6 Reasons Why Blackberries Can Cause Diarrhea

You can snack on blackberries to meet your daily fruit requirements or add them to dessert for a nutritious twist on cakes and tarts.

But if you experience certain side effects, such as diarrhea, after eating blackberries, there may be an underlying issue causing you to be incompatible with the fruit.

Some common causes of diarrhea from blackberries include salicylate sensitivity, allergies and food poisoning. Other causes, such as blackberries that are moldy or unripe, may be preventable.

Salicylates are chemicals that are naturally found in various fruits and vegetables. Salicylate sensitivity occurs when your body is unable to process the amount of salicylates you eat in one sitting.

Blackberries contain salicylic acid, the compound from which salicylates are derived, according to July 2014 research in ​Pharmacognosy Review​. Eating too many blackberries may trigger symptoms of salicylate sensitivity or allergy, which can include diarrhea.

"For people with an overactive immune system, it's possible to have a food sensitivity response to any food, including blackberries," says dietitian Jenna Volpe, RDN, LD. "Food sensitivity reactions involve the release of chemical mediators from white blood cells in the gut, in response to eating a reactive food. This can lead to diarrhea."

Food allergies are different from sensitivities and intolerances, but they can have similar symptoms — diarrhea included. Allergies to blackberries are rare but possible.

Blackberries contain proteins that your immune system may recognize as dangerous, although they're actually safe. When this "mistake" occurs, your body reacts by creating antibodies and histamine to fight against the blackberry proteins. This causes inflammation in the intestines, which can lead to stomach pain, cramping, diarrhea, nausea and vomiting.

Whenever you get diarrhea and vomiting after eating a certain food, food poisoning is a possibility. In fact, diarrhea is a core symptom of food poisoning, according to the USDA.

Food poisoning can occur with any food, but it's more common in fresh meats, fruits and vegetables. This acute digestive condition is caused by infectious organisms found in the food.

If you have food poisoning from eating blackberries, you may develop diarrhea, vomiting and nausea within a few hours to one day after eating the contaminated blackberries. The only treatment for food poisoning is a modified diet that consists of bland foods, drinking more fluids and getting rest. It's uncommon for food poisoning to cause any long-term effects.

There's a reason why you toss out moldy bread in your cupboard. Eating spoiled food with mold shouldn't be taken lightly.

Mold produces toxic chemicals, so accidentally eating moldy blackberries can cause side effects like diarrhea and nausea, according to the Cleveland Clinic. If you do get these side effects, visit your doc stat.

"Blackberries are highly perishable, which means they don't have a very long shelf life before they start growing moldy. Organic blackberries will get moldy even quicker," Volpe says. "People most likely to get diarrhea from moldy blackberries are people with a mold allergy."

Eating moldy foods can also lead to food poisoning, according to the USDA. To avoid eating moldy blackberries, Volpe recommends inspecting the fruit for white fuzz.

When blackberries are ripe, they're a deep black color with a plump texture — that's how you know they're in their prime.

Before they've ripened, blackberries can appear green, red or purple. These colors are an indication that the blackberries aren't ready to be eaten.

Unripe blackberries contain solanine, which is a poisonous compound. When eaten in large quantities, this can lead to solanine poisoning. Symptoms of solanine poisoning can include gastrointestinal issues like diarrhea, abdominal pain and vomiting, according to Michigan State University.

The fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) in blackberries can be the culprit of diarrhea.

Fructose, a natural type of sugar, is a FODMAP found in blackberries — and it can lead to diarrhea when eaten in excess. One cup of blackberries contains 3.5 grams of fructose, per the USDA. Eating more than 40 grams of fructose per day is associated with diarrhea, according to Harvard Health Publishing.

FODMAPs like fructose are known for being difficult to digest, especially for people with irritable bowel syndrome (IBS). Malabsorption of these sugars can lead to digestive problems like diarrhea, bloating, gas and abdominal pain, according to May 2016 research in ​The Journal for Nurse Practitioners​.

Certain fruits are known to trigger IBS symptoms like diarrhea. Blackberries are especially high in the FODMAP sorbitol, so they're not usually part of a low-FODMAP diet, according to Monash University (which is where the low-FODMAP diet was originally created).