Sociodemographic and lifestyle variables are compound- and class-specific correlates of urine phytoestrogen concentrations in the U.S. population

Urinary biomarkers for amyotrophic lateral sclerosis: candidates, opportunities and considerations

Amyotrophic lateral sclerosis is a relentless neurodegenerative disease that is mostly fatal within 3-5 years and is diagnosed on evidence of progressive upper and lower motor neuron degeneration. Around 15% of those with amyotrophic lateral sclerosis also have frontotemporal degeneration, and gene mutations account for ∼10%. Amyotrophic lateral sclerosis is a variable heterogeneous disease, and it is becoming increasingly clear that numerous different disease processes culminate in the final degeneration of motor neurons. There is a profound need to clearly articulate and measure pathological process that occurs. Such information is needed to tailor treatments to individuals with amyotrophic lateral sclerosis according to an individual's pathological fingerprint. For new candidate therapies, there is also a need for methods to select patients according to expected treatment outcomes and measure the success, or not, of treatments. Biomarkers are essential tools to fulfil these needs, and urine is a rich source for candidate biofluid biomarkers. This review will describe promising candidate urinary biomarkers of amyotrophic lateral sclerosis and other possible urinary candidates in future areas of investigation as well as the limitations of urinary biomarkers.

Lignan exposure: a worldwide perspective

Dietary lignans are phytoestrogens that are mostly found in plant-based foods, especially whole grains, seeds, nuts, legumes and vegetables. An accurate assessment of lignan exposure is crucial to evaluate their potential health benefits and to establish future recommendations and dietary guidelines. This narrative review aimed to (i) summarize the pros and the cons of the current main assessment methods for lignan exposure─i.e., dietary questionnaires, food composition tables and biomarkers, (ii) describe the individual lignans more consumed from a worldwide perspective, as well as their main food sources, (iii) determine the lignans concentrations in both urine and blood, and explore their heterogeneity among countries, and finally (iv) discuss the main determinants of lignan exposure.

Challenges and Lessons Learned in Generating and Interpreting NHANES Nutritional Biomarker Data

For the past 45 y, the National Center for Health Statistics at the CDC has carried out nutrition surveillance of the US population by collecting anthropometric, dietary intake, and nutritional biomarker data, the latter being the focus of this publication. The earliest biomarker testing assessed iron and vitamin A status. With time, a broad spectrum of water- and fat-soluble vitamins was added and biomarkers for other types of nutrients (e.g., fatty acids) and bioactive dietary compounds (e.g., phytoestrogens) were included in NHANES. The cross-sectional survey is flexible in design, and biomarkers may be measured for a short period of time or rotated in and out of surveys depending on scientific needs. Maintaining high-quality laboratory measurements over extended periods of time such that trends in status can be reliably assessed is a major goal of the testing laboratories. Physicians, health scientists, and policy makers rely on the NHANES reference data to compare the nutritional status of population groups, to assess the impact of various interventions, and to explore associations between nutritional status and health promotion or disease prevention. Focusing on the continuous NHANES, which started in 1999, this review uses a "lessons learned" approach to present a series of challenges that are relevant to researchers measuring biomarkers in NHANES and beyond. Some of those challenges are the use of multiple related biomarkers instead of a single biomarker for a specific nutrient (e.g., folate, vitamin B-12, iron), adhering to special needs for specimen collection and handling to ensure optimum specimen quality (e.g., vitamin C, folate, homocysteine, iodine, polyunsaturated fatty acids), the retrospective use of long-term quality-control data to correct for assay shifts (e.g., vitamin D, vitamin B-12), and the proper planning for and interpretation of crossover studies to adjust for systematic method changes (e.g., folate, vitamin D, ferritin).

Triclosan and prescription antibiotic exposures and enterolactone production in adults

BACKGROUND

The gut microbiome plays an important role in the development of disease. The composition of the microbiome is influenced by factors such as mode of delivery at birth, diet and antibiotic use, yet the influence of environmental chemical exposures is largely unknown. The antimicrobial compound triclosan, found in many personal care products and widely detected in human urine, is an environmental exposure for which systemic microbiotic effects may be of particular interest. To investigate the relationship between triclosan and gut microflora, we assessed the association between triclosan and enterolactone, an intestinal metabolite that is produced via bacterial transformation of dietary lignans (seeds, nuts) and has known susceptibility to oral antibiotics.

METHODS

We examined urinary triclosan and enterolactone for 2005-2008 U.S. National Health and Nutrition Examination Survey subjects, aged ≥20 years (n=3041). We also examined the association between prescription antibiotic use and enterolactone to confirm its susceptibility to changes in bacterial composition of the body. Associations between natural log-transformed enterolactone and (1) detected vs. not detected (<2.3 ng/mL) triclosan, (2) triclosan quintiles (Q1-Q5), and (3) any vs. no antibiotics were estimated with multiple linear regression, adjusting for sex, age, race, body mass index, poverty income ratio, education, fiber intake, bowel movement frequency, cotinine and creatinine (n=2441).

RESULTS

Triclosan was detected in 80% of subjects (range: <2.3-3620 ng/mL), while enterolactone was detected in >99% of subjects (range: <0.1-122,000 ng/mL). After adjustment, enterolactone was not associated with triclosan (detect vs. non-detect: β= 0.07 (95% CI: -0.15, 0.30); Q5 (≥104.5 ng/mL) vs. Q1 (none): β= 0.06 (95% CI: -0.21, 0.34)). In sex-stratified analyses, triclosan was associated with higher enterolactone in women (detect vs. non-detect: β= 0.31 (95% CI: -0.07, 0.70), but not men β= -0.18 (95% CI: -0.47, 0.11). However, any antibiotic use (n=112), as compared to no antibiotic use, was associated with significantly lower enterolactone (β=-0.78 (95%CI: -1.22, -0.36)), with no sex-specific effects. This association was driven by inverse associations with the following antibiotic classes: macrolide derivatives, quinolones, sulfonamides, and lincomycin derivatives.

CONCLUSIONS

Antibiotics, but not triclosan, are negatively associated with urinary enterolactone. Antibiotics may reduce enterolactone by killing certain gut bacteria. At levels detected in the U.S., triclosan does not appear to be acting similarly, despite broad antimicrobial properties. Additional study of determinants of triclosan exposure and enterolactone production may be needed to better understand positive associations among women.

Urinary isoflavone concentrations are inversely associated with cardiometabolic risk markers in pregnant U.S. women

Some evidence suggests that phytoestrogens, such as soy-derived isoflavones, may have beneficial effects on cardiovascular health and glycemic control. These data are mainly limited to postmenopausal women or individuals at elevated cardiometabolic risk. There is a lack of data for pregnant women who have elevated estrogen levels and physiologically altered glucose and lipid metabolism. We analyzed data from 299 pregnant women who participated in the NHANES 2001-2008 surveys. Multivariable linear regression analyses were used to examine the association between urinary concentrations of isoflavonoids and cardiometabolic risk markers, adjusted for body mass index, pregnancy trimester, total energy intake, dietary intake of protein, fiber, and cholesterol, and demographic and lifestyle factors. Cardiometabolic risk markers were log-transformed, and geometric means were calculated by quartiles of urinary concentrations of isoflavonoids. Comparing women in the highest vs. lowest quartiles of urine total isoflavone concentrations, we observed significant, inverse associations with circulating concentrations of fasting glucose (79 vs. 88 mg/dL, P-trend = 0.0009), insulin (8.2 vs. 12.8 μU/mL, P-trend = 0.03), and triglyceride (156 vs. 185 mg/dL, P-trend = 0.02), and the homeostasis model assessment of insulin resistance (1.6 vs. 2.8, P-trend = 0.01), but not for total, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol. The concentrations of individual isoflavonoids, daidzein, equol, and O-desmethylangolensin were inversely associated with some cardiometabolic risk markers, although no clear pattern emerged. These data suggest that there may be a relation between isoflavone intake and cardiometabolic risk markers in pregnant women.

Urinary phytoestrogens and depression in perimenopausal US women: NHANES 2005-2008

BACKGROUND

Fluctuating hormonal levels observed during the menopausal transition may increase vulnerability to depression in susceptible women. Thus, it is of interest to examine the effect of natural estrogens such as phytoestrogens on the risk of depression in perimenopausal women.

METHODS

Our analysis included 193 perimenopausal women of the National Health and Nutrition Survey (NHANES) 2005-2008 aged 45-55 years. Urinary concentrations of phytoestrogens (isoflavones and lignans) were measured by HPLC-APPI-MS/MS. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). Logistic regression models examined the association of phytoestrogens concentrations (creatinine-standardized and log-transformed) with depression (yes/no).

RESULTS

Unadjusted odds ratios (OR) of the associations between urinary phytoestrogen concentrations and perimenopausal depression were below 1; however, only lignans were significantly inversely associated with depression. The latter findings were not attenuated in multivariate analysis including age, race, body mass index, poverty income ratio, smoking, alcohol consumption, cancer, diabetes, and cardiovascular disease (lignans: OR=0.66; 95% confidence intervals (CI) 0.50-0.87, enterodiol: OR=0.63; 95% CI 0.51-0.78, enterolactone: OR=0.75; 95% CI 0.60-0.93).

LIMITATIONS

Our cross-sectional study design does not allow for causal inferences. Because information to precisely assess perimenopausal symptoms was missing, we defined perimenopause based on women's age.

CONCLUSIONS

Lower lignans but not isoflavones concentrations were statistically significantly associated with an increased risk of depression in perimenopausal women. Because of medical risks associated with the use of hormone therapy, further investigation on the effect of lignans on the risk of depression in perimenopausal women is warranted.

Urinary lignans and inflammatory markers in the US National Health and Nutrition Examination Survey (NHANES) 1999-2004 and 2005-2008

PURPOSE

Chronic inflammation has been implicated in the etiology of various chronic diseases. We previously found that certain urinary isoflavones are associated with markers of inflammation. In the present study, we examined the associations of serum C-reactive protein (CRP) and white blood cell (WBC) count with lignans, which are more frequent in the Western diet than isoflavones.

METHODS

Our analysis included 2,028 participants of NHANES 2005-2008 and 2,628 participants of NHANES 1999-2004 aged 18 years and older. The exposures of interest were urinary mammalian lignans (enterodiol and enterolactone). Outcome variables were two inflammatory markers (CRP [≤10 mg/L] and WBC [≥3.0 and ≤11.7 (1,000 cells/μL)]). Log-transformed CRP concentration and WBC count by log-transformed creatinine-standardized concentrations of mammalian lignans were used for linear regression.

RESULTS

Statistically significant inverse associations of urinary lignan, enterodiol, and enterolactone concentrations with circulating CRP and WBC counts were observed in the multivariate-adjusted models: In NHANES 2005-2008, per one-percent increase in lignan concentrations in the urine, CRP concentrations and WBC counts decreased by 8.1 % (95 % CI -11.5, -4.5) and 1.9 % (95 % CI -2.7; -1.2), respectively. Per one-percent increase in enterodiol and enterolactone, WBC counts decreased by 2.1 % (95 % CI -2.8, -1.3) and 1.3 % (95 % CI -1.9, -0.6), respectively. In NHANES 1999-2004, analogous results were 3.0 % (95 % CI -5.6, -0.3), 1.2 % (95 % CI -2.0; -0.4), 1.0 % (95 % CI -1.8, -0.2), and 0.8 % (95 % CI -1.4, 0.2).

CONCLUSIONS

Mammalian lignans were inversely associated with markers of chronic inflammation. Due to the cross-sectional design, our findings require confirmation in prospective studies.