Background: The introduction of solid foods is an important dietary event during infancy and is associated with a time of dramatic shifts in gut microbial composition. The influence of solid food introduction on gut bacterial dynamics remains understudied.
Methods: 15 healthy, full-term, vaginally born, and breast-fed infants of the Baby, Food and Mi sub-study of the Baby & Mi Study were investigated. Caregivers were asked to collect daily stool samples and food diaries for 17 days, commencing three days prior to the introduction of solids. Additional stool samples were available up to one year as part of the Baby and Mi study. The exposure of interest, nutritional patterns, was analyzed using food composition output from ESHA’s Food Processor. The number of food items and food groups introduced were used to calculate dietary diversity scores. The outcome of interest, gut bacterial dynamics, was analyzed using RStudio.
Results: The mean (SD) age at the introduction of solid foods is 5.5 (0.66) months (n = 15). Over the study period, the proportion of estimated energy intake from solid foods was low (7.5%; SD 6.74%) (n = 14). Alpha diversity increased over time and was highest at 1 year. The gut microbial community influenced by dominant bacterial taxa changed with increasing age. With introduction of solids, individual community composition changed, though to a varying extent. Shannon alpha diversity was directly associated with calories from carbohydrates, particularly daily fiber intake. The infant’s dietary diversity score was directly associated with alpha diversity and was also positively associated with the degree of change occurring in this time period.
Conclusion: Fiber intake and the dietary diversity scores had the closest relationships to the gut microbiome’s alpha diversity and community structure in infants at the time of solid food introduction. / Thesis / Master of Science (MSc) / The introduction of solid foods is an important life-event during infancy. This is also when the gut microbiome is developing to its mature state. Since nutrition is an important factor influencing the microbiome, investigating the dietary choices at the introduction to solid foods is the aim of the following study. Here, daily stool samples and food diary entries were collected for 15 healthy, breast-fed infants. It is important to measure the diversity of the bacteria in the gut of an individual (alpha) and between people (beta), as well as bacteria present. Carbohydrates drive the change in alpha diversity, especially fiber. Feeding infants a diet with many different foods shows increased alpha diversity and change in the microbiome immediately after introduction. Interestingly, the infant gut microbiome reacts to fiber in a manner comparable to the adult gut microbiome, i.e. increased bacterial diversity, which is associated with better health outcomes in adults.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25499 |
| Date | January 2020 |
| Creators | Homann, Chiara-Maria |
| Contributors | Morrison, Katherine, Medical Sciences |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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