On the other end of the spectrum, Rosenfeld says middle-aged women are often recommended to take supplemental soy to help with mood swings caused by menopause.
But how well that helps, exactly, also remains an open-ended question. In order to understand how soy is broken down in the body, we need to talk about an important compound: S-equol. When soy phytoestrogens mix with the right intestinal bacteria, S-equol is produced, making it easier for the body to reap cardiovascular and hormonal benefits from soy that have been noted in several studies. Researchers have found that, in some cases, phytoestrogens can help alleviate symptoms like hot flashes and night sweats.
In the U. And even when it does abound in the body, S-equol might react poorly with the high-fat diet a typical American might consume. They found that the mice that received S-equol became fatter and had worse metabolic disorders. However, the supplements did relieve their anxiety and depressive behaviors. A pilot study from found that both soy phytoestrogens and S-equol supplements were helpful aids to stop hot flashes.
But their effects varied: For women who experienced more than eight hot flashes per day, S-equol supplements were a more effective treatment. For women with fewer hot flashes, both supplements proved moderately effective. Many soy studies are funded by industry groups — a predicament that can make our understanding of phytoestrogens more murky. When studies are funded by the industry — say, a large company that sells soy products — results may be cherry-picked to show only the benefits of the plant.
McCullough M. The bottom line on soy and breast cancer risk. The American Cancer Society website. August 2, Glover A, Assinder SJ. Acute exposure of adult male rats to dietary phytoestrogens reduces fecundity and alters epididymal steroid hormone receptor expression.
J Endocrinol. Martinez J, Lewi JE. An unusual case of gynecomastia associated with soy product consumption. Endocr Pract. Messina M. Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence. Fertil Steril. Soy alert! Weston A. Price Foundation website. Updated March 9, However, for those on thyroid medications for hypothyroidism , managing soy intake may be helpful.
According to the Mayo Clinic, avoiding soy at least 4 hours after taking your medication is recommended. Menopause occurs when women experience a reduction in estrogen levels. However, the American Heart Association states that this effect is somewhat unlikely. Early evidence showed that soy could even reduce the risk for heart disease. Finally, a study revealed that soy could help prevent and even reduce bone loss associated with osteoporosis , reducing the risk for fractures.
Researchers conclude that their findings indicate that postmenopausal women and other people with low bone density could benefit from consuming soy. Research on the potential health benefits and risks of soy is ongoing. As it continues, what we do know about this plant-based food will evolve.
Despite its popularity, soy remains a controversial food. This article examines the evidence for and against eating soy. Soy is arguably one of the most controversial nutrition topics. This article reviews the latest scientific evidence to determine whether eating soy is….
A fasting blood sample was collected on the morning of day 11 of cycle 1 and on day 11 of cycle 3. Each woman completed a series of daily hour diet records from day 2 through day 10 of cycle 1 diet record 1 and day 2 through day 10 of cycle 3 diet record 2.
In addition, women in the soymilk-supplemented group recorded their soymilk consumption throughout the dietary study period. The intake of all soy products soymilk, tofu, miso, soybeans, etc. We approximated isoflavone intake from soy products other than soymilk with the use of data from previous studies 17 , Detailed information about estimation of isoflavone intake has been described elsewhere Chemical structures of estrone, estradiol, genistein, genistin, daidzein, and daidzin.
Each woman was weighed before and after the dietary study period. After the dietary study period, the onset dates of the following two menstruations were reported by the subjects. The blood samples were centrifuged at g for 10 minutes at room temperature within 3 hours of sample collection, and the serum was separated.
Serum concentrations of estrone, estradiol, and sex hormone-binding globulin SHBG were determined by radioimmunoassay using kits purchased from Eiken Chemical Co. Tokyo , respectively. The intra-assay coefficients of variation were 7. To evaluate the effects of soymilk consumption on hormone status, the concentrations of estrone, estradiol, and SHBG prior to and after the dietary study period were compared with the soymilk-supplemented and control groups using the Mann- Whitney test.
The Mann-Whitney and the Wilcoxon matched pairs signed rank tests were used to compare values of variables at baseline and changes in those variables over the study period. Values for serum hormone concentrations and nutrient intakes were log transformed for Wilcoxon matched pairs signed rank test. Analysis of variance was applied to compare the lengths of the four cycles in each group. All P values were calculated from two-tailed tests of statistical significance.
Some blood samples could not be collected on day 11 of cycle 1 or day 11 of cycle 3 in some participants because of school holidays. Actual sampling dates varied from day 9 through day 13 for cycle 1 and from day 7 through day 14 for cycle 3. Sixty women 31 in the soymilk-supplemented group and 29 in the control group began the study. An initial comparison of preintervention age, height, weight, and other lifestyle variables, such as smoking status, parity, and age at menarche, showed no statistically significant differences between the soymilk-supplemented group and the control group Table 1.
Prior to random assignment, the initial diet for each group was almost identical with respect to intake of macronutrients and micronutrients as well as soy products and isoflavone Table 1. Both the soymilk-supplemented group and the control group significantly decreased their intake of energy and of most nutrients over the dietary study period. However, nutrient densities calculated as nutrient intake divided by energy did not change statistically significantly except for increases in protein 9.
In the control group, nutrient densities did not change significantly for any nutrient we tested. The mean standard deviation [SD] daily soymilk consumption estimated from the diet records was Based on the basis of the records of daily soymilk consumption throughout the dietary study period, the mean SD soymilk consumption was The mean isoflavone intake was about 4. Intake of soy products other than soymilk and isoflavone from these products was decreased in terms of the nutrient densities There were no statistically significant changes in isoflavone intake divided by energy in the control group before and after the dietary study period.
The initial and final concentrations of serum hormones are shown for each group in Table 2. SHBG remained relatively stable in both groups. The 3rd and 4th menstrual cycles were, on average, nearly 2 days longer than the 1st menstrual cycle in the soymilk-supplemented group, whereas, in the control group, these two cycles were nearly 1 day shorter than the 1st menstrual cycle Table 3.
However, these changes in cycle length were not statistically significant in both groups. There was no significant difference in the mean length of the four menstrual cycles between the two groups the means [SD] were We restricted our statistical analysis to women who provided blood samples no more than 1 day apart in cycles 1 and 3 21 women in the soymilk-supplemented group and 23 women in the control group.
Among these women, the days of blood collection ranged from day 9 through day 12 in cycle 1 as well as in cycle 3. There were no significant differences in the hormone concentrations at baseline between the two groups.
The mean SD of soymilk intake per day was The mean SD of estimated isoflavone intake collectively from soymilk and other soy products was The corresponding figures for isoflavone intake in the control group were Changes in intake of nutrients as well as isoflavone in the selected subgroups were similar to those observed for the complete subgroups, i.
Serum estrone concentration was significantly decreased by Estradiol concentrations decreased by The 4th menstrual cycle was 3. However, these changes did not attain statistical significance.
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