The gut microbiome

In recent years, there has been a lot of talk about the gut microbiome, probiotics and an increased interest in fermented foods and beverages.. but what exactly is the gut microbiome?

Did you know that humans harbour around 10-100 trillion microorganisms; most of which are present in the gut? Of these microorganisms, about 99% are bacteria and are collectively known as known as the gut microbiome. They have a number of metabolic roles such as

  • vitamin production
  • production of short chain fatty
  • digestion of food
  • brain function and mood
  • regulation of the immune system and metabolism.

Where do these bacteria come from?

Each and everyone of us have a microbiome which is unique to us, similar to your finger print! Before birth, we are protected in a sterile environment and a result, our gut has not been exposed to any pathogens or microorganisms and too, is sterile. Upon birth, rapid colonisation occurs. Depending on the mode of delivery, early colonization of microbes will resemble which bacteria the infant has been in contact with. Different modes of delivery will provide different microbes. Naturally, vaginal delivery is the most common form and exposure to vaginal and faecal microbes occur, some of which include Lactobacillus and Prevotella species. Caesarean section on the other hand skips this and exposes the infant to microbes in the air and on the skin such as Staphylococcus species. This begins the development of the infants gut microbiome.

This microbial community continues to develop for the first 2-3 years of life with subsequent variations throughout adulthood. Some factors affecting its diversity include genetics, environment, antibiotic use and stress. Gestational age is also a big factor. Premature infants are usually kept in sterile environments and treated with antibiotics to prevent infection. As a result, microbial diversity is reduced and a delayed development occurs. By three years of age, an adult like microbiota has formed. The health of this microbiome is also effected by environmental factors such as antibiotic use, diet, stress and probiotic/prebiotic exposure.

Bacterial diversity is key for a healthy microbiome and it is also associated with better health. An imbalance within the microbiome is known as ‘dysbiosis’. Dysbiosis is liked to weight gain, IBS, poor mental health as well as other gut issues.

The changing microbiome
Over the past number of decades, a change has occurred. The diversity of our microbiome has reduced as well as the number of microorganisms in our gut. This is a result of increased antibiotic use, poor dietary habits and less women are breast feeding. With this change in microorganisms have come new diseases. Research suggests that a reduced number of gut bugs as well as an altered ratio of certain types of bacteria, may be linked to mental health issues, development of autoimmune diseases such as autism, obesity and food intolerances. Notice how often you hear of people having trouble with foods we’ve eaten for centuries such as bread and milk? Or how the levels of obesity are constantly creeping up and up. I could speak for hours about these issues however that subject is for another day.

What is a healthy gut microbiome?

Research in this area is in its infancy and so it is unclear what the exact definition of a ‘healthy’ gut microbiome looks like. There are thousands of different bacterial strains, all of which have different effects and functions and there is a lack of research to identify what exactly is a good or a bad strain. The best way to measure the health of your gut is measuring its performance. Are you digesting food well? Do you get sick easily? How is your day to day mood? Focusing on this patterns and making changes to your habits will benefit your microbiome and your health. Good sleeping habits, healthy eating and reducing stress will all help promote the diversity of healthy bacteria. Some ways to improve gut health include:

    • Eating a variety of food – A varied diet promotes growth and diversity of bacteria in the gut.
    • Probiotic supplements – Probiotics contain various strains of bacteria known to benefit human health. These bacteria compete with disease causing bacteria in the gut for a place to live and may have a beneficial affect on our health.
    • Consumption of fermented foods – Fermented foods contain naturally occurring probiotics. Consumption of these foods exposes the gut to more bacteria thus, diversifying our microbiomes.
    • Limiting intake of artificial sweeteners – Artificial sweeteners have a negative effect on the gut microbiome 
    • Consuming prebiotic fibres – Prebiotics feed the good bacteria in the gut keeping them healthy and active.
    • Limiting antibiotic use – Antibiotics kill disease causing bacteria, however they also kill good bacteria. The more frequent the use of antibiotics the lower the count of bacteria in the gut which can have detrimental effects on our health.

So now we know what exactly the gut microbiome is and how it benefits our health, we need to find out the best way to support these gut bugs. Keep an eye out the next few days for some more in dept. explanation on probiotics, prebiotics and fermented foods and how they can improve our individual microbiome and health.

If you found this interesting or helpful, be sure to share with family and friends. I also cover a range of topics daily on my Instagram page @f.i.g_nutrition_ have a fab day! 

Sarah x