Everything You Need to Know About Probiotics

If you’ve ever taken antibiotics, you might have been told to take them with a big dollop of yogurt because it contains something called “probiotics.” Or maybe you’ve seen probiotic supplements that say they support gut health, keep you regular, and even control your appetite. That all sounds great, but what are probiotics?

The bacteria living inside your intestines are crucial for your health. Probiotic supplements are good for your beneficial gut bacteria, but they aren’t the end-all, be-all when it comes to gut health. Here’s what you should know about probiotics, plus my top recommendations to maintain a rockstar gut biome.  

What are probiotics?

Probiotics are the good gut bacteria that are normally found in your intestines. They help digest food, produce vitamins, and destroy microorganisms that would otherwise make you weak.

The human gut biome consists of about 100 trillion bacteria cells, more than 10 times more than there are human cells in your body. Think of your gut biome as a significant organ in your body. Keeping it healthy and balanced is essential to reduce your risk of disease and upgrade your performance. After all, your gut bacteria control your mind, appetite, and even your stress levels.

So, if you already have good bacteria in your gut, why would you want to add more with a probiotic supplement?

Unfortunately, modern life is full of factors that wipe out good gut bacteria, like the overuse of antibiotics, diets high in processed foods, and foods containing inflammatory histamines.^{[1] [2]} Histamines are a type of immune cell that triggers inflammation throughout the body. When your gut bacteria get thrown off, you can develop something called histamine intolerance, which leads to increased inflammation, congestion, hives, and migraines — just to name a few symptoms. In fact, research shows that an unhealthy gut contributes to obesity, diabetes, rheumatoid arthritis, autism, depression, and chronic fatigue.^[3] [4]

Here’s the absolute best thing you can do to repair an unhealthy gut: Feed the good bacteria with a nutrient-dense, anti-inflammatory diet, and kill the bad guys by limiting your exposure to kryptonite foods. Think of probiotic-rich foods and supplements as part of your overall gut health toolkit.

Related: Signs Your Gut Is Unhealthy and Why You Should Fix It

Benefits of probiotics

• Fill your system with good gut bacteria: Great news if you’re working on healing your gut after years of eating inflammatory foods like gluten, processed food, and refined sugar.
• Support gut health when you take antibiotics: Antibiotics may wipe out the bad bacteria, but they can also clear your system of the good bacteria that promote a healthy gut.
• Easy to supplement: Probiotics usually come in the form of a powder or capsule — but make sure you’re consuming the right strains. (More on that below.)

However, probiotics won’t go very far if you aren’t already supporting your gut with a diet filled with fibrous vegetables, grass-fed and wild-caught meats, ditching industrial meat, and managing your stress. Keep reading to learn about the best sources of probiotics, including probiotic foods.

Related: Move Over Probiotics. Synbiotics Are the Gut Supplement You Need

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Best sources of probiotics

If you’re concerned about your gut bacteria, and you take probiotics to help those bacteria flourish, you may be doing the exact opposite of what you want — depending on the specific bacteria that you’re supplementing.

For example, if you’re taking a histamine-producing bacteria in yogurt like Lactobacillus casei, you’ll be doing more harm than good. That’s why it’s important to be aware of which bacteria produce histamines, which degrade them, and which don’t affect them at all. Foods in the Bulletproof Diet’s green zone are low in histamine so you don’t feel foggy and fatigued.

To repair an unhealthy gut and decrease histamine intolerance, you need to eat an anti-inflammation diet, minimizing histamine-producing bacteria and maximizing histamine degrading bacteria. Here’s what that means in terms of probiotic strains:^{[5] [6] [7] [8] [9]}

• Avoid these: Lactobacillus casei, Lactobacillus reuteri, and Lactobacillus bulgaricus. These strains produce histamines, and they’re found in most yogurts and fermented foods.
• Try these and see how you feel: Streptococcus thermophilus and Lactobacillus rhamnosus are neutral bacteria, which means they may help degrade histamines if you handle them well. Streptococcus thermophilus is found in yogurt and fermented milks. Lactobacillus rhamnosus is available as a probiotic supplement or yogurt starter.
• Increase these: Bifidobacterium infantis, Bifidobacterium longum, Lactobacillus plantarum, and some soil-based organisms. (No, you don’t have to eat dirt to get soil-based organisms in your system. Just go on a nature walk barefoot, and eat fresh, organic, and local meat and vegetables.)

I’ve experimented with Primal Defense Ultra, AOR Probiotic-3, Prescript Assist, and Align GI. To learn more about my probiotic stack, listen to my conversation with food and nutrition scientist Dr. Grace Liu in this episode of the Bulletproof Radio podcast.

Probiotic foods that help you feel great

If you want to feel great and support your good gut bacteria, eat these foods:

• Antioxidant-rich foods: Colorful foods like blueberries and chocolate and beverages like coffee and green tea are rich in polyphenols, antioxidants that boost populations of beneficial gut bacteria.^{[10] [11] [12]}
• Grass-fed, organic dairy: If you tolerate dairy, you can get a dose of gut-friendly probiotics from yogurt or kefir. My favorite (and best-tasting) source of balanced bacteria is a yogurt-like product called Amasi, which contains 30 carefully controlled strains of bacteria. Learn more about Amasi in my interview with natural health expert Jordan Rubin in this episode of the Bulletproof Radio podcast.
• Prebiotic fiber: Think of prebiotic fiber as food for your good gut bacteria. Fiber is good for you, but different types of fiber have different benefits. Prebiotic fiber ferments in your gut, where it becomes a buffet for good gut bacteria. Prebiotics are found in chicory, cruciferous vegetables, bananas, and cooked and cooled white rice. Learn more about the best sources of prebiotic fiber here.

Probiotic “health” foods that you should avoid

You might have seen headlines saying that red wine and fermented foods are good for you, but the reality is that the risks associated with these foods far outweigh their “benefits.” Yeah, you’ll get a dose of probiotics from kombucha — but you might also feel fatigued and unfocused because fermented foods don’t work for everyone.

Here’s why. Certain foods have higher histamine contents or help release stored histamine. Some people can tolerate histamines better than others. If these foods make you feel tired and weak, don’t eat them. It’s that simple.

• Matured or fermented foods, depending on the bacteria and yeasts that are involved in the process: Sauerkraut, kombucha, pickles, fermented soy products, soy sauce, fish sauce, fermented coffee (Bulletproof Coffee is safe because it’s tested for toxins and certified clean)
• Microbiologically produced foods: Most yogurt, buttermilk, kefir, mature cheese, sauerkraut, wine (especially reds)
• Processed, smoked, and fermented meats: Lunchmeat, crappy bacon, sausage, pepperoni, salami, and so on.
• Alcohol: Red wine, white wine, champagne, beer
• Yeasty foods: Specifically, breads made with yeast
• Certain vegetables, fruit, and nuts: Tomato, strawberries, kiwi, pineapple, peanuts, cashews, walnuts, and more.

A note on yogurt, since it’s so heavily marketed as gut-friendly: Not all probiotics are created equal, and all of that “probiotic-rich” yogurt might actually be making you feel bloated and foggy. Although some probiotic supplements are good for you, most manufactured probiotics are only minimally effective at repopulating the gut biome because not all strains of probiotics interact with the gut in the same way.

Oh, and if that probiotic yogurt is loaded with refined sugar, it’s not going to make you feel great. Read your labels.

Gut health, like biohacking in general, comes down to a lot of trial and error. Over the last decade, I estimate I’ve spent around $25,000-$50,000 on various strains of probiotics to fix my gut, including the time I took pig whipworm eggs. Some supplements will make you feel great. Others will make you feel inflamed and tired. Probiotic supplementation is a catch-22, and you should not just grab whatever has the best label on the shelf.

Instead, throw away the pre-packaged, processed, and sugary junk in your kitchen. Fill your plate with low-toxin and nutrient-dense foods that will heal your gut and help you perform on all cylinders. After eating like this regularly, you’ll feel focused, energized, and lighter. Why? You’re protecting your gut and reducing histamine intolerance — and it feels incredible.

Related: How to Start the Bulletproof Diet in 10 Easy Steps