1. Not Eating a Diverse Range of Foods
Generally, a rich and diverse gut flora is considered to be a healthy one.
A lack of diversity within the gut bacteria limits recovery from harmful influences, such as infection or antibiotics.
A diet consisting of a wide variety of whole foods, such as fruits, vegetables and whole grains, can lead to a more diverse gut flora. In fact, changing up your diet can alter your gut flora profile after only a few days.
This is because the food you eat provides nutrients that help bacteria grow. A diet rich in whole foods provides your gut with a variety of nutrients that help promote the growth of different types of bacteria, resulting in a more diverse gut flora.
Unfortunately, over the past 50 years, much of the diversity in the Western diet has been lost. Today, 75% of the world’s food supply comes from only 12 plants and five animal species.
Interestingly, studies show that those living in rural regions of Africa and South America have a more diverse gut flora than those living in the US and Europe.
Their diets are generally unaffected by the Western world and are rich in fiber and a variety of plant protein sources.
2. Lack of Prebiotics in the Diet
Prebiotics are a type of fiber that passes through the body undigested and promotes the growth and activity of friendly gut bacteria.
Many foods, including fruits, vegetables and whole grains, naturally contain prebiotic fiber.
A lack of them in the diet may be harmful to your overall digestive health.
Foods high in prebiotics include:
- Lentils, chickpeas and beans
- Jerusalem artichokes
One study in 30 obese women found that taking a daily prebiotic supplement for three months promoted the growth of the healthy bacteria Bifidobacterium and Faecalibacterium.
Prebiotic fiber supplements also promote the production of short-chain fatty acids.
These fatty acids are the main nutrient source for the cells in your colon. They can be absorbed into your blood, where they promote metabolic and digestive health, reduce inflammation and can reduce the risk of colorectal cancer.
Moreover, foods rich in prebiotic fiber may play a role in reducing insulin and cholesterol levels.
3. Drinking Too Much Alcohol
Alcohol is addictive, highly toxic and can have harmful physical and mental effects when consumed in large amounts.
In terms of gut health, chronic alcohol consumption can cause serious problems, including dysbiosis.
One study examined the gut flora of 41 alcoholics and compared them to 10 healthy individuals who consumed little-to-no alcohol. Dysbiosis was present in 27% of the alcoholic population, but it was not present in any of the healthy individuals.
Another study compared the effects of three different types of alcohol on gut health.
For 20 days, each individual consumed 9.2 ounces (272 ml) of red wine, the same amount of de-alcoholized red wine or 3.4 ounces (100 ml) of gin each day.
Gin decreased the number of beneficial gut bacteria, whereas red wine actually increased the abundance of bacteria known to promote gut health and decreased the number of harmful gut bacteria like Clostridium.
The beneficial effect of moderate red wine consumption on gut bacteria appears to be due to its polyphenol content.
Polyphenols are plant compounds that escape digestion and are broken down by gut bacteria. They may also help reduce blood pressure and improve cholesterol.
4. Antibiotic Use
Antibiotics are important medicines used to treat infections and diseases caused by bacteria, such as urinary tract infections and strep throat.
They work by either killing bacteria or preventing them from multiplying and have saved millions of lives over the past 80 years.
However, one of their drawbacks is that they affect both good and bad bacteria. In fact, even a single antibiotic treatment can lead to harmful changes in the composition and diversity of the gut flora.
Antibiotics usually cause a short-term decline in beneficial bacteria, such as Bifidobacteria and Lactobacilli, and can temporarily increase harmful bacteria like Clostridium.
However, antibiotics can also lead to long-term alterations in the gut flora. After completing a dose of antibiotics, most bacteria return after 1–4 weeks, but their numbers often don’t return to previous levels.
In fact, one study found that a single dose of antibiotics reduced the diversity of Bacteroides, one of the most dominant bacterial groups, and increased the number of resistant strains. These effects remained for up to two years.
5. Lack of Regular Physical Activity
Physical activity is simply defined as any movement of the body that burns energy.
Walking, gardening, swimming and cycling are all examples of physical activity.
Being physically active has a number of health benefits, including weight loss, lower stress levels and a reduced risk of chronic disease.
What’s more, recent studies suggest that physical activity may also alter the gut bacteria, improving gut health.
Higher fitness levels have been associated with a greater abundance of butyrate, a short-chain fatty acid that’s important for overall health, and butyrate-producing bacteria.
One study found that professional rugby players had a more diverse gut flora and twice the number of bacterial families, compared to the control groups matched for body size, age and gender.
Moreover, athletes had higher levels of Akkermansia, a bacteria shown to play an important role in metabolic health and the prevention of obesity.
Similar results have been reported in women.
A study compared the gut flora of 19 physically active women to 21 non-active women.
Active women had a higher abundance of health-promoting bacteria, including Bifidobacterium and Akkermansia, suggesting that regular physical activity, even at low-to-moderate intensities, can be beneficial.
6. Cigarette Smoking
Tobacco smoke is made up of thousands of chemicals, 70 of which can cause cancer.
Smoking causes harm to nearly every organ in the body and raises the risk of heart disease, stroke and lung cancer.
Cigarette smoking is also one of the most important environmental risk factors for inflammatory bowel disease, a disease characterized by ongoing inflammation of the digestive tract.
Furthermore, smokers are twice as likely to have Crohn’s disease, a common type of inflammatory bowel disease, compared to non-smokers.
In one study, smoking cessation increased gut flora diversity, which is a marker of a healthy gut.
7. Not Getting Enough Sleep
Getting good sleep is very important for overall health.
Studies show that sleep deprivation is linked to many diseases, including obesity and heart disease.
Sleep is so important that your body has its own time-keeping clock, known as your circadian rhythm.
It’s a 24-hour internal clock that affects your brain, body and hormones. It can keep you alert and awake, but it can also tell your body when it’s time to sleep.
It appears that the gut also follows a daily circadian-like rhythm. Disrupting your body clock through a lack of sleep, shift work and eating late at night may have harmful effects on your gut bacteria.
A 2016 study was the first to explore the effects of short-term sleep deprivation on the composition of gut flora.
The study compared the effects of two nights of sleep deprivation (about 4 hours per night) versus two nights of normal sleep duration (8.5 hours) in nine men.
Two days of sleep deprivation caused subtle changes to the gut flora and increased the abundance of bacteria associated with weight gain, obesity, type 2 diabetes and fat metabolism.
Nevertheless, sleep deprivation’s effects on gut bacteria is a new area of research. Further studies are required to determine the impact of sleep loss and poor sleep quality on gut health.
8. Too Much Stress
Being healthy isn’t only about diet, physical activity and adequate sleep.
High stress levels can also have harmful effects on the body. In the gut, stress can increase sensitivity, reduce blood flow and alter the gut bacteria.
Studies in mice have shown that different types of stress, such as isolation, crowding and heat stress, can reduce gut flora diversity and alter gut profiles.
Stress exposure in mice also affects bacterial populations, causing an increase in potentially harmful bacteria like Clostridium and reducing beneficial populations of bacteria like Lactobacillus.
One study in humans looked at the effect of stress on the composition of gut bacteria in 23 college students.
The composition of gut bacteria was analyzed at the beginning of the semester and at the end of the semester during final examinations.
The high stress associated with final exams caused a reduction in friendly bacteria, including Lactobacilli.
While promising, research on the relationship between stress and gut flora is fairly new, and human studies are currently limited.