While questions have swirled for years around a possible linkbetween soy consumption and changes in cognition, this researchoffers no evidence to support such claims. "There were nolarge effects on overall cognition one way or another," saidthe study's lead author, Victor Henderson, MD, professor of healthresearch and policy and of neurology and neurological sciences atStanford. The findings from the 2.5-year study in middle-aged and olderwomen, which was larger and longer than any previous trials on soyuse, appear in the June 5 issue of Neurology , the medical journal of the American Academy of Neurology. Theresults are in line with the largest previous study in this area: a12-month trial of Dutch women during which daily soy intake showed"no significant effect on cognitive endpoints." That workwas published in a 2004 issue of the Journal of the American Medical Association . Still, there are a number of randomized clinical trials on soy'seffect on cognition and memory in women that have presentedconflicting takes about its benefits and harms. While improvedcognition was seen in some findings, other research suggested thatsoy could have an adverse effect on memory. Soy and soy-based products contain an estrogen-like compound calledisoflavones, and some women choose to take soy supplements as analternative to estrogen. It has been thought that isoflavones mightbe able to boost memory and perhaps overall brain function. Thehippocampus, the part of the brain that controls memory, is rich inestrogen beta receptors, and isoflavones are known to activatethese receptors. Henderson's interest in the matter is part of his broader researchagenda on finding new strategies to improve cognitive function inaging. For this work, he and his colleagues conducted the NationalInstitutes of Health-sponsored Women's Isoflavone Soy Health Trial,which was done between 2004 and 2008 to determine the effect of soyisoflavones on the progression of atherosclerosis and, secondarily,the effect on cognition. During this study, 350 healthy women ages45-92 were randomized to receive daily 25 grams of isoflavone-richsoy protein (a dose comparable to that of traditional Asian diets)or a placebo. A battery of neuropsychological tests was given tothe participants at the start of the study and again 2.5 yearslater. Henderson and his colleagues examined changes to the composite of14 scores and found no significant differences in global cognition-- that is, overall mental abilities -- from baseline to study-endbetween women who took the supplements and those on placebo. Duringa planned secondary analysis, they did identify a statisticallysignificant difference in one of the identified cognitive factors:Women in the supplement group showed a greater improvement invisual memory (memory for faces). Henderson said this could beimportant, but "the finding needs to be replicated in futurestudies." According to Henderson, this research "helps provide a firmanswer" about soy and overall cognition, and he and hisco-authors note in the paper that postmenopausal women shouldn'tpursue a high-soy diet or take supplements for the primary goal ofglobal cognitive benefit. At the same time, Henderson said the work is not meant discouragewomen who consume soy for other purposes. "I don't think theyshould be disappointed at all," he said. "They should bepleased that there aren't negative effects on overall cognitivefunction and that there are potential gains in aspects of memory.If a woman enjoys eating soy and if there may be other healthbenefits, she should keep doing what she's doing." The researchers note that while these results are reasonablydefinitive -- Henderson said the sample size was large enough thatif there were major effects, the researchers would have likely seenthem -- the cognitive effects of soy isoflavones might differ forwomen of reproductive age and for men. More study is needed inthese populations, he said. He also emphasized the need forresearchers to continue studying a variety of interventions toimprove cognition among older adults, including nutritionalapproaches, physical and mental activities, and pharmaceuticalapproaches. The senior investigators in the Women's Isoflavone Soy Health Trialinclude Wendy Mack, PhD, professor of preventive medicine, andHoward Hodis, MD, professor of medicine, with the USC Keck Schoolof Medicine. Other researchers from USC and the University ofHawaii Cancer Center also contributed to the study. The work was funded by the National Center of Complementary andAlternative Medicine, the Office of Dietary Supplements and theOffice of Research on Women's Health. Solae LLC, based in St.Louis, provided study products without charge. The e-commerce company in China offers quality products such as China Hydraulic Axial Pump , Hydraulic Pump Spare Parts, and more. For more , please visit Hydraulic Piston Pump today!
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