Rats fed curcumin for 12 weeks after undergoing removal of their ovaries showed a greater gut microbiome diversity than those administered distilled water, observed the research team from the China Academy of Chinese Medical Sciences, Beijing.
Curcumin, an active ingredient of turmeric, had demonstrated weight-gain prevention effects in previous studies in menopausal rats. The researchers wondered whether possible changes in gut microbial composition induced by curcumin might be involved; an aspect which had not been investigated until this study.
Rats which had undergone the ovariectomy (OVX), but were fed distilled water, showed reduced gut bacterial diversity compared with the control group rodents (SHAM) which underwent a sham operation. However, ovariectomised rats given curcumin (CUR) displayed significantly different numbers of seven bacterial genera compared with the OVX group.
“Estrogen deficiency induced by ovariectomy caused changes in the distribution and structure of intestinal microflora in rats, and curcumin could partially reverse changes in the diversity of gut microbiota,” wrote first author Dr. Zhiguo Zhang.
Curcumin prevents weight gain
Consistent with previous studies, rats in the OVX group displayed significant weight gain compared with the SHAM group. However, curcumin supplementation prevented this weight gain in the CUR group. The curcumin did not however have an estrogenic effect, as it prevented neither reduced serum estradiol levels nor uterine weight loss.
The small size (18 subjects) is a limitation of the study. However, if results are replicated in subsequent larger animal trials, they may justify for future intervention trials in humans; with curcumin as a possible therapeutic agent to prevent post-menopausal weight gain and maintain gut health.
“At the phyla level, compared to SHAM rats, model (OVX) rats had a higher ratio of phyla Firmicutes and Bacteroidetes in the gut, which may lead to overweight rats,” observed the researchers.
Previous studies in both menopausal women and animals have displayed significant changes to microbiome composition after ceasing ovulation. Additionally, a higher Firmicutes/ Bacteroidetes ratio has been associated with obesity in humans.
The study observed two other potentially beneficial effects of curcumin. The CUR group showed lower levels of Anaerotruncus, a bacterium which has been linked with pre-natal stress and age-related macular degeneration.
Additionally, the researchers found that curcumin lowered the abundance of Helicobacter pylori, the bacterium responsible for stomach ulcers. More research is needed to explore the relationship between H. pylori, menopause and curcumin, the researchers proposed.
Volume 9, issue 10, 1146 DOI: 10.3390/nu9101146
“Effect of Curcumin on the Diversity of Gut Microbiota in Ovariectomized Rats”
Authors: Zhiguo Zhang, Yanjing Chen, Lihua Xiang, Zhen Wang, Gary Guishan Xiao, and Jingqing Hu.