Gut Instinct

Resident Clinical Nutritionist BROOKE BENSON CAMPBELL (BHSc Nut Med) explains why your belly is the key to good health…

While we collectively pride ourselves on our self-control, self-discipline, rational thinking and our ability to empathise — all facets of a Homo sapien or human being – we may be a little surprised to realise that technically human cells only make up around 43% of the body’s total cell count. The other 57% of cells? They belong to bacterial microbes that live primarily in the gut. Yep, that’s right — your gut is full of creepy crawly bacterial cells, making you more microbe than human. And, as scientists use genetics to uncover specific microbes that are actually present in the gastrointestinal tract and what they’re doing there, they are discovering that these microscopic bugs play an even larger role in human health that previously suspected. Here, I delve into the world of all things probiotics and microbiota to discover why everything from mood to muscle growth, weight to mental performance, and sleep to chronic disease is influenced by the bacteria that resides within us. Cue epic science-fiction music…
While we know that nerves and anxiety can result in “butterflies” in the tummy, and that depression can cause Irritable Bowel Syndrome, it turns out that reverse is also true — the bugs in our intestinal tract can alter our mood. Most of the neurotransmitters that regulate our mood — including 50% of the dopamine (our reward and motivation brain chemical) and 95% of the serotonin (our happy brain chemical) — in our bodies are produced by microbes in the intestine, where they also influence appetite and feelings of fullness. Members of the Lactobacillus and Bifidobacterium groups (found in most shelf-stable probiotic supplements) also often produce GABA, a neurotransmitter that works to reduce anxiety. In fact, the gastrointestinal tract and brain are so intimately connected that the gut is known as “the second brain”.
Interestingly, a growing body of research suggests that a well-balanced microbiome can improve mood even if you don’t have a clinical case of depression or anxiety — helping to ease stresses and lengthen that short fuse. One study of healthy adults published in the journal Brain, Behaviour and Immunity found that a positive shift in gut bacteria populations resulted in significantly fewer reports of sad mood and negative thoughts. In another study, researchers at UCLA gave healthy people yogurt twice a day for a month, then conducted brain scans as they were shown pictures of actors with frightened or angry facial expressions. Normally, such images would trigger increased activity in emotion-processing areas of the brain linked to a state of heightened stress. However, the people on the yoghurt diet exhibited a calmer response. Yet another study, men who consumed probiotics for a month reported feeling less stress than when they were given a placebo. They also had much lower levels of the stress hormone cortisol, making probiotics the Yoga of the supplement world.
However, to get the Matthew McConaughey chilled-Southerner vibe, it is also important to minimise your intake of foods that are known to have a negative impact on good gut bacteria. Added sugar (namely fructose and glucose) prevents production of proteins that foster the growth of those bugs, according to recent studies. And a 2017 British study found that men who ate 67-plus grams of added sugar a day were three times more likely to develop anxiety or depression, when compared to those who ate less than 40 grams (still a huge amount). A diet high in salt may also cause changes in your microbiome. In mice, high salt intake decreased levels of microbes that provide anti-inflammatory protection and have been linked to reduced anxiety and depression. The take-away: watch the white stuff to boost gut health.
Speaking of sugar, in a study published in the journal Diabetes, author John March and colleagues found that they were able to reduce blood glucose levels in diabetic rats using gut bacteria — a huge breakthrough for the 1.7 million Australians with Type 2 Diabetes. Each day for 90 days, the researchers orally administered a probiotic, and monitored blood glucose levels, comparing the outcomes to diabetic rats who did not receive the supplement. At the end of 90 days, they found that the rats that received the probiotic had blood glucose levels up to 30% lower than those that did not receive the probiotic — a huge breakthrough. It seems that we are not what we eat, but what our bacteria does with it that matters.
Weight loss and fat distribution is another area where probiotics show huge promise. Research in the British Journal of Nutrition studied the effects that one type of probiotic, Lactobacillus rhamnosus, had on people with obesity. Women who took the probiotic supplement lost more weight during the study than women who took a placebo. Additionally, the group taking a probiotic supplement continued to lose more weight in the weight-maintenance stage, after they finished dieting. Another 2013 study looked at the effects of Lactobacillus fermentum and Lactobacillus amylovorus. During the study individuals who were overweight but otherwise healthy ate yoghurt that contained these Lactobacillus strains for six weeks. At the end of the period, with no other exercise or training, the participants lost an average of 3-4% body fat.
Researchers have also examined the effects of Lactobacillus gasseri for fat loss. In this study, people with extra belly fat who drank fermented milk products containing the helpful bacteria lost 8.2-8.5% of their belly fat over 12 weeks, and again, without any other dietary or exercise regime.
How do probiotics help with weight loss? Different microorganisms behave in different ways. While some breakdown indigestible fibre into beneficial fatty acids, others can reduce absorption of fat and increase the amount of fat excreted from the body (such as bacteria from the Lactobacillus family). Certain strains can also aid in the release of the satiety hormone which helps the body to burn both calories and fat and increases specific proteins that contribute to reduced fat storage. The evidence on this one is clear: to keep that summer body throughout the winter months, a probiotic is essential. In fact, in one study, 125 people supplemented with probiotics containing Lactobacillus rhamnosus over a three-month period, lost 50% more weight when compared to a placebo-group. The reduction came from BMI, waist size and hip circumference.
And if you are training to maintain that shredded muscle tone, emerging research also demonstrates that probiotics play a key role in the muscle growth process and improved recovery by increasing uptake of amino acids in the small intestine. Interestingly, studies show that elite athletes not only have stronger hearts and fitter muscles than the average Joe, but they also carry special gut bacteria that may actually boost their performance.
A recent study, published in Nature Medicine, shows that marathon runners and endurance athletes have higher levels of a bacteria called Veillonella in their guts, particularly after finishing a race, than ordinary people. Even more exciting, when researchers isolated a strain of Veillonella from a marathon runner and administered the bacteria to mice, they found that the mice ran for 13% longer on a treadmill test, compared with mice not given this probiotic.
It appears that Veillonella feeds on lactic acid, a compound produced in the muscles during exercise, and in turn, the bacteria produce a compound called propionate, which may aid athletic performance. Studies also shed light on the possible link between gut microbes and communication between nerves and muscles. Researchers found that germ-free mice (without any microbial colonisation) had reduced levels of key proteins essential for the assembly and function of a neuromuscular junction – a chemical structure that allows a motor nerve to communicate with a skeletal muscle fibre. These junctions allow signals to be transmitted to the muscle fibre, causing muscle contraction, and transplanting gut microbes into these germ-free mice restored expression of these key proteins to normal levels. It seems muscle tone and strength really does begin in the gut. Other strains have also been shown to support oxygen utilisation and muscle recovery, so next time you invest in protein powder or pre-workout fuel, a probiotic should also be front of mind.
The takeaway here — the bacteria living in your gut have a huge impact on the way you feel, perform and function. So, how can we look after our most important organ and the nearly two trillion microbial genes that live within it? Read on…

Remember that your body recognises nature: On average, we spend nearly 90% of our time indoors. That presents a huge problem as partnering with nature is crucial to feeding the microbiome. The natural world around us is filled with friendly bacteria that help us thrive, so make a habit of talking a walk outside after lunch, going hiking on weekends, or doing basically any outdoor activity several times a week. Not only will you expose yourself to new bacteria, but you’ll also find cortisol levels will lower. Lower cortisol levels lead to a healthier microbiome, which in turn leads to even lower stress levels, which then boosts the microbiome… you get the drift.

You are what you eat: The single most important factor for a healthy microbiome is diet, and a big part of a healthy diet is fibre. Not only is it filling, but it also feeds our good bacteria and produces many of our B vitamins. It provides a vital detox pathway and binds to toxins to remove them from the body. Unfortunately, we now consume about 10% of the fibre our ancestors did, and this is contributing to chronic illness. The answer here: at the risk of sounding like your mother, eat more vegetables… a LOT more! Also supplement your smoothie with a Prebiotic fibre made from Inulin — it will aid in feelings of fullness (without adding calories) and as a natural prebiotic, it feeds the probiotics already living in your gut. Perfect!

Now, if all else fails, grab yourself a high strength probiotic with as many different strains as possible to keep all bases covered. In this case, it may just be as easy as popping a pill. ■


Brooke Benson Campbell (BHSc) is a Clinical Nutritionist and Naturopath, speaker, writer and presenter with a passion for all things health, beauty and wellbeing. A self-proclaimed human test subject, she is constantly trialling the newest products, seeking the latest discoveries and reading the current clinical studies, in order to share her findings with the public through private practice, social media and industry education. Follow Brooke at her Instagram @the.b.b.c 

For the full article grab the January 2020 issue of MAXIM Australia from newsagents and convenience locations. Subscribe here.

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