How Sugar Affects the Beneficial Bacteria in Your Gut

According to the US Department of Health and Human Services, we consume roughly 152 pounds of sugar per person a year, up from 2 pounds a year two hundred years ago (1). That 152 pounds of sugar a year – which equals 3 pounds per week – puts quite a strain not just on our bodies, but on the beneficial bacteria we carry and which do so much for our health. Here’s how and why.

What Our Microbiome Does for Us

We contain trillions of bacteria. In fact, there are more bacterial cells in your body than human cells. There are roughly 40 trillion bacterial cells in your body and only 30 trillion human cells. That means you are more bacteria than human (2, 3). What’s more, there are up to 1,000 species of bacteria in the human gut microbiome, and each of them plays a different role in your body.  While some bacteria are associated with disease, most of our bacteria are actually extremely important for our immune system, heart, weight and many other aspects of health.

Digestive health. A healthy gut microbiome controls gut health by communicating with the intestinal cells, digesting certain foods and preventing disease-causing bacteria from sticking to the intestinal walls. The microbiome may play a role in intestinal diseases like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) when the balance of our beneficial bacteria becomes unbalanced or compromised.

Weight. An imbalance of healthy and unhealthy microbes is sometimes called gut dysbiosis, and it may contribute to weight gain (4). Several well-known studies have shown that the gut microbiome differed completely between identical twins, one of whom was obese and one of whom was healthy. This demonstrated that differences in the microbiome were not genetic.

Interestingly, in one study, when the microbiome from the obese twin was transferred to mice, they gained more weight those that had received the microbiome of the lean twin, despite both groups eating the same diet (5).

Neurological health. Studies show that the balance of bacteria in the gut microbiome may affect your emotions and the way your brain processes information from your senses, like sights, sounds, flavors, or textures. Scientists suspect that changes in that balance may play a role in diseases like autism spectrum disorder, anxiety, and depression, as well as chronic pain.

Certain species of bacteria can help produce chemicals in the brain called neurotransmitters. For example, serotonin is an antidepressant neurotransmitter that’s mostly made in the gut (6, 7). Additionally, the gut is physically connected to the brain through millions of nerves. Therefore, the gut microbiome may also affect brain health by helping control the messages that are sent to the brain through these nerves (8, 9).

A number of studies have shown that people with various psychological disorders have different species of bacteria in their guts, compared to healthy people. For instance, a recent study highlighted a connection between anxiety and the absence of certain healthy gut microbes. Another found that certain bacteria are altered in people with PTSD. This suggests that the gut microbiome may affect brain health (10, 11).

A small number of studies have also shown that certain probiotics can improve symptoms of depression and other mental health disorders (12, 13).

Immune system health. The microbiota plays a fundamental role in the training and function of the our immune system. In return, the immune system has largely evolved as a means to maintain the symbiotic relationship between us as hosts with these highly diverse and evolving microbes. When operating optimally the microbiota allows for the protective responses to pathogens and tolerance to innocuous antigens. However, in high-income countries overuse of antibiotics and changes in diet have cultivated microbiota that lack the resilience and diversity required to establish balanced immune responses. Researchers suspect this accounts for some of the dramatic rise in autoimmune and inflammatory disorders in parts of the world where our symbiotic relationship with the microbiota has been the most affected.

Metabolic processes. The gut microbiome also may help control blood sugar, which could affect the risk of type 1 and 2 diabetes. One recent study examined 33 infants who had a genetically high risk of developing type 1 diabetes. It found that the diversity of the microbiome dropped suddenly before the onset of type 1 diabetes. It also found that levels of a number of unhealthy bacterial species increased just before the onset of type 1 diabetes (14).

Keeps harmful bacteria in check. Studies have found that if you have too much of a certain kind of bad bacteria in your gut microbiome, you’re more likely to have:

  • Crohn’s disease
  • Ulcerative colitis
  • Irritable bowel syndrome (IBS)

Bacteria multiply rapidly. Healthy, diverse colonies of beneficial bacteria manage the balance of our microbiome, preventing harmful bacteria from taking root or helpful bacteria from expanding to a point where they become detrimental to our health.

Sugar vs Our Microbiome

We all know sugar will rot our teeth but sugar consumption is related to a host of modern, diet-related ills including obesity, diabetes, many cancers, metabolic syndrome, Alzheimer’s, and so much more. Sugar makes up a great portion of the highly processed standard American diet wreaking so much havoc on our health. There are three main reasons for sugar becoming such a major ingredient: sugar hooks us, sugar gives texture and color to many food products, and sugar makes a great preservative.

This preservative effect is fairly alarming. After all, sugar is a major preservative due to its antimicrobial properties. There are several ways in which sugar inhibits microbial growth. The most notable is simple osmosis, or dehydration. Sugar’s other antimicrobial mechanisms include interference with a microbe’s enzyme activity and weakening the molecular structure of its DNA. Sugar may also provide an indirect form of preservation by serving to accelerate accumulation of antimicrobial compounds from the growth of certain other organisms.

While sugar’s antimicrobial properties are great news for food manufacturers thanks to longer shelf lives, that’s bad news for our microbiome and especially the beneficial bacteria colonizing our digestive tracts. Here’s what happens thanks to our high sugar diets:

1. Suppression of certain strains of beneficial bacteria due to the antibacterial property of sugar on those species while paradoxically feeding certain strains of harmful bacteria. Additionally, sugar can alter the ability of beneficial bacteria to produce the nutrients useful for maintaining and regulating health.

2. Because our diets are heavily processed, high in sugar, and lack sufficient fiber and other nutrients needed for survival, beneficial bacteria cannot thrive. This allows hardier, harmful bacteria to recolonize the intestines or expand unchecked.

3. Low numbers of beneficial bacteria means they cannot produce the necessary enzymes and nutrients we need for our digestive system, neurological system, metabolism and immune system, increasing our risks for poor health across a sea of areas.

How to Nourish Our Microbiome

Our modern diets, flying in the face of our evolutionary history, are highly processed – packed with sugar, refined carbs, and preservatives and additives made in labs using a host of chemicals. Our beneficial bacteria can’t live on this sort of diet. They need our older diet, aka the whole foods diet that we evolved on (15).

Beneficial bacteria love fiber, the kind found in real foods like beans, fruit and vegetables, whole grains, nuts and seeds. They also love the pectin in fruit and the inulin in garlic, leeks and onions. None of this will be found in your fiber supplement. You need to eat real food to reap the true benefits.

Bottom line: whole foods come packed with fiber, vitamins and minerals that our good bacteria need to thrive, to produce essential nutrients for many of our bodily functions, and to keep harmful bacteria in check.

Being a Good Host

Our microbiome when healthy keeps us in good health too. When we feed it sugar, we are actively harming our beneficial bacteria in a number of ways, and the effects don’t take long to manifest either. We all know that sugar isn’t good for us. If we want to live in optimal heath, full of energy and vitality, we should start by limiting our sugar and processed food consumption while upping our whole foods intake until it makes up an overwhelming majority of the foods we eat. When we do this, not only does our overall health improve, but so does the health of our beneficial bacteria which do so much for us.

Like this article? Please share it so that others can learn these health secrets and start living their best lives now.



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