by Bianca Garilli, ND
The rise in childhood overweight and obesity has been dramatic over the past three decades, with the number of overweight children tripling in that time frame, resulting in approximately 1 in 5 children (17%) in the US now estimated to be overweight.*1 Furthermore, while more children are becoming overweight, the heaviest children are getting even heavier.1 From 1971-1974 to 2009-2010, the prevalence of obesity in US children increased:**2
- From 4.8% to 12.1% in children ages 2-5
- From 4% to 18% in children ages 6-11
- From 6.1% to 18.4% in children ages 12-19
The consequences of obesity, widely recognized to be a chronic inflammatory state, can be life-altering and, in fact, have the potential to reduce longevity. Former US Surgeon General Richard Carmona, has profoundly predicted: “Because of the increasing rates of obesity, unhealthy eating habits and physical inactivity, we may see the first generation that will be less healthy and have a shorter life expectancy than their parents.” 2
The concerns related to overweight and obesity in children include a myriad of both psychological issues (depression, poor body image, low self-confidence, eating disorders and more) and physical health comorbidities (type 2 diabetes, heart disease, stroke, sleep apnea, early puberty, fatty liver and many other diseases).2
In order to reduce this concerning trend, it is imperative to understand the root causes of the problem. In the journal Obesity Review, Davison et al. brought forth the ecological model to describe child risk factors for obesity:3 these include unhealthy eating habits, lack of physical activity, and sedentary lifestyle set within the context of personal biological, environmental and genetic factors. Some of these factors are clearly linked to age and gender as well as parenting style and parents’ lifestyles, school policies, and community and neighborhood demographics and engagement. Cultural influences are also important while genetic susceptibility, although significant, is typically most noteworthy when coupled with contributing environmental and behavioral factors. Genetic aspects are believed to play a major role in less than 5% of cases of childhood obesity.3
More recently, research has shed light on the possibility and potential mechanism(s) of an intergenerational transfer of obesity from mother to offspring. Over a three-year time period (January 1, 2009 – December 31, 2012) data regarding maternal pre-pregnancy BMI and results from infant gut microbiota profiled at a mean age of 3.7 months were gathered from the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort consisting of 935 full-term infants.4 The children’s BMI scores were recorded at 1 and 3 years of age, and risk was assessed for childhood overweight and obesity.4
The results from this 2018 Canadian study published in JAMA Pediatrics showed infants born vaginally to overweight or obese mothers were 3x more likely to become overweight by 1 year of age with similar risks seen at 3 years of age when compared to children born vaginally to normal weight mothers.4 Cesarean-delivered infants of overweight mothers were found to have a 5-fold risk of being overweight at 1 year of age and a similar risk at 3 years of age when compared to children born vaginally to normal weight mothers.4
Analysis of the findings indicate that birth mode coupled with the infant gut microbiota composition were potential mediating factors linking maternal pre-pregnancy overweight to childhood overweight at ages 1 and 3 years old.4 A higher abundance of Firmicutes species, particularly the Lachnospiraceae family, of bacteria were seen in the overweight infants born to overweight mothers, while the genera of Lachnospiraceae differed between infants delivered vaginally and those delivered via C-section.4
This new information ties into previous research showing a shift towards the Firmicutes species in adults with an increasing body mass index.5-6 It is possible that overweight pregnant mothers may have higher levels of energy extracting efficient microbes, Firmicutes, which act in part as the intergenerational transmission vector of overweight to their offspring at the time of birth. Mode of birth, cesarean vs. vaginal, may modulate the quantity and family of Firmicutes which enter the infant gut and begin the initial seeding process which will set the stage for the child’s infant microbiome.4
Why is this Clinically Relevant?
- Supporting healthy weight in mothers prior to pregnancy is a critical step in reducing risk of overweight in the child
- Balancing mothers’ gut microbiota through a healthy, varied diet and targeted probiotics may be helpful steps to reduce risk of maternal and thus childhood overweight, but additional research is needed to fully elucidate this relationship and therapeutic potential
- An imbalance in the newborn gut microbiota may increase the risk of overweight at age 1 and 3 years and increases life-long potential chronic illness states
- Vaginal versus cesarean birth mode in overweight mothers may reduce risk of overweight in their newborn children
* Overweight in children/teens is defined as a BMI ≥85th% and <95th%for children and teens of the same age and sex7
**Obesity is defined as a BMI ≥95th% for children and teens of the same age and sex2
- Obesity Society. Childhood Overweight. http://www.obesity.org/obesity/resources/facts-about-obesity/childhood-overweight. Accessed February 24, 2018.
- AHA. Overweight in Children. http://www.heart.org/HEARTORG/HealthyLiving/HealthyKids/ChildhoodObesity/Overweight-in-Children_UCM_304054_Article.jsp#.WpGn3ajwbIU. Accessed February 24, 2018.
- Krushnapriya S, et al. Childhood obesity: causes and consequences. J Family Med Prim Care. 2015;4(2):187–192.
- Tun HM, Bridgman SL, Chari R, et al. Roles of birth mode and infant gut microbiota in intergenerational transmission of overweight and obesity from mother to offspring. JAMA Pediatr. 2018;172(4):368-377.
- Koliada A, Syzenko G, Moseiko V, et al. Association between body mass index and Firmicutes/Bacteroidetes ratio in an adult Ukrainian population. BMC Microbiol. 2017; 17: 120.
- Kasai C, Sugimoto K, Moritani I, et al. Comparison of the gut microbiota composition between obese and non-obese individuals in a Japanese population, as analyzed by terminal restriction fragment length polymorphism and next-generation sequencing. BMC Gastroenterol. 2015;15:100.
- CDC. Defining Childhood Obesity. https://www.cdc.gov/obesity/childhood/defining.html. Accessed February 24, 2018.