Berries and Gut Bacteria: How They Boost Your Microbiome
Among the many foods studied for their effects on the gut microbiome, berries stand out as one of the most promising — and most accessible — dietary choices. The connection between berries and gut bacteria centers on two key compounds: polyphenols and dietary fiber, which together can influence which microbes thrive in the colon and how the gut environment functions. This article explains the science behind how berries interact with your microbiota, compares the top berry types by their unique gut benefits, addresses whether blueberries are good for gut health, and offers practical guidance on how much to eat and how to incorporate them into your daily routine.
Berries and Gut Bacteria: The Science of a Symbiotic Relationship
The relationship between berries and gut bacteria is best understood as a partnership. When you eat berries, most of their polyphenols and a portion of their fiber pass through the small intestine largely intact, reaching the colon where your gut microbiota can act on them. There, beneficial bacteria ferment these compounds, breaking them into smaller metabolites that the body can absorb or that exert local effects on the intestinal lining.
Several key biological players are involved in this process:
- Polyphenols: These are plant-derived chemical compounds that give berries their deep red, purple, and blue colors. The most studied berry polyphenols are anthocyanins, a subclass of flavonoids. Polyphenols are poorly absorbed in the upper GI tract, meaning most reach the colon intact, where they serve as substrates for gut microbes.
- Dietary fiber: Berries contain both soluble and insoluble fiber. Fiber is a well-established prebiotic — a substance that selectively stimulates the growth and activity of beneficial gut bacteria.
- Microbial metabolites: When bacteria ferment berry compounds, they produce metabolites such as short-chain fatty acids (SCFAs) — including acetate, propionate, and butyrate — which nourish colon cells, help maintain the intestinal barrier, and modulate immune responses.
Research published in journals such as Food & Function and Nutrition Reviews has consistently found that berry consumption is associated with increases in beneficial bacterial genera such as Bifidobacterium, Lactobacillus, and Akkermansia, alongside shifts in overall microbial diversity. Higher diversity is generally regarded by researchers as a marker of a resilient, well-functioning gut ecosystem, though it is important to note that the relationship between diversity and health is complex and not yet fully understood.
While berries are not a treatment for any medical condition, the accumulated evidence suggests they represent one of the most evidence-supported fruit categories for supporting a balanced gut flora. The effect is modest compared to, say, a major shift in overall dietary patterns — but it is reproducible across multiple studies and likely contributes meaningfully to long-term gut health.
How Berries Benefit Your Gut Microbiota: Key Mechanisms
Understanding how berries and gut bacteria interact requires looking at several overlapping biological mechanisms. Below are the four primary pathways through which berry consumption appears to influence the gut ecosystem.
Discover the Microbiome Test
ISO-certified EU lab • Sample stays stable during shipping • GDPR-secure data
1. Polyphenol Fermentation by Gut Microbes
Most polyphenols in berries, particularly anthocyanins, are not efficiently absorbed in the small intestine. Instead, they travel to the colon in relatively intact forms, where they are metabolized by resident gut bacteria. This is a classic example of a prebiotic-like effect: the polyphenols don't just act on the body directly — they shape the microbial community that in turn affects the body.
Research has shown that polyphenol metabolism can favor the growth of certain bacterial species while suppressing others. For example, some in vitro and animal studies have demonstrated that berry polyphenols stimulate the growth of Akkermansia muciniphila, a bacterium that lives in the mucus layer of the gut and is associated with improved intestinal barrier function and metabolic health markers. Human evidence is growing but still developing; studies published in 2020–2025 have reported increases in Akkermansia abundance following regular consumption of blueberry and raspberry polyphenols in small cohorts.
2. Short-Chain Fatty Acid Production
When gut bacteria ferment fiber and polyphenols, they produce SCFAs. Among these, butyrate is particularly important: it serves as the primary energy source for colonocytes (the cells lining the colon), helps maintain the integrity of the intestinal barrier, and has been shown to have anti-inflammatory effects in experimental models.
Diets rich in fiber from sources like berries have been associated with higher fecal concentrations of SCFAs in several observational and intervention studies. This matters because low SCFA production has been linked — in associational research — with conditions including gut inflammation, increased intestinal permeability (sometimes colloquially called "leaky gut"), and impaired immune regulation.
3. Supporting Microbial Diversity
Microbial diversity — the variety of different bacterial species present in the gut — is one of the most commonly studied indices in microbiome science. While high diversity is not a guarantee of health, low diversity has been associated with a range of unfavorable outcomes in clinical research.
Berries contribute to diversity in two ways: by providing fermentable prebiotic fiber that supports fiber-loving species, and by supplying polyphenols that are metabolized by a different set of bacterial taxa. This dual contribution means berries may support a broader range of microbes than a single-nutrient source would.
View example recommendations from the InnerBuddies platform
Preview the nutrition, supplement, food diary and food recipe platform recommendations that InnerBuddies can generate based on your gut microbiome test
4. Modulating Gut Inflammation
Chronic, low-grade gut inflammation is thought to underlie many modern health concerns, from digestive discomfort to metabolic issues. Berry-derived metabolites — including SCFAs and specific polyphenol breakdown products — have been shown in laboratory and animal models to downregulate inflammatory signaling pathways such as NF-κB.
In human trials, regular berry intake has been associated with reductions in inflammatory biomarkers like C-reactive protein (CRP) and interleukin-6 (IL-6) in some studies, though results are not uniform across all trials and the effect sizes vary. It is reasonable to conclude that berry consumption is associated with a lower inflammatory profile, but it should not be presented as a standalone anti-inflammatory therapy.
A Note on Prebiotics vs. Probiotics
It is worth clarifying that berries are not probiotics — probiotics are live microorganisms that confer a health benefit when consumed in adequate amounts. Berries are better classified as prebiotic foods (or more precisely, as foods with prebiotic-like activity), because they nourish existing beneficial bacteria rather than introducing new ones. The distinction matters when evaluating health claims: eating berries supports your resident gut microbes; it does not replace the need for diverse food sources or, where indicated, targeted probiotic supplementation.
Top Berries for a Healthier Gut: A Comparison
Not all berries have identical nutrient profiles, and their effects on gut bacteria may differ accordingly. The table below summarizes the most studied berry types, their key gut-relevant compounds, and the current state of research.
| Berry | Key Gut-Relevant Compounds | Research Highlights | Fiber (per 100g, approx.) |
|---|---|---|---|
| Blueberries | Anthocyanins (malvidin, delphinidin), pterostilbene, fiber | Linked to increased Akkermansia and Bifidobacterium abundance in human trials; among the most studied berries for microbiome effects | ~2.4 g |
| Wild blueberries | Higher anthocyanin density than cultivated blueberries, fiber | Small studies suggest stronger antioxidant and polyphenol effects; microbiome-specific data is promising but limited | ~2.4 g |
| Strawberries | Ellagic acid, pelargonidin, fiber | Associated with increases in Christensenellaceae and other beneficial taxa in small intervention studies | ~2.0 g |
| Raspberries | Ellagitannins, anthocyanins, notably high fiber for a fruit | Ellagitannin metabolites (urolithins) produced by certain gut bacteria; fiber content supports SCFA production | ~6.5 g |
| Blackberries | Anthocyanins (cyanidin-3-glucoside), ellagic acid, high fiber | Fiber-rich; some evidence of antioxidant-driven microbiome shifts, though fewer dedicated human trials | ~5.3 g |
| Cranberries | Proanthocyanidins (PACs), quercetin, hippuric acid | PACs are studied for urinary tract effects; emerging research suggests gut barrier and microbial benefits | ~4.6 g |
How to read this comparison: fiber values are approximate and can vary by variety and ripeness. Research highlights reflect published findings through early 2025 and are subject to revision as new studies emerge. Raspberries and blackberries stand out for fiber content; blueberries lead in direct microbiome research; cranberries bring unique proanthocyanidin chemistry; and strawberries offer a favorable combination of palatability and polyphenol diversity.
A practical takeaway is that variety across berry types likely provides a broader range of polyphenols and fibers — and therefore a broader range of substrates for different gut microbes — than relying on a single type exclusively.
Are Blueberries Good for Gut Health? A Deep Dive
"Are blueberries good for gut health?" is one of the most frequently asked questions in this space, and the short answer — based on the available evidence — is yes, with a few important caveats.
What the Research Shows
Blueberries are among the most rigorously studied berries for microbiome effects. Multiple human intervention studies published between 2019 and 2024 have found that regular blueberry consumption (typically 100–200 g per day over 4–12 weeks) is associated with:
- increases in Bifidobacterium and Lactobacillus abundance
- modest increases in Akkermansia muciniphila, a bacterium associated with gut barrier integrity and metabolic health in preclinical research
- increases in fecal SCFA concentrations in some (but not all) trials
- reductions in markers of oxidative stress and, in some studies, inflammatory biomarkers
Blueberries owe much of their gut impact to their anthocyanin content, particularly malvidin and delphinidin glycosides, as well as to their pterostilbene — a structurally related compound with documented anti-inflammatory properties. The fiber content of blueberries is moderate for a fruit, so a meaningful portion of their gut benefit appears to derive from polyphenol-microbe interactions rather than fiber alone.
Are Blueberries Probiotic?
No. Blueberries do not contain live microorganisms and therefore are not probiotic. They function as a prebiotic-like food: their compounds nourish existing gut bacteria. If you see claims that blueberries are "probiotic," that is a mischaracterization of the science.
Why Do Some Sources Say to Quit Eating Blueberries?
Online search results sometimes surface headlines suggesting people should avoid blueberries. These claims typically stem from a few specific contexts, none of which apply to the general population:
2-minute self-check Is a gut microbiome test useful for you? Answer a few quick questions and find out if a microbiome test is actually useful for you. ✔ Takes 2 minutes ✔ Based on your symptoms & lifestyle ✔ Clear yes/no recommendation Check if a test is right for me →- Salicylate sensitivity: Berries contain natural salicylates, compounds that some individuals — particularly those with salicylate intolerance or aspirin-exacerbated respiratory disease — may react to with digestive symptoms, headaches, or skin reactions. This is a real but relatively uncommon sensitivity and does not apply to most people.
- FODMAP content: Blueberries are generally considered low FODMAP in standard serving sizes (about 20 berries or 40 g), making them suitable for most people following a low-FODMAP diet for IBS. Larger portions may contain enough excess fructose to provoke symptoms in sensitive individuals.
- Clickbait framing: Some articles extrapolate preliminary or animal-based findings into blanket dietary advice without appropriate context.
The balanced conclusion: for people without a diagnosed sensitivity, blueberries are a well-supported dietary choice for supporting gut health. Those with salicylate intolerance or IBS-related fructose sensitivity should work with a healthcare professional to determine their individual tolerance.
Practical Guide: How to Eat More Berries for Gut Health
Understanding the science is useful; applying it is where the benefit is realized. Below is practical guidance on portions, frequency, and preparation methods that align with current nutritional research.
How Many Berries Should You Eat?
Most intervention studies showing positive microbiome effects use daily doses in the range of 100–200 g of berries per day — roughly one cup, or about 150 whole berries of mixed types. For general dietary guidance, a reasonable target consistent with dietary fiber recommendations is:
- ½ to 1 cup of berries daily, ideally varied across types
- At least 3–5 servings of fruit per day overall (consistent with most national dietary guidelines), with berries representing a meaningful share
Consistency appears to matter more than any single large serving: the studies demonstrating microbiome changes typically involve sustained intake over several weeks rather than one-off consumption.
Fresh, Frozen, or Dried?
| Form | Polyphenol Retention | Fiber | Practical Considerations |
|---|---|---|---|
| Fresh | High (if eaten soon after purchase) | Full | Best flavor and texture; more expensive off-season; short shelf life |
| Frozen | Well-preserved — flash-freezing retains polyphenols effectively | Full | Cost-effective year-round; excellent for smoothies and cooking; minimal nutritional loss |
| Dried | Concentrated but altered — some polyphenols degrade, sugar content is higher per gram | Concentrated (but so is sugar) | Convenient snack; easier to overconsume; check for added sugars |
| Juiced | Reduced — most fiber removed; polyphenols partially retained | Minimal | Higher sugar-to-fiber ratio; lacks the prebiotic fiber that makes whole berries valuable |
Bottom line: frozen berries are nutritionally comparable to fresh for most gut-health purposes and are the most practical year-round choice. Whole berries — fresh or frozen — are preferable to juice because the fiber component is essential to the prebiotic effect.
Simple Ways to Add Berries to Your Routine
- Breakfast: Stir a handful into oatmeal, yogurt, or high-fiber cereal — the combination of berry polyphenols with dairy or oat beta-glucan can complement the prebiotic effect.
- Smoothies: Blend frozen mixed berries with leafy greens, a source of protein, and a fermented food like kefir or yogurt for a combined prebiotic-probiotic meal.
- Snacks: Keep washed berries visible and accessible; pair with nuts or seeds for a fiber-and-healthy-fat combination.
- Savory dishes: Add strawberries or blackberries to salads; use cranberry or pomegranate sauces as condiments (watch for added sugar).
- Baking: Add berries to muffins, pancakes, or homemade energy bars — though heat reduces some polyphenol content, the fiber remains intact.
For a broader look at how berry intake fits into an overall dietary strategy, see our related resource on understanding your gut microbiome.
Potential Downsides and Considerations
Responsible health content requires acknowledging limitations and potential risks alongside benefits. Berries are well-tolerated by most people, but a few considerations are worth noting.
Salicylate Sensitivity
As noted above, berries contain natural salicylates. Individuals with salicylate intolerance — an underdiagnosed condition estimated to affect a small percentage of the population — may experience digestive upset, joint pain, headaches, or skin reactions when consuming high-salicylate foods. Berries are considered moderate-to-high in salicylate content. If you suspect sensitivity, elimination and reintroduction under professional guidance is more reliable than self-diagnosis.
Intestinal FODMAPs and IBS
For people with irritable bowel syndrome (IBS), FODMAP content is relevant. Most berries are low to moderate FODMAP at standard serving sizes, but portion sizes matter — especially for blueberries and blackberries, which can become moderate in excess fructose at larger servings. A dietitian trained in the low-FODMAP approach can help identify individual thresholds.
Allergies and Oral Allergy Syndrome
Berry allergies, while less common than allergies to fruits like apples or kiwi, do exist. Some individuals with birch pollen allergy experience oral allergy syndrome (itching or tingling of the lips and mouth) when eating strawberries, raspberries, or other berries — a cross-reactivity phenomenon that is usually mild but should be evaluated by an allergist if symptoms are significant.
Pesticide Residues
Strawberries and other berries often appear on environmental working groups' lists of produce with higher pesticide residue levels. Thorough washing under running water reduces surface residues. Organic options are available but should be weighed against individual budget — the gut-health benefits of regular berry consumption generally outweigh concerns about conventional pesticide residues for most people, though washing is always advisable.
Prebiotics vs. Probiotics — One More Time
It bears repeating because the confusion is widespread: berries are prebiotic foods, not probiotic ones. Probiotics are live bacterial cultures (found in fermented foods like yogurt, kefir, and sauerkraut). Prebiotics — including the fiber and polyphenols in berries — feed beneficial bacteria already present. Both play complementary roles in a gut-healthy diet, and a balanced eating pattern typically includes both.
Become a member of the InnerBuddies community
Perform a gut microbiome test every couple of months and view your progress while following-up on our recommendations
Beyond Berries: Other Foods That Support the Gut Microbiome
No single food — berries included — functions as a "magic bullet" for the microbiome. The strongest dietary pattern for supporting gut bacterial balance is one that emphasizes diversity across multiple food categories. Berries are best understood as one powerful component of a broader strategy.
Fiber-Rich Plant Foods
The most consistently supported dietary factor for promoting a diverse, resilient microbiome is overall plant variety. Research suggests that people who eat 30+ different plant foods per week have more diverse gut microbiota than those who eat fewer than 10. Key categories include:
- Leafy greens: spinach, kale, arugula — rich in magnesium and fiber
- Legumes: lentils, chickpeas, black beans — among the best sources of prebiotic fiber, particularly galactooligosaccharides
- Whole grains: oats, barley, quinoa — provide beta-glucan and other soluble fibers
- Alliums: garlic, onions, leeks — contain fructans that serve as prebiotic substrates
- Nuts and seeds: almonds, flaxseed, chia — provide fiber, polyphenols, and omega-3 fatty acids
Fermented Foods
Where berries nourish resident bacteria, fermented foods introduce live microorganisms. A notable 2021 Stanford study published in Cell found that a high-fermented-food diet increased microbial diversity and reduced inflammatory markers more effectively than a high-fiber diet over a 10-week period — though the two approaches are complementary rather than competing. Good sources include yogurt with live cultures, kefir, kimchi, sauerkraut, miso, and kombucha.
The Big Picture
The concept of dysbiosis — an imbalance in gut microbial composition — is widely discussed but should be interpreted cautiously. Dysbiosis is not a single defined condition, and its relationship to specific symptoms varies. What researchers agree on is that dietary patterns rich in diverse plant foods, adequate fiber, polyphenol sources like berries, and fermented foods are associated with microbial communities that tend to be more diverse and metabolically active.
The microbiota-gut-brain axis — the bidirectional communication network between gut microbes and the nervous system — is another active area of research. While early findings suggest diet-driven microbiome changes may influence mood and cognition, this field remains largely in the preclinical and early clinical stages. It is an area of genuine scientific interest but not yet a basis for specific dietary prescriptions aimed at brain health.
If you want to move from general guidance to understanding your own gut bacterial composition, a gut microbiome test can provide personalized data to inform your dietary choices — as an educational tool rather than a diagnostic test.
Key Takeaways
- Berries and gut bacteria interact primarily through polyphenols and dietary fiber, which reach the colon and are fermented by resident microbes.
- Berry polyphenols — especially anthocyanins — act as prebiotic-like compounds, selectively supporting beneficial bacterial genera such as Bifidobacterium, Lactobacillus, and Akkermansia.
- Fermentation of berry compounds produces short-chain fatty acids like butyrate, which nourish colon cells and help maintain the intestinal barrier.
- Different berries offer different polyphenol and fiber profiles, so variety across blueberries, strawberries, raspberries, blackberries, and cranberries is more beneficial than relying on a single type.
- Blueberries are among the most studied berries for microbiome effects and are considered beneficial for gut health for people without salicylate sensitivity or FODMAP-related intolerance.
- Frozen berries retain polyphenols well and are a practical, cost-effective year-round option; whole berries are preferable to juice because the fiber is essential to the prebiotic effect.
- A daily intake of roughly one cup (100–200 g) of varied berries is consistent with the doses used in published intervention studies.
- Berries are prebiotic foods, not probiotics — they nourish existing gut bacteria rather than introducing new ones.
- Most people tolerate berries well, but individuals with salicylate intolerance, IBS-related fructose sensitivity, or berry allergies should approach them individually.
- Berries work best as part of a broader dietary pattern that includes diverse plant foods, adequate fiber, and fermented foods — no single food is a microbiome solution on its own.
Frequently Asked Questions
How do berries improve gut bacteria?
Berries improve gut bacteria primarily through two mechanisms: their polyphenols (especially anthocyanins) and their dietary fiber both reach the colon, where resident gut microbes ferment them. This fermentation selectively promotes the growth of beneficial bacterial genera like Bifidobacterium and Akkermansia and produces short-chain fatty acids that support the intestinal lining. The effect is considered modest but consistent across multiple studies.
Which berries are best for gut health?
Blueberries have the strongest direct evidence for microbiome benefits, with multiple human trials linking them to increases in beneficial bacteria. Raspberries and blackberries stand out for their high fiber content, while cranberries offer unique proanthocyanidins and strawberries provide a favorable mix of polyphenols and palatability. Choosing a variety of berries likely provides the broadest range of substrates for different gut microbes.
Are blueberries good for gut health?
Yes — for most people. Blueberries are rich in anthocyanins and fiber and have been associated with increases in beneficial gut bacteria, including Akkermansia, in human intervention studies. The exceptions are individuals with salicylate intolerance or FODMAP-related fructose sensitivity, who may need to limit portions. For the general population, blueberries are considered a supportive choice for gut health.
Are berries prebiotic or probiotic?
Berries are prebiotic, not probiotic. Probiotics are live microorganisms found in fermented foods like yogurt and kefir. Berries contain compounds — fiber and polyphenols — that nourish the beneficial bacteria already present in your gut, functioning as prebiotic substrates. Both prebiotic and probiotic foods play complementary roles in supporting a healthy microbiome.
How many berries should I eat per day for gut benefits?
Most published intervention studies use daily servings of approximately 100–200 g (about one cup) of berries over periods of 4–12 weeks. This amount is broadly consistent with general fruit intake guidelines and is achievable by most people through regular meals and snacks. Consistency over time appears more important than consuming a single large portion.
2-minute self-check Is a gut microbiome test useful for you? Answer a few quick questions and find out if a microbiome test is actually useful for you. ✔ Takes 2 minutes ✔ Based on your symptoms & lifestyle ✔ Clear yes/no recommendation Check if a test is right for me →Are frozen berries as good as fresh for gut health?
In most cases, yes. Flash-freezing preserves polyphenols and fiber effectively, and frozen berries show minimal nutritional degradation compared to fresh. They are also more practical and affordable year-round. The key advantage of whole berries — whether fresh or frozen — over juice is the intact fiber, which is central to the prebiotic effect.
Can eating too many berries cause digestive problems?
For most people, berry intake at typical dietary levels does not cause problems. However, large quantities may provoke symptoms in individuals with IBS (due to excess fructose at higher FODMAP servings), salicylate intolerance, or berry allergies. People with these sensitivities should experiment with portion sizes under professional guidance rather than avoid berries entirely unless medically advised.
What is the connection between berry polyphenols and gut microbiome diversity?
Polyphenols are poorly absorbed in the upper GI tract and reach the colon, where different bacterial species metabolize them. This creates selective pressure: species capable of using polyphenols as substrates are favored, which can shift community composition. Multiple studies have found that regular berry consumption is associated with increased microbial diversity, though the magnitude of the effect varies by individual and baseline diet.
Do berries contain FODMAPs?
Most berries are low to moderate FODMAP at standard serving sizes. Blueberries (about 40 g or 20 berries) are considered low FODMAP, as are strawberries and raspberries in moderate portions. Larger servings may increase FODMAP load, particularly excess fructose, so people following a low-FODMAP diet for IBS should adhere to established serving thresholds rather than eliminate berries outright.
Can berries help with gut inflammation?
Berry consumption has been associated with lower levels of inflammatory biomarkers in some human studies, and berry-derived metabolites (SCFAs and polyphenol breakdown products) have demonstrated anti-inflammatory effects in laboratory models. However, results are not uniform across all trials, and berries should be viewed as a supportive dietary component rather than a treatment for inflammatory conditions. Anyone with a diagnosed inflammatory condition should follow their healthcare provider's guidance.
Are wild blueberries better for gut health than regular blueberries?
Wild blueberries tend to have a higher anthocyanin density than cultivated varieties, which suggests a potentially stronger polyphenol-driven effect on gut bacteria. However, direct comparative microbiome studies specifically contrasting wild and cultivated blueberries are limited. Both types are nutritious and polyphenol-rich, so the practical difference for most people is likely modest — choosing either type regularly is more important than the distinction between them.
Should I take a probiotic if I eat a lot of berries?
Berries and probiotics serve different functions: berries provide substrates that feed your resident gut microbes, while probiotics introduce live organisms. Eating berries does not negate the potential benefit of a probiotic, nor does taking a probiotic make berry consumption redundant. A balanced approach that includes both — along with diverse fiber sources and fermented foods — is supported by current evidence for overall gut microbiome health.
Conclusion
The relationship between berries and gut bacteria is grounded in a clear biological mechanism: polyphenols and fiber in berries reach the colon, where gut microbes ferment them into metabolites that nourish the intestinal lining, modulate inflammation, and shift microbial community composition in generally favorable directions. Blueberries, raspberries, blackberries, strawberries, and cranberries each bring a distinct polyphenol and fiber profile, and incorporating a variety of types likely provides the broadest support for microbial diversity.
What this evidence does not establish is that berries alone can fix an unhealthy gut or address a specific medical condition. Individual responses vary considerably — shaped by baseline diet, existing microbial composition, genetics, and any underlying sensitivities. For most people, a daily serving of one cup of mixed berries is a safe, enjoyable, and evidence-supported dietary habit. For those wanting to understand their own gut's response in more detail, personalized microbiome testing can offer useful educational context — not as a diagnostic tool, but as a way to make more informed dietary decisions.
Ultimately, berries are a powerful but singular component of a broader dietary pattern. Pairing them with diverse plant foods, adequate fiber, and fermented foods offers the most robust approach to supporting a healthy gut microbiome over time.
Keywords
berries and gut bacteria, best berries for gut health, are blueberries good for gut health, berry polyphenols and gut microbiome, how do berries improve gut bacteria, gut microbiome, polyphenols, prebiotics, anthocyanins, Akkermansia, Bifidobacterium, Lactobacillus, short-chain fatty acids, butyrate, gut inflammation, intestinal permeability, microbial diversity, antioxidants, dietary fiber, blueberries, strawberries, raspberries, blackberries, cranberries, wild blueberries, salicylates, gut flora balance, dysbiosis, microbiota-gut-brain axis, fermented foods, prebiotic fiber, colon health