How Hormonal Changes Shape Your Gut Microbiota Across Life Stages

Although many of us have some microbes in common, your gut microbiota is unique to you, much like a fingerprint. The first significant amounts of microbes to populate the gut are those that are transferred to the gut when we're born, and which types of microbes we receive during birth is influenced by how we're born (vaginal delivery or caesarean section).

Genetics also plays a role in determining the makeup of your microbiota, but the types (composition) and amounts (abundance) of the different types you have are also dynamic and change throughout your life. There are many different factors which can impact the gut microbiota in either a positive or negative way, including:

• Diet

• Physical activity

• Sleep

• Stress

• Illness

• Antibiotics

• Environment

Changing hormone levels play a role in changing the gut microbiota

For women in particular, changes in hormone levels that occur during different life phases also produce changes in your gut microbiota. Higher levels of oestrogen are associated with higher gut microbiota diversity, which is generally thought to be a sign of a "healthy" gut microbiota.

Puberty The gut microbiota becomes more “adult-like” during puberty in girls, but not boys. This is thought to be influenced by female sex hormones (oestrogen and progesterone).

There is also some newer research that suggests exposure to certain antibiotics in early life may increase the likelihood of earlier onset of puberty in girls. 

Pregnancy

Immune and hormone changes can influence the gut microbiota during pregnancy. Dysbiosis (an imbalance) in the gut microbiota has also been linked to pregnancy complications like gestational diabetes and pre-eclampsia.

The gut microbiota can also influence baby’s future health, by playing a role in immune system development and neurodevelopment.

Perimenopause

Hormone changes during perimenopause and post menopause can impact gut microbiota diversity, resulting in a less diverse microbiota. These changes are suggested to be one of the factors behind the increased risk for certain lifestyle diseases including diabetes and heart disease that is seen in women after menopause. 

As your gut microbiota shifts during these different phases of life, you might also notice changes in gut function and symptoms in these periods. You can help look after your gut and gut microbiota at every stage of life by making mindful health choices, including a diet based on minimally-processed foods (especially plenty of plant foods!), regular physical activity, stress management, adequate sleep, and by limiting use of antibiotics to when only really necessary.

You can learn more about the gut microbiota and how to look after your gut in The SB Nutrition Guide to Gut Health.