Myrte J. Tielemans

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.

Macronutrient composition and gestational weight gain: a systematic review

BACKGROUND Abnormal gestational weight gain is associated with unfavorable pregnancy outcomes. Several risk factors have been identified, but the effect of macronutrient intake during pregnancy on gestational weight gain has not been systematically evaluated in both high-income countries and low- and middle-income countries. OBJECTIVE We conducted a systematic review of the literature in 8 different databases (until 12 August 2015) to assess whether energy intake and macronutrient intake (i.e., protein, fat, and carbohydrate) during pregnancy were associated with gestational weight gain (following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines). RESULTS Of 7623 identified references, we included 56 articles (46 observational studies and 10 trials, 28 of which were in high-income countries and 28 of which were in low- and middle-income countries). Eleven of the included articles were of high quality (20%). Results of 5 intervention and 7 high-quality observational studies suggested that higher energy intake during pregnancy is associated with higher gestational weight gain (n = 52). Results from observational studies were inconsistent for protein intake (n = 29) and carbohydrate intake (n = 18). Maternal fat intake (n = 25) might be associated with gestational weight gain as suggested by observational studies, although the direction of this association might depend on specific types of fat (e.g., saturated fat). Macronutrient intake was not consistently associated with the prevalence of inadequate or excessive gestational weight gain. Associations were comparable for high-income countries and low- and middle-income countries. CONCLUSIONS The current literature provides evidence that energy intake is associated with gestational weight gain, but the roles of individual macronutrients are inconsistent. However, there is a need for higher-quality research because the majority of these studies were of low quality.

A Priori and a Posteriori Dietary Patterns during Pregnancy and Gestational Weight Gain: The Generation R Study

Abnormal gestational weight gain (GWG) is associated with adverse pregnancy outcomes. We examined whether dietary patterns are associated with GWG. Participants included 3374 pregnant women from a population-based cohort in the Netherlands. Dietary intake during pregnancy was assessed with food-frequency questionnaires. Three a posteriori-derived dietary patterns were identified using principal component analysis: a “Vegetable, oil and fish”, a “Nuts, high-fiber cereals and soy”, and a “Margarine, sugar and snacks” pattern. The a priori-defined dietary pattern was based on national dietary recommendations. Weight was repeatedly measured around 13, 20 and 30 weeks of pregnancy; pre-pregnancy and maximum weight were self-reported. Normal weight women with high adherence to the “Vegetable, oil and fish” pattern had higher early-pregnancy GWG than those with low adherence (43 g/week (95% CI 16; 69) for highest vs. lowest quartile (Q)). Adherence to the “Margarine, sugar and snacks” pattern was associated with a higher prevalence of excessive GWG (OR 1.45 (95% CI 1.06; 1.99) Q4 vs. Q1). Normal weight women with higher scores on the “Nuts, high-fiber cereals and soy” pattern had more moderate GWG than women with lower scores (−0.01 (95% CI −0.02; −0.00) per SD). The a priori-defined pattern was not associated with GWG. To conclude, specific dietary patterns may play a role in early pregnancy but are not consistently associated with GWG.

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.

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.

Maternal fish consumption, fatty acid levels and angiogenic factors: The Generation R Study

INTRODUCTION Angiogenic factors, such as placental growth factor (PlGF) and soluble Flt-1 (sFlt-1), are key regulators of placental vascular development. Evidence from in vitro studies indicates that fatty acids can affect angiogenesis. We investigated the associations of maternal fish consumption and fatty acids levels with angiogenic factors during pregnancy, and in cord blood in a large population-based prospective cohort. METHODS First trimester fish consumption was assessed among 3134 pregnant women using a food-frequency questionnaire. Plasma fatty acid levels were measured in second trimester. Plasma PlGF and sFlt-1 were measured in first and second trimester and in cord blood. Associations of fish consumption or fatty acid levels with angiogenic factors were assessed by multivariable linear regression analyses. RESULTS There were no consistent associations of total fish or lean fish consumption with levels of PlGF, sFlt-1, or sFlt-1/PlGF ratio. Neither fatty fish nor shellfish were associated with angiogenic factors. Plasma omega-3 polyunsaturated fatty acids, which are the main type of fatty acids in fish, were inconsistently associated with angiogenic factors in second trimester and cord blood. Yet, higher levels of arachidonic acid, an omega-6 polyunsaturated fatty acid, were associated with lower levels of PlGF and sFlt-1. DISCUSSION We found no consistent associations of fish consumption or fatty acids levels with angiogenic factors in a population with low fish consumption. Studies including populations with higher fish consumption are required to fully grasp the potential effects of maternal fish consumption on placental angiogenesis.