Reduced radiation damage from ingestion of cabbage family plants.
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Animal Nutritional Physiological Phenomena↗
Biomedical subjects
M S Kurzer
Publications and source records attributed to M S Kurzer.
Isotope dilution gas chromatographic-mass spectrometric method for the determination of unconjugated lignans and isoflavonoids in human feces, with preliminary results in omnivorous and vegetarian women.
We describe an isotope dilution gas chromatographic-mass spectrometric (GC/MS) method for the identification and quantitative determination of the lignans enterolactone, enterodiol, and matairesinol and the isoflavonoids daidzein, equol, O-desmethylangolensin, and genistein in feces. Following the addition of deuterated internal standards for all compounds, the feces samples are extracted and purified in several ion exchange chromatographic steps. Following formation of trimethylsilyl ethers, the samples are analyzed by combined capillary column GC/MS in the selective ion monitoring mode and corrected for all losses during the procedure using the deuterated internal standards. Results on the reliability of the method and values for nine Finnish omnivorous and nine vegetarian women are presented.
4-Butyrolactone↗
Fecal lignan and isoflavonoid excretion in premenopausal women consuming flaxseed powder.
Lignans and isoflavonoids are diphenolic compounds found in plant foods, particularly whole grains and legumes. They have been shown to have anticarcinogenic properties in animal and cell studies, and have been associated with reduced cancer risk in epidemiological studies. In order to perform further epidemiological and metabolic studies on these compounds, it is necessary to be able to monitor concentrations in biological samples. In this study, we examined the effects of consumption of flaxseed, a concentrated source of lignans, on fecal lignan excretion and evaluated the effect of high lignan consumption on fecal excretion of isoflavonoids. Thirteen women were studied for two diet periods of three menstrual cycles each in a cross-over design. During the control period, they consumed their usual diets; during the treatment period they consumed their usual diets supplemented with 10 g/day ground flaxseed. Feces were collected on days 7-11 of the last menstrual cycle in each diet period. Five-day fecal composites were analyzed for lignans and isoflavonoids by isotope dilution gas chromatography-mass spectrometry. Fecal excretion of the lignans enterodiol, enterolactone, and matairesinol increased significantly with flax consumption, from 80.0 +/- 80.0 (SD) to 2560 +/- 3100; 640 +/- 480 to 10,300 +/- 7580; and 7.33 +/- 10.0 to 11.9 +/- 8.06 nmol/day, respectively. There were no differences in fecal excretion of the isoflavonoids, daidzein, equol, genistein, and O-demethylangolensin.
Adult↗
Lignans and flavonoids inhibit aromatase enzyme in human preadipocytes.
Lignans and flavonoids are naturally-occurring diphenolic compounds found in high concentrations in whole grains, legumes, fruits and vegetables. Seven lignans and six flavonoids were evaluated for their abilities to inhibit aromatase enzyme activity in a human preadipose cell culture system. The lignan, enterolactone (Enl) and its theoretical precursors, 3'-demethoxy-3O-demethylmatairesinol (DMDM) and didemethoxymatairesinol (DDMM) decreased aromatase enzyme activity, with Ki values of 14.4, 5.0 and 7.3 microM, respectively. The flavonoids, coumestrol, luteolin and kaempferol also decreased aromatase enzyme activity, with Ki values of 1.3, 4.8 and 27.2 microM, respectively. Aminoglutethimide, a pharmaceutical aromatase inhibitor, showed a Ki value of 0.5 microM. Kinetic studies showed the inhibition by all compounds to be competitive. Smaller decreases in aromatase activity were observed with the lignan, enterodiol (End) and its theoretical precursors, O-demethylsecoisolariciresinol (ODSI), demethoxysecoisolariciresinol (DMSI) and didemethylsecoisolariciresinol (DDSI). The flavonoids, O-demethylangolensin (O-Dma), fisetin and morin showed no inhibitory effects. The inhibition of human preadipocyte aromatase activity by lignans and flavonoids suggests a mechanism by which consumption of lignan- and flavonoid-rich plant foods may contribute to reduction of estrogen-dependent disease, such as breast cancer.
Adipose Tissue↗
Urinary lignan and isoflavonoid excretion in premenopausal women consuming flaxseed powder.
Lignans and isoflavonoid phytoestrogens, produced from plant precursors by colonic bacteria, may protect against certain cancers. We examined the effects of flaxseed consumption on urinary lignans and isoflavonoids. Eighteen women consumed their usual omnivorous diets for three menstrual cycles and their usual diets supplemented with flaxseed powder (10 g/d) for three cycles in a randomized crossover design. Three-day urine samples from follicular and luteal phases were analyzed for lignans and isoflavonoids by isotope-dilution gas chromatography--mass spectrometry. Excretion of the lignans enterodiol and enterolactone increased with flaxseed from 1.09 +/- 1.08 and 3.16 +/- 1.47 to 19.48 +/- 1.10 and 27.79 +/- 1.50 mumol/d, respectively (P < 0.0002). Enterodiol and enterolactone excretion varied among subjects in response to flaxseed (3- to 285-fold increase). There were no differences in excretion of isoflavonoids (daidzein, genistein, equol, and O-desmethylangolensin) or the lignan matairesinol with flaxseed. Excretion was not altered by phase of menstrual cycle or duration of flaxseed consumption.
Administration, Oral↗
Effect of the menstrual cycle on energy and nutrient intake.
Midfollicular and midluteal dietary intakes of 18 women were evaluated between four and six ovulatory menstrual cycles. Phase lengths were established by basal body temperatures and urinary luteinizing hormone excretion. Midfollicular and midluteal diet records were collected 6-8 d after menstrual onset and 6-8 d after ovulation, respectively. Significant increases in energy [0.66 MJ (159 kcal), P = 0.003], protein (6.1 g, P = 0.02), carbohydrate (15.3 g, P = 0.04), and fat (8.6 g, P = 0.002) intakes were observed in midluteal phase when compared with midfollicular phase. Intakes of vitamin D, riboflavin, potassium, phosphorus, and magnesium also were significantly higher during midluteal phase (P < 0.05). These results support the regulation of food intake by menstrual cycle hormones and suggest that it is essential to consider phase of menstrual cycle in studies of nutrient intake performed in premenopausal women.
Adult↗
Flavonoid inhibition of aromatase enzyme activity in human preadipocytes.
Eleven flavonoid compounds were compared with aminoglutethimide (AG), a pharmaceutical aromatase inhibitor, for their abilities to inhibit aromatase enzyme activity in a human preadipocyte cell culture system. Flavonoids exerting no effect on aromatase activity were catechin, daidzein, equol, genistein, beta-naphthoflavone (BNF), quercetin and rutin. The synthetic flavonoid, alpha-naphthoflavone (ANF), was the most potent aromatase inhibitor, with an I50 value of 0.5 microM. Three naturally-occurring flavonoids, chrysin, flavone, and genistein 4'-methyl ether (Biochanin A) showed I50 values of 4.6, 68, and 113 microM, respectively, while AG showed an I50 value of 7.4 microM. Kinetic analyses showed that both AG and the flavonoids acted as competitive inhibitors of aromatase. The Ki values, indicating the effectiveness of inhibition, were 0.2, 2.4, 2.4, 22, and 49 microM, for ANF, AG, chrysin, flavone, and Biochanin A, respectively. Chrysin, the most potent of the naturally-occurring flavonoids, was similar in potency and effectiveness to AG, a pharmaceutical aromatase inhibitor used clinically in cases of estrogen-dependent carcinoma. These data suggest that flavonoid inhibition of peripheral aromatase activity may contribute to the observed cancer-preventive hormonal effects of plant-based diets.
Adipocytes↗
Effect of flax seed ingestion on the menstrual cycle.
Lignans are a group of phytochemicals shown to have weakly estrogenic and antiestrogenic properties. Two specific lignans, enterodiol and enterolactone, are absorbed after formation in the intestinal tract from plant precursors particularly abundant in fiber-rich food and are excreted in the urine. We evaluated the effect of the ingestion of flax seed powder, known to produce high concentrations of urinary lignans, on the menstrual cycle in 18 normally cycling women, using a balanced randomized cross-over design. Each subject consumed her usual omnivorous, low fiber (control) diet for 3 cycles and her usual diet supplemented with flax seed for another 3 cycles. The second and third flax cycles were compared to the second and third control cycles. Three anovulatory cycles occurred during the 36 control cycles, compared to none during the 36 flax seed cycles. Compared to the ovulatory control cycles, the ovulatory flax cycles were consistently associated with longer luteal phase (LP) lengths (mean +/- SEM, 12.6 +/- 0.4 vs. 11.4 +/- 0.4 days; P = 0.002). There were no significant differences between flax and control cycles for concentrations of either estradiol or estrone during the early follicular phase, midfollicular phase, or LP. Although flax seed ingestion had no significant effect on LP progesterone concentrations, the LP progesterone/estradiol ratios were significantly higher during the flax cycles. Midfollicular phase testosterone concentrations were slightly higher during flax cycles. Flax seed ingestion had no effect on early follicular phase concentrations of DHEA-S, PRL, or sex hormone-binding globulin. Our data suggest a significant specific role for lignans in the relationship between diet and sex steroid action, and possibly between diet and the risk of breast and other hormonally dependent cancers.
4-Butyrolactone↗
Sex steroid-binding protein in nonendocrine diseases.
In humans, sex steroid-binding protein (SBP) is a protein from the liver which binds with high affinity sex steroid hormones. The plasma concentration of SBP is regulated in part by hormonal factors. It has been shown that estrogens and/or thyroid hormones increase the production of SBP by hepatoma cell lines. It is therefore assumed that the increase in SBP levels in patients given oral estrogens or thyroid hormones is the consequence of a direct stimulation of the liver production of SBP by these hormones. The effects of androgen, progestagen and glucocorticoid hormones are unclear or still a matter of controversy. Moreover, the regulation of the metabolic clearance rate of SBP and the influence of nonhormonal factors on the production of SBP are still speculative. Changes in SBP have been described in a few nonendocrine diseases. A slight hormonal dysfunction may be either the primary or the sole cause of the changes in SBP occurring in these diseases. As an example, elevated SBP levels have been reported in men with liver cirrhosis together with testicular hypofunction and increased estrogen levels. It is therefore difficult to demonstrate that the increase in SBP is due to the liver dysfunction rather than to the endocrinological side effects of cirrhosis. The aim of this review is to present some aspects of the nonhormonal regulation of SBP. There is accumulating evidence in the literature for a relation between SBP levels and body weight and fat distribution, energy balance, diet and physical activity, and lipid metabolism. Therefore, it is tempting to propose that SBP is an index which reflects the status of endocrine, metabolic and nutritional functions. Measurement of SBP may be considered of interest in the light of previous epidemiological studies and the preventive approach to diseases such as hormone dependent tumors, cardiovascular diseases and osteoporosis.
Disease↗
Effect of 12 weeks' light-moderate underfeeding on 24-hour energy expenditure in normal male and female subjects.
The effect of 12 weeks' light-moderate underfeeding on the 24-h energy expenditure of a fixed physical activity programme was studied in six male and six female subjects. During a control period of 2 weeks, measurements were made of 24-h energy expenditure by direct calorimetry, the lean and fat body masses and the subjects' habitual energy intakes. The average body weight was 107 per cent of ideal, and did not change significantly during the control period. The subjects were asked to continue to record their daily food intake while reducing it by 25 per cent and to continue their daily activity habits during a period of 12 weeks. The mean change in body weight was -2.9 kg with an average change in body energy content of -66 MJ. The 24-h energy expenditure was measured three times during the period, ie, after 4, 8 and 12 weeks from the start of the decreased energy intake, and found to be practically the same as the control value, ie, with average differences (s.d.) of -0.2(3.9), -0.8(5.7) and +0.6(4.2) per cent from the control value. In the six subjects who had the largest loss of body weight, this was found to be 5.0 kg, and the mean differences (s.d.) in energy expenditure were found to be -1.0(3.4), 0.0(5.6) and -0.6(3.9) per cent, respectively, from the control value. A significant part of the between-subjects variation in the differences from the control value is due to random measurement error and it is concluded that a loss of body energy content of the magnitude reported here, and due mainly to a reduced food intake, does not result in a significant increase in the efficiency of energy conversion, ie, in metabolic adaptation.
Adult↗
Energy expenditure during sleep in men and women: evaporative and sensible heat losses.
Evaporative and sensible heat losses were measured during sleep in 38 male and 21 female subjects in a direct whole-body calorimeter (24 m3). The subjects were all apparently healthy, had a mean body weight of 66 kg and had spent the preceding day in the calorimeter performing different fixed physical activity programmes. Heat losses were measured continuously between 11.30 p.m. and 6.30 a.m. The average (+/- s.e.m.) rate of total heat loss during the 7h of sleep was 90.6 +/- 1.21 and 74.4 +/- 1.22 watts for men and women respectively. The total heat loss during basal resting conditions immediately following sleep was 83.8 +/- 1.5 and 69.2 +/- 1.6 watts, respectively. Heat production during basal resting conditions, as measured by indirect calorimetry about 1 h after awakening on the morning of the preceding day, was found to be 85.6 +/- 1.3 and 71.2 +/- 1.1 watts, respectively. The increase in heat loss during sleep above that of basal resting conditions could largely be attributed to an increase in the evaporative heat loss. The heat loss fell during the night by about 14 per cent in women and about 30 per cent in men, approaching basal resting values in the last hour of sleep. Heat production during sleep was calculated for the male subjects by correcting the heat loss data for the published decreases in rectal temperature during the night and was found to be on average 9 per cent lower than the heat loss. The present data, as well as previously reported data, suggest that the energy expenditure of sleep is 0.95 X BMR rather than 1.0 X BMR as reported in the recent FAO/WHO/UNU Expert consultation (1985).
Adolescent↗
Effect of activity on the energy cost of sitting in men and women: implications for calorimeter studies.
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Adult↗
Effects of energy deprivation on sex hormone patterns in healthy menstruating women.
To determine whether short-term energy deprivation affects sex hormone patterns, six healthy women were studied for two menstrual cycles. Two diets containing recommended levels of all nutrients and differing substantially only with respect to energy content were provided in sequence. During the first cycle, energy intake was 40 +/- 2 kcal/kg body weight, and weight was essentially constant. For the second cycle, energy intake was reduced to 41% of the original intake, averaging 17 +/- 1 kcal/kg initial body weight. During the low-energy diet, weight loss ranged from 3.2 to 6.7 kg. The two leanest women, who also lost the most weight, became anovulatory and amenorrheic in the low-energy period. Within a specific phase of cycle, however, the diet did not affect concentrations of estradiol, progesterone, luteinizing hormone, or follicle-stimulating hormone. Testosterone and androstenedione levels peaked midcycle normally and were decreased with the low-energy diet, while levels of sex hormone-binding globulin increased and those of dehydroepiandrosterone sulfate did not change. These results demonstrate short-term dietary and body composition effects on the menstrual cycle and serum androgens.
Adult↗
Menstrual cycle and basal metabolic rate in women.
Basal metabolic rate, resting metabolic rate (RMR), and energy cost of selected activities were measured in six healthy young women who were participating in a study of protein requirements. The women were confined to a metabolic unit for 92 days during which they consumed a defined formula diet. The basal metabolic rate of the women was 20.7 +/- 2.6 kcal/kg body weight/day and the caloric requirement for maintenance of weight was 38.7 kcal/kg body weight/day. Basal metabolic rate varied significantly with the menstrual cycle. Basal metabolic rate decreased at menstruation and fell to its lowest point approximately 1 wk before ovulation subsequently rising until the beginning of the next menstrual period. RMR was 0.99 +/- 0.16 kcal/kg/h. The energy expenditure while sitting was 1.06 times RMR, while walking it was 2.81 times RMR, and while performing treadmill exercise it was 3.47 times RMR.
Basal Metabolism↗
Menstrual cycle and protein requirements of women.
A nitrogen balance study was done to determine the protein requirement of healthy young women and to evaluate the impact of the menstrual cycle on nitrogen utilization. Six healthy young women were fed a defined formula diet with progressively decreasing levels of egg white protein: 4 mg nitrogen/basal kcal for 42 days, 3 mg nitrogen/basal kcal for 28 days and 2.5 mg nitrogen/basal kcal for 22 days. Dietary energy was fixed at about 38 kcal/kg body weight and exercise was standardized. Excreta, menstrual fluids, and integumentary losses were collected. A statistically significant (P less than .001) biphasic cycle in urinary nitrogen excretion was found in every subject. Linear regression analysis predicted nitrogen requirement to be 73 +/- 20 mg nitrogen/kg body weight. When expressed per kilogram of body weight, there appears to be no significant difference in protein requirement between women and men. The urinary nitrogen cycle, however, was found to be unique to women, implying a hormonal regulation of nitrogen utilization. The failure to account for this cycle in women could lead to erroneous estimates of nitrogen requirement or large coefficients of variation.
Adult↗
Nitrate and nitrogen balances in men.
Nitrate is a nitrogen-containing compound that is not detected by the traditional Kjeldahl method of nitrogen analysis. Nitrate balance studies were done in order to determine if nitrate production in the human body contributes to the irrationally positive nitrogen balances that have been reported in healthy adults. Seven healthy young men, confined to a metabolic unit, received five diets for 9 days each: a mixed foods diet, a fiber-free egg formula diet, and egg formula with California small white beans, lima beans, and wheat bran added. Nitrate-nitrogen intake with the mixed foods diet was 75 mg/day and nonnitrate nitrogen intake was 19 g/day; crude Kjeldahl nitrogen balance (intake--(urinary + fecal)) was 0.64 +/- 1.23 g/day. Nitrate-nitrogen excretion exceeded intake by 0.10 +/- 0.05 g/day. With the four other diets, nitrate-nitrogen intake was almost nil (about 2 mg/day) and nonnitrate nitrogen intake was 95 mg/kg body weight; crude Kjeldahl nitrogen balances ranged from -0.63 +/- 0.73 to 0.02 +/- 0.45 g N/day. With these four diets, feces contained about 80 mg nitrate-nitrogen/day and urine contained about 8 mg. Saliva obtained before lunch had about 1 ppm nitrate-nitrogen with the formula diets and 5 ppm with the mixed foods diet. Net synthesis of nitrate is quite variable but appears to be of the order of 100 mg nitrate-nitrogen/day. Although the excess nitrate excretion increased total nitrogen excretion by less than 5%, it could account for as much as 10 to 20% of unexplained positive nitrogen balances previously reported in well-controlled studies.
Adult↗