The word “bacteria” is enough to make most people cringe. And the knowledge that there are about 39 trillion bacteria in the human body can seem horrifying (there are more bacteria in the body than there are cells!). Yes, there are the bad, harmful bacteria that can cause disease and illness. But there are also the helpful, good bacteria that research increasingly indicates play a role in health promotion and disease prevention.

We all have bacteria in our digestive tract. While it’s unpleasant to think about, the reality is that they’re there to stay. The collection of bacteria, fungi, viruses, and parasites (called microorganisms) in our gut is called the microbiome. Some are potentially harmful, but many of them are the good guys with the potential to help fight off illness and chronic disease.

Everyone’s microbiome is unique; in other words, no two people have the same microbiome. That’s because the microbiota is determined, initially, by your DNA. When you’re born, you’re exposed to your mother’s microorganisms during delivery, and, if you’re breastfed, through your mother’s breast milk. Over time, the environment and your diet influence the type of microorganisms. For example, people who eat foods of animal origin have a very different microbiome (or gut flora) than those who eat plant-based foods.

Research has shown that people who eat a typical American diet have less diverse microbiota than those eating a plant-based diet. The more diversity you have in your gut, the more likely you are to have better digestion, nutrient absorption, and a healthy immune system. Other factors affect it as well, including antibiotics (which tend to wipe out the good bacteria along with the bad) and illness. An imbalance of bacteria is thought to lead to digestive disorders (including diarrhea and constipation), skin problems, urinary and vaginal infections, colds, mental health issues, and even weight gain.

Probiotics: the good guys

Of course, we all want good bacteria (probiotics) in our gut. But how do we get it? Probiotics are usually bacteria, although yeasts can be probiotics, too. You can affect the balance of bacteria in your gut in three ways: via the environment, by food, and by taking supplements.

The environment: Believe it or not, the more we’re exposed to dirt, the better our microbiome may be. Now, no one is saying that you need to live in filth, but our culture tends to promote excessive cleanliness, and that may not be such a good thing, especially if you have kids in the house. Studies show that being exposed to a variety of microbes, especially during childhood, helps to strengthen your immune system. So don’t be afraid to dig in the dirt, go camping, or be outside, in general. Other things that can help include having a pet (or being near animals), avoiding antibacterial cleaners, and occasionally washing dishes by hand versus using the dishwasher.

Food: Eating certain foods is a great way to get your probiotics. Choose foods that contain live cultures, such as yogurt, buttermilk, acidophilus milk, kefir (a fermented probiotic milk drink), kimchi (a fermented Korean vegetable dish), sauerkraut (fermented cabbage), tempeh (fermented soybeans), miso (fermented soybean paste), olives, and kombucha (a fermented tea drink). Some cheeses (Brie, feta, gruyere) may contain probiotics, too.

Supplements: Not surprisingly, there are many types of probiotics supplements available. Supplements may contain just one strain of probiotic, or they may multiple strains. Common strains of probiotics include the Lactobacillus, Bifidobacteria, Saccharomyces boulardii, and Bacillus coagulans. It’s a good idea to check with your doctor before taking a probiotic supplement. Some people should not take them, including people who have an overgrowth of yeast, small intestine bacterial overgrowth, or a compromised immune system.

Probiotics and diabetes

It seems like probiotics can help a whole host of issues (although more research is needed). What about diabetes? Last year, research from Ontario was presented at the American Heart Association’s Scientific Sessions. In this study, 80 people followed either the DASH diet (for high blood pressure) or the DASH diet plus probiotic-rich foods. Of the 80 people, 15% had prediabetes. After three months, those on the DASH diet plus probiotics had lowered their A1C by 8.9%compared to 3.4% for the DASH diet–only group.

Other studies have indicated that probiotics can lower glucose and insulin levels in those with diabetes. Lactobacillus acidophilus and L. casei improved glucose tolerance and hyperglycemia (high blood sugar) in animal studies. Human studies have also shown promise, but many of these studies had fewer than 20 participants, and it’s hard to rule out the effect of other factors that may have affected glycemic control. Still, things look promising as far as the link between probiotics taken for more than 8 weeks and lower fasting blood sugar and A1C levels. In one study, people with Type 2 diabetes were given C. ficifolia (a type of pumpkin), C. ficifolia and probiotic yogurt, or simply dietary advice. Those given C. ficifolia and probiotics alone or together had lower total cholesterol and triglycerides (blood fats), higher HDL (“good”) cholesterol, and lower blood pressure. All interventions lead to lower LDL (“bad”) cholesterol, A1C, and blood sugar.

 In particular, probiotics may promote heart health, which is extremely important if you have diabetes. For now, your best bet is to take advantage of foods that are natural sources of probiotics. If, after checking with your doctor, you decide to take a probiotic supplement, choose one with multiple strains of probiotics and with at least 30 billion Colony Forming Units (CFUs). It’s also advisable to go with a supplement that has a “USP Verified” seal. Don’t forget, too, that checking your blood sugar is an important way to see if probiotic foods and/or supplements have an effect on your diabetes control.