December 1, 2016
By: Alyssa Lincheid
The gut microbiome is an exciting area of research as an increasing amount of studies show how influential our gut flora is to the development of allergies and obesity, as well as its effect on mental, bone, and dental health. Interestingly, our diets impact the diversity of our gut flora and these various types of bacteria influence our overall health.
Food allergies have increased in prevalence over the last two decades affecting about 8% of children and 5% of adults (Blazquez & Berin, 2016). Recent studies have found that certain environmental factors such as mode of birth (vaginal or C-section), exposure to pets at an early age, and the presence of older siblings impact the bacterial diversity in our guts. Protective microbiota tend to produce short-chain fatty acids (SCFAs) in the body which can influence the genetic expression of antibodies. These antibodies may decrease food allergy susceptibility. In addition, a high fat diet may influence the diversity of bacteria in the gut and increase the risk for food allergies.
There is also emerging evidence that some added food colorants and emulsifiers may impact the gut microbiome. In a recent study, symptoms of attention deficit hyperactivity disorder (ADHD) were lowered after a reduction in food additive intake. This suggests that there may be a connection between food intake and the microbiota-gut-brain axis. One study also showed that gut microbiota composition is altered in individuals with depression, autism spectrum disorder (ASD), and irritable bowel syndrome, indicating that specific microbes may impact brain health. In one recent study, animals with either the presence or absence of certain bacteria during a particular neurodevelopmental stage had either normal or abnormal social behaviors later in life. This may be related to autism spectrum disorder since one of the symptoms of ASD is a deficit in reciprocal social interactions. Alzheimer’s and Parkinson’s disease could also be influenced by gut bacteria according to some research. Short-chain fatty acids produced by certain bacteria may also impact mental health by possibly increasing the absorption of polyunsaturated fatty acids (PUFAs) which have been shown to be beneficial to the brain (Kennedy et al., 2016). Large-scale investigations have also indicated that a high intake of polyphenols, natural compounds occurring in foods such as cocoa, citrus fruit, and tea, may help maintain normal brain function and mental health by reducing inflammation of the central nervous system. Short chain fatty acids have also been positively correlated with increases in fractional calcium absorption in adolescents and increases in measures of bone density and strength in animal models (Weaver, 2015).
Concerning dental health, there are certain types of microbiomes that may be associated with dental plaque formation. One study identified 87 environmental DNA sequences of bacteria that were associated with either cavity-free cases or cavity-active cases (Peterson et al., 2013). Obesity may also be influenced by bacterial fermentation of nutrients, lower intestinal barrier function, overexpression of genes associated with disorders, and disruptions to both innate and adaptive immunity based on certain types of bacteria in the gut (Chen et al., 2014).
Although a lot has been discovered in recent years about the gut microbiome, there is still a need for more research. Researchers have just begun to scratch the surface of this scientifically and clinically significant topic.
Blázquez, A., & Berin, M. (2016). Microbiome and food allergy. Translational Research,
Chen, J., He, X., & Huang, J. (2014). Diet effects in gut microbiome and obesity. Journal of Food Science, 79(4), R442-R451. doi: 10.1111/1750-3841.12397
Kennedy, P., Murphy, A., Cryan, J., Ross, P., Dinan, T., & Stanton, C. (2016). Microbiome in brain function and mental health. Trends in Food Science & Technology, 1-13.
Peterson, S., Snesrud, E., Liu, J., Ong, A., Kilian, M., Schork, N., & Bretz, W. (2013). The dental plaque microbiome in health and disease. PloS One, 8(3), e58487. doi:
Weaver, C. (2015). Diet, gut microbiome, and bone health. Current Osteoporosis Reports, 13(2), 125-130.