9 Major Side Effects of Eating Too Many Cranberries

Cranberries are the fruit berries of the evergreen cranberries plant and belong to the subgenus Oxycoccus of the genus Vaccinium. They are cultivated in many American states and Canadian provinces. They contain essential nutrients like vitamins, minerals, antioxidants, and dietary fibers, etc, and provide many health and beauty benefits. Despite these benefits, eat cranberries in moderation as there are some side effects of eating too many cranberries.

Side Effects of Eating Too Many Cranberries

Some major side effects of eating too many cranberries are as follows.

(1) Too Much Dietary Fiber Is Bad For Stomach

Cranberries improve digestive health as dietary fiber in them are natural laxatives that improve bowel movement, and relieve constipation and other digestive problems like abdominal pain, gas, bloating, flatulence, and indigestion, etc.

However, don’t eat too many cranberries as excess fiber may over-activate the bowel movement, and cause diarrhea, constipation,  indigestion, irritable bowel syndrome, intestinal gas, and intestinal blockage, etc.

Dietary fibers reduce our body’s ability to absorb nutrients and may cause malabsorption.

(2) Too Many Antioxidants Are Bad For Our Health

Vitamin C, vitamin A and other antioxidantal compounds in pears protect our cells from free radical damage and reduce the risk of several cancers.

Free radicals are the unstabilized ions that stabilize by stealing electrons from neighboring molecules, and doing so causes oxidative damage to them.

In moderation, antioxidants react with the free radicals and stabilize them, but, in excess quantities, they also react with the healthy cells.

Eat cranberries in moderation as high levels of antioxidants may increase cancer risk.

As per a 2011 study involving 35,500 men, high levels of vitamin E may increase prostate cancer risk by 17 percent.

As per another study conducted in 1996, high levels of vitamin A may increase lung cancer risk in male smokers by 18 percent.

(3) Cranberry Allergy

Avoid cranberries if you are allergic to them.

Some common allergic reactions of cranberries are skin rashes, itchiness, swelling of the mouth, tongue, lips, and face, severe breathlessness, etc.

If you experience any such symptom ( or other symptoms) after eating cranberries, discontinue the use, and consult a doctor immediately.

(4) Cranberries And High Blood Pressure

Hypertension is a leading cause of several cardiovascular problems and affects millions around the world.

Potassium in cranberries ( 80 mg per 100 gram of fresh cranberries) relaxes blood vessels, improves blood circulation, and relieves hypertension or high blood pressure.

Cranberries may interact with the blood pressure medication.

If you are on blood pressure medication, consult with your doctor before eating cranberries to ensure there’s no food-drug intolerance.

(5) Cranberries And Managing Diabetes

Cranberries have a low glycemic index of 45 and release sugar into the bloodstream at a slow pace.

It prevents a sudden rise in blood sugar levels and aids in managing diabetes.

Dietary fibers in cranberries slow down sugar absorption and help in regulating blood sugar levels.

Avoid eating too many cranberries as otherwise, it may drop blood sugar below normal level and cause symptoms like skin rashes, itchiness, swelling of mouth, tongue, lips, and face, severe breathlessness, etc.

Cranberries may interact with diabetes medication.

If you are on diabetic medication, consult your doctor before adding cranberries to your routine to avoid food-drug intolerance.

(6) Eating Cranberries During Pregnancy And Nursing Period

Cranberries are loaded with essential nutrients, and eating cranberries or drinking cranberries juice in moderation helps in maintaining a healthy pregnancy. 

It protects the fetus from free radical damage, reduces the risk of gestational diabetes, reduces the risk of UTI, and prevents constipation.

However, eating too many cranberries may cause diarrhea, and other digestive problems in pregnant women and nursing mothers.

Consult with your doctor before adding cranberries to your pregnancy routine to ensure there’s no complication involved and there’s no food-drug intolerance.

(7) Not Good For Individuals WIth Aspirin Allergy

The salicylic acid in the cranberries may interact with the Aspirin medicine and influence their effectiveness.

In some cases, it may trigger Aspirin allergy, and cause symptoms like flushing, skin rashes, itching, blocked and runny nose, and breathing difficulty, etc.

Eat cranberries in moderation, and consult with a doctor if you are on Aspirin medication.

(8) May Cause Stomach Inflammation ( Atrophic Gastritis)

Vitamin B12 in cranberries enhances the production of digestive enzymes and improves digestion and metabolism.

However, in excessive quantities, these digestive enzymes may irritate the inner lining of the stomach, and give rise to Atrophic Gastritis or Hypochlorhydria.

Eat cranberries in moderation to reduce the risk.

(9) May Increase The Risk of Kidney Stones

Overeating cranberries or drinking cranberries juice in excess increases oxalate levels in our body.

A high level of oxalates increases the risk of kidney stones as oxalate binds with the calcium to form calcium oxalate ( type of oxalate).

Our kidneys remove oxalate from our body through urine and prevent this binding.

However, when there are too many oxalates, they overburden the kidneys and make it difficult for kidneys to get rid of oxalates.

If you have kidney disorders, consult your doctor before adding cranberries or other high oxalate food to your diet.


The information contained in the post is for general purpose only and shouldn’t be considered as medical advice or as an alternative to medical advice. Although I’ve tried my best to keep the information contained in this post as accurate and updated as possible, I make no guarantee of the accurateness of the same.

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