Everything About Gut Bacteria

What is gut bacteria?

The gut microbiome is a vast ecosystem of organisms such as bacteria, yeasts, fungi, viruses and protozoans. A study discovered that there are trillions of bacteria that influence our health in many ways; good and bad. Our gut bacteria have a home in our digestive pipes, which goes all the way from our mouths, downwards. Due to the influence that it has on our health, it is increasingly treated by scientists as an organ in its own right. Our gut bacteria are vital for the way that we break down food and toxins, making vitamins and training our immune systems.

Studies of the human microbiome have revealed that “even healthy individuals differ remarkably in the microbes that occupy habitats such as the gut, skin. Much of this diversity remains unexplained, although diet, environment, host genetics and early microbial exposure have all been implicated”. It is safe to say that as our understanding of the microbiome grows, so too will our knowledge surrounding how people respond differently on an individual level to the variety of factors mentioned above. It is surprising to note that these gut bacteria, although the word may have a negative connotation, are essential for nearly all human bodily functions. Therefore, the relationship between microbes and humans can be very beneficial for maintaining health.

Most of the microbes in your intestines are found in a "pocket" of your large intestine called the cecum, and they are referred to as the gut microbiome.

What role does gut bacteria play in the body?

As stated before, our gut bacteria have an influence on a number of bodily functions. This includes but is not limited to: digestion, inflammation, weight gain, the production of vitamin K and even mental health.

Absorption of dietary fats - A growing body of work implicates microbially produced metabolites as crucial executors of diet-based microbial influence on the host. The research goes to show how short-chain fatty acids are absorbed in the gut and affect various physiological processes thereafter.

Digestion of flavonoids - Additionally, it has been found that the microbiome contributes to diminished post-dieting flavonoid levels and reduced energy expenditure. Flavonoids are phytonutrients that are found in a number of fruits and vegetables. Therefore, our gut bacteria plays a crucial role in digesting these and their nutrients to keep us healthy.

Digestion of fiber, promoting weight loss – Humans cannot digest fiber on their own, but it passes into the intestine where the gut bacteria live and absorbs water, “bulking” us up to the point where we eventually pass waste. The average fiber intake of adults in the United States is less than half recommended levels and is lower still among those who follow currently popular low-carbohydrate diets, such as Atkins and South Beach. Increasing consumption of dietary fiber with fruits, vegetables, whole grains, and legumes across the life cycle is a critical step in stemming the epidemic of obesity found in developed countries. Fiber consumption is important for digestion to not only keep you regular, but to ensure that your body is getting the vitamins and minerals it needs to function. A healthy, fibrous diet has been shown to positively affect obese people, but more on that later.

Inflammation -  Gut inflammation especially is associated with a number of autoimmune diseases. Due to the large surface area of the gut, it needs to have a tight barrier to stave off intestinal pathogens, inflammatory bowel disease, irritable bowel syndrome, obesity, celiac disease, non-celiac gluten sensitivity, and food allergies. Leaky gut, or intestinal permeability, for example, is associated with inflammation of the gut, and with small intestinal bacterial overgrowth.

Obesity – An increasing number of research studies indicate that our gut microbiota does play an important role in our health. It affects our metabolism and can be linked to obesity, cardiovascular disease and type 2 diabetes

The researchers analysed blood plasma and stool samples from 674 participants in the Malmö Offspring Study, MOS. They found 19 different metabolites that could be linked to the person's BMI; glutamate and so-called BCAA (branched-chain and aromatic amino acids) had the strongest connection to obesity.

They also found that the obesity-related metabolites were linked to four different intestinal bacteria

Obesity is associated with phylum-level changes in the microbiota, reduced bacterial diversity and altered representation of bacterial genes and metabolic pathways. A diversity of organismal assemblages can nonetheless yield a core microbiome at a functional level, and deviations from this core are associated with different physiological states (obese compared with lean). 

The gut may play a role in feelings of satiety by affecting leptin and ghrelin, which are commonly known as the hunger hormones. Balance in the gut could then mean that we would more easily control our appetite while still getting all the energy we need.

Mental health – The microbiome in our guts, populated by billions of bacteria, appears to play a significant role not only in our digestive health, but also our mental health.


What foods can you eat to improve your gut bacteria

Gut health on yellow background | DNAfit Blog

You want to eat as diverse a diet as possible, and you also want to take part in exercise (high level athletes have more diverse microbiota than non-athletes).

Eat foods that are high in fiber

  • Wholegrains
  • Fruit and vegetables
  • Nuts and seeds

Eat foods that contain polyphenol antioxidants

  • Red wine
  • Dark chocolate
  • Green tea

Eat fermented foods containing “good” bacteria, probiotics

  • Sauerkraut
  • Yoghurt
  • Kefir
  • Blue cheese
  • Pickles
  • Kimchi



Probiotic foods | DNAfit Blog

  • Garlic
  • Legumes
  • Oats
  • Bananas
  • Berries



The human microbiome is an entire ecosystem that influences our health just as much as any other organ. We are connected by one digestive tract and the bacteria that co-exist with us inside of it can either influence us positively or negatively. The foods that we consume can alter our gut bacteria for better or worse, and a healthy microbiome will mean a healthy life and can lower your risk of diseases such as obesity, inflammatory gastrointestinal diseases, type 2 diabetes and our mental health. For this reason, it is always important to consider the microbiome when attempting to stay healthy, and listening to your body in accordance to the foods that you eat and how you react to them is one of the ways to do this.


As genetics also plays a role, there have been studies that look at the microbiome, as well as DNAfit’s Diet Fit genetic test which can educate you on your “ideal diet type”.

Discover Diet Fit


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