Your gut is host to trillions of tiny microorganisms that play a critical role in how your body processes nutrients from the food you eat and in gut health. Not only do these organisms influence what happens in your intestinal tract, they impact your immune system. Plus, these tiny, beneficial organisms protect your gut against harmful bacteria and viruses that cause food poisoning. This collection of organisms, known as the gut microbiome, is the focus of much research.
Research into the gut microbiome is in its early stages. So far, we don’t know what the ideal composition of the gut microbiome should be to maximize health, but a more diverse microbiome is linked with better health. One reason that antibiotics have negative effects on the gut microbiome short term is they kill off healthy gut bacteria and reduce the diversity of the microbiome.
Some studies suggest that the negative effects of one course of antibiotics can last for up to a year. It’s also clear that diet plays a key role in what bacteria survive and thrive in the gut’s ecosystem. Some dietary components help build and support a healthy gut ecosystem and others are harmful to this fragile environment. Let’s look at some dietary components that support microbiome health and two that are harmful.
3 Dietary Components That Promote Microbiome Health
You may already know fermented foods contain bacteria that may colonize your gut, improve the diversity of your microbiome, and offer some health benefits. However, most people don’t eat enough of these foods to have an impact. A classic example of a probiotic-rich food is yogurt with active cultures. Other sources include kefir, kombucha, fermented vegetables, such as sauerkraut, kimchi, and miso. How many of these foods do you eat each day? Most people get less than one serving of these foods daily. No wonder so many people suffer from gut issues!
You can get probiotics from fermented foods such as the ones above or take a probiotic supplement. Most dietitians recommend getting probiotics from dietary sources since probiotic supplements may not contain enough of the gut-friendly bacteria listed on the label and there’s no guarantee that the bacteria in a probiotic supplement are still viable when they reach you. If you choose a supplement, research and buy from a reputable manufacturer.
The bacteria in your gut thrive on certain types of fiber that they can ferment. This fiber is called prebiotic fiber. Some of the best sources include onions, garlic, asparagus, leeks, dandelion greens, chicory root, Jerusalem artichokes, oats, and apples. Many of these foods have other health benefits too. For example, garlic and onions contain sulfur compounds that promote the synthesis of glutathione, your body’s master internal antioxidant.
Resistant starch is carbohydrates that your digestive system can’t break down or absorb. However, the friendly bacteria in your gut can digest and absorb them and when these hungry bacteria dine on these non-digestible carbohydrates, they produce short-chain fatty acids that have health benefits that extend beyond your gut.
For example, studies show that the short-chain fatty acids bacteria produce from resistant starch reduce inflammation in the gut and help keep cells in the large intestinal tract healthy. Plus, consuming resistant starch helps with blood sugar control. Some studies even show consuming more of these non-digestible starches helps with weight loss and weight control. Resistant starch also supports the growth of friendly gut bacteria.
Some sources of resistant starch include brown rice, legumes, green bananas, whole grains, and plantains. If you cook a starchy white potato or white rice and refrigerate it for 12 hours or more, a portion of its carbohydrates converts to resistant starch. When you reheat the rice or potatoes, the resistant starch remains. When you eat it, you get less of a blood sugar spike since cooling altered the structure of the carbohydrates.
2 Dietary Components That are Bad for Your Microbiome
Meat from Antibiotic Treated Animals
The biggest source of antibiotic exposure isn’t the pills you get at your pharmacy but meat from farm animals treated with antibiotics. Farmers often give farm animals antibiotics to prevent infection since the animals live in such close quarters. Small amounts of these antibiotics remain in the meat you eat. If you consume enough antibiotic-treated meat, it could theoretically impact your gut microbiome. Evidence that you get enough antibiotic exposure from eating meat to harm your gut microbiome is lacking, but experts believe it bears more research. Plus, when you consume a diet high in animal protein, you take in less fiber, the dietary component that gut bacteria feed and thrive on.
Fast food is high in fat and sugar and low in fiber and nutrients. Doesn’t sound like a good deal for your microbiome, does it? Science suggests that it isn’t either. In one study, researchers asked a group of Africans to switch from their traditional diet of vegetables and beans to the equivalent of an American fast-food diet. In only 14 days, their gut microbiome shifted, and they developed other markers suggestive of worsening metabolic health. Fast food doesn’t nourish, and it doesn’t keep your gut microbiome happy either. Now you have another reason to drive past the drive-thru and nourish your body with whole, fiber-rich foods.
The Bottom Line
There’s growing evidence that what happens in your gut affects your health. It starts with having a healthy, diverse gut microbiome. Although research looking at which populations of bacteria are ideal is in its infancy, having a good variety of bacteria in your gut is a good start. You can get that by adding more fermented foods, foods high in fermentable fiber, and resistant starch to your diet. Do it slowly as resistant starch and fermentable fiber can cause gas and bloating if you introduce too much too fast. Also, avoid junk food and a diet high in factory-farmed meat. Neither is beneficial for your health long-term.
- Adv Nutr. 2013; 4(6):587-601. doi: 10.3945/an.113.004325.
- Medical News Today. “What are the worst foods for gut health?”
- Microbiome volume 7, Article number: 86 (2019)
- Journal of Food Protection, Vol. 82, No. 10, 2019, Pages 1636-1642.
- Human Microbiome Journal. Volume 9, August 2018, Pages 11-15.
- IFL Science .” Your Gut Bacteria Don’t Like Junk Food – Even If You Do”
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