Effect of dietary fiber intake on lipoprotein cholesterol levels independent of estradiol in healthy premenopausal women

Exploring the cholesterol-lowering effects of cereal bran cell wall-enriched diets

Cell wall polysaccharides (dietary fiber) in cereal grains contribute to health benefits. The novelty of the current study was an effort to explore the in vivo therapeutic potential of different cereal bran cell walls against hypercholesterolemia. For this purpose, the cell walls were isolated from different cereal brans (wheat, maize, oats, and barley), and the intake of these cereal bran cell walls was evaluated for their anti-lipidemic activity in normal and hypercholesterolemic rats. The serum taken from the rats was tested for cholesterol, lipid, and triglyceride profiles before and after treatment. The outcomes of the current study have shown that the cereal cell wall has a significant hypercholesterolemia effect. The biochemical parameters of the control animals were within the normal clinical ranges, indicating that the experimental diets were safe. Among cereal bran cell walls, barley bran significantly decreased cholesterol (56.35 ± 1.35 mg/dL), low-density lipoprotein (56.35 ± 1.05 mg/dL), triglycerides (105.29 ± 1.95 mg/dL), and increased high-density lipoprotein level (48.35 ± 1.35 mg/dL). These findings provide conclusive evidence that the cereal cell wall is beneficial in the treatment of hypercholesterolemia and may potentially provide protection against other acute, recurring, or chronic illnesses.

Nutrient scoring for the DEGS1-FFQ - from food intake to nutrient intake

BACKGROUND

While necessary for studying dietary decision-making or public health, estimates of nutrient supply based on self-reported food intake are barely accessible or fully lacking and remain a challenge in human research. In particular, detailed information on dietary fiber is limited. In this study we introduce an automated openly available approach to assess self-reported nutrient intake for research purposes for a popular, validated German food frequency questionnaire (FFQ).

METHODS

To this end, we i) developed and shared a code for assessing nutrients (carbohydrates, fat, protein, sugar, fiber, etc.) for 53 items of the quantitative, validated German DEGS1-FFQ questionnaire implementing expert-guided nutritional values of diverse sources with several raters. In a sample of individuals (n_GUT-BRAIN = 61 (21 female) overweight, omnivorous), we ii) cross-validated nutrient intake of the last 7 days and the last 24 h and iii) computed test-retest reliability across two timepoints. Further, iv) we reported newly computed nutrient intake for two independent cross-sectional cohorts with continuous weight status and different dietary habits (n_Mensa = 134 (79 female, 1 diverse), n_GREADT = 76 male). Exploratively, we v) correlated computed, energy-adjusted nutrient intake with anthropometric markers and HbA1c and vi) used linear mixed models to analyse the predictability of BMI and WHR by nutrient intake.

RESULTS

In overweight adults (n = 61 (21 female), mean age 28.2 ± 6.5 years, BMI 27.4 ± 1.6 kg/m²) nutrient intakes were mostly within recommended reference nutrient ranges for both last 7 days and last 24 h. Recommended fiber intake was not reached and sugar intake was surpassed. Calculated energy intake was significantly higher from last 24 h than from last 7 days but energy-adjusted nutrient intakes did not differ between those timeframes. Reliability of nutrient values between last 7 days and 24 h per visit was moderate (Pearson's rho_all ≥ 0.33, rho_max = 0.62) and absolute agreement across two timepoints was low to high for 7 days (Pearson's rho_min = 0.12, rho_max = 0.64,) and low to moderate for 24 h (Pearson's rho_min = 0.11, rho_max = 0.45). Associations of dietary components to anthropometric markers showed distinct sex differences, with overall higher intake by males compared to females and only females presenting a negative association of BMI with fiber intake. Lastly, in the overweight sample (but not when extending the analysis to a wider BMI range of 18.6-36.4 kg/m²), we could confirm that higher BMI was predicted by lower energy-adjusted fiber intake and higher energy-adjusted fat intake (when adjusting for age, sex and physical activity) while higher WHR was predicted by higher energy intake.

CONCLUSION

We provide an openly available tool to systematically assess nutrient intake, including fiber, based on self-report by a common German FFQ. The computed nutrient scores resembled overall plausible and reliable measures of nutrient intake given the known limitations of FFQs regarding over- or underreporting and suggest valid comparability when adjusting for energy intake. Our open code nutrient scoring can help to examine dietary intake in experimental studies, including dietary fiber, and can be readily adapted to other FFQs. Further validation of computed nutrients with biomarkers and nutrient-specific metabolites in serum, urine or feces will help to interpret self-reported dietary intake.

Performance of the Global Diet Quality Score with Nutrition and Health Outcomes in Mexico with 24-h Recall and FFQ Data

BACKGROUND

The Global Diet Quality Score (GDQS) is intended as a simple global diet quality metric feasible in low- and middle-income countries facing the double burden of malnutrition.

OBJECTIVE

The aim of this study was to evaluate the performance of the GDQS with markers of nutrient adequacy and chronic disease in nonpregnant nonlactating (NPNL) Mexican women of reproductive age and to compare it with the Alternate Healthy Eating Index-2010 (AHEI-2010) and the Minimum Dietary Diversity for Women (MDD-W).

METHODS

We included NPNL women aged 15 to 49 y from the Mexican National Health and Nutrition Surveys (2012 and 2016) with 24-h recall (n = 2542) or a FFQ (n = 4975) (separate samples). We evaluated the correlation of the GDQS with the energy-adjusted intake of several nutrients and evaluated its association with health parameters using covariate-adjusted linear regression models.

RESULTS

The GDQS was positively correlated with the intake of calcium, folate, iron, vitamin A, vitamin B-12, zinc, fiber, protein, and total fat (rho = 0.09 to 0.38, P < 0.05) and was inversely correlated with the intake of added sugar (rho = -0.37 and -0.38, P < 0.05) using both instruments, and with total fat, SFA, and MUFA only with 24-h recall data (rho = -0.06 to -0.16, P < 0.05). The GDQS was inversely associated with serum ferritin, BMI, waist circumference, and serum total and LDL cholesterol using FFQ data (P < 0.05), and was positively associated with serum folate using 24-h recall data (P < 0.05). Similar correlations and associations were observed with the MDD-W (only with micronutrients) and the AHEI-2010 (only with chronic disease-related nutrients and health markers).

CONCLUSIONS

In comparison to other diet metrics, the GDQS can capture both dimensions of nutrient adequacy and health markers related to the risk of chronic disease. The performance of the GDQS was satisfactory with either 24-h recall or FFQ.

Effectiveness of simplified diabetes nutrition education on glycemic control and other diabetes-related outcomes in patients with type 2 diabetes mellitus

BACKGROUND & AIMS

The study aimed to evaluate the effectiveness of the Simplified Diabetes Nutrition Education (SDNE) on glycemic control and other diabetes-related outcomes in patients with type 2 diabetes mellitus (T2DM).

METHODS

This a randomized controlled trial (RCT) randomized 208 patients with T2DM [mean age = 48.8 ± 11.8 years, Glycated Hemoglobin (HbA1c) = 9.5 ± 2.4%, and Body Mass Index = 28.0 ± 5.6 kg/m²] to intervention group (n = 104) or control group (n = 104). Participants in the intervention group received a weekly diabetes nutrition module based on the health belief model for 12 weeks in addition to the usual care whereas the control participants were given the usual care. We evaluated HbA1c and diabetes-related outcomes (metabolic parameters, dietary intake, and physical activity level) at baseline, 12 weeks, and 22 weeks. Health beliefs, diabetes knowledge, and health literacy were also evaluated.

RESULTS

After 22 weeks, HbA1c improved significantly in the intervention group (-1.7%) from the baseline value, compared to the control group (+0.01%) (p < 0.001). Furthermore, the intervention group also showed better improvement in metabolic parameters than the control group (p < 0.05). Besides, dietary intake and physical activity levels improved significantly among the intervention group compared to the control group (p < 0.05). Likewise, health beliefs, diabetes knowledge, and health literacy also improved significantly in the intervention group compared to the control group (p < 0.05).

CONCLUSION

SDNE improves glycemic control and other diabetes-related outcomes among the intervention group compared to the control group.

TRIAL REGISTRATION

ClinicalTrials.gov with ID: NCT04433598. Registered on 16 June 2020 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04433598.

The role of ideation on the effect of an SBC intervention on consistent bed net use among caregivers of children under 5 years in Nigeria: a multilevel mediation analysis

Background

Malaria remains a significant public health challenge in Nigeria. Consistent bed net use (sleeping under a treated net every night) has been identified as a key malaria prevention behavior. This paper explores the relationship between mass media social and behavior change interventions, psychosocial factors, and consistent bed net use.

Methods

Data is from the endline survey of a USAID-funded social and behavior change communication campaign conducted from 2012 to 2017 across five states in Nigeria. The outcome measure was consistent bed net use, and the mediator variable was a composite measure called ideation from a set of psychosocial factors believed to influence bed net use. The independent variable was recall of malaria specific media messages. Multilevel mediation analysis explored if recall of malaria specific media messages had any effect on bed net related ideation and if this ideation had any effect on consistent net use.

Results

Respondents included in this study were on average aged 31 years, mostly married or cohabiting (97.5%) and female 75%. Four in 10 (39.7%) respondents were able to recall malaria specific messages. Respondents with low, moderate and high recall were 23, 32 and 80% more likely to have a higher ideational score in the emotional domain compared to those not able to recall. Respondents were more likely to have higher ideational scores in the cognitive domain if they had low (AOR = 1.26, 95% CI 1.15–1.38), moderate (AOR = 1.16, 95% CI 1.00–1.34) or high recall (AOR = 1.55, 95% CI 1.16–2.06), respectively compared to those with no recall. Similarly, respondents with low (AOR = 1.03, 95% CI .99–1.08), moderate (AOR = 1.15, 95% CI 1.08–1.23) and high (AOR = 1.15, 95% CI 1.01–1.30) recall were more likely to have a higher ideational score in the social domain compared to those with no recall. After adjusting for recall of media messages and other potential covariates, all three ideational domains also had a significant positive effect on consistent bed net use. For every unit increase in ideational score, the likelihood of reporting consistent bed net use increased by 5 to 10%. There was a significant indirect effect of recalling malaria specific messages on consistent bed net use through each of the ideational domains.

Conclusion

Access to a bed net is a critical first step in the process of bed net utilization. However, psychosocial factors e.g., emotional, cognitive, and social domains of ideation also play a major role in bed net use. Mass media SBC interventions could potentially influence bed net related ideation and consequently improve net use behavior. Future Social and behavior change interventions should employ approaches that improve these domains of ideation within their audiences in order to increase bed net utilization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11709-5.

Effect of thermally treated barley dietary fiber against hypercholesterolemia

Dietary fiber is a nondigestible constituent of vegetal foods, formed by insoluble and soluble dietary fiber. The intake of dietary fiber, especially soluble dietary fiber, is limited and demands researcher's attention. The modification of cereal's dietary fiber, predominantly insoluble fiber, could be one possible solution. The current study evaluated the comparative effects of several thermal treatments on the modification of insoluble dietary fiber in barley and explored their therapeutic potential in vivo against hypercholesterolemia. The two cultivars of barley, Haider-93 and Jau-87, were thermally treated using different techniques, and dietary fiber was extracted. Successively, the intake of these dietary fibers was evaluated for its antilipidemic activity in normal and hypercholesterolemic rats. In the first phase, thermal treatments especially cooking without soaking increased the soluble fiber (68.08%). The roasting all increased the soluble fiber contents, however, at relatively lower rate (53.91%). The results of efficacy study revealed that biochemical parameters in control animals were within the normal clinical ranges, thus appraising the safe status of the experimental diets. The thermally treated barley fiber decreased total cholesterol (12.14%-12.63%), low-density lipoprotein (14.12%-14.85%), and triglycerides (2.25%-4.32%). The study recorded increasing trends for high-density lipoprotein in both normal and hypercholesterolemic rats. In the nutshell, thermal modification of dietary fiber increased the ratio of soluble to insoluble dietary fiber that improved its hypocholesterolemic potential. The thermally treated barley dietary fiber is effective in reducing the lipid profile in Sprague-dawley rats than untreated dietary fiber and, therefore, can be considered as a functional food and ingredient to cope different lifestyle diseases.

Health Benefits of Lactic Acid Bacteria (LAB) Fermentates

Consuming fermented foods has been reported to result in improvements in a range of health parameters. These positive effects can be exerted by a combination of the live microorganisms that the fermented foods contain, as well as the bioactive components released into the foods as by-products of the fermentation process. In many instances, and particularly in dairy fermented foods, the microorganisms involved in the fermentation process belong to the lactic acid group of bacteria (LAB). An alternative approach to making some of the health benefits that have been attributed to fermented foods available is through the production of ‘fermentates’. The term ‘fermentate’ generally relates to a powdered preparation, derived from a fermented product and which can contain the fermenting microorganisms, components of these microorganisms, culture supernatants, fermented substrates, and a range of metabolites and bioactive components with potential health benefits. Here, we provide a brief overview of a selection of in vitro and in vivo studies and patents exclusively reporting the health benefits of LAB ‘fermentates’. Typically, in such studies, the potential health benefits have been attributed to the bioactive metabolites present in the crude fermentates and/or culture supernatants rather than the direct effects of the LAB strain(s) involved.

Effect of Fiber-Rich Snacks on C-Reactive Protein and Atherogenic Index in Type 2 Diabetes Patients

Background and aims: High levels of non-HDL and atherogenic cholesterol can induce inflammation, and as risk factor for cardiovascular diseases. This study was to evaluate the effects of fiber-rich snacks on non-HDL cholesterol, atherogenic index, and Creactive protein (CRP) levels in type 2 diabetes patients (T2DM). Material and Methods: Twenty T2DM patients, were recruited from the Policlinic of Endocrine, Dr. Sardjito General Hospital, Yogyakarta, Indonesia. The subjects received daily 32g fiber-rich snacks made of Dioscorea esculenta, arrowroot, cassava and pumpkin for 4 weeks. Fasting non-HDL cholesterol, atherogenic index, CRP and HbA1c levels were measured before and after intervention. Paired t-test was used to evaluate the results. Results: The fiber-rich snack intervention in T2DM patients significantly reduced levels of non-HDL cholesterol and CRP levels (p<0.05), but the decreased the atherogenic index was not significant (p>0.05). The intervention also significantly reduced the CRP levels (p<0.05) but did not affect HbA1c levels. Body weight, body mass index (BMI), waist circumference decreased significantly after consuming the snacks (p<0.05). Conclusions: This study showed fiber-rich snack has a positive effect in improving non-HDL cholesterol, atherogenic index and CRP levels but does not affect HbA1c levels in T2DM patients.

Gender and Age Stratified Analyses of Nutrient and Dietary Pattern Associations with Circulating Lipid Levels Identify Novel Gender and Age-Specific Correlations

Dyslipidemia is a precursor to a myriad of cardiovascular diseases in the modern world. Age, gender, and diet are known modifiers of lipid levels, however they are not frequently investigated in subset analyses. Food and nutrient intakes from National Health and Nutrition Examination Study 2001–2013 were used to assess the correlation between lipid levels (high-density lipoprotein (HDL) cholesterol, triglycerides (TG), low-density lipoprotein (LDL) cholesterol, and total cholesterol (TC):HDL cholesterol ratio) and nutritional intake using linear regression. Associations were initially stratified by gender and significant gender correlations were further stratified by age. Analyses were performed at both the dietary pattern and nutrient level. Dietary pattern and fat intake correlations agreed with the literature in direction and did not demonstrate gender or age effects; however, we observed gender and age interactions among other dietary patterns and individual nutrients. These effects were independent of ethnicity, caloric intake, socioeconomic status, and physical activity. Elevated HDL cholesterol levels correlated with increasing vitamin and mineral intake in females of child bearing age but not males or older females (≥65 years). Moreover, increases in magnesium and retinol intake correlated with HDL cholesterol improvement only in females (all age groups) and males (35–64), respectively. Finally, a large amount of gender-specific variation was associated with TG levels. Females demonstrated positive associations with sugar and carbohydrate while males show inverse associations with polyunsaturated fatty acid (PUFA) intake. The female-specific association increased with the ratio of carbohydrate: saturated fatty acid (SFA) intake, suggesting that gender specific dietary habits may underlie the observed TG-nutrient correlations. Our study provides evidence that a subset of previously established nutrient-lipid associations may be gender or age-specific. Such discoveries provide potential new avenues for further research into personalized nutritional approaches to treat dyslipidemia.

Effect of Fiber-Rich Snacks on C-Reactive Protein and Atherogenic Index in Type 2 Diabetes Patients

Background and aims: High levels of non-HDL and atherogenic cholesterol can induce inflammation, and as risk factor for cardiovascular diseases. This study was to evaluate the effects of fiber-rich snacks on non-HDL cholesterol, atherogenic index, and C-reactive protein (CRP) levels in type 2 diabetes patients (T2DM).

Material and Methods: Twenty T2DM patients, were recruited from the Policlinic of Endocrine, Dr. Sardjito General Hospital, Yogyakarta, Indonesia. The subjects received daily 32g fiber-rich snacks made of Dioscorea esculenta, arrowroot, cassava and pumpkin for 4 weeks. Fasting non-HDL cholesterol, atherogenic index, CRP and HbA1c levels were measured before and after intervention. Paired t-test was used to evaluate the results.

Results: The fiber-rich snack intervention in T2DM patients significantly reduced levels of non-HDL cholesterol and CRP levels (p<0.05), but the decreased the atherogenic index was not significant (p>0.05). The intervention also significantly reduced the CRP levels (p<0.05) but did not affect HbA1c levels. Body weight, body mass index (BMI), waist circumference decreased significantly after consuming the snacks (p<0.05).

Conclusions: This study showed fiber-rich snack has a positive effect in improving non-HDL cholesterol, atherogenic index and CRP levels but does not affect HbA1c levels in T2DM patients.

Does Partner Selection Mediate the Relationship Between School Attendance and HIV/Herpes Simplex Virus-2 Among Adolescent Girls and Young Women in South Africa: An Analysis of HIV Prevention Trials Network 068 Data

OBJECTIVE

School attendance prevents HIV and herpes simplex virus-2 (HSV-2) in adolescent girls and young women, but the mechanisms to explain this relationship remain unclear. Our study assesses the extent to which characteristics of sex partners, partner age, and number mediate the relationship between attendance and risk of infection in adolescent girls and young women in South Africa.

DESIGN

We use longitudinal data from the HIV Prevention Trials Network 068 randomized controlled trial in rural South Africa, where girls were enrolled in early adolescence and followed in the main trial for more than 3 years. We examined older partners and the number of partners as possible mediators.

METHODS

We used the parametric g-formula to estimate 4-year risk differences for the effect of school attendance on the cumulative incidence of HIV/HSV-2 overall and the controlled direct effect (CDE) for mediation. We examined mediation separately and jointly for the mediators of interest.

RESULTS

We found that young women with high attendance in school had a lower cumulative incidence of HIV compared with those with low attendance (risk difference = -1.6%). Partner age difference (CDE = -1.2%) and the number of partners (CDE = -0.4%) mediated a large portion of this effect. In fact, when we accounted for the mediators jointly, the effect of schooling on HIV was almost removed, showing full mediation (CDE = -0.3%). The same patterns were observed for the relationship between school attendance and cumulative incidence of HSV-2 infection.

CONCLUSION

Increasing school attendance reduces the risk of acquiring HIV and HSV-2. Our results indicate the importance of school attendance in reducing partner number and partner age difference in this relationship.

Implementation and reporting of causal mediation analysis in 2015: a systematic review in epidemiological studies

Background

Causal mediation analysis is often used to understand the impact of variables along the causal pathway of an occurrence relation. How well studies apply and report the elements of causal mediation analysis remains unknown.

Methods

We systematically reviewed epidemiological studies published in 2015 that employed causal mediation analysis to estimate direct and indirect effects of observed associations between an exposure on an outcome. We identified potential epidemiological studies through conducting a citation search within Web of Science and a keyword search within PubMed. Two reviewers independently screened studies for eligibility. For eligible studies, one reviewer performed data extraction, and a senior epidemiologist confirmed the extracted information. Empirical application and methodological details of the technique were extracted and summarized.

Results

Thirteen studies were eligible for data extraction. While the majority of studies reported and identified the effects of measures, most studies lacked sufficient details on the extent to which identifiability assumptions were satisfied. Although most studies addressed issues of unmeasured confounders either from empirical approaches or sensitivity analyses, the majority did not examine the potential bias arising from the measurement error of the mediator. Some studies allowed for exposure-mediator interaction and only a few presented results from models both with and without interactions. Power calculations were scarce.

Conclusions

Reporting of causal mediation analysis is varied and suboptimal. Given that the application of causal mediation analysis will likely continue to increase, developing standards of reporting of causal mediation analysis in epidemiological research would be prudent.

The effects of the DASH diet education program with omega-3 fatty acid supplementation on metabolic syndrome parameters in elderly women with abdominal obesity

BACKGROUND/OBJECTIVES

The purpose of this study was to investigate the overall effects of a tailored Dietary Approaches to Stop Hypertension (DASH) nutritional intervention program which included omega-3 fatty acids supplementation, on dietary self-efficacy, dietary knowledge, and dietary behaviors in Korean elderly women with abdominal obesity. Furthermore, we investigated the effects of the program on metabolic syndrome parameters including the antioxidant capacities in these subjects.

SUBJECTS/METHODS

A randomized, controlled trial was conducted for 8 weeks. The experimental group (n = 21) received a weekly tailored nutritional program for 8 weeks and the control group (n = 18) received only one educational session. The clinical survey was conducted before and after the intervention period.

RESULTS

After the intervention, dietary self-efficacy (P = 0.023), frequency of fruit intake (P = 0.019), and dietary fiber intake (P = 0.044) were higher in the experimental group than in the control group. The oxidative stress (P < 0.001) was lower in the experimental group than in the control group. Moreover, low density lipoprotein (LDL) cholesterol (P = 0.023) had significantly decreased in the experimental group but not in the control group after the intervention.

CONCLUSIONS

The intervention program including omega-3 fatty acid supplementation had a positive effect on dietary self-efficacy, dietary behaviors, and oxidative stress among aged women with abdominal obesity.

Dietary fiber intake and total mortality: a meta-analysis of prospective cohort studies

Greater intake of dietary fiber has been associated with lower risk of several chronic diseases. Some observational studies have examined the association between dietary fiber intake and total mortality, but the results were inconclusive. We conducted a meta-analysis of data from prospective cohort studies to quantitatively assess the association. Eligible studies were identified by searching the PubMed and Embase databases for all articles published through November 30, 2013, and by reviewing the reference lists of retrieved articles. Study-specific estimates adjusting for potential confounders were combined to calculate a pooled relative risk and 95% confidence interval using a random-effects model. Seven prospective cohort studies of dietary fiber intake and total mortality, including 62,314 deaths among 908,135 participants, were identified. The pooled adjusted relative risk of total mortality for the highest category of dietary fiber intake versus the lowest was 0.77 (95% confidence interval: 0.74, 0.80). In a dose-response meta-analysis, the pooled adjusted relative risk for a 10-g/day increment of dietary fiber intake was 0.89 (95% confidence interval: 0.85, 0 92). By source of fiber, cereal and, to a lesser extent, vegetable fiber were significantly associated with lower total mortality, while fruit fiber showed no association. In conclusion, high dietary fiber intake may reduce the risk of total mortality.

Dietary fiber intake and its association with indicators of adiposity and serum biomarkers in European adolescents: the HELENA study

PURPOSE

To evaluate total, energy-adjusted dietary fiber (DF), water-soluble fiber (WSF), and water-insoluble fiber (WIF) intakes in European adolescents and to investigate their association with indicators of adiposity and serum biomarkers.

METHODS

This study, conducted from 2006 to 2007, included 1804 adolescents aged 12.5-17.5 years (47% males) from eight European cities completing two non-consecutive computerized 24-h dietary recalls. GLM multivariate analysis was used to investigate associations.

RESULTS

Mean DF intake (20 g/day) of the sample met the European Food Safety Authority recommendation, but was below those of the World Health Organization and of the Institute of Medicine. Total DF, WSF and WIF intakes were higher in males (P < 0.001), but following energy-adjustments significantly higher intakes were observed among females (P < 0.001). Bread and cereals contributed most to total DF, WSF and WIF intakes, followed by potatoes and grains, energy-dense but low-nutritious foods, fruits and vegetables. Moreover, energy-adjusted WSF and WIF were positively associated with body fat percentage (BF%), waist to height ratio and low-density lipoprotein cholesterol, while energy-adjusted WSF was inversely associated with serum fasting glucose (β = -0. 010, P = 0.020).

CONCLUSION

Total DF intakes are rather low in European adolescents. An inverse association with serum fasting glucose might indicate a possible beneficial role of DF in preventing insulin resistance and its concomitant diseases, even though DF intakes were positively associated with adolescents' BF%. Therefore, further longitudinal studies should elaborate on these potential beneficial effects of DF intake in the prevention of obesity and related chronic diseases.

Lipid concentrations and couple fecundity: the LIFE study

CONTEXT

A role of lipids in human fecundity is hypothesized as cholesterol is the main substrate for steroid synthesis and has also been shown to affect the hormonal milieu and steroidogenesis in both men and women.

OBJECTIVE

The objective of the study was to evaluate the association between male and female serum lipid concentrations and time to pregnancy (TTP).

DESIGN/SETTING

A population-based prospective cohort study recruiting couples from 16 counties in Michigan and Texas (2005-2009) using sampling frameworks allowing for identification of couples planning pregnancy in the near future.

PARTICIPANTS

Five hundred one couples desiring pregnancy and discontinuing contraception were followed up for 12 months or until a human chorionic gonadotropin pregnancy was detected.

MAIN OUTCOME AND MEASURES

Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated after adjusting for age, body mass index, race, and education in relationship to female, male, and joint couple lipid concentrations.

RESULTS

Serum free cholesterol levels were higher on average among male and female partners of couples who did not became pregnant during the study follow-up (female, P = .04; male, P = .009), and levels in female partners were associated with significantly longer TTP in models based on both individual and couples concentrations (individual models: FOR 0.98, 95% CI 0.97, 0.99; couple models: FOR 0.98, 95% CI 0.97, 0.99). Male free cholesterol concentrations were associated with TTP only in the couple-based models (FOR 0.98, 95% CI 0.97, 0.99). Sensitivity analyses suggested that the observed associations are unlikely to be explained by potential unmeasured confounding such as diet.

CONCLUSIONS

Our results suggest that serum free cholesterol concentrations in both men and women have an effect on TTP, highlighting the importance of cholesterol and lipid homeostasis for male and female fecundity.

Undaria pinnatifida soluble fiber regulates Angptl3-LPL pathway to lessen hyperlipidemia in mice

Angiopoietin-like protein 3 (Angptl3)-lipoprotein lipase (LPL) pathway may be a useful pharmacologic target for hyperlipidemia. The present study was conducted to test the effect of soluble fiber extracted from Undaria pinnatifida (UP), on hyperlipidemia in apolipoprotein E-deficient (ApoE(-/-)) mice. Forty mice were divided into four groups (n = 10): control group (C57BL/6J mice), ApoE(-/-) mice group, and two groups of ApoE(-/-) mice treated with UP fiber (5 or 10 % per day). UP soluble fiber treatment significantly decreased plasma and hepatic total cholesterol, triglycerides levels, plasma low-density lipoprotein cholesterol, and malondialdehyde concentrations and increased plasma high-density lipoprotein cholesterol level and downregulated protein expression of Angptl3 concomitantly with upregulated protein expression of LPL. In addition, T0901317 caused elevated expression of hepatic Angptl3 protein, and the effect of T0901317 was also abrogated by UP soluble fiber in C57BL/6J mice. The present results suggest that the UP soluble fiber regulates Angptl3-LPL pathway to lessen hyperlipidemia in mice.

Changes in weight loss and lipid profiles after a dietary purification program: a prospective case series

OBJECTIVE

The purpose of this case series was to describe immediate changes to weight and lipid profiles after a 21-day Standard Process whole food supplement and dietary modification program.

METHODS

Changes in weight and lipid profiles were measured for 7 participants (6 men and 1 woman) participating in a 21-day program. The dietary modifications throughout the Standard Process program were consumption of (1) unlimited fresh or frozen vegetables and fruits and preferably twice as many vegetables as fruits, (2) ½ to 1 cup of cooked lentils or brown rice each day, (3) 4 to 7 teaspoons of cold pressed oils per day, and (4) at least 64 oz of water a day. After day 10 of the program, participants were allowed to consume 1 to 2 servings of baked, broiled, or braised poultry or fish per day. Participants consumed a whey protein-based shake as meal replacement 2 times per day. Nutritional supplementation included a cleanse product on days 1 to 7, soluble fiber supplementation including oat bran concentrate and apple pectin on all days, and "green food" supplementation on days 8 to 21.

RESULTS

Weight loss ranged between 5.2 (2.4 kg) and 19.9 lb (9.0 kg) (average, 11.7 lb; 5.3 kg). Total cholesterol levels decreased with ranges between 11 and 77 mg/dL, and low-density lipoprotein cholesterol levels decreased in a range between 7 and 67 mg/dL.

CONCLUSION

After participating in a dietary program, the 7 participants demonstrated short-term weight loss and improvements in their lipid profiles.

Phytoestrogen and fiber intakes in relation to incident vasomotor symptoms: results from the Study of Women's Health Across the Nation

OBJECTIVE

Although reduction of vasomotor symptoms (VMS; hot flashes and night sweats) has been reported in postmenopausal women who used isoflavones, a clear dose response has not been shown, has largely not been reported for perimenopausal women, and has largely only been reported for reducing prevalent VMS, not preventing newly developing VMS. We analyzed longitudinal data from the Study of Women's Health Across the Nation for the relation of dietary phytoestrogen and fiber intake to incident VMS in this multiracial/ethnic cohort.

METHODS

The Study of Women's Health Across the Nation included 3,302 premenopausal and early perimenopausal women, 1,651 of whom reported no VMS at baseline and were followed with annual visits for 10 years. Dietary intakes of isoflavones, coumestrol, lignans, and fiber were assessed by a food frequency questionnaire at baseline and in annual visits 5 and 9 and interpolated for intervening years. The number of days experiencing VMS in the past 2 weeks was self-reported annually. Using multinomial logistic regression with generalized estimating equations, we modeled incident VMS in relation to isoflavones, lignans, fiber, coumestrol, or total phytoestrogen intake and covariates.

RESULTS

No consistent monotonic relations were observed between any dietary phytoestrogen or fiber and incident VMS, although adjusted odds ratios for some individual quartiles were statistically significant.

CONCLUSIONS

For certainty of any effect of dietary phytoestrogens or fiber on the prevention of incident VMS, a randomized, placebo-controlled, double-masked trial with sufficient numbers of women in different racial/ethnic, menopausal status, and metabolic groups over years of follow-up is required, but our results suggest that a clinically significant or large effect is improbable.

Invited commentary: dietary fiber, estradiol, and cholesterol

The limitations of examining mediating factors by adjusting for them in standard regression models have been well-documented in the literature. Although alternative analytic models have been suggested, they are rarely used. In the accompanying article, Mumford et al. (Am J Epidemiol. 2010;173(2):145-156) use marginal structural linear mixed models to determine the association between dietary fiber intake and cholesterol through pathways that do not involve estradiol. Their findings suggest that overall high fiber intake decreases levels of total and low density lipoprotein (LDL) cholesterol and that there are multiple pathways through which fiber can act. The estradiol-mediated pathway seems to lead to increases in total and LDL cholesterol which are more than counterbalanced by pathways leading to decreases in total and LDL cholesterol. In addition to answering a scientifically interesting question, this work provides a concrete example of the use of marginal structural models for examination of direct effects and may serve as a guide to future researchers.