that consuming this herb does for normal, unafflicted mice (humans). Second, the study may provide evidence for a possible new approach to the treatment of type 1 diabetes. That is, immuno-stimulation only of those cells (NK/NKT) involved in modulating the disease. Echinacea is one such uniquely tailored, immuno-stimulant, whose effect is on NK cells." Idiopathic autoimmune uveitis usually is treated by oral corticosteroids. It's an inflammation of part or all of the uvea, the middle (vascular) tunic of the eye, although it also commonly involves the sclera, cornea and the retina. On the basis of the known interaction of echinacea alkylamides with cannabinoid CB2 receptors, which implies immune modulating and anti-inflammatory activities, a group of Italian clinicians investigated the safety and efficacy of E. purpurea in this autoimmune disease.42 Fifty-one patients with low-grade autoimmune uveitis were treated with conventional therapy, including oral prednisone. In addition, 32 of these patients were given echinacea as an add-on therapy. At the last follow up, which was nine months later, 87.5 percent of patients receiving echinacea were in clinical remission, compared to 82.3 percent of the control group. However, steroid-off time was significantly higher in the echinacea group (indicating that patients receiving echinacea needed less prednisone to induce remission). The authors concluded that the oral intake of echinacea appears safe and effective in the control of low-grade autoimmune uveitis. No patient showed any side effects or aggravation from the use of echinacea for their autoimmune disease. Clinical Effects on Immune Function A traditional lipophilic echinacea root preparation has been shown to prevent winter infections when taken regularly. A randomized, double-blind placebo-controlled trial carried out by Dr. Anna Macintosh and co-workers in 1999 demonstrated that an echinacea root liquid and a liquid formula made from three tonic herbs both significantly reduced the incidence of winter colds in students.43 The echinacea liquid consisted of a flavored blend of E. angustifolia and E. purpurea roots (in equal quantities) standardized to contain at least 1 mg/mL of alkylamides. The trial was conducted on 265 medical students because this group tends to be highly stressed and susceptible to winter infections. The students were assigned to receive either one of the two active formulas or the placebo in late autumn and were followed for 105 days. Three dosage protocols were tested over the length of the trial: high (4 mL twice/day), followed by medium (3 mL twice/day), followed by low (2 mL twice/day). Whereas the incidence of colds remained at about 10 percent of the test population for the placebo group, the incidences for the echinacea and the tonic formula fell to 2 percent and 3 percent at 42 and 70 days, winding back to 4 percent and 8 percent at 105 days, respectively. This reduction in effect at 105 days probably reflects the effect resulting from the reduced dose protocol. The differences between the active liquids and placebo were at the borderline of statistical significance at 42 days (p = 0.06 to 0.07), and achieved statistical significance at 70 days (p = 0.03). Results at 105 days were not significantly different from placebo (reflecting the low-dose protocol). There was no significant difference between side effects for the three groups, although there was a slightly greater incidence of digestive upset for the echinacea group. In particular, the echinacea treatment did not increase or aggravate allergies. The authors suggested their study demonstrated that the effective dose for the echinacea root combination as a preventative treatment was approximately 5 mL per day. To further understand the effects of a traditional echinacea root product at a clinical level, a small study was undertaken to investigate its effects on heat-shock proteins and whole-blood parameters. Healthy volunteers were dosed with two tablets per day of a commercial echinacea preparation for two weeks, with assessment at the beginning and the end of the trial. Positive results were evident, with increased heat-shock protein levels (hsp70) and increased white cell counts within normal physiological limits. (Heat-shock proteins are molecular chaperones that modulate the immune response.)44 Further work is planned to evaluate these effects in a much larger study. This increase in white cell count for echinacea root ties in well with research from the team of Dr. Miller in Canada mentioned previously. This clinical research, together with that of Dr. Miller, implies that echinacea acts mainly on innate immunity and hence, will work best as an infection preventative, as shown in the study by Dr. Macintosh. Recent research has made a substantial contribution to a new understanding of lipophilic extracts of echinacea. From this research, the following can be concluded:
Long-term use of echinacea is not only safe, but also distinctly beneficial. There is no sound reason why a general contraindication of echinacea in autoimmune disease should exist; in fact, there is evidence to suggest it could be beneficial. The traditional way echinacea was used has been validated by scientific research at the cutting edge of modern immunology. References
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All Rights Reserved, Naturopathy Digest, 2011.
Date Last Modified - Friday, 17-Oct-2008 12:10:57 PDT
About the Author: Kerry Bone was an experienced research and industrial chemist before studying herbal medicine full-time in the UK, where he graduated from the College of Phytotherapy and joined the National Institute of Medical Herbalists. He is a practicing herbalist; co-founder and head of research and development at MediHerb; and principal of the Australian College of Phytotherapy. Kerry also is the author of several books, including Principles and Practice of Phytotherapy and The Essential Guide to Herbal Safety.
