Our gut plays host to over one hundred trillion microbes, more than the number of cells that make up our entire bodies. This microbiome plays a crucial role in digestion and absorption of food and immune-system construction, but recent research has found that gut bacteria can affect your health in a startling variety of ways.
Gut bacteria affects body weight, fat, and good cholesterol
Because of its important role in digestion and absorption, it makes sense that gut bacteria can affect your health in terms of weight, but new research published in Circulation Research, an American Heart Association journal, has also found that gut bacteria can affect your cardiovascular health. Only 30% of the gut microbiome has been mapped, and researchers in the study were happy to contribute further to that percentage with new evidence that the gut biome goes way beyond digestion.
Jingyuan Fu, Ph.D., study lead author and associate professor of genetics at University Medical Center Groningen in the Netherlands, pointed out that the health of the gut biome can now be a good predictor of cardiovascular health, saying:
“Our study provides new evidence that microbes in the gut are strongly linked to the blood level of HDL (good cholesterol) and triglycerides and may be added as a new risk factor for abnormal blood lipids, in addition to age, gender, BMI and genetics.”
Gut bacteria affects the joints
Because gut bacteria plays a role in developing the immune system, it seems logical to make the connection between autoimmune disorders and problems in the gut. Jose Scher, a rheumatologist at New York University, made this connection and conducted two studies to see if this connection was verifiable. He found that abnormalities in the gut bacteria did, indeed affect the health of the joints and contribute to autoimmune disorders.
- Rheumatoid arthritis: In this study, Scher found that people with rheumatoid arthritis were more likely to have Prevotella copriin their gut than those without the disease
- Psoriatic arthritis: Scher also found that people with this type of autoimmune disorder had lower levels of certain types of healthy gut bacteria
Researchers are continuing to look at the rise of autoimmune disorders in the developed world, possibly as a consequence of increased antibiotic and anti-bacterial soap use. Both of these substances alter the environment of the gut, destroying not only the bad bacteria but also the good bacteria. This change affects not only how the gut functions for digestion but also how it works to support the immune system in the body.
New York University microbiologist Martin Blaser believes widespread overuse of antibiotics is largely to blame for our weakened gut bacteria, saying:
“Our microbiome has changed significantly over the past century, and especially over the past 50 years. We’re losing microbes with each generation; they are going extinct. These changes have consequences.”
In Blaser’s own research, these consequences include a lack of Helicobacter pylori, a crucial gut bacteria that is present in only 6% of children in the U.S. This lack has been associated with an increased risk of asthma, which is susceptibility of the lungs to be affected by airborne irritants. The rates of asthma in the U.S. have risen almost 28% in the last 30 years. These rates are nearly non-existent in developing countries where antibiotic use is rare.
Gut bacteria affects brain function
It makes sense that gut bacteria would affect the health of the immune system, but what about brain function? New research is linking brain function and conditions such as autism with gut health (or lack thereof). Many researchers have noted that people with autism often have a gastrointestinal issue as well (e.g., gluten sensitivity, food allergies, and digestive troubles).
A study from the California Institute of Technology (CIT) focused on a common species of gut bacteria called Bacteroides fragilis. In children with autism, B. fragilis is found in smaller amounts. Researchers fed laboratory mice this human bacteria and observed as the mice displayed fewer symptoms of autism. They appeared less anxious and interacted more with their fellow mice.
Researchers in this study have identified one possible explanation for this change. B. fragilis seems to ameliorate the autism-like symptoms seemingly caused by 4-ethylphenylsulphate, or 4EPS, produced by gut bacteria and present at levels 40 times higher in mice with autism symptoms than those mice without symptoms. Microbiologist Sarkis Mazmanian from CIT believes this breakthrough research could indicate that for some people, changing the gut microbiome could become a viable treatment option for autism.
Other research has found similar links between certain gut bacteria and decreased symptoms of depression and anxiety. One study compared the effects of Lexapro, a popular antidepressant, and bifidobacterium, finding that both reduced levels of stress hormone and increased perseverant behaviors in mice. This research is still in its infancy, but more researchers are moving to human trials as evidence points to positive results in neurological and mood disorders by altering gut bacteria.
So how does gut bacteria affect your health, and what are the implications for the various conditions it can treat? Imagine being able to skip the prescription pain medications and invasive treatments to see improvements in rheumatoid arthritis simply by eating a Mediterranean diet or a vegan diet. With this research you may be able to improve mood and relieve the symptoms of depression and anxiety by taking a probiotic or eating a daily cup of bacteria-rich yogurt. Gut bacteria is still an emerging area of promising research for all kinds of conditions, but with positive results more time, attention, and research dollars may increase the speed of potential discoveries and treatments.