You’ll find bacterium not the most popular topic of conversation when we talk health and fitness. Yet those tens of trillions of microscopic living organisms in our bodies known collectively as bacteria are some of the most important features of human health and wellbeing.

The human body is made up of some 30 to 40 trillion cells with estimates of between 30 trillion and 100 trillion microbes. There are around 10,000 catalogued species of microbes that live on and in our bodies. These microbes are known as the human microbiome which is made up of communities of bacteria, archaea, fungi and viruses.

Bacteria represent the largest community of microbes and are found on the surface of the skin, inside the mouth, the nose and urinary tract. But where most of the bacteria resides is in the intestines where an estimated 500 to 1,000 species colonise the human gut alone.

We tend associate bacteria with something bad and harmful. Indeed bad bacteria can be harmful, especially when it disrupts the healthy microbiome and results in all kinds of disease – obesity, cancer and diabetes to name a few. Even though we use antibiotics to fight bacterial infections, use of these medications can cause an imbalance between good and bad bacteria. When antibiotics kill off friendly bacteria, hostile bacteria can flourish in its place leading to poor health and impaired immunity among other inflammatory disease.

This is the reason why health experts, and a bunch of nutritionists and naturopaths, discourage the use and overuse of antibiotics in favor of a healthy diet plan that includes probiotics.

What are Probiotics?

Probiotics are good bacteria found naturally in our bodies. The word probiotic means ”pro life” or “for life” from the original Latin and Greek languages. Probiotics are key to balancing our digestive system by promoting healthy gut flora and keeping the disease-causing pathogenic bad bacteria at bay. Probiotics are the beneficial bacteria that are paramount to our gastro-intestinal health and for that matter our overall health and wellbeing.

Probiotic populations include Lactobacillus, Bifidobacterium, Bacteroides, Clostridium, Escherichia, Streptococcus and Ruminococcus. The two types of well-known, powerful blend bacteria we commonly see in probiotic supplements are Lactobacillus and Bifidobacteriub.

As probiotics help to maintain healthy levels of gut flora, they are immensely important to supporting our immunity as the majority of our immune system is located in our digestive tract. Therefore, for good immune defenses it is crucial we have a healthy bacterial environment and one of the simplest and effective ways to support that is with dietary probiotics.

A healthy intake of probiotics help:

  • Strengthen the immune system
  • Improve digestion and intestinal motility
  • Improve nutrient absorption
  • Fight pathogenic bacteria
  • Reduce cold and flu
  • Stabilise blood sugars
  • Alleviate lactose intolerance
  • Reduce the risk of some cancers
  • Improve mental health
  • Lower bad and total cholesterol levels
  • Improve liver, lung and heart health
  • Lower blood pressure
  • Improve skin condition
  • Reduce allergy risks
  • Lower inflammation
  • Support hormone balance.

While the range of health benefits applies to everyone, there is research that probiotics may be particularly beneficial to men. This is namely due to the role that probiotics have in promoting optimal hormone balance, including healthy levels of testosterone.

So if we want to maximise our levels of testosterone then it’s important we lead a lifestyle and follow a balanced diet that supports healthy hormone production. And one of the ways we can achieve this simply is through incorporating probiotics in our daily diet.

How are probiotics related to testosterone?

A link between probiotics and testosterone might be news for many but there are at least several scientific studies to support there is a relationship.

A 2014 study published in PLoS ONE, a peer-reviewed open access scientific journal, showed that when male mice were placed on a diet of lactic acid bacteria from human milk, they grew larger testicles and had significantly higher circulating testosterone levels compared to their age-matched controls.

In what appeared to be a surprising result of the diet study, the researchers observed “unusually large testes” and “social dominance behaviors” among the male mice who were fed probiotic yoghurt or purified lactic acid bacteria.

Further, the researchers noted that their data suggests the association between the prevention of age- and diet-related testicular atrophy and probiotic microbe Lactobacillus reuteri was correlated with increased numbers and the size of Leydig cells. Perhaps herein is how the probiotics produced a positive effect on hormones as the main function of Leydig cells is to secrete androgens, of which includes testosterone.

The results of a 2011 study showed mice administered with Lactobacillus rhamnosus, (one of several species of probiotic bacteria commonly found in yoghurt) had significantly lower stress-induced levels of corticosterone compared with broth-fed control animals.

Here the probiotic bacteria was found to stimulate levels of the neurotransmitter gamma-aminobutyric acid (GABA) which helped the mice remain more calm during a stressful situation than the controlled rodent group, effectively suppressing the rise in stress hormones.

The findings have important implications for men because as we know a rise in cortisol correlates to lower testosterone.

It’s also interesting to note the researchers of the study concluded that as healthy bacteria may have a role in modulating GABA in mice; it might also have beneficial effects in the treatment of depression and anxiety in people.

As such, a diet that includes enough healthy probiotics may therefore not only help our physiological response to any stress we encounter, but have a positive influence on our overall hormone balance.

While this research wasn’t conducted with people, it is still highly valuable as rodent studies have been shown to model very well. For example, mouse models have been used to successfully validate effective and safe drug use for humans.  Mouse research has also help advance treatments for a number of diseases and conditions. Furthermore, the mouse genome is 99% similar to the human genome. In fact, mice and humans share a number of genetic, anatomical and physiological features.

So is it any wonder mice are the most popular animal models in research? Then given this we can be confident that the rodent and probiotic studies here are useful for us too.

The top four probiotic foods  

While there are many good readily available probiotic food sources out there, there are a few standouts worth highlighting. The below is a brief outline of what we see as the four top powerful probiotic foods you can use to get enough healthy bacteria in your daily diet.


Sauerkraut is essentially a form of fermented cabbage. It is made from fresh cabbage treated with brine (sea salt and water) and a few other seasonings thrown in for flavor before being pounded and stored away in a jar for several weeks to ferment.

It’s the fermentation of this food, a process that’s been used for thousands of years to preserve perishables, that gives Sauerkraut its health-promoting magic. Sauerkraut is literally packed with live and active probiotics. And as a good source of dietary fiber, vitamins and minerals, Sauerkraut really comes out on top for its overall health benefits and nutritional value.


Kefir is a fermented milk drink. It is similar to drinking yoghurt and has a slightly tangy and yet creamy and refreshing taste. Kefir contains a broad range of beneficial lactic acid bacteria and yeasts, which give the food its immense health benefits.

Kefir is simply made by placing “kefir grains” or powdered Kefir starter culture into a glass of milk and then left covered to sit at room temperature for 24 to 48 hours.  The grains are then strained from the milk leaving ready-to-drink Kefir. Kefir with its abundance of nutrients, enzymes and probiotics is incredibly beneficial for digestion and gut health and a great addition to a robust health diet plan.

Cultures for Health Water Kefir Grains


 Kombucha is a type of fermented tea brewed by combining water, tea, sugar and a serve of SCOBY or “symbiotic culture of bacteria and yeast” to produce


a refreshing and effervescent beverage. Kombucha is a natural detox that contains a range of probiotics, enzymes, amino acids and vitamins.

Kombucha promotes healthy gut bacteria and supports your immune system and digestion.  In fact, the tonic provides many health benefits overall and was even known as the “Immortal Health Elixir” to the Chinese and the Far East in ancient times.

Read the Wonder drink Kombucha reviews



Yoghurt is a food produced by fermentation of pasteurized milk and is one of the most popular dietary sources of probiotics on the supermarket shelf. Yoghurt comes in a wide range of flavors and toppings and is probably the most versatile of all probiotic foods.

The bacteria used to make yogurt are known as “yoghurt cultures.” These are the live and active cultures Lactobacillus bulgaricus and Streptococcus thermophilus which turn the pasteurized milk into yoghurt during fermentation.

You’ll find some fortified yoghurts also contain Lactobacillus acidophilus and Bifidus and like other probiotic foods, yoghurt is packed with lots of good nutrients for great overall health.


There’s plenty of readily available food sources of probiotics you’ll find in the supermarket aisle: Bananas, pickles, artichokes, cabbage, chicory, garlic, soy beans, asparagus, tomatoes, legumes, leeks and onions. And these are all great products to include as part of your healthy diet plan.

Then there’s sauerkraut, kefir, kambucha and yoghurt. So if you want great health and wellbeing, the kind of which will boost your testosterone and perhaps even the size of your testes, be sure to include any of these four probiotic superfoods in your diet regime.