INGREDIENTS

Blackberries: What They Actually Do in Your Body

By Valerie Wright  *  Updated: April 16th, 2026

Blackberries contain pigment compounds called anthocyanins that your body processes differently than most antioxidants. Your gut bacteria also break down a second group of compounds in the fruit, called ellagitannins, into smaller molecules that circulate in your blood for days and help calm inflammation at a cellular level.¹ ² That two-layer system is what makes blackberries more interesting than a standard antioxidant label suggests.

How Pectin Works in Your Gut

The deep purple color of a ripe blackberry comes from anthocyanins. The dominant one in blackberries makes up roughly two-thirds of the total pigment content.³ These are water-soluble compounds that belong to the flavonoid family, and they interact with the same inflammatory switches in the body that over-the-counter pain relievers target.⁴


The practical constraint is absorption. Anthocyanins are poorly absorbed in the upper digestive tract. Most of what you eat passes through to your colon, where gut bacteria break the molecules apart into smaller fragments. Those fragments are actually absorbed more efficiently than the original compounds.⁵ So the benefit isn't just about eating anthocyanins. It's about what your gut does with them afterward.


A review of 66 studies found that anthocyanin-rich foods were associated with a consistent blood pressure-lowering effect, though the degree of benefit varied based on the dose, form (whole fruit vs. extract vs. juice), and the person's starting blood pressure.⁶ That variability matters. It suggests that the context you consume anthocyanins in is just as relevant as the amount.

What Your Gut Does with Ellagitannins

Blackberries are one of the richest food sources of ellagitannins, a type of polyphenol your body can't absorb directly.² They pass through the stomach and small intestine intact. When they reach the colon, specific gut bacteria break them down into smaller metabolites called urolithins.¹


Urolithin A is the most studied of these. It shows up in the bloodstream and can be detected in urine up to seven days after you eat blackberries.¹ ² Early research, mostly from lab and animal studies, suggests urolithin A helps support the body's cellular cleanup process (the way your cells recycle damaged parts) and may help regulate the body's built-in antioxidant defenses.⁷


Here's the honest constraint: not everyone produces urolithins equally. Researchers have identified three groups based on how people's gut bacteria handle ellagitannins. About 70% of healthy adults fall into the group that efficiently produces urolithin A. Around 20% produce a different mix. And roughly 10% produce very little of either.¹ Which group you belong to depends on your gut bacteria, and that's shaped by your overall diet, age, and gut health.

 

"There is a consistent human interindividual variability in the metabolism of ellagitannins, yielding the so-called gut microbiota-associated urolithin metabotypes." 
- González-Sarrías et al., 2022¹

 

Two people eating the same bowl of blackberries may get meaningfully different results. That's not a reason to skip them. It's a reason to understand that eating blackberries alongside other fiber-rich, gut-friendly foods (greens, onions, whole grains) supports the bacteria that make those metabolites in the first place.

Fiber in Blackberries: Function Over Amount

One cup of raw blackberries (144g) delivers about 8 grams of dietary fiber on roughly 62 calories.⁸ That's 29% of the recommended daily value. For a fruit, that fiber density is unusually high.


What makes blackberry fiber distinct is that almost all of it, somewhere between 92% and 97%, is insoluble.⁹ Insoluble fiber adds bulk to stool and speeds transit through the digestive tract. It's the mechanical side of gut health. The kind that keeps things moving, rather than slowing digestion down the way soluble fiber does.
 

The seeds contribute a meaningful share of that insoluble fiber. When blackberries are juiced and strained, the seeds and their fiber are removed entirely. When they're blended whole, the seeds break apart but stay in the drink. That distinction matters if fiber is what you're after. A strained blackberry juice and a whole blended blackberry are nutritionally different products.

What Changes with Processing

Fresh blackberries are fragile. They start losing quality within two days at room temperature, which is why most commercially available blackberries are frozen or processed shortly after harvest.


Freezing preserves anthocyanins well. A 2008 study found no significant change in anthocyanin content or antioxidant capacity in quick-frozen blackberries over six months of storage at standard freezer temperatures.¹⁰ That's reassuring for anyone buying frozen berries or consuming products made with frozen blackberry.


Heat-based processing tells a different story. The same study found that canning, pureeing, and juicing caused anthocyanin losses of up to 65% right after processing. Storing those products at room temperature led to further losses of up to 75% over six months.¹⁰


Ellagitannins hold up better during freezing, though their levels can shift over time as ice crystal damage makes some compounds easier to extract from the fruit tissue.¹¹


The bottom line: frozen whole blackberries and frozen blended products keep the most anthocyanins and fiber intact. Juiced, strained, or shelf-stable products lose significant amounts of both.

 

Format Anthocyanins Fiber Ellagitannins
Fresh (raw) Full content; degrades within days at room temp ~8g per cup; seeds intact Intact; highest bioavailable precursor load
Frozen (IQF) Stable for 6+ months at -20°C Retained fully; seeds intact Stable; slight increase in extractability over time
Blended (whole) Retained in liquid; seeds broken but present Retained; seeds fragmented but fiber stays Released from cell matrix; accessible to gut bacteria
Juiced (strained) Partial loss; up to 65% reduction with thermal processing Minimal; seeds and pulp removed Partially retained in liquid; reduced seed-bound portion
Freeze-dried powder Concentrated per gram; sensitive to light and humidity Concentrated; texture altered Concentrated; shelf stability depends on storage conditions

Tolerance and Side Effects

Blackberries are generally easy on the stomach. At standard serving sizes (one cup or less), they're considered low in fermentable sugars, which makes them one of the better berry choices for people with sensitive digestion or IBS.


The seeds can bother some people. They're small and hard, and there's a longstanding belief that seeds can get stuck in colon pockets (diverticula). Most doctors no longer consider that a real risk, but it comes up enough that it's worth addressing.


The fiber content, while great for regularity, can cause bloating or loose stools if you ramp up quickly. If you're not used to eating 8 grams of fiber in one sitting, start with a smaller portion and increase over a week or two.


Blackberries also contain moderate amounts of oxalates. For most people, this doesn't matter. For anyone with a history of calcium oxalate kidney stones, it's worth knowing, though blackberries aren't among the highest-oxalate fruits.

Who Blackberries Work For (and Who Should Adjust)

Blackberries are a practical fit for people who want more fiber without more calories. At 62 calories per cup with 8 grams of fiber, few fruits match that ratio. They're also a solid option for anyone managing blood sugar. The fiber slows glucose absorption, and the sugar content is modest, about 6 grams per cup.


People who get the most from blackberries tend to be those already eating a varied diet that supports healthy gut bacteria. The urolithin pathway depends on having the right microbial populations in your gut. Eating blackberries alongside other gut-friendly foods, like greens, garlic, and whole grains, helps build that ecosystem.


People with histamine sensitivity should pay attention. Like most berries, blackberries can trigger histamine release in sensitive individuals. If you notice flushing, itching, or digestive discomfort after eating berries, it may be worth discussing with a healthcare provider.

Why We Use Blackberries in a Whole Blended Drink

Sunrise Blends includes blackberries in Berry Breeze, one of the HeartBeets Grab-N-Go blends. The berries go in whole, not juiced or strained, so the seeds, fiber, and full pigment content stay in the bottle.


That matters because of everything above. Straining removes the insoluble fiber. Heat processing breaks down anthocyanins. Freezing and blending keeps both intact. The blackberries in Berry Breeze also sit alongside beetroot, turmeric, ginger, and avocado oil. Each of those contributes something specific. Turmeric and black pepper support absorption. Avocado oil provides the fat that helps your body take up fat-soluble nutrients. The blackberries bring the anthocyanins, the fiber, and the raw material your gut bacteria need to produce urolithins.


These ingredients aren't in there for the label. They're there because they work, and several of them work better together than apart.

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Sources cited in this article:

  1. González-Sarrías A, Espín JC, Tomás-Barberán FA. Ellagitannins, urolithins, and neuroprotection: Human evidence and the possible link to the gut microbiota. Neuroscience & Biobehavioral Reviews. 2022;142:104914.
  2. Espín JC, Larrosa M, García-Conesa MT, Tomás-Barberán FA. Biological significance of urolithins, the gut microbial ellagic acid-derived metabolites: the evidence so far. Evidence-Based Complementary and Alternative Medicine. 2013;2013:270418.
  3. Chen L, Teng H, Xie Z, et al. Enhancement on antioxidant, anti-hyperglycemic and antibacterial activities of blackberry anthocyanins by processes optimization involving extraction and purification. Frontiers in Nutrition. 2022;9:1007804.
  4. Bowen-Forbes CS, Zhang Y, Nair MG. Anthocyanin content, antioxidant, anti-inflammatory and anticancer properties of blackberry and raspberry fruits. Journal of Food Composition and Analysis. 2010;23(6):554-560.
  5. Felgines C, Talavéra S, Texier O, Gil-Izquierdo A, Lamaison JL, Rémésy C. Blackberry anthocyanins are mainly recovered from urine as methylated and glucuronidated conjugates in humans. Journal of Agricultural and Food Chemistry. 2005;53(20):7721-7727.
  6. Cleveland Clinic. What are anthocyanins? 4 health benefits. 2022. Reviewed by registered dietitian.
  7. Moreira-Silva I, Carvalho R, Gonçalves RF, et al. Urolithin as a metabolite of ellagitannins and ellagic acid from fruits and nuts produced by the gut microbiota: its role on non-communicable diseases. Current Nutrition Reports. 2025;14:55.
  8. USDA Agricultural Research Service. Blackberries, raw. FoodData Central. 2019.
  9. FoodStruct. Blackberry nutrition and calories: complete data of all nutrients. 2023. Based on USDA FoodData Central.
  10. Hager TJ, Howard LR, Prior RL. Processing and storage effects on monomeric anthocyanins, percent polymeric color, and antioxidant capacity of processed blackberry products. Journal of Agricultural and Food Chemistry. 2008;56(3):689-695.
  11. Veberic R, Stampar F, Schmitzer V, et al. Changes in the contents of anthocyanins and other compounds in blackberry fruits due to freezing and long-term frozen storage. Journal of Agricultural and Food Chemistry. 2014;62(29):6926-6935.

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