Why Understanding Your Microbiota Is Key to Health and Longevity


Microbiota, microbiome, gut flora, intestinal flora. Scientific phrases commonly spoken by microbiologists, but now becoming etched in common parlance. The terms gut flora and intestinal flora are old terms. The term ‘flora’ technically refers to any species belonging to the plant kingdom. The organisms that colonize the human body are certainly not plants; they are bacteria, yeasts, fungi, viruses, archae and other microorganisms. Their habitation within and introduction to your body has a profound influence on your future health, initiated long before you are born.

The terms ‘microbiota’ and ‘microbiome’ are a more accurate reflection of the microorganisms residing in and on the human body, yet the terms are often used incorrectly:

Microbiota: refers to all microbial species associated with humans
Microbiome: refers to the catalogue of these microbes + their genes

The microbiota of humans consists of approximately 10-100 trillion microbial cells. Put into perspective, this is approximately ten times the population of the human cells in your body. Your microbiome comprises as much as 3% of your body mass. Primarily, they reside in the gut, however no surface of the human body is uncolonised by microbes. Your integument (skin), respiratory tract (including the lungs), and urogenital tracts are teeming with microbial life. Many of these organisms are symbionts; they live within other organisms, such as us! In the majority of cases, this symbiotic living arrangement benefits both the microbes and their host. Some members of the microbiota are pathogenic (disease causing). Their populations are smaller and unable to cause disease until the surrounding environment changes to favor their growth.
Microbiome research is taking place worldwide, aiming to understand the role of the microbiota to human health. Here is what the current body of research has uncovered.

The human microbiota is highly specialized
Knowledge of the different microbial species present during times of health versus disease, between individuals and between different sites on the same individual is not new; this was established as early as the 17th century. Modern medical science wants answers to these questions:

Why do these differences exist?
What affects the transformations from one state, person or site to another?

Research has established that microbes of the human gut are not acquired merely from the environment in which we live. Evolution has carefully selected a specific community of microbes that flourish in the stable, warm and nutrient dense environs of the human gut. Everything you touch and eat introduces microbes to your body, everyday. It appears that the most diverse microbial communities are located in the oral cavity and the gut. We can postulate this is due to their role in eating, as no other sites come into contact with literally thousands of microbial samples (foods) in quite the same way as your mouth and digestive tract. The Hologenome Theory of Evolution questions that natural selection is not simply based on an individual organism, but the organism together with its attendant microbial populations.

What influences the colonization process?
Approximately one third of human gut microbiota is the same in all individuals. The remaining two thirds are specific to each individual. It is fascinating to consider that our microbiome is as diverse as fingerprints, our faces and our genetic profile. Diversity can be influenced by the following factors:

• Method of infant delivery. Some research suggests that cesarean delivery may impact on early biodiversity of intestinal bacteria. Babies delivered vaginally are exposed to mother’s microbes much sooner, instantly initiating colonization of the infant. Other research suggests there is little difference in microbial colonization between babies delivered vaginally versus C-section by the time they are 3 years old.
• Dietary interventions. Babies who are breast-fed are colonized early via microbes from mothers skin. Research also shows that breast fed infants have higher levels of gut microbes in general. The introduction of solids also has a significant impact on a breast-fed baby’s microbial population, as it begins to look more like the profile of a formula fed baby.
• Pharmaceutical interventions: Antibiotic treatment is the most well known drug therapy for causing dysbiosis, but evidence is mounting for other drugs too, such as oral antacid medications and anti-diabetic drugs and oral contraceptives.
• Longer term dietary changes. Science continues to show the inseparable link between an individual’s microbiota, digestion and metabolism. Some studies suggest that dietary changes can influence microbial populations within a week or even a day of the eating pattern shifting.
• Environmental interventions: individuals from highly antiseptic environs have less diversity in their microbiome.

Take away points
• A balanced gut microbiota assists with proper digestive function. As it exists at the interface between food nutrients and the intestinal lining, it assists in breaking down foods left partially digested by the stomach and small intestine.
• Your microbiota is like an army, preventing resurgence and attack from pathogenic microorganisms.
• A balanced microbiota helps fulfill the body’s production of some B vitamins and vitamin K.
• The interface provided by your microbiota is an immune barrier. Dysbiosis (unbalanced gut microbial populations) is linked with all major immune disorders, such as allergy, atopy, recurrent infections, autoimmune disorders, some cancers, cardiovascular disease and many chronic digestive disorders.
• Prebiotics act as nourishment for gut microbiota. They induce both the growth and metabolism of beneficial members of the microbiome. Prebiotics are non-digestible fibers such as inulin, pectin, starch, beta-glucans and various oligosaccharides (complex sugars).
• Probiotics are live microorganisms that are supplied via food, beverages (particularly fermented or soured types) and supplementation.
Simply taking an over the counter probiotic may not be enough to fully restore the healthy function of our microbiota, or replenish populations of healthy gut microbes and treat dysbiosis. Your diet possibly needs to change. You may require certain species of microbes, or even certain strains of microbes to regain health. Knowing how long to take probiotics, prebiotics and what nutritional changes to make should be undertaken with a complementary or integrative health professional to achieve the results you need, and to stop problems recurring for you in the future.

Written by Annalies Corse BMedSc, BHSc.

1. Biasucci, G. et al. (2008). Cesarean delivery may affect the early biodiversity of intestinal bacteria. The Journal of Nutrition.138 (9) 1796S-1800S.
2. Guaraldi, F and Salvatori, G. (2012). Effect of breast and formula feeding on gut microbiota shaping in newborns.Frontiers in Cellular and Infection Microbiology.2: 94.
3. Gut Microbiota World Watch. PubLic Information Service from the European Society of Neurogastroenterology and Motility. Last updated: January 2016. Available at: http://www.gutmicrobiotawatch.org/en/gut-microbiota-info/
4. Jakobsson, H., et al. (2014). Decreased gut microbiota diversity, delayed Bacteroidetes colonization and reduced Th1 responses in infants delivered by caesarean section. Gut. Apr; 63 (4): 559-66.
5. Salvucci, E. (2014). “Microbiome, holobiont and the net of life”. Critical Reviews in Microbiology: 1–10.
6. Turnbaugh P., (2006). An obesity-associated gut microbiome with increased capacity for energy harvest. Nature. 444:1027–1031.
7. Ursell, L. et al. (2012). Defining the Human Microbiome. Nutrition Reviews. Aug; 70 (Suppl 1): S38–S44.

Neurotransmitters: minute chemicals delivering powerful messages

The nervous system of human beings is undoubtedly one of the most complex and challenging systems to try and understand. Whilst we all have a good understanding of brain health, and what to do to keep our brain healthy (such as learning languages or musical instruments, engaging in hobbies, meditation and social interaction), you may not know much about the smaller, minute chemical details of what makes our nervous system tick. These chemicals are known as neurotransmitters, and their functions are far more expansive and important to your health than you may realize.

Every day, your nervous system receives millions of signals from sensory organs such as the eyes, ears, skin, nose and tongue. These actions allowing us to read, listen to music or taste food are relatively straightforward to comprehend. However, your nervous system also controls the movement of every muscle fiber in your body (including the cardiac muscle of the heart, and the smooth muscle of your entire digestive tract). The nervous system also responds to the ever-changing chemical environment of your body,such as fluctuations in acidity/alkalinity, inflammatory changes and mood, to name just a few. It is bewildering to contemplate just how the nervous system achieves all this. By looking at individual neurotransmitters, we can begin to appreciate the minute yet utterly powerful actions of these chemical messengers.

Acetylcholine (ACh) was the first neurotransmitter ever discovered. Out of all neurotransmitters, ACh is probably the most far reaching in terms of effect. It is involved in nerve impulse transmissions in both sympathetic (stress) and parasympathetic (rest/digest) responses throughout every cell and organ in the body.

Its name simply comes from its chemical structure; ‘acetyl’ is a very small chemical species that contains only a little carbon and hydrogen (C3H6), while choline is more like a lipid (fat). We make our own ACh; we do not need to obtain it from food or supplements. Without ACh, our nervous system would simply cease to function. Diseases like Alzheimer’s disease show marked
reduction in ACh concentrations in specific areas of the brain, while Myasthenia gravis is an autoimmune disease affecting the role of ACh in muscle contraction.

Generally not appreciated as a neutransmitter, histamine is well known for its role in allergy and inflammation. However, its role as a neurotransmitter is essential for preventing sleep, keeping us awake (hence the reason why antihistamines generally make us drowsy). It is synthesized in the body via the amino acid, histidine. Again, histidine is readily supplied by most foods in our diet. Many people on the path to healing allergies and food intolerances are eating a low histamine diet to reduce the occurrence of hives, rashes, sneezing and gut pain. However, the strong link between histamine, the brain and nervous system mean that migraines, drowsiness and moodiness are reported as alleviated for many people adopting low histamine diets.
Dopamine is synthesized via several steps that begin with an essential component of our diet, the amino acid phenylalanine. Phenylalanine is firstly converted to tyrosine (in the liver). After several steps, tyrosine is then converted to Dopamine. Interestingly, this process relies heavily on vitamin B6, and would not occur if we did not consume any phenylalanine in the diet. Luckily, phenylalanine is found in most foods, regardless of the diet we follow.

Dopamine is rather versatile. It has a role to play in movement, memory, mood, pleasure/reward, behavior, sleep, learning and attention. Both excessive and insufficient levels of dopamine are implicated in ill health, spanning both physical and mental health conditions.

Conditions associated with abnormalities of dopamine function include Parkinson’s disease (dopamine deficiency) and possibly Schizophrenia (overstimulation of specific dopamine receptors in the brain). Low dopamine activity has also been linked to addiction, ADHD, risk-taking and strong reward/pleasure-seeking behaviors.

Adrenaline and noradrenaline
Adrenaline (epinephrine) is both a neurotransmitter and a hormone. It is synthesized in the adrenal glands and some neurons. It is actually synthesized from dopamine; hence it follows the same pathway as dopamine production, with a few extra chemical reactions to finally produce adrenaline. It is an excitatory neurotransmitter, with low levels being associated with fatigue, inability to focus, poor attention span, difficulty sleeping and difficulty losing weight. Interestingly, these are often symptoms described by individuals under high stress, with adrenal exhaustion.

Noradrenaline (norepinephrine) is related to adrenaline, but is farmore widespread throughout the body. Like adrenaline, it is excitatory; thus it increases wakefulness, alertness and vigilance. It is paramount during stress, the ‘fight or flight’ response allowing us to focus and retrieve memories. It also increases restlessness and can promote anxiety. Generally, high levels are associated with prolonged stress and ADHD.

Serotonin is regularly referred to by its more chemical name, 5-hydroxytryptamine (5-HT). Serotonin is another of our neurotransmitters derived from an amino acid; in this case, tryptophan. Tryptophan is an essential amino acid; we must supply it to our body via our diet.

90% of serotonin in the human body is located in the gastrointestinal (GI) tract, making this neurotransmitter extremely interesting to medical science. Not only does serotonin regulate motility of the GI tract, it is involved in central nervous system functions such as sleep, appetite, mood, learning and memory. Clinically, abnormalities of serotonin function have been linked with an array of health conditions from over-eating and obesity, through to major depression, obsessive-compulsive disorder (OCD) and anxiety. The emerging scientific evidence linking gut health with mental health is due in part to the activity of serotonin in these two anatomically separate, yet biochemically linked organs.

Glycine is an amino acid neurotransmitter, which is non-essential in the diet. It can be synthesized in the human liver, but this relies on the adequate supply of activated vitamin B9 from our diet. Glycine is simple in its molecular structure (it is the smallest amino acid). It functions primarily in the spinal cord, having inhibitory
effects on information that co-ordinates movement, vision and hearing. It assists in reducing hyper excitability of the nervous system, with some studies linking low glycine levels with hyperactivity, schizophrenia, bipolar disorder and epilepsy.

Glutamate is the major excitatory neurotransmitter of our nervous system. It links in with pathways for many of the other neurotransmitters, and receptors responding to glutamate are located throughout our brain and spinal cord. Glutamate comes from the amino acid, glutamic acid (it is the base pair of this acid). Humans synthesize glutamate within our nerve cells from a range of precursor substances, including glutamine. As glutamate is excitatory in its role, it’s responsible for cognition, memory and learning. In diseases involving glutamate, this neurotransmitter can accumulate outside of nerve cells, continually stimulating them and leading to excitotoxicity. This can eventually lead to destruction of functional nerve tissue. Examples include Alzheimer’s disease and the cascade of destruction that follows a stroke.

Gamma-amino butyric acid (GABA)
GABA is the inhibitory neurotransmitter partner of the excitatory glutamate. These two neurotransmitters work together to balance brain activity. While it may sound negative to have inhibitory effects on the nervous system, GABA is vital for the sedation that precedes sleep, and it is imperative for relaxation. Humans synthesize GABA in the brain from its excitatory partner, glutamate. Again, vitamin B6 is required for this biochemical conversion. Supplements of GABA do exist, mainly for the treatment of hyperactivity and poor sleep. However, there is no evidence GABA taken orally will cross the blood brain barrier to reach GABA target nerve cells in the brain. Additionally, the human body is very proficient at GABA regulation, meaning supplementation is likely ineffective.

Takeaway points

Inhibitory (Calming) NeurotransmittersGABA
Acetylcholine (both)
Dopamine (both)
Excitatory (Stimulating)NeurotransmittersDopamine (both)
Acetylcholine (both)

Written by Annalies Corse, ND.

1 Waymire, J. Acetylcholine Neurotransmission. Neuroscience Online. Department of Neurobiology and Anatomy, The UT Medical School at Houston. Available at: http://neuroscience.uth.tmc.edu/s1/chapter11.html
2 Glutamate-Related Biomarkers in Drug Development for Disorders of the Nervous System: Workshop Summary. Available at: http://www.ncbi.nlm.nih.gov/books/NBK62187/
3 Lopez-Corcuera, B. (2001). Glycine neurotransmitter transporters: an update. Molecular Membrane Biology. 18(1): 13-20. Available at: http://www.ncbi.nlm.nih.gov/pubmed/11396606
4 University of Bristol. Serotonin. A molecule of happiness. Available at: http://www.chm.bris.ac.uk/motm/serotonin/home1.htm
5 Maintz, L., Novak, N. (2007). Histamine and Histamine Intolerance. The American Journal of Clinical Nutrition. Available at: http://ajcn.nutrition.org/content/85/5/1185.longGoldstein, D. (2010). Adrenaline and Noradrenaline. Citable Reviews in the Life Sciences. Available at: http://www.els.net/WileyCDA/ElsArticle/refId-a0001401.html

The Paleo Diet: Fact or Fad?


Humans are social creatures, we love sharing our time, opinions and ideas with others. We enjoy looking to others for inspiration, and we like to experiment with everything from how we dress, what we study to what we eat and hobbies we enjoy. Inevitably, this leads to the phenomenon of the fad, that social construct which seemingly appears from nowhere, but is suddenly everywhere. Whilst fads are obvious when it comes to fashion, they are very pervasive when it comes to food, diet and nutrition. Every year could be crowned with the title of a particular diet. In 2015, it was most certainly the Paleo Diet.

When it comes to fashion, fads are not particularly harmful (unless you consider 12-inch high heels and the man bun as dangerous to health). Fashion fads do not need to be based on fact; they are simply creative expressions that people find attractive. On the other hand, diet fads (whether you like it or not) are inextricably linked to science, evidence and fact. Some diet fads have no scientific basis whatsoever; others do. As a consumer, you probably do not want to trawl through medical and scientific journals to back up your decision to try a diet. You would rather read a recipe book or a new diet book showing you how to eat according to this new diet straight away. Who wouldn’t? These books are much prettier to look at, easier to understand and relaxing to read than any medical journal. Let’s take a look at the Paleo diet, and examine some of the evidence behind 2015’s most popular diet.

Well before the term paleo started appearing in the scientific literature of the 80’s, other clinicians and scientists studied the effects of the typical western diet, comparing them to primitive diets and their effects on health. The most notable of these include Nutrition and Physical Degeneration, A Comparison of Primitive and Modern Diets and Their Effects by Dr Weston Price (1939), Primitive Man and His Food by Arnold DeVries (1952), The Stone Age Diet by Walter Voegtlin (1975) and Boyd Eaton’s The Paleolithic Prescription (1988).

Fast-forward to 1991, and medical journals started to accumulate research supporting that how our Paleolithic ancestors not only ate, but also lived should form the foundations of how to treat modern disease. Modern epidemics of metabolic syndrome, cardiovascular disease, cancer and inflammatory diseases (the non-infectious diseases) were clearly the plagues of modern man, with diet firmlyplaced at the center of the debate. The idea of lifestyle medicine was born.

Evidence for the Paleo diet mainly comes in the form of anecdotal evidence. This is your own, personal experience. If you lost weight, improved your sleep, cured your acne, or were able to safely discontinue your cholesterol or diabetes medications on a Paleo diet, science wont really be interested. In science, we need studies in animals, human tissues, large populations or controlled trials to be sure that a hypothesis (theory) has been tested extensively, and accurately. Since 2007, studies have started to accumulate, looking specifically at the paleo diet. Their greatest success appears to be in attaining a health body weight and improving health in those with metabolic syndrome (obesity, elevated fasting blood glucose, elevated blood triglycerides and high blood pressure). Evidence in other conditions, such as dementia, Autism, cancer and autoimmune disease is ongoing.

Counter evidence against the principles of the Paleo diet (particularly that is was devoid of dairy) has been published since 2014, with dairy proteins having been isolated from the dentalcalculus (plaque) in ancient dental fossils. Some anthropologists are also reminding us that there would be no one type of paleo diet, as our ancestors would have had a very limited diet, which would have varied depending on where they lived in the world. Additionally, their ancient fruits and vegetables would have been virtually unrecognizable to us and nothing like our modern edible plant based foods.

There is no denying that the Paleo diet is indeed a nutritional fad. It shows all the hallmarks of a modern trend including blogs, Instagram feeds, celebrity endorsements, recipe books, treats and snacks all devoted to this way of eating. Despite the fact that it’s fashionable at present, the Paleo diet is not in the same category as other harmful nutritional fads of years gone by, such as the cabbage soup diet, the lemon detox diet or the baby food diet. There is some scientific evidence to support the health claims of the Paleo diet, but will that be enough for us to remain loyal followers of this nutritional paradigm? Modern man loves nothing more than looking out for the next big thing. Only time will tell if the Paleo diet will be remembered as a trend, or the diet that saved its modern followers from a future of chronic disease.

1 Alberti KG, Eckel RH, Grundy SM, et al. Harmonizing themetabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, andBlood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; andInternational Association for the Study of Obesity. Circulation. 2009; 120(16):1640-5.

2 Eaton, S. and Konner, M (1985) Paleolithic Nutrition. A consideration of its nature and current implications. New England Journal of Medicine. 312(5): 283-9.
3 Huang PL. A comprehensive definition for metabolic syndrome. Dis Model Mech. 2009; 2(5-6): 231-7.
– See more at: http://thefitbusymum.com.au/the-paleo-diet-fact-or-fad#sthash.g8ZxcY3A.dpuf

Image credit: Centre for Dance Nutrition