Huperzine A, a phytochemical derived from the Chinese medicinal herb club moss (Huperzia serrata), promotes nerve cell growth and may benefit those suffering from Alzheimer’s disease and other neurodegenerative disorders, according to researchers at State Key Laboratory of Drug Research in Shanghai, China.*
Previous studies have demonstrated that huperzine A inhibits the breakdown of the neurotransmitter acetylcholine by inhibiting the enzyme acetylcholinesterase. Acetylcholine is responsible for relaying messages throughout the central and peripheral nervous systems. Numerous acetylcholinesterase-inhibiting drugs have been approved for treating Alzheimer’s disease.
This study investigated huperzine A’s effects on neurite outgrowth and nerve growth factor expression in a model of primary neuronal cells (PC12) in the laboratory. Neurites are outgrowths of neurons that form connections between cells, allowing for the transmission of messages. Nerve growth factor promotes neurite growth and may protect normal nerves from oxidative damage.
After just 24 hours of treatment with huperzine A, levels of nerve growth factor increased in the PC12 cells. After 48 hours of treatment, the number of neurite-bearing cells increased dramatically. Furthermore, treating PC12 cells with huperzine A inhibited acetylcholinesterase activity. The researchers concluded that huperzine A has direct or indirect neurotrophic (nerve-growth-promoting) activity, and suggested that huperzine A may be beneficial in treating neurodegenerative disorders such as Alzheimer’s disease.
Human studies are under way in the US to evaluate whether huperzine A benefits individuals with Alzheimer’s disease.
—Christie C. Yerby, ND
* Tang LL, Wang R, Tang XC. Effects of huperzine A on secretion of nerve growth factor in cultured rat cortical astocytes and neurite outgrowth in rat PC12 cells. Acta Pharmacol Sin. 2005 June;26(6):673-8.
Intensive diet and lifestyle changes slow the progression of low-grade prostate cancer, according to a landmark multi-institutional study.* While it is well known that a low-fat, plant-based diet is associated with a decreased risk of prostate cancer, this new research indicates that diet can influence the outcome of established prostate cancer.
At the onset of this 12-month study of men with biopsy-confirmed prostate cancer, all 93 participants had Gleason scores (a grading system for prostate cancer) of less than 7 and prostate-specific antigen (PSA) levels of between 4 and 10 ng/mL. Due to the low-risk nature of their prostate cancer, all the subjects had chosen a “watchful waiting” approach instead of conventional treatment such as surgery, chemotherapy, or radiation. The treatment group of 44 men consumed a vegan diet and supplemented daily with one serving of tofu, 58 grams of soy protein, 3 grams of fish oil, 400 IU of vitamin E, 200 mcg of selenium, and 2 grams of vitamin C. In addition, the treatment group walked 30 minutes six days per week, engaged in 60 minutes of stress management daily, and participated in a 60-minute support group once weekly. The 49 men who made up the control group followed the diet and lifestyle advice of their personal physicians.
At the end of one year, the treatment group demonstrated an average 4% decrease in PSA level, as compared with a 6% increase in the control group, representing a statistically significant difference. Increased PSA is considered a sign of disease progression and highly predictive of men who will require treatment, as opposed to continued watchful waiting.
Additionally, the researchers examined the effects of serums from the study and control patients on a line of androgen-dependent human prostate cancer cells in the laboratory. Serum from the men in the treatment group inhibited cancer cell growth by 70%, while serum from men in the control group decreased cancer cell growth by only 9%.
Diet and lifestyle factors appear to have a positive influence on men with untreated, low-grade prostate cancer. Further investigation is indicated to determine whether such changes may similarly benefit men undergoing conventional treatment for prostate cancer.
—Linda M. Smith, RN
* Ornish D, Weidner G, Fair WR, et al. Intensive lifestyle changes may affect the progression of prostate cancer. J Urol. 2005 Sept;174(3):1065-9; discussion 1069-70.
Consuming omega-3 fatty acids such as those found in cold-water fish offers protection against dry eye syndrome, according to emerging research from Brigham and Women’s Hospital in Boston.* Dry eye syndrome is a common condition marked by burning, itching, redness, and irritation. While factors such as aging, climate, medications, and cigarette smoke may contribute to dry eye syndrome, little is known about how nutrition influences the condition. Scientists previously have speculated that essential fatty acid intake may play a role in dry eye syndrome.
To study the relationship between dry eye syndrome and intake of omega-3 and omega-6 fatty acids, researchers examined data from the Women’s Health Study, which enrolled more than 32,000 female health professionals between the ages of 45 and 84. The participants completed a food-frequency questionnaire that yielded information on dietary fatty acid intake, and reported clinically diagnosed cases of dry eye syndrome. Dietary sources of omega-3 fatty acids include cold-water fish such as salmon, mackerel, and sardines, as well as flaxseed and walnuts. Omega-6 fatty acids are found in eggs, poultry, and vegetable oils.
Nearly 5% of the study group reported diagnoses of dry eye syndrome. After adjustment for demographic factors, hormone therapy, and total fat intake, the researchers noted that women consuming the most omega-3 fatty acids experienced a 17% lower risk of dry eye syndrome compared to women with the lowest intake. Furthermore, a higher ratio of omega-6 to omega-3 fatty acids was associated with a significantly increased risk of dry eye syndrome. Greater consumption of tuna, a source of omega-3 fats, was associated with a decreased risk of dry eye syndrome.
These findings suggest that dietary omega-3 fatty acid intake offers protection against dry eye syndrome. Further studies are indicated to determine whether omega-3 fatty acids may help to manage established cases of dry eye syndrome.
—Elizabeth Wagner, ND
* Miljanovic B, Trivedi KA, Dana MR, Gilbard JP, Buring JE, Schaumberg DA. Relation between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women. Am J Clin Nutr. 2005 Oct;82(4):887-93.