Diabetic peripheral neuropathy (DPN) is severe diabetic complication in which nerves degenerate, beginning with the feet and hands and moving toward the trunk. The first symptoms are tingling, followed by intractable pain, then gradual loss of sensation. DPN dramatically lowers quality of life, and late-stage nerve damage can require leg amputation. There’s no effective treatment other than controlling blood sugar, but since one-third of diabetics develop DPN by age 40, there’s a market for drugs and supplements that alleviate symptoms.
Current drug treatment uses mostly antidepressants, anticonvulsants and opioid pain killers, all of which have many side effects including being barely conscious! Using opioid pain killers daily for years is more or less like being a heroin addict. Traditional Chinese herbal medicine (CHM) is thought to offer safe, effective alternatives. Is this realistic?
When medical researchers want a fast overview of treatments, they utilize meta-analyses, which are studies that pool many research studies—each of which has it own statistical basis--within a global statistical framework to provide a single conclusion regarding the efficacy of a treatment. The good thing about meta-analyses is that many patients become one set, providing diversity otherwise unachievable. The bad thing is that upon independent review of studies concerning natural products, many are thrown out or weighted lightly due to poor design.
Three recent meta-analyses investigate CHM for DPN. Herbal blends frequently included Astragalus, Angelica, Peony, Condonopsis, Rehmannia, Cassia, Sichuan Lovage.
• 49 randomized trials involving 3,639 participants, all published in China. Thirty-eight different CHM taken internally.1
• Topically applied medicines: 23 randomized controlled trials, including different 22 CHM.2
• 163 studies claimed to be randomized controlled trials were reduced to 10 studies with 653 individuals that actually met the criteria to be included in the meta-analysis.3
The overall result is that ZERO treatments were judged effective, but most were safe. I did find one clearly effective treatment: aconite, commonly known as wolfsbane or monkshood. Aconite contains narcotic alkaloids, which, used judiciously block pain. Overdose, however, causes coma or death.
The moral of the story is that one should not expect to see safe, effective herbal treatments for severe nerve degeneration that requires dangerous anti-seizure or narcotic drugs to control. The meta-analysis themselves are not “flawed” or “biased.” They inform you that you’re tilting at windmills. The correct question to ask in a clinical trial is: “How can CHM help control blood sugar and improve metabolism so that DPN never occurs?”
1. Chen W, Zhang Y, Li X, Yang G, Liu JP. Cochrane Database Syst Rev. 2013;10, CD007796.
2. Chen W, Luo YF, Liu JP. Forsch Komplementmed. 2011;18,134-45.
3. Hao CZ, Wu F, Lu L, Wang J, Guo Y, Liu AJ, Liao WJ, Zheng GQ. PLoS One. 2013;10, e76113.