Last week we spoke about the range of micro-organisms making up the gut microflora or micro-biome. In a healthy person up to 1000 different micro-organisms are represented. But as we mentioned, this can change depending upon diet, lifestyle and exposure to antibiotics and toxins. With chronic fibre deficiency, the microbiome can change irreversibly.
This week we discuss the concepts of pre-biotics, probiotics and the new term, post-biotics.
Pre-biotics are the food sources for the microbiome. They consist mostly of carbohydrates and fibres that are not able to be metabolised by the body, but can be utilised by the microflora. In the past we thought of fibre as either water soluble (like the gelatinous substance we find when we cook oats) or non-soluble fibre roughage as we find in wheat bran. However further studies have shown more than 30 different types of fibre – and all feed different bacterial species. In fact even whether foods are raw or cooked presents differing forms of fibre.
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Pro-biotics are live bacteria and other micro-organisms that thrive in the healthy gut. It is common for doctors to give probiotics to their patients after antibiotic treatments or in cases of chronic diarrhoea to try to restore a normal micro-flora. However most of these supplements have only a narrow diversity of species and limited efficacy. Another natural source is fermented foods such as sauerkraut, miso, tempeh, kimchi, cultured buttermilk and yoghurt and kombucha.
In traditional societies in Africa fermented sorghum porridge or sour milk are commonly used. (In Lesotho a common beverage is motoho, a thin fermented porridge which I disliked but was often pressured to take for social etiquette reasons in the course of my community health activities!)
Post-biotics are metabolites of the bacteria in the intestine that have beneficial activities on the body. These include short-chain fatty acids (SCFAs) such as propionate, butyrate and acetate (vinegar). I remember learning about these substances way back in physiology class in 2nd year medicine, but in those days their role in health was relatively unknown. We will discuss these in more detail. Here is a scientific report of research showing the benefits of a high fibre diet in managing viral infections, and particularly suppressing the cytokine storm – one of the really dangerous consequences of Covid-19 infections.
Much of the following information is found on online videos with Dr Will Bulsiewicz. As mentioned earlier in this series, he has recently released the book “Fiber-fueled”, which is based on over 600 studies referenced in his book. I am still waiting for my copy, but this is such a topical subject, I want to share as much as we can with you.
This is particularly relevant in our Covid-19 pandemic, as a healthy gut means a better immune system to protect you against the ravages of this frightening disease.
Up to 97% of Americans, and most probably most Westernised societies, are starved of fibre. This is the greatest nutritional deficiency in our modern age. Recommended daily fibre intake for women is 25 gms, and for men 38 gms. Thankfully nutritional labels on all packaged foods we buy report the fibre contents of the foods we eat. It would be helpful for you to take the time for a day or two to work out how much fibre you ingest. You might find you need to make some healthful changes. Note that no animal product has dietary fibre. There is no fibre in red meat, or white meat, or dairy products or eggs. (This is one of the big problems with a Banting or ketogenic diet). Most processed foods have had fibre removed. Thus white bread and pastries have very little fibre.
Popular beverages have no fibre – even fruit juices -perhaps minimal amounts in cloudy juices. Smoothies still retain the fibre, but juicing removes most of the fibre.
Dr B says there are over 400,000 plant species in our world. Evidently there are 300,000 types of edible plants. Each plant has its own unique fibre. The more diverse our diet, with a rainbow of colours and groups of plants, the better we can feed and sustain a diverse microflora. Thus it is helpful to have plenty of fruits, vegetables of all colours, whole grains, and legumes like beans, peas and lentils, with some seeds and nuts.
What is the role of probiotics? We inherit our microflora from our mothers from even before we are born, but then the birthing and breast-feeding provides the widest range of healthy, protective microflora for our well-being. This is then modified over the next few years by our environment and our diet.
As mentioned before, taking antibiotics (lifesaving at times, but often abused unnecessarily for viral infections) can significantly disturb the homeostasis of our microbiome. A diet deficient in fibre is also conducive to dysbiosis (imbalance in our homeostasis).
Exposure to antibiotics in our food – poultry, milk and meat – from agricultural husbandry practices, also can affect our microbiome. Certain environmental toxins and agricultural chemicals may also affect our microflora. But by far the most important determinant in a healthy microbiome is our diet.
Post-biotics is such an important topic that I will rather keep that for next week. As an introduction short-chain fatty acids (SCFAs) such as butyrate have been found to have profound effects on the integrity of the gut permeability, on the immune system, and even on the integrity of the blood-brain barrier.
Here is a quotation from one paper: “SCFAs have been shown to alter chemotaxis and phagocytosis (the ability of immune cells to move to areas of infection, and eat up bacteria); induce reactive oxygen species (chemicals that kill bacteria and abnormal cells); change cell proliferation (growth and multiplication) and function; have anti-inflammatory, anti-tumorigenic (anticancer), and antimicrobial effects; and alter gut integrity.”
Once again I am just amazed at the complexity and wonderful design of the human organism – we are truly “fearfully and wonderfully made”. Psalms 139:14.
We will chat again next week. In the mean time, make sure you are increasing the diversity of your gut microbiome by ingesting a wide variety of plants and their fibres to boost your immunity.
Dave Glass
Dr David Glass graduated from UCT in 1975. He spent the next 12 years working at a mission hospital in Lesotho, where much of his work involved health education and interventions to improve health, aside from the normal busy clinical work of an under-resourced mission hospital.
He returned to UCT in 1990 to specialise in obstetrics/gynaecology and then moved to the South Coast where he had the privilege of, amongst other things, ushering 7000 babies into the world. He no longer delivers babies but is still very clinically active in gynaecology.
An old passion, preventive health care, has now replaced the obstetrics side of his work. He is eager to share insights he has gathered over the years on how to prevent and reverse so many of the modern scourges of lifestyle – obesity, diabetes, ischaemic heart disease, high blood pressure, arthritis, common cancers, etc.
He is a family man, with a supportive wife, and two grown children, and four beautiful grandchildren. His hobbies include walking, cycling, vegetable gardening, bird-watching, travelling and writing. He is active in community health outreach and deeply involved in church activities. He enjoys teaching and sharing information.
