The complementary roles of iron and estrogen in menopausal differences in cardiometabolic outcomes.

Biological hormonal changes are frequently cited as an explanatory factor of sex and menopause differences in cardiometabolic diseases (CMD) and its associated risk factors. However, iron metabolism which varies between sexes and among women of different reproductive stages could also play a role. Recent evidence suggest that iron may contribute to CMD risk by modulating oxidative stress pathways and inflammatory responses, offering insights into the mechanistic interplay between iron and CMD development. In the current review, we provide a critical appraisal of the existing evidence on sex and menopausal differences in CMD, discuss the pitfall of current estrogen hypothesis as sole explanation, and the emerging role of iron in CMD as complementary pathway. Prior to menopause, body iron stores are lower in females as compared to males, but the increase during and after menopause, is tandem with an increased CMD risk. Importantly, basic science experiments show that an increased iron status is related to the development of type 2 diabetes (T2D), and different cardiovascular diseases (CVD). While epidemiological studies have consistently reported associations between heme iron intake and some iron biomarkers such as ferritin and transferrin saturation with the risk of T2D, the evidence regarding their connection to CVD remains controversial. We delve into the factors contributing to this inconsistency, and the limitation of relying on observational evidence, as it does not necessarily imply causation. In conclusion, we provide recommendations for future studies on evaluating the potential role of iron in elucidating the sex and menopausal differences observed in CMD.

Effect of aerobic exercise, slow deep breathing and mindfulness meditation on cortisol and glucose levels in women with type 2 diabetes mellitus: a randomized controlled trial.

Background: Aerobic exercise combined with breathing exercise can be an integral part of diabetes mellitus treatment. This single-center, randomized, parallel-group study investigated the effect of the combination of aerobic exercise with slow deep breathing and mindfulness meditation on the glucose and cortisol levels of women with type 2 diabetes mellitus (T2DM). Materials and Methods: Fifty-eight middle-aged women with T2DM (mean age: 45.67 ± 2.92 years) were randomly assigned to either the aerobic training group (AT: n = 29; mean age [46.1 ± 2.7 years]) or the aerobic exercise combined with slow deep breathing and mindfulness meditation (AT + DMM: n = 29; mean age [45.24 ± 3.14 years]). Aerobic exercise was performed at 60%-75% of the maximum heart rate. The women in each group were asked to perform the training three times weekly over a 6-week period. The duration of each session was 40 min for the AT group and 60 min for the AT + DMM group. The two groups were asked to perform aerobic exercise at 60%-75% of the maximum heart rate. Their fasting blood glucose (FBG) and serum cortisol levels were measured at the baseline and after the 6 weeks. Results: Compared with the AT group, the group undertaking 6 weeks of aerobic training combined with slow, deep breathing exercises and mindfulness meditation showed significantly lower levels of FBG (p = 0.001) and cortisol levels (p = 0.01) than the AT group. Conclusion: The addition of slow deep breathing and mindfulness meditation to aerobic exercise can better control the glucose and cortisol levels of women with T2DM and thereby improve their outcomes and decrease their cardiometabolic risk.

Effect of oat supplementation interventions on cardiovascular disease risk markers: a systematic review and meta-analysis of randomized controlled trials.

PURPOSE: Oat supplementation interventions (OSIs) may have a beneficial effect on cardiovascular disease (CVD) risk. However, dietary background can modulate such effect. This systematic review assesses the effects of OSIs on CVD risk markers among adults, accounting for different dietary backgrounds or control arms. METHODS: We included randomized clinical trials (RCTs) that assessed the effect of oat, oat beta-glucan-rich extracts or avenanthramides on CVD risk markers. RESULTS: Seventy-four RCTs, including 4937 predominantly hypercholesterolemic, obese subjects, with mild metabolic disturbances, were included in the systematic review. Of these, 59 RCTs contributed to the meta-analyses. Subjects receiving an OSI, compared to control arms without oats, had improved levels of total cholesterol (TC) [weighted mean difference and (95% CI) - 0.42 mmol/L, (- 0.61; - 0.22)], LDL cholesterol [- 0.29 mmol/L, (- 0.37; - 0.20)], glucose [- 0.25 nmol/L, (- 0.36; - 0.14)], body mass index [- 0.13 kg/m2, (- 0.26; - 0.01)], weight [- 0.94 kg, (- 1.84: - 0.05)], and waist circumference [- 1.06 cm, (- 1.85; - 0.27)]. RCTs on inflammation and/or oxidative stress markers were scarce and with inconsistent findings. RCTs comparing an OSI to heterogeneous interventions (e.g., wheat, eggs, rice, etc.), showed lowered levels of glycated haemoglobin, diastolic blood pressure, HDL cholesterol and apolipoprotein B. The majority of included RCTs (81.1%) had some concerns for risk of bias. CONCLUSION: Dietary OSIs resulted in lowered levels of blood lipids and improvements in anthropometric parameters among participants with predominantly mild metabolic disturbances, regardless of dietary background or control. Further high-quality trials are warranted to establish the role of OSIs on blood pressure, glucose homeostasis and inflammation markers.

Systematic Review of Human and Animal Evidence on the Role of Buckwheat Consumption on Gastrointestinal Health.

BACKGROUND: Buckwheat is a commonly cultivated crop with growing evidence that it is beneficial to gastrointestinal (GI) health. This systematic review summarizes the role of buckwheat in modifying GI health outcomes and microbiomes. METHODS: Four medical databases and Google Scholar were systematically searched. Clinical trials, observational studies, animal in vivo, and in vitro studies with human and animal GI-derived samples were included. RESULTS: There were 32 studies (one randomized controlled trial [RCT], one non-randomized trial, 3 observational, 9 in vitro, and 18 animal in vivo studies) included. In preclinical studies, buckwheat extracts were observed to have cytotoxic potential against human-derived GI cancer cell lines. Animals fed with buckwheat had lower GI mucosal inflammation, higher alpha diversity in the GI microbiome, and higher levels of fecal short-chain fatty acids. Human evidence studies and clinical trials were limited and predominantly of moderate risk of bias. The majority of in vitro studies with GI-derived samples and in vivo studies were reliable without restrictions in study design. CONCLUSION: In vivo and in vitro studies show that buckwheat may have potential GI benefits due to its anti-oxidant and anti-inflammatory potential; however, human evidence remains limited, and its impact on health in humans remains to be elucidated in future trials.

A systematic review of phytochemicals in oat and buckwheat.

Consumption of oat and buckwheat have been associated with various health benefits that may be attributed to their nutritional composition. We performed a systematic review to evaluate the profile and quantity of bioactive compounds present in oat and buckwheat. Among 154 studies included in final analysis, 113 and 178 bioactive compounds were reported in oat and buckwheat, respectively. Total phytosterols, tocols, flavonoids and rutin content were generally higher in buckwheat, ß-glucans were significantly higher in oat, while avenanthramides and saponins were characteristically present in oat. The majority of studies included in current review were published before 2010s. The heterogeneous methodological procedures used across the studies precluded our possibility to meta-analyse the evidence and raises the need for harmonization of separation and extraction methods in future studies. Our findings should further stimulate the exploration of metabolites related to identified phytochemicals and their roles in human health.

Bioactive compounds and nutritional composition of Swiss chard (Beta vulgaris L. var. cicla and flavescens): a systematic review.

Swiss chard (Beta vulgaris L. var. cicla or flavescens) is a green leafy vegetable whose bioactive compounds have been studied due to its effects on health. We systematically reviewed the nutritional profile and bioactive composition of Swiss chard and reported their concentrations. Four main databases were searched for studies analyzing the chemical composition of Swiss chard. Screening, selection of articles, and data extraction were carried out by two independent reviewers. Twenty-eight articles of 1102 records identified by bibliographic search met our inclusion criteria for final analysis. We found a total of 192 chemical compounds categorized into 23 groups. The cicla variety was the most studied, and nutrients and phytochemicals were reported mainly on leaves. Betalains with 20% of the reported data, fats (16%), flavonoids (11%), non-flavonoid phenolics (11%), terpenes and derivatives (8%), carbohydrates (7%), and minerals (6%) were among the most reported categories. Swiss chard leaves have the highest content of fiber, sodium, magnesium, flavonoids, and vitamin C, while stems are high in potassium. Swiss chard should be considered a source of nutrients and phytochemicals, and further research is needed on identifying and quantifying other bioactive compounds and understanding their impact on health.

Efficacy of Dietary Supplements to Reduce Liver Fat.

Liver fat accumulation is an important pathophysiological feature of non-alcoholic fatty liver disease that may be modulated by dietary supplements (DS). A systematic search of the literature was conducted for randomized controlled trials (RCTs) pertaining to the effect of a DS on liver fat as assessed using quantitative tomographic imaging in human adults. Where feasible, data were pooled, and meta-analyses conducted using random-effect model. Quality assessment was done according the Cochrane Collaboration's tool for assessing risk of bias. Twenty RCTs, involving 1171 overweight and obese adults, of which 36% were females, with or without comorbidities, were included. Only RCTs assessing omega-3 fatty acids (n = 4) and resveratrol (n = 4) qualified for meta-analysis. Results did neither favor omega-3 (effect size -1.17; weighted mean difference (WMD) (95% confidence interval (CI)) -3.62, 1.28; p < 0.001) nor resveratrol supplementation (0.18; 95% CI -1.08, 1.43; p = 0.27). The findings of the qualitatively summarized RCTs suggested that catechins (n = 1), Lactobacillus reuteri (n = 1), and carnitine (n = 1) may reduce liver fat. All other DS did not show any influence. The current evidence is scarce, of limited quality and does not support DS use to reduce liver fat. Further well-designed trials are warranted.

Effects of phytoestrogen supplementation on intermediate cardiovascular disease risk factors among postmenopausal women: a meta-analysis of randomized controlled trials.

IMPORTANCE: Phytoestrogens are becoming popular constituents of human diets and are increasingly used by postmenopausal women. OBJECTIVE: Our study aims to determine the effects of phytoestrogen supplementation on intermediate cardiovascular disease (CVD) risk factors in postmenopausal women. EVIDENCE REVIEW: Five electronic databases (Medline, EMBASE, Web of Science, Cochrane CENTRAL, Google Scholar) were systematically searched to identify eligible studies, that is, randomized controlled trials (RCTs) that assessed the association of phytoestrogen supplementation with CVD risk factors (serum lipids, homocysteine, fibrinogen, markers of inflammation, oxidative stress and endothelial function, carotid intima-media thickness [CIMT]) in postmenopausal women. Data were extracted by two independent reviewers using a predefined data collection form. FINDINGS: In total, 56 RCTs were identified, including 4,039 individual postmenopausal women. There was substantial heterogeneity in quality across studies. Twenty-six (46%) RCTs showed poor quality and there was an indication of publication bias presence for some of the biomarkers. Results are reported in pooled mean difference (95% CI) of changes. Use of phytoestrogens was associated with a decrease in serum total cholesterol (-0.27 mmol/L [-0.41 to -0.13]), low-density lipoprotein (-0.25 mmol/L [-0.37 to -0.13]), triglycerides (-0.20 mmol/L [-0.28 to -0.11]), and apolipoprotein B (-0.13 g/L [-0.23 to -0.03]) and with an increase in serum apolipoprotein A-1 (0.04 g/L [0.02-0.07]. Also, phytoestrogen supplementation was associated with a decrease in serum intercellular adhesion molecule 1 (-18.86 ng/mL [-30.06 to -7.65]) and E-selectin (-2.32 ng/mL [-4.05 to -0.59]). There was no association observed between phytoestrogen supplementation and inflammatory markers, fibrinogen, homocysteine, or other endothelial function markers. In contrast, use of phytoestrogens was associated with an increase in CIMT (9.34 µm [95% CI, 0.39-18.29]). Effect estimates of phytoestrogen supplementation on oxidative stress could not be pooled. CONCLUSIONS AND RELEVANCE: Phytoestrogen supplementation seems to modestly improve the CVD risk profile of postmenopausal women by influencing blood lipids and parameters of endothelial function. In women with an increased risk of atherosclerosis, although modest, a harmful effect on CIMT progression may be present. Because of limited quality and the heterogeneous nature of the current evidence, additional rigorous studies are needed to explore the role of phytoestrogens in menopausal cardiovascular health. : Video Summary: http://links.lww.com/MENO/A593.

Video Summary: http://links.lww.com/MENO/A593.

Associations between Phytoestrogens, Glucose Homeostasis, and Risk of Diabetes in Women: A Systematic Review and Meta-Analysis.

Phytoestrogens might have advantageous effects on diabetes in women. We performed a systematic review and meta-analysis to determine the effect of phytoestrogens on glucose homeostasis and the risk of type 2 diabetes (T2D) among women. Randomized controlled trials (RCTs) and prospective observational studies that assessed associations of phytoestrogens (supplementation, dietary intake, or biomarkers) with fasting glucose or insulin, homeostatic model assessment of insulin resistance (HOMA-IR), or with the risk of T2D were included. We identified 18 RCTs (n = 1687 individuals) investigating the effect of phytoestrogen supplementation on glucose homeostasis and 9 prospective population-based studies (n = 212,796 individuals) examining the association between phytoestrogen intake and the risk of T2D. Compared with placebo, phytoestrogen supplementation resulted in improvements in fasting glucose and HOMA-IR: the pooled mean differences of changes were -0.12 mmol/L (95% CI: -0.20, -0.03 mmol/L) and -0.24 mmol/L (95% CI: -0.45, -0.03 mmol/L), respectively. Although there was no significant decrease in insulin concentrations with overall phytoestrogen supplementation, the pooled mean difference in changes was -0.99 pmol/L (95% CI: -4.65, 2.68 pmol/L). However, the results of RCTs varied by type of phytoestrogens: soy-derived isoflavones and genistein improved glucose homeostasis, whereas isoflavone mix and daidzein had no effect or were associated with an adverse glycemic profile. Higher dietary phytoestrogen intake was associated with a 10% lower risk of developing T2D in observational studies (pooled RR: 0.90; 95% CI: 0.85, 0.96; for the highest compared with the lowest quantiles). Results were similar when the analyses were restricted to only medium- and high-quality studies. Overall, phytoestrogens may have a positive influence on glycemia and could be used for diabetes prevention in women. However, for some individual types of phytoestrogens, such as mixed isoflavones, caution is needed in recommending their use in women, because their use could lead to an adverse glycemic profile in women.

Phytoestrogen supplementation and body composition in postmenopausal women: A systematic review and meta-analysis of randomized controlled trials.

Phytoestrogen-based medications are commonly used by menopausal women, and especially by obese postmenopausal women, to relieve menopausal symptoms. Substitution of animal with soy protein is often used in weight loss regimens, yet the effect of phytoestrogens, the main constituent of soy foods, on body composition is not completely understood. We conducted a systematic review and meta-analysis to investigate the associations between phytoestrogen supplementation and body weight and the main parameters of body composition in postmenopausal women. A literature search was done using 5 electronic databases from inception to April 2018. Randomized controlled trials (RCTs) with postmenopausal women comparing phytoestrogen supplementation followed by usual diet and placebo were included in the present meta-analysis. From 5932 references, we identified 23 RCTs that met our inclusion criteria, with a total of 1880 postmenopausal women. No association was observed between phytoestrogen supplementation and body weight, body mass index, waist and hip circumference, total fat mass or percentage of body fat. However, the use of phytoestrogens supplementation was associated with a slight decrease in waist-hip ratio; the pooled mean difference was -0.01 cm (95%CI: -0.01 to -0.006). In subgroup analysis, we found a modest decrease in body weight with phytoestrogens supplementation compared with placebo in healthy postmenopausal women [pooled mean difference of changes -0.28 kg (95%CI: -0.52 to -0.04)] and in RCTs with a median number of participants of 66 or less [pooled mean difference of changes -0.49 kg (95%CI: -0.87 to -0.11)]. In contrast, phytoestrogen supplementation was associated with increased body weight in postmenopausal women with preexisting metabolic disorders (prediabetes, type 2 diabetes, prehypertension and hyperlipidemia) [pooled mean difference of changes: 0.78 kg (95%CI: 0.53-1.03)]. In addition, there were some indications that some types of phytoestrogens, such as daidzein, but not soy products or isoflavone mix, could lead to modest adverse changes in body composition in menopausal women. Therefore, future studies should investigate the potential adverse effects of phytoestrogen supplementation on body composition among postmenopausal women.

Serum dehydroepiandrosterone levels are associated with lower risk of type 2 diabetes: the Rotterdam Study.

AIMS/HYPOTHESIS: Previous literature documents controversial results for the impact of dehydroepiandrosterone (DHEA) in glucose metabolism. We aimed to assess the associations between serum levels of DHEA and its main derivatives DHEA sulphate (DHEAS) and androstenedione, as well as the ratio of DHEAS to DHEA, and risk of type 2 diabetes. METHODS: We used data on serum levels of DHEA, DHEAS and androstenedione from 5189 middle-aged and elderly men and women from the prospective population-based Rotterdam Study. Type 2 diabetes was defined as a fasting blood glucose ≥7.0 mmol/l or a non-fasting blood glucose ≥11.1 mmol/l. RESULTS: During a median follow-up of 10.9 years, 643 patients with incident type 2 diabetes were identified. After adjusting for age, sex, cohort, fasting status, fasting glucose and insulin, and BMI, both serum DHEA levels (per 1 unit natural log-transformed, HR 0.76, 95% CI 0.67, 0.87) and serum DHEAS levels (per 1 unit natural log-transformed, HR 0.82, 95% CI 0.73, 0.92) were inversely associated with risk of type 2 diabetes in the total population. Further adjustment for alcohol, smoking, physical activity, prevalent cardiovascular disease, serum total cholesterol, use of lipid-lowering medications, systolic BP, treatment for hypertension, C-reactive protein, oestradiol and testosterone did not substantially affect the association between DHEA and incident type 2 diabetes (per 1 unit natural log-transformed, HR 0.80, 95% CI 0.65, 0.99), but abolished the association between DHEAS and type 2 diabetes. Androstenedione was not associated with risk of type 2 diabetes, nor was DHEAS to DHEA ratio. CONCLUSIONS/INTERPRETATION: DHEA serum levels might be an independent marker of type 2 diabetes.

Dietary mineral intake and lung cancer risk: the Rotterdam Study.

OBJECTIVE: Limited data are available on the role of mineral intake in the development of lung cancer (LC). We investigated whether dietary calcium, copper, iron, magnesium, selenium and zinc intake were associated with LC risk. METHODS: We analyzed data from 5435 participants of the Rotterdam Study, a prospective population-based cohort study among subjects aged 55 years and older. At baseline (1990-1993), diet was measured by a validated food frequency questionnaire. LC events were diagnosed on the basis of pathology data and medical records. Hazard ratios (HRs) on LC for energy-adjusted mineral intake were calculated using Cox regression models while adjusting for potential confounders. RESULTS: During a follow-up period of 22 years, we identified 211 incident cases of LC. A higher zinc intake was associated with 42 % reduction in risk of LC (top tertile vs. first tertile: HR 0.58, 95 % CI 0.35; 0.94, P-for trend = 0.039). Similarly, high intake of iron was associated with reduced risk of LC (top tertile vs. first tertile: HR 0.58, 95 % CI 0.37; 0.92, P-for trend = 0.021). There was no association between dietary intake of calcium, copper, magnesium and selenium and LC risk. CONCLUSIONS: Our results suggest that dietary zinc and iron intake are associated with reduced risk of LC. No evidence was found for an association between calcium, copper, magnesium and selenium intake and LC risk.

Maternal weight status, diet, and supplement use as determinants of breastfeeding and complementary feeding: a systematic review and meta-analysis.

CONTEXT: Infant feeding practices are influenced by maternal factors. OBJECTIVE: The aim of this review is to examine the associations between maternal weight status or dietary characteristics and breastfeeding or complementary feeding. DATA SOURCES: A systematic literature search of the Embase, Cochrane Library, Google Scholar, MEDLINE, PubMed, and Web of Science databases was performed. STUDY SELECTION: Interventional and cohort studies in healthy mothers and infants that reported on maternal weight status, diet, or supplement use were selected. DATA EXTRACTION: Outcomes assessed included delayed onset of lactogenesis; initiation, exclusivity, duration, and cessation of breastfeeding; and timing of complementary feeding. DATA ANALYSIS: Eighty-one studies were included. Maternal underweight, diet, and supplement use were not associated with infant feeding practices. Obese women had a relative risk of failure to initiate breastfeeding (risk ratio [RR] = 1.23; 95%CI, 1.03-1.47) and a delayed onset of lactogenesis (RR  =  2.06; 95%CI, 1.18-3.61). The RR for breastfeeding cessation was 1.11 (95%CI, 1.07-1.15) per increase in category of body mass index. CONCLUSIONS: Prevention of obesity in women of reproductive age, as well as counseling of obese women after delivery, could be targeted to improve infant feeding practices.

Use of Plant-Based Therapies and Menopausal Symptoms: A Systematic Review and Meta-analysis.

IMPORTANCE: Between 40% and 50% of women in Western countries use complementary therapies to manage menopausal symptoms. OBJECTIVE: To determine the association of plant-based therapies with menopausal symptoms, including hot flashes, night sweats, and vaginal dryness. DATA SOURCES: The electronic databases Ovid MEDLINE, EMBASE, and Cochrane Central were systematically searched to identify eligible studies published before March 27, 2016. Reference lists of the included studies were searched for further identification of relevant studies. STUDY SELECTION: Randomized clinical trials that assessed plant-based therapies and the presence of hot flashes, night sweats, and vaginal dryness. DATA EXTRACTION: Data were extracted by 2 independent reviewers using a predesigned data collection form. MAIN OUTCOMES AND MEASURES: Hot flashes, night sweats, and vaginal dryness. RESULTS: In total, 62 studies were identified, including 6653 individual women. Use of phytoestrogens was associated with a decrease in the number of daily hot flashes (pooled mean difference of changes, -1.31 [95% CI, -2.02 to -0.61]) and vaginal dryness score (pooled mean difference of changes, -0.31 [95% CI, -0.52 to -0.10]) between the treatment groups but not in the number of night sweats (pooled mean difference of changes, -2.14 [95% CI, -5.57 to 1.29]). Individual phytoestrogen interventions such as dietary and supplemental soy isoflavones were associated with improvement in daily hot flashes (pooled mean difference of changes, -0.79 [-1.35 to -0.23]) and vaginal dryness score (pooled mean difference of changes, -0.26 [-0.48 to -0.04]). Several herbal remedies, but not Chinese medicinal herbs, were associated with an overall decrease in the frequency of vasomotor symptoms. There was substantial heterogeneity in quality across the available studies, and 46 (74%) of the included randomized clinical trials demonstrated a high risk of bias within 3 or more areas of study quality. CONCLUSIONS AND RELEVANCE: This meta-analysis of clinical trials suggests that composite and specific phytoestrogen supplementations were associated with modest reductions in the frequency of hot flashes and vaginal dryness but no significant reduction in night sweats. However, because of general suboptimal quality and the heterogeneous nature of the current evidence, further rigorous studies are needed to determine the association of plant-based and natural therapies with menopausal health.

Dietary polyunsaturated fatty acids intake modifies the positive association between serum total cholesterol and colorectal cancer risk: the Rotterdam Study.

BACKGROUND: It remains unclear whether serum total cholesterol is associated with colorectal cancer (CRC) risk. Interplay between dietary fatty acids and serum total cholesterol on CRC risk may be present as well. We aimed to investigate the association between serum total cholesterol with CRC. Furthermore, we investigated whether this association was modified by intake of dietary polyunsaturated fatty acids (PUFAs). METHODS: We analysed data from 6628 participants of the Rotterdam Study, a prospective population-based follow-up study among patients aged 55 years and older. Serum total cholesterol was measured at baseline. During a mean follow-up time of 12.9 years, we identified 248 new CRC cases based on pathology data and medical records. Multivariable HRs were calculated using Cox regression models. RESULTS: After adjustment, serum total cholesterol levels were associated with a higher risk of CRC (HR 1.49; 95% CI 1.08 to 2.06 for highest vs lowest tertile). Statistically significant effect modification was present for PUFAs intake (P-interaction=0.04). After stratification by median PUFAs intake, an increased risk with increasing tertiles of serum total cholesterol was observed among patients with low PUFAs intake (3rd tertile vs 1st tertile: HR 2.43; 95% CI 1.41 to 4.18), whereas no association was observed among patients with high PUFAs intake (3rd tertile vs 1st tertile: HR 0.93; 95% CI 0.55 to 1.58). CONCLUSIONS: Taken together, these findings suggest that high levels of serum total cholesterol increase CRC risk, but this risk may be reduced by high dietary PUFAs intake.

The effects of lutein on cardiometabolic health across the life course: a systematic review and meta-analysis.

BACKGROUND: The antioxidant lutein is suggested as being beneficial to cardiometabolic health because of its protective effect against oxidative stress, but evidence has not systematically been evaluated. OBJECTIVE: We aimed to evaluate systematically the effects of lutein (intake or concentrations) on cardiometabolic outcomes in different life stages. DESIGN: This is a systematic review with meta-analysis of literature published in MEDLINE, Embase, Cochrane Central, Web of Science, PubMed, and Google Scholar up to August 2014. Included were trials and cohort, case-control, and cross-sectional studies in which the association between lutein concentrations, dietary intake, or supplements and cardiometabolic outcomes was reported. Two independent investigators reviewed the articles. RESULTS: Seventy-one relevant articles were identified that included a total of 387,569 participants. Only 1 article investigated the effects of lutein during pregnancy, and 3 studied lutein in children. Furthermore, 31 longitudinal, 33 cross-sectional, and 3 intervention studies were conducted in adults. Meta-analysis showed a lower risk of coronary heart disease (pooled RR: 0.88; 95% CI: 0.80, 0.98) and stroke (pooled RR: 0.82; 95% CI: 0.72, 0.93) for the highest compared with the lowest tertile of lutein blood concentration or intake. There was no significant association with type 2 diabetes mellitus (pooled RR: 0.97; 95% CI: 0.77, 1.22), but higher lutein was associated with a lower risk of metabolic syndrome (pooled RR: 0.75; 95% CI: 0.60, 0.92) for the highest compared with the lowest tertile. The literature on risk factors for cardiometabolic diseases showed that lutein might be beneficial for atherosclerosis and inflammatory markers, but there were inconsistent associations with blood pressure, adiposity, insulin resistance, and blood lipids. CONCLUSIONS: Our findings suggest that higher dietary intake and higher blood concentrations of lutein are generally associated with better cardiometabolic health. However, evidence mainly comes from observational studies in adults, whereas large-scale intervention studies and studies of lutein during pregnancy and childhood are scarce.

The effects of lutein on respiratory health across the life course: A systematic review.

BACKGROUND: Lutein, a fat-soluble carotenoid present in green leafy vegetables and eggs, has strong antioxidant properties and could therefore be important for respiratory health. DESIGN: We systematically reviewed the literature for articles that evaluated associations of lutein (intake, supplements or blood levels) with respiratory outcomes, published in Medline, Embase, Cochrane Central, PubMed, Web of Science and Google Scholar, up to August 2014. RESULTS: We identified one Randomized Control Trial (RCT), two longitudinal, four prospective and six cross-sectional studies. The individual studies obtained a Quality Score ranging between 3 and 9. Six studies were performed in children, which examined bronchopulmonary dysplasia (BPD), asthma and wheezing. In adults, 7 studies investigated asthma, respiratory function and respiratory mortality. The RCT found a borderline significant effect of lutein/zeaxanthin supplementation in neonates on the risk of BPD (OR 0.43 (95% CI 0.15; 1.17). No association was found between lutein intake or levels and respiratory outcomes in children. A case-control study in adults showed lower lutein levels in asthma cases. Three studies, with a prospective or longitudinal study design, in adults found a small but a significant positive association between lutein intake or levels and respiratory function. No association was found in the other two studies. In relation to respiratory mortality, one longitudinal study showed that higher lutein blood levels were associated with a decreased mortality (HR 0.77 (95% CI 0.60; 0.99), per SD increase in lutein). CONCLUSION: The published literature suggests a possible positive association between lutein and respiratory health. However, the literature is scarce and most studies are of observational nature.

Dietary Fiber Intake Modifies the Positive Association between n-3 PUFA Intake and Colorectal Cancer Risk in a Caucasian Population.

BACKGROUND: The association between dietary fat intake and the risk of colorectal cancer (CRC) is still unclear. OBJECTIVES: We analyzed whether intakes of dietary polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) were associated with CRC risk and whether these associations were modified by dietary fiber (DF) intake. METHODS: This study was embedded in the Rotterdam Study, a prospective cohort study among subjects aged ≥55 y (n = 4967). At baseline, diet was measured by a food-frequency questionnaire. CRC events were diagnosed on the basis of pathology data and medical records. Multivariable adjusted HRs were calculated using Cox regression models. RESULTS: During a mean follow-up period of 14.6 y, we identified 222 incident cases of CRC. There was no association between total PUFA, n-6 (ω-6) PUFA, or SFA intake and CRC risk. n-3 PUFA intake was associated with an increased risk of CRC [tertile 3 vs. tertile 1: HR = 1.44 (95% CI: 1.02, 2.04), P-trend = 0.04]. When data were analyzed by food sources, only n-3 PUFAs from nonmarine sources were associated with an increased risk of CRC. A significant interaction between n-3 PUFA and DF intakes was found (P-interaction = 0.02). After stratification by median DF intake, an increased risk of CRC caused by n-3 PUFA intake was observed in participants with a DF intake less than the median [tertile 3 vs. tertile 1: HR = 1.96 (95% CI: 1.20, 3.19), P-trend = 0.01]. No association was observed in subjects with DF intake equal to or higher than the median. CONCLUSIONS: This study suggests that intake of n-3 PUFAs by adults is associated with an increased risk of CRC, which may be driven mainly by sources other than fish. Moreover, a complex interaction with DF intake may be present.