CHAPTER 1
THE HUMAN GUT MICROBIOME: OUR SANCTUARY OF HEALTH
"All disease begins in the gut." Hippocrates The Father of Modern Medicine 350BC
The Power of Balanced Gut Flora on Weight & Health
If you think you exist alone in this universe, think again. As you may have discovered, we share our bodies with trillions of microorganisms which are of crucial importance to a well-balanced gut microbiome when it comes to keeping us healthy and at a manageable weight.
In this chapter, let's look more closely at how this plays out.
Our gut microbiome is akin to a garden – our inner garden of health and wellness. If we have more flowers than weeds, we enjoy great health. However, when the weeds take over, diseases (and medical bills) begin to crop up.
The microbiome is an ecosystem dependent on the presence of more good critters than bad. When bad bacteria are in control, the immune system cannot do its job and destroy disease-causing microbes. This results in major illnesses like diabetes, heart disease, metabolic syndrome, autism, and other brain disorders. Functional and behavioral disorders are implicated, as well, these including such afflictions as headaches, fatigue, anxiety, depression, acne, eczema, and frequent colds and infections.
Whether all of these conditions are a cause or an effect of unhealthy gut flora is unclear. However, research does point out that fixing the gut flora brings about improvement in our overall health.
Your Ideal Weight
It is acceptable to align "ideal" weight with "ideal" health.
However, the concept of one's ideal weight is a myth. In truth, our medical knowledge limits us to certain measures that we have devised based on our understanding of what is or isn't ideal. We have not, however, actually come up with an ideal measure in this area. While measures such as BMI and waist-hip ratio are helpful, they are by no means representative of an ideal.
It's not that measures are not important. They are, to some extent. The problem is that people tend to get fixated on a number on the scale. It's far more important to achieve your optimal weight – where you feel healthy, energetic, and active – rather than to keep aiming for that elusive ideal weight based on any given measurement.
Why is the microbiome important for you to maintain a healthy weight?
There are many reasons.
The Microbiome and Our Genes
If you eat an olive and gain a pound, you likely feel like losing weight is impossible because you were born with "fat genes." Yet, are genes equivalent to our destiny? If you inherited so-called fat genes, does this mean obesity is a given? Current research answers with a resounding "no."
Most of our genes are open to lifestyle changes, or, more scientifically stated, we might say that: "Genes can be modified by our neurobiome and our gut microbiome." This means that, even if you have so-called fat genes, obesity is not your destiny. You can fight back against these inherited fat genes by changing your lifestyle, as I propose in this book.
This is a major breakthrough, as it means we canchoose to live a lifestyle that has a proven, positive, genetic impact not only for ourselves, but also for our successors, with whom we share our genetic blueprint.
The most powerful word here is "Choice" – we have the ability to choose to make small, easy and healthy choices each day. As these good choices accumulate, they send new positive messages to our genome (our gene structure) and microbiome (our bacterial hosts) – the two centers of powerful change in every cell. This process of creating small, positive change on a daily basis also causes a beneficial change in the neurobiome – the wiring that forms the control center for our body. When practiced over time, this becomes the new "normal." Our new habit.
Now, doesn't that sound like the "normal" you would like to have? I bet it does.
A recent study from Yale University found that, in a group of 4,765 people with an average age of 72, those who carried a gene variant linked to dementia – but also had positive attitudes about aging – were 50% less likely to develop the disorder than people who carried the gene, but faced aging with more pessimism or fear. This study only offers further support for the power of the choices we make.
Throughout this book, you will learn how to make healthier choices. And, when you do, you will boost your immune system and foster greater gut health. This transformation forms the basis of clear thinking which is due to the powerful impact of the gut-brain connection, about which you'll learn more in Part III of this book.
The Firmicutes: Bacteroides Balance
Countless studies have shown that obese people have higher levels of bad, "chubby" fat-storing bacteria from the phylum Firmicutes, along with less overall diversity in their gut microbial flora, whilst lean people have higher levels of bacteria from the phylum Bacteroidetes. 10 These "chubby" bacteria extract every ounce of energy from the food consumed. This causes you to pile on weight, even if you don't eat more than others. How unfair is that?
In addition to associations with obesity, these bacteria have also been associated with metabolic syndrome and type 2 diabetes.
Gut Bugs and Weight loss connection
A study in the British Journal of Nutrition found that obese women who were given a daily probiotic supplement on top of a calorie-restricted diet to lose weight lost more weight than women who followed the same restricted diet but were given a placebo – in other words, having more good bacteria in the gut helps support lasting weight loss.
Gut Bugs and Appetite Regulation
Your body produces a number of different hormones that affect your appetite, including leptin, ghrelin, and peptide YY (PYY).
Some studies have shown that different bacteria in the gut can affect how much of these hormones are produced and whether you feel hungry or full.
Short-chain fatty acids (SCFA) are chemicals produced when certain species of gut bacteria break down fiber. Prebiotic foods which are broken down into SCFAs can allow for a reduction of appetite and a decrease in weight gain.
Other studies have shown that prebiotics supplements, which contain compounds that are fermented by gut bacteria, can have a similar effect on appetite.
People who ate sixteen grams of prebiotics per day for two weeks had higher levels of hydrogen in their breath. This indicates gut bacterial fermentation, less hunger, and higher levels of the hormones GLP-1 and PYY, which make you feel full.
Important Note: Your gut bacteria can produce chemicals that can help make you feel full. By affecting your appetite, your gut bacteria may play a role in your weight.
Bad Bacteria Munches Away & You Get Fat
Researchers believe that people are more likely to gain weight from "unfriendly" gut bacteria. To start with, these bacteria are prone more to fat storing than fat burning.
They are also more efficient at breaking down food, and this enables the body to absorb more calories.
Sugar Consumption
Our modern diet is replete with sugar. Sugar not only makes us gain weight, but it also feeds the bad bacteria. One of the reasons many of us are always hungry, and especially for sugar, is likely that the bad bacteria in our guts are shouting, "Feed me!"
Food Cravings
Bugs in your gut may influence food cravings. For instance, mice bred in germ-free environments have a greater number of sweet taste receptors in their gut when compared to normal mice. Research has also found that chocolate cravers have microbial breakdown products in their urine that are different from those of people who are indifferent to chocolate – and, yes, those people do exist.
First-Line Defense
The human gut (alongwith it's microbiome) is a gatekeeper between us and the world, and what you may not realize is that it even determines our actual exposure to the environment.
If we were to stretch out the entire inner lining of the gut and spread it on a flat surface, it would cover the area of two tennis courts! Just like with anything else in life, the more we expose this surface to the good stuff, which is healthy, wholesome, food, the better off our health and our weight will be.
Food, drugs, and environmental chemicals must first pass through the gates of cells on the skin, in the gut, and in the airways before a decision is made to let them pass into the bloodstream or not. Additionally, the human microbiome plays a critical role in the maturation and function of our immune system.
The Immune System Resides in the Gut
Eighty percent of our immune system lives within the ecosystem of the gut and affects almost every aspect of how you feel each day. This determines your risk of catching the flu, developing allergies, or even dealing with something as serious as an autoimmune disorder, where the body rages against itself.
The health of your gut microbiome is central to the health of your immune system. When you have more bad critters inhabiting your gut than good ones, the immune system is up in arms and on high alert at all times. This is when it attacks not only foreign harmful bugs, but the body's own cells, causing more inflammation – which, as we'll see later in more detail, is the cause of all evil.
Increasing the Nutritional Value of Food
Evidence is mounting that the make-up of our microbial community influences the nutritional value of food.
How does that work?
Well, it appears that our gut bugs help digest and break down the proteins, carbs, and fatty acids in our foods in order to help us extract its nutrients. Such nutrients include essential vitamins like B, vitamins 12 and 9 (folate), and vitamin K.
Folate keeps our DNA control mechanisms functioning properly; in simple parlance, it keeps your fat genes switched off. Yes, ladies, folate is a very important component in your diet.
Research has in fact shown that, in the obese, the Bifidum species of bacteria which is especially active in producing folate is typically lower. Less Bifidum means less control over your genes and more belly fat.
Protection Against Heart Disease
According to a study in the journal Atherosclerosis, patients with hypertriglyceridemia – a coronary artery disease precursor characterized by elevated triglyceride levels (possibly caused by a rich diet and a sedentary lifestyle) – showed positive results when taking probiotics. After taking a daily probiotic supplement for twelve weeks, their triglyceride levels improved and they saw an additional decrease in risk factors for heart disease.
Protection from Other Diseases
A happy gut is one with much diversity. Hundreds of known bacterial species exist and, the more diversity there is in your microbiome (both in terms of the number of different species and the evenness of those species), the better off your health will be.
Another study in the International Journal of Endocrinology found that those with low bacterial diversity have more overall adiposity (unhealthy fat), insulin resistance, abnormally elevated cholesterol and lipid levels in the blood, and a more pronounced inflammatory phenotype.
Preventing the Growth of Pathogens
Keeping a dense and diverse microbial community will also protect your gut from being colonized by pathogens, as well as minimize the overgrowth of disease-causing organisms according to a study in Nature Immunology. These harmful pathogens –which you can ingest from mishandled food, untreated water, or improper hygiene – can cause mild diseases like food poisoning on to more severe issues like tuberculosis or colitis.
Gut Feelings
When we're anxious, our stomachs twist. When we're in love, we get butterflies in our stomachs. When we're depressed, we lose our appetite or go for those comfort foods we love, which are not necessarily good for us.
Our gut and our emotions are intimately connected.
Why?
An astounding 95 percent of the serotonin in your body, your happy hormone, is made and stored in your gut.
It seems obvious to reason that the composition of your gut microbiota plays a critical role in influencing things such as anxiety, depression, stress, and even autism through our gut-brain axis. In fact, much research is now demonstrating this. For instance, a study in the journal PNAS (Proceedings of National Academy of Sciences)found that, when mice infected with an anxiety-inducing bug were given a strain of probiotics, it not only reduced their levels of stress hormones, but also reduced anxiety- and depression-related behavior.
Such studies have opened doors to the possibilities of using probiotics – now termed "psychobiotics" – to treat neurological disorders such as PTSD, anxiety, and depression. We will talk more about this in Chapter 6.
Brain Health
Our gut microbiota not only make us happy, but these little gut bugs might be affecting our brain directly.
According to researchers at the University College Cork in Ireland, gut bacteria play a role in regulating genes which are considered crucial for proper nerve signal functioning and also for myelin – a crucial insulating sheath required for nerve function. Along these lines, probiotics have been shown to have a therapeutic effect on multiple sclerosis, a condition where the immune system attacks the brain and spinal cord – leading to severe tremors, temporary vision loss, pain, fatigue, and impaired coordination.
Other common diseases like Alzheimer's and Parkinson's may actually start in the gut. For example, in people who have died from Parkinson's disease, scientists have found the same protein clumps that damage dopamine-producing neurons in the gut – as they did in the brain.
The same phenomenon exists in people with Alzheimer's disease.
Plaques and tangles that form in the brains of people with Alzheimer's disease also form in their guts. This means that we may be able to use gut biopsies, which are easier to take than endoscopies, to diagnose and treat such brain conditions before they take hold – an idea being researched currently.
The Foundations of Our Biological Destiny: Gut Bugs and Growing Babies
All of our gut flora are laid out from birth and inherited from our mothers.
Before a baby is born, it is sterile, as no ecosystem has had a chance to develop. However, when a baby goes through the mother's birth canal, the baby is "seeded" with these microbes, thus starting a new ecosystem in a new being. Additionally, the vernix (the natural white coating found on a newborn's skin) is replete with healthy oils and chemicals, providing another immune and microbiome shot.
This process is essential to helping a baby establish a healthy bacterial environment in areas like the skin and the gut. A team of researchers at USCS studied such microbes' metabolic byproducts – molecules in a newborn's poop. They discovered that the guts of newborns with healthy gut flora had a wide variety of chemicals that can reduce inflammation and nourish immune cells called T-regulatory cells, which are crucial in reducing a child's tendency toward allergies.
Researchers from the Norwegian Institute of Public Health in another study also determined that this "seeding" process of the baby's intestine is an extremely delicate process that can be disrupted by medical interventions ... the most common of which is antibiotic administration to the mother or the baby.
IMPORTANT NOTE: The practice of washing babies immediately after birth actually destroys all the good bugs and immunity that have just been acquired on their journey to the outside world.
Caesarean section babies miss out on this "seeding."
Researchers have tried smearing these surgically delivered babies with the vaginal fluids from their mothers in the moments just after birth, though, and the results are astonishing. After tracking the babies and their microbiomes for a month, the researchers, as reported in the journal Nature Medicine, stated that this exercise alone had partly restored normal microbiome development in babies born via C-section in comparison to normally delivered babies.
Childhood Obesity: New epidemic, New Challenges
"The early years are when you give your child a foundation for establishing a proper diet. If kids learn about the importance of eating healthy early in their lives, they will not have to relearn it, as an adult."
