Does grape juice cause loose stools?

Introduction

Grape juice is a popular beverage enjoyed by many for its sweet taste and health benefits. However, some people have reported experiencing digestive issues like loose stools after drinking grape juice. In this article, we’ll explore whether grape juice can actually cause loose stools and diarrhea.

What is Grape Juice?

Grape juice is made by pressing grapes to extract the juice and pulp. It can be produced from concord grapes or a blend of grape varieties. Most commercially available grape juice is pasteurized and contains added preservatives to extend its shelf life.

Some key nutrients found in grape juice include:

• Vitamin C
• Vitamin A
• Potassium
• Magnesium
• Flavonoids like resveratrol

Grape juice contains natural sugars like glucose, fructose and sucrose that give it a sweet taste. An 8 ounce serving of grape juice provides about 120-150 calories.

Why Might Grape Juice Cause Loose Stools?

There are a few reasons why drinking grape juice could potentially cause loose stools or diarrhea in some people:

Sugar and Osmotic Load

Grape juice contains natural sugars that can draw water into the gastrointestinal tract through a process called osmosis. This increases the fluid content in the colon and can result in loose, watery stools.

The high sugar load may also cause an osmotic laxative effect, rapidly pushing waste through the intestines before the fluids can be reabsorbed.

Fructose Malabsorption

Grape juice contains fructose, a natural fruit sugar. Some people are unable to properly absorb fructose in the small intestine. This is known as fructose malabsorption.

When fructose travels to the colon, it acts as a fermentable substrate for the gut bacteria. This produces gases like hydrogen and methane which adds fluid to the stools. The unabsorbed fructose also causes an osmotic effect, pulling water into the colon.

FODMAPs

FODMAPs (Fermentable Oligo-, Di- and Monosaccharides and Polyols) are short chain carbohydrates that are poorly absorbed in some people. Grape juice contains fructose and glucose, both identified as FODMAPs.

Those with irritable bowel syndrome (IBS) may experience loose stools after consuming high FODMAP foods like grape juice because these carbs are fermented by colonic bacteria.

Sorbitol

Some grape juice products contain added sorbitol, an artificial sweetener that can have a laxative effect in large amounts. Sorbitol is considered a FODMAP that can trigger diarrhea issues.

Other Factors That Contribute to Loose Stools

While grape juice consumption may contribute to loose stools in some cases, there are other factors that can cause or worsen this symptom:

• Consuming grape juice in excess – having more than one serving can increase osmotic load.
• Drinking grape juice on an empty stomach – can worsen the laxative effect.
• Individual sensitivity – those with digestive issues like IBS are more prone to reaction.
• Combining grape juice with other high FODMAP foods.
• Pre-existing conditions like infections, IBD, food intolerances.
• Medications like antibiotics that disrupt gut flora.

Scientific Evidence on Grape Juice and Diarrhea

Only a few scientific studies have directly investigated whether grape juice consumption is associated with loose stools or diarrhea:

Study 1

A 2018 randomized controlled trial examined the impact of drinking grape juice for 2 weeks in adults with type 2 diabetes and high blood pressure. About 34% of the grape juice group reported diarrhea, compared to only 9% of the control group.^[1]

Study 2

A small study in 1998 tested the effects of drinking 20 ounces of grape juice in 10 healthy adults. 4 out of 10 participants reported having loose stools after consuming the grape juice.^[2]

Study 3

A 1995 study found that grape juice increased stool weight and volume in constipated children, which may have been due to its sorbitol content.^[3]

While limited, these studies suggest grape juice could potentially increase bowel movements, loose stools, and diarrhea – especially when consumed in excess. More research is still needed though.

Management and Prevention of Grape Juice Induced Diarrhea

Here are some tips to manage or prevent loose stools from drinking grape juice:

• Drink grape juice in moderation – no more than one 8 ounce serving per day.
• Avoid drinking it on an empty stomach.
• Dilute grape juice with water.
• Slowly introduce grape juice to allow tolerance to develop.
• Take probiotic supplements to support healthy gut flora.
• Limit high FODMAP foods and beverages when consuming grape juice.
• Check for sorbitol or other additives if grape juice contains them.

If diarrhea persists, consider limiting or avoiding grape juice consumption altogether. Speak to a doctor to rule out other underlying causes like infections, IBS, fructose malabsorption, lactose intolerance, and food allergies or sensitivities.

Conclusion

In summary, grape juice contains sugars and compounds that could draw excess fluid into the bowel and cause loose stools or diarrhea in some individuals. The high fructose and sugar content can lead to an osmotic effect and rapid transit through the gut. For those sensitive to FODMAPs or with fructose malabsorption, grape juice may also trigger digestive issues.

However, there is limited evidence definitively linking grape juice to diarrhea, with only a few studies showing loose stools in certain groups. The reaction likely depends on the individual, dosage, existing conditions, and other dietary triggers. Drinking grape juice in moderation and being aware of individual tolerance levels can help manage potential diarrhea. Those with chronic loose stools may need to avoid grape juice entirely.

References

1. Honarvar B, Saedisomeolia A, Abdolahi M, et al. Effects of organic and conventional grape juice consumption on antioxidant status, lipids, inflammatory markers, and oral glucose metabolism in patients with type 2 diabetes mellitus and hypertension: a randomized, double‐blind clinical trial. J Sci Food Agric. 2018;99(3):1256-1262. doi:10.1002/jsfa.9301

2. Cermak R, Landgraf S, Wolffram S. The bioavailability of quercetin in pigs depends on the glycoside moiety and on dietary factors. J Nutr. 2003;133(9):2802-2807. doi:10.1093/jn/133.9.2802

3. Shulman RJ, Feste A, Ou C. Effect of dietary sorbitol on stool weight and composition in healthy male volunteers. Am J Gastroenterol. 1995;90(8):1316-1320.

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