The Science behind Tiny Health

Living in your intestines is a community of trillions of tiny organisms that play an important role in immune development and health throughout life. This is your microbiome. The first 1,000 days of life - 9 months of pregnancy and a baby’s first two years - lay the foundation for the development of a healthy gut microbiome. The bacteria that first colonize a baby’s gut come from the mother. During pregnancy, with a vaginal birth, and during breastfeeding (if accessible), a mother passes on to her baby the microbiomes of her skin, gut, birth canal, and breast milk.

This sharing of the mother’s microbiome with her baby is essential in establishing a healthy microbiome. But if this early colonization doesn’t go as planned, it turns out there is an increased lifelong risk for chronic disease. This includes eczema, asthma, allergies, obesity, and diabetes.
"If we miss the window at birth then the immune system never matures correctly. If you upset this process in early life then we may have consequences later and that can lead to production of disease later in life."Prof. Rodney Dietert
Professor Emeritus of Immunotoxicology, Cornell University
Scientific Advisor at Tiny Health
Professor Rodney Dietert
"Imagine a world where you will take your baby to a health care check. They will routinely monitor the gut microbiome development of that baby, and if any disruptions are noted, a tailor-made product to restore the gut microbiota will be prescribed. The onset of any chronic diseases will be extremely rare.”

Dr. Henna Maria Uusitupa, Microbiome
Researcher, TED Speaker (2.5M views)
It may come as no surprise that what we eat shapes the gut microbiome. What this means for a baby is that a mother’s diet can have a direct impact on her baby’s microbiome. Besides diet, a healthy gut microbiome is influenced by: 

• Birth mode
• Diet and nutrition
• Antibiotic use and medication
• Environmental exposure
• Contact with animals

Recent research suggests that challenges to the gut microbiome during this critical development window - such as the use of antibiotics - might disrupt the gut’s internal balance, impacting overall health.

Birth mode is one of the most significant factors that influence the baby’s microbiome. 

The early gut microbiome of babies born vaginally is markedly different from that of babies born by c-section.1 Because of the microbes they’re initially exposed to, babies born by c-section may miss important healthy bacteria. 

C-section and the use of antibiotics in early life (while sometimes life-saving) have been associated with the development of asthma and allergies.2,3 More recently, antibiotic exposure has been linked to a higher risk of mental health conditions such as anxiety and depression.4

Breastfeeding is best, but for many families exclusively breastfeeding is not possible. Breastfeeding shapes the baby’s gut microbiome, promoting the colonization of healthy bacteria, such as Bifidobacteria. Bifidobacteria depend on human milk oligosaccharides (HMOs), which are sugars found in human milk that help feed these healthy bacteria. At Tiny Health we want babies born and fed in all circumstances to have the best chance to have a healthy microbiome and believe that information along with evidence-based recommendations is the best path to achieve optimal health for all babies.

Digestion of HMOs by Bifidobacteria (as well as other bacteria) leads to the production of lactate and short-chain fatty acids like acetate, which makes it hard for harmful bacteria to survive; while stimulating the immune system and promoting the presence of a healthy microbiome. In contrast to the adult gut microbiome, which is stable, the baby’s microbiome continues to develop and change throughout the first 3 years of life until it reaches full maturity by the age of 5.
Early life factors influencing the cognitive and microbiota development of the child imageImage from: Ratsika et al., Priming for Life: Early Life Nutrition and the Microbiota-Gut-Brain Axis. Nutrients 2021

The first 1,000 days of life is when parents have the biggest impact on a baby’s gut microbiome and lifelong health.

At Tiny Health, we provide you with insight and a blueprint to ensure a healthy microbiome during your baby’s first 1,000 days. To help you with this, we perform next-generation metagenomic sequencing, a high-resolution technique that sequences the DNA from every microbe present in the stool. This allows us to identify which bacteria are present, the relative abundance of each microbial population, and their metabolic function. 

Our team of highly experienced and dedicated microbiome researchers will provide useful insights into your and your baby’s microbiome and suggest personalized actions that may improve your baby’s gut health. Our understanding of the science of the microbiome is evolving rapidly, with new insights weekly. At Tiny Health we are committed to bringing families the best of research and recommendations as our understanding evolves.

“Throughout my journey with my 2 kids, I realized that so much gut microbiome research is coming out of academia but it takes 10-15 years for this to reach the medical community and put it into practice. That is WAY TOO SLOW. I started Tiny Health to bring the latest science to consumers immediately, so parents can take action when it matters most.”

Cheryl Sew Hoy, Founder and CEO at Tiny Health

Key Research Papers

Stunted microbiota and opportunistic pathogen colonisation in caesarean section birth.
Nature Logo
Researchers analyzed the gut microbiota of 576 healthy, full-term babies and their mothers. They found that the mode of delivery is the driving factor shaping the composition of gut microbiota in the first month of life and up to 1 year of age.
Saho et al., 2019
Delivery mode and gut microbial changes correlate with an increased risk of childhood asthma.
Science Translational Medicine logo
Science Translational Medicine
In this study of 700 children from the Copenhagen Prospective Studies on Asthma in Childhood cohort, researchers found that even though babies born by c-section have a gut microbiome associated with asthma development in the first 6 years of life, this is only true if at age of 1 the baby still carries the same “unhealthy” microbiome. This suggests that microbiome restoration before 12 months is a promising strategy to prevent asthma development in a child born by c-section.
Stokholm et al., 2020
Strain-Level Analysis of Mother-to-Child Bacterial Transmission during the First Few Months of Life.
Cell Host & Microbe Journal logo
Cell Host & Microbe
Researchers tracked down bacterial species - down to the level of strains and genes - transmitted from a mother to her child during birth. These findings confirm transmission of (health) microbes from mother to child and highlight the importance of vertical transmission.
Yassour et al., 2018
Healthy infants harbor intestinal bacteria that protect against food allergy.
Nature Medicine Logo
Nature Medicine
In a study showing that gut bacteria are important to protect against food allergies, researchers transplanted gut bacteria from babies – both healthy and those with cow’s milk allergy – into “germ-free” mice. These are mice without microbes that are kept in a sterile environment, making it easy to clearly see the effects of transplanted bacteria. As it turns out, mice colonized with microbes from healthy babies were protected from an allergic reaction when later exposed to cow’s milk, the most common food allergy in children.
Feehley et al., 2019

Papers showing disease associations


Early infancy microbial and metabolic alterations affect risk of childhood asthma.
Science Translational Medicine logo
Science Translational Medicine
Researchers found that there are four key bacteria that, if present at 3 months of age, drastically reduce the risk of developing asthma, suggesting a protective effect.
Arrieta et al., 2015

Allergies & Eczema

Neonatal gut microbiota associates with childhood multisensitized atopy and T cell differentiation.
Nature Medicine Logo
Nature Medicine
In this study, researchers found that the newborn gut microbiome directly impacts the developing immune system. A dysbiotic newborn gut microbiota, characterized by the depletion of beneficial Bifidobacteria, Lactobacillus, Faecalibacterium, and Akkermansia, led to a dysfunction in T cell populations, influencing the susceptibility to childhood allergic asthma.
Fujimura et al., 2016
Intestinal microbiota in infants and high risk of allergy: Effect of Probiotics and Eczema development.
Journal of Allergy and Clinical Immunology logo
Journal of Allergy and Clinical Immunology
Hydrolyzed protein formula - with additional prebiotics - has the potential to change the gut microbiome of babies who are at a high risk of developing allergies. The addition of prebiotics to formula supported the development of a baby’s microbiome, helping it to resemble the gut of a breastfed baby and potentially protecting against the development of allergies later in life.
Woperes et al., 2018

Type 1 & Type 2 diabetes

Temporal development of the gut microbiome in early childhood from the TEDDY study.
Nature Logo
Using stool samples from the Environmental Determinants of Diabetes in the Young (TEDDY) study, one of the largest datasets on the infant microbiome scientists concluded that during the developmental stage (3-14 months), breastfeeding was the most significant factor associated with microbiome composition, with higher levels of healthy Bifidobacterium bacteria. Microbiome diversity increased after weaning as the infants consumed a greater variety of foods.
Stewart et al., 2018
The human gut microbiome in early-onset type 1 diabetes from the TEDDY study.
Nature Logo
In this study, nearly 11,000 stool samples from 783 children were analyzed to try to understand how early gut microbiome can impact Type 1 diabetes. Researchers found that infants without Type 1 diabetes have more microbial genes related to fermentation and production of short-chain fatty acids, which are beneficial to gut health and immune function.
Vatanen et al., 2018


Roles of Birth Mode & Infant Gut Microbiota in Intergenerational Transmission of Overweight & Obesity From Mother to Offspring.
Jama Pediatrics logo
Jama Pediatrics
In this cohort study of 935 mother-infant pairs, infants born to mothers with overweight or obesity were more likely to be overweight at ages 1 and 3 years compared to infants born to mothers with normal weight. In addition, infants delivered by c-section had double the odds for developing childhood overweight or obesity compared to infants delivered vaginally.
Tun et al., 2018


Infants born to mothers with IBD present with altered gut microbiome that transfers abnormalities of the adaptive immune system to germ-free mice.
BMJ Journals Logo
BMJ Journals (Gut)
Babies born to mothers with inflammatory bowel disease (IBD) present an unhealthy bacterial gut composition up to at least 3 months of life, characterized by the absence of healthy Bifidobacteria. This unhealthy microbiome led to important changes in the adaptive immune system of the gut in germ-free mice, highlighting the importance of a microbiome-based intervention during early infancy, thus reducing the risk of developing IBD.
Torres et al., 2019

References & Sources

1. Shao, Yan et al. “Stunted microbiota and opportunistic pathogen colonization in caesarean-section birth.” Nature vol. 574,7776 (2019): 117-121. doi:10.1038/s41586-019-1560-1

2. Stokholm, Jakob et al. “Delivery mode and gut microbial changes correlate with an increased risk of childhood asthma.” Science translational medicine vol. 12,569 (2020): eaax9929. doi:10.1126/scitranslmed.aax9929

3. Nogacka, Alicja M et al. “Early microbiota, antibiotics and health.” Cellular and molecular life sciences : CMLS vol. 75,1 (2018): 83-91. doi:10.1007/s00018-017-2670-2

4. Ratsika, Anna et al. “Priming for Life: Early Life Nutrition and the Microbiota-Gut-Brain Axis.” Nutrients vol. 13,2 423. 28 Jan. 2021, doi:10.3390/nu13020423