Fiber

Fiber and Miscarriage

High fiber diet lowers rate of miscarriage in sheep

Gilts fed with the high fiber diet had lower circulating estrogen concentrations on days 17, 18 and 19 of the cycle and increased LH pulse frequency on day 18. More oocytes recovered on day 19 from gilts receiving the high fiber diet were at metaphase II after 46-h culture in medium containing 10% of their own follicular fluid, despite fewer large (>7 mm) follicles in these gilts when compared with control animals. There was no effect of diet on ovulation rate, corpora lutea size or progesterone concentrations on days 10-12 after insemination, but embryo survival on days 27-29 after insemination was higher in gilts that received the high fiber diet.

http://www.reproduction-online.org/cgi/content/full/133/2/433

Fiber and Fertility

Replacing refined carbohydrates with high fiber foods improves fertility in large study

In a study of some 17,000 women conducted by the Harvard School of Public Health, researchers were able to define a group of "fertility foods" able to improve odds. Eating more high fiber, low-glycemic foods -- like whole grains, vegetables, and some fruits, while reducing the intake of refined carbohydrates and sugars was one of the dietary tenets that were key to increasing fertility.

http://www.webmd.com/baby/features/getting-pregnant-easy-ways-to-encourage-fertility

Fiber and Hormones

Dietary fiber causes estrogen, progesterone, LH and FSH levels to decrease

Dietary fiber consumption was inversely associated with hormone concentrations (estradiol, progesterone, LH, and FSH) and positively associated with the risk of anovulation by using random-effects models with adjustment for total calories, age, race, and vitamin E intake. Each 5-g/d increase in total fiber intake was associated with a 1.78-fold increased risk of an anovulatory cycle. The adjusted odds ratio of 5 g fruit fiber/d was 3.05.

http://www.ajcn.org/cgi/content/full/90/4/1061

Dietary fiber lowers risk of endometrial cancer by 18%

Ten articles representing 1 case-cohort study and 9 case-control studies that evaluated several aspects of fiber consumption and endometrial cancer risk were identified through searches in various databases. On the basis of 7 case-control studies, the random-effects summary risk estimate was 0.82 per 5 g/1000 kcal dietary fiber, with no evidence of heterogeneity.

http://www.ajcn.org/cgi/content/abstract/86/6/1730

Dietary fiber lowers progesterone

Elevated rates of steroid clearance may lead to lower reproductive success in several mammalian species. Metabolic clearance rate of progesterone tended to be lower in cows fed the high cornstarch diet (25 l/hxBW) versus the high fiber diet (40 l/hxBW). The half-life of progesterone was increased in cows fed the high cornstarch diet (73 min) versus the high fiber diet (24 min).

http://www.ncbi.nlm.nih.gov/pubmed/20223860

Dietary fiber lowers androstenedione by 8%

In contrast, higher dietary fiber intake was associated with lower serum levels of androstenedione (higher in women who miscarry) (-8% between the lowest and highest quartiles of intake), but not estrogens. Similarly, consumption of fruits (-12%), vegetables (-9%) and whole grains (-7%) showed inverse associations with androstenedione levels. CONCLUSIONS: The consistency of the observed differences in sex hormone levels associated with fiber-rich foods indicates that these nutritional factors may affect sex hormone concentrations and play a role in breast cancer etiology and prevention.

http://www.ncbi.nlm.nih.gov/pubmed/17010253

100 grams per day of prunes, high in soluble fiber, lower estrogen levels in one month

Nineteen healthy premenopausal women consumed their habitual diets for 3 menstrual cycles and then consumed 100 g prunes/d for the next 3 cycles. RESULTS: Prune supplementation increased total and soluble fiber intakes by 4 and 2 g/d, respectively. Mean luteal 2-hydroxyestrone (2OHE1) excretion decreased from 3.92 to 2.20 nmol/mmol creatinine during the third cycle. Luteal 16alpha-hydroxyestrone (16alphaOHE1) excretion decreased from 1.38 to 0.87 and 0.87 nmol/mmol creatinine during the first and third cycles, respectively. Follicular 16alphaOHE1 excretion decreased significantly only during the first cycle (from 0.82 to 0.45 nmol/mmol creatinine).

http://www.ncbi.nlm.nih.gov/pubmed/12450912

Fiber and Insulin Resistance

Dietary fiber improves insulin sensitivity and leads to weight reduction

A recent study in The Journal of the American Medical Association (JAMA) confirmed that fiber consumption could predict insulin levels, weight gain, and other cardiovascular risk factors more strongly than saturated fat consumption.

http://www.chiro.org/nutrition/ABSTRACTS/Polycystic_Ovary_Syndrome.shtml

Studies show that insulin sensitivity increases and body weight decreases in people on high fiber diets.

http://www.thorne.com/altmedrev/.fulltext/6/3/272.pdf

Fiber and Inflammation

Soluble fiber reduces inflammatory cytokines

We show that a diet rich in soluble fiber protects mice from endotoxin-induced sickness behavior by polarizing mice Th2 when compared to a diet containing only insoluble fiber. Mice fed soluble fiber became less sick and recovered faster from endotoxin-induced sickness behaviors than mice fed insoluble fiber. In response to intraperitoneal endotoxin, mice fed soluble fiber had up-regulated IL-1RA and reduced IL-1β and TNF-α in the brain as compared to mice fed insoluble fiber. Importantly, mice fed soluble fiber had a basal increase in IL-4 in the ileum and spleen which was absent in MyD88 knockout mice. Con-A stimulated splenocytes from mice fed soluble fiber showed increased IL-4 and IL-5 and decreased IL-2, IL-12 and IFN-γ when compared to mice fed insoluble fiber. Likewise, endotoxin-stimulated macrophages from mice fed soluble fiber demonstrated decreased IL-1β, TNF-α, IFN-γ, IL-12 and nitrate and increased IL-1RA, arginase 1 and Ym1 when compared to mice fed insoluble fiber.

http://www.ncbi.nlm.nih.gov/pubmed/20138982