2 Minute Medicine is pleased to announce that we are launching Wellness Check, a new series dedicated to exploring new research evidence focused on wellness. Each week, we will report on articles examining different aspects of wellness, including (but not limited to) nutrition, sleep, reproductive health, substance use and mental health. This week, we explore the latest evidence-based updates in nutrition.
1. Low to moderate caffeine intake (<200mg per day) compared to no caffeine intake was associated with lower risk of gestational diabetes.
2. Low to moderate caffeine intake was not associated with risk of preeclampsia.
Evidence Rating Level: 2 (Good)
During pregnancy, women are recommended to consume less than 200mg of caffeine per day to prevent potential pregnancy complications. However, whether caffeine exposure during early or mid-pregnancy is truly associated with differential risk of maternal complications has not been extensively studied.
This prospective cohort study examined 2802 non-obese, non-smoking, pregnant women across the United States (US). Women who conceived using fertility medications or in vitro fertilization, or had prior pregnancy complications or major chronic diseases were excluded. The amount of caffeine consumed daily was surveyed at 10-13 and 16-22 gestational weeks based on self-reported consumption of caffeinated coffee, tea, soda, and energy drinks. The primary outcome was diagnoses of cardiometabolic pregnancy complications such as gestational diabetes (GDM), preeclampsia, and gestational hypertension (GH).
Within the cohort, 599 (23.6%) patients reported consuming no caffeinated beverages, 1734 (68.3%) consumed between 1-100mg/day and 186 (7.3%) consumed 101-200mg/day. Compared to those who consumed no caffeine, patients who consumed 1-100mg/day had 47% reduction in risk of GDM but no change in risk of preeclampsia or GH. However, this study was limited in that the sample size was not large enough to conduct separate analyses based on beverage type. Furthermore, time of diagnosis of GH and preeclampsia was unknown. Nonetheless, this study would lend support to current recommendations for women to not consume more than 200mg/day of caffeine. Furthermore, these findings may be reassuring for women with low-moderate caffeine intake during pregnancy.
1. In this study, a Mediterranean diet reduced odds of low-weight births in high-risk pregnancies.
2. Furthermore, mindfulness-based stress reduction reduced odds of low-weight births.
Evidence Rating Level: 1 (Excellent)
High stress and poor maternal nutrition have been associated with higher risk of infants being born small for gestational age (SGA), defined as birth weight below the 10th percentile. Infants born SGA often have increased morbidity and mortality in the perinatal period as well as increased risk for long-term adverse health outcomes. However, there are currently no effective preventative or therapeutic strategies against SGA. Therefore, developing interventions that potentially target maternal nutrition and stress to reduce SGA could be highly beneficial.
This randomized control trial aimed to determine the effectiveness of a Mediterranean diet or mindfulness-based stress reduction techniques in reducing risk of newborns born SGA. This study followed 1184 adult, pregnant patients at high risk for SGA at a single institution in Spain. Patients with pregnancies with fetal abnormalities or neonatal malformations were excluded from the study. Patients were randomized between 19-23 weeks of gestation, 1:1:1 to 3 study groups: 1) Mediterranean diet group (n=392), which received monthly individual and group education sessions and free extra-virgin olive oil and walnuts; 2) stress reduction group (n=391) where they underwent an 8-week stress reduction program that met weekly and provided guided meditation and prenatal yoga practices; 3) control group (n=401) who received standard pregnancy care. The primary outcome was percentage of newborns born SGA and secondary outcomes included rate of adverse perinatal events such as preterm birth, preeclampsia, low Apgar score, or perinatal mortality and morbidity.
Compared to the control group, odds of newborns born SGA were significantly decreased in the Mediterranean diet group (odds ratio 0.58) and stress reduction group (odds ratio 0.66). Furthermore, odds of secondary outcomes were also decreased in both Mediterranean diet and stress reduction group. However, this study was limited in that the study population was highly homogenous, with patients being predominantly White, with normal body mass index and of medium-to-high socioeconomic status. Nonetheless, these results suggest the exciting potential impact of nutritional and psychological interventions that can effect SGA, but further studies in more diverse pregnant patients are needed.
1. In this study, long-term high sulfur microbial diet was associated with increased risk of colorectal cancer.
2. Body weight and family history of colorectal cancer did not modify association between high sulfur microbial diet and colorectal cancer risk.
Evidence Rating Level: 2 (Good)
A diet high in low-calorie beverages and animal protein and fat has been thought to potentially increase intestinal sulfide production by gut microbiota and consequently increase the risk of colorectal cancer (CRC). However, the role of gut microbes that reduce dietary sulfur to potentially carcinogenic hydrogen sulfide in modulating risk of CRC has not been extensively tested.
This study pooled data from three prospective cohort studies of 214,797 adult male (40-74 years old) and female (25 to 55 years old) United States (US) health professionals, in which dietary intake was assessed using semi-quantitative food frequency questionnaire (FFQ) starting from 1986, 1984, and 1991. Participants who had a prior diagnosis of CRC, inflammatory bowel disease, or other cancers were excluded. Stool samples were collected from select group of participants (developmental cohort) from 2012-2014 and sequenced to identity gut microbiota composition. The relative abundance of 43 previously identified sulfur-metabolizing bacteria was determined in the 519-participant developmental cohort. The primary outcome was incidence of CRC, which was determined based on self-reported diagnosis of CRC in biennial questionnaires, medical records, tumor registries, and death certifications.
In this study, greater adherence to sulfur microbial diet was associated with increased risk of CRC (hazard ratio 1.27) and particularly, distal CRC (hazard ratio of 1.25). Overall, long-term adherence to sulfur microbial diet was associated with higher abundance of sulfur-metabolizing gut bacteria and increased risk of CRC. However, this study was limited in its homogenous study population of US health professionals which minimized sociodemographic confounding, warranting further study. Nonetheless, this study was significant in suggesting that adherence to a sulfur microbial diet (including red meats, low intake of fruits, whole grains, vegetables) is associated with increased risk of CRC.
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