Terry D. Shultz

In vitro binding of steroid hormones by natural and purified fibers

The in vitro binding of estrone, estradiol-17 beta, estriol, testosterone, dihydrotestosterone, and estrone-3-glucuronide by wheat, oat, and corn brans, oat hulls, cellulose, lignin, and cholestyramine resin was measured. The extent of steroid sequestration was characteristic and reproducible for each hormone. Cholestyramine bound an average of 90% of all the steroids tested, whereas cellulose bound the least (12%). Of the other substances tested, each bound the following percentage of unconjugated hormones: lignin, 87%; wheat and oat brans, 45% each; corn bran 44%; and oat hulls, 32%. The conjugated steroid was less likely to bind than the unconjugated steroids. Lignin appeared to be an important component in the interaction with steroid hormones. The results support the hydrophobic nature of adsorption and suggest that the components of fiber in diet should be considered separately when evaluating in vivo metabolic effects.

Nutrient intake and hormonal status of premenopausal vegetarian seventh‐day adventists and premenopausal nonvegetarians

The relationship between dietary nutrients and plasma estrone, estradiol-17 beta, estriol, dehydroepiandrosterone sulfate, and prolactin levels was investigated in 14 premenopausal Seventh-day Adventist vegetarian (SV) women and 9 premenopausal non-Seventh-day Adventist nonvegetarian (NV) women. The SV subjects consumed less fat, especially saturated fat, and used significantly less fried food than the NV subjects. Plasma levels of estrone and estradiol-17 beta in the SV subjects were significantly lower than in the NV subjects. SV estradiol-17 beta and estriol levels were positively correlated with linoleic acid and protein intake, while NV prolactin levels were significantly correlated with intakes of oleic and linoleic acids and total fat. The data suggest that specific dietary nutrients were related to the hormonal milieu of these SV and NV subjects.

Binding of steroid hormones in vitro by water-insoluble dietary fiber

Abstract Previous work conducted in our laboratory has shown that steroid hormones bind to natural (e.g., brans, oat hulls) and purified (e.g., cellulose, lignin) fiber components. To explore this relationship further, we assessed the in vitro binding of estrone, estradiol-17β, and testosterone to a water-insoluble fiber fraction obtained from composite food samples of 18 Seventh-day Adventist (SDA) novegetarian (NV), 20 SDA lacto-ovovegetarian (LOV), and 15 SDA vegan (V) men. Three-day dietary food records and 72-hr food composites were obtained contemporaneously from each subject. The LOV and V subjects consumed significantly more crude, dietary and water-insoluble fiber than the NV subjects. Waterinsoluble fiber bound an average of 73% of all estrogens tested, and 56% of the testosterone. Binding levels of testosterone were significantly higher in the Vs than in the LOVs and omnivores. Additionally, there was a significant correlation, when all groups were combined, between water-insoluble fiber intakes and binding of estrone and testosterone. These results suggest that diet may modify hormonal status, possibly through binding of steroid hormones by dietary fiber, leading to altered enterohepatic circulation of these hormones.

Effect of pyridoxine and pyridoxal on the in vitro growth of human and murine cancer cells

Abstract Previous work conducted in our laboratories, using a murine model, suggested that the consumption of high levels of vitamin B-6 [pyridoxine (PN)] may suppress tumor development either by immune enhancement or by pyridoxal 5′-phosphate (PLP) growth regulation. To explore this relationship further, we assessed the effects of PN and pyridoxal (PL) on the growth of human (MCF-7, mammary; DU-145, prostate; CAKI-1, renal) and mouse (H238, fibrosarcoma) cancer cell lines. The incubation of cancer cells for 3 (H238) to 20 (MCF-7, DU-145, CAKI-1) days in culture media supplemented with high doses of PN (2.5–5.0 mM) or PL (0.05–5.0 mM) showed significant reductions in proliferation (13% to 100%) as compared to control cultures. PL was more efficacious than PN as a cytotoxin. Cell mortality was observed in a dose-dependent manner, but sensitivity to PN and PL at concentrations approximating physiologic levels (0.005 mM) did not retard growth. Intracellular levels of PL and PLP were significantly elevated in H238 cultures exposed to pharmacologic, but not physiologic concentrations of PN and PL. MCF-7, DU-145, CAKI-1, and H238 cells cultured for 3 h in media supplemented with 0.5 mM PL and labeled with [ 3 H] precursors generally incorporated significantly less leucine, uridine, and thymidine into TCA-precipitable material than did control cultures. In contrast, cells supplemented with 0.005 mM PL showed no inhibition in incorporation. The results indicate that physiological concentrations of PN and PL may not be directly cytotoxic to human or animal cancer cells in vivo .

Effect of high-fat intake on lactogenic hormone bioactivity in premenopausal women.

To determine if dietary fat affects the bioactivity of circulating prolactin and growth hormone (lactogenic hormones), a controlled feeding study was conducted in six premenopausal women over two complete menstrual cycles. After an initial 7-10 d dietary adjustment, subjects were randomly assigned to either low-fat (25% of calories) or high-fat (46%) diets. The diets were similar in proportions of energy, protein, P:S ratio, and cholesterol. All subjects completed both diets in a crossover experimental design. Fasting blood samples were collected on alternate days throughout the study. Plasma hormone bioactivity was assayed by the Nb2 lymphoma cell method. Luteal-phase lactogenic hormone bioactivity appeared to be higher (averaging 28%; p less than 0.07) in response to high- rather than low-fat diets. No differences were seen in levels of radioimmunoreactive prolactin or growth hormone. Substantial changes in short-term fat intake may alter the level of lactogenic hormone bioactivity in young women.