Grape juice is a popular beverage with numerous health benefits. Many people even believe that it can help prevent the stomach flu.

However, you may wonder whether this claim stands up to scientific scrutiny.

This article tells you whether grape juice can fight stomach bugs.

Theories about grape juice and the stomach flu

Theories that grape juice lowers your risk of the stomach bug often circulate online during the most germ-filled months of the year.

Some people suggest that grape juice changes the pH — or acidity level — of your stomach acid, thus stopping pathogens from multiplying and making you sick.

However, stomach viruses multiply most profusely in your intestinal tract, which is naturally kept at a more neutral pH (1, 2).

Others assert that grape juice has antiviral properties, which are usually attributed to its vitamin C content.

Vitamin C is a potent antioxidant with antiviral properties and has been shown to boost immunity.

While most research has examined vitamin C consumed orally or in a lab setting, there’s some more recent and ongoing research on the effects of intravenously administered vitamin C on immunity.

One older test-tube study found that vitamin C inactivated a virus that causes the stomach bug and prevented it from multiplying (3).

Furthermore, diets that regularly incorporate foods rich in vitamin C may help protect your digestive system (4).

Even though grape juice contains some vitamin C, it’s far from the best way to obtain this nutrient.

A 3/4-cup (180-mL) serving of 100% grape juice contains 63% of the Daily Value (DV) for vitamin C, while a large orange packs over 100% and 1 cup (76 grams) of raw broccoli contains 85% (5, 6, 7).

SUMMARY

Some of the most common theories about drinking grape juice to prevent the stomach flu are that the beverage prevents viruses from multiplying and has antioxidant and antiviral properties.

What the research says

Specific studies on grape juice have not found it to prevent the stomach flu.

While grape juice appears to offer antiviral properties, these attributes have only been demonstrated in test-tube studies — not clinical trials in humans (8, 9).

An older test-tube study suggested that grape juice may inactivate certain human stomach viruses but probably wouldn’t be effective at doing so when people drink it (10).

Other test-tube research using grape extracts and infusions indicate that compounds in grape skin, such as sodium bisulfite, vitamin C, tannins, and polyphenols, may neutralize viral activity (11, 12, 13).

Furthermore, test-tube studies reveal that grape seed extract may prevent some viruses from multiplying enough to cause illness (14).

However, drinking grape juice doesn’t give you the same concentration of these compounds.

Overall, there’s no solid evidence that drinking grape juice is an effective way to prevent the stomach bug. That said, much of the research is dated and was conducted in test tubes, so newer, human studies are needed.

SUMMARY

Most studies on grape juice and stomach viruses are outdated or were conducted in test tubes. As such, their results don’t translate to everyday grape juice consumption. Currently, no evidence supports the idea that drinking this juice prevents stomach bugs.

Better ways to prevent a stomach virus

Drinking grape juice is not a reliable or effective method to keep yourself from getting a stomach virus.

Better, evidence-based ways to boost immunity and prevent the stomach flu include:

  • washing your hands with soap and water, especially after using the restroom, being in public places, and before eating meals (15)
  • avoiding shared utensils, food, or beverages
  • distancing yourself from people with contagious cold or flu symptoms (16)
  • following a diet rich in whole fruits and vegetables, which are naturally high in vitamin C and other immune-boosting plant compounds (17)
  • practicing regular physical activity (18)

Incorporating these habits into your routine is more likely to keep you healthy than simply drinking grape juice.

SUMMARY

Hand washing, social distancing, nutritious diets, and exercise are much more effective ways to boost immunity and prevent illnesses than drinking grape juice.

The bottom line

Many people enjoy grape juice for its sweetness and presumed immune-protective effects.

However, there’s no evidence that drinking grape juice is an effective way to prevent the stomach virus.

Better ways to bolster your immunity and lower your risk of getting the stomach flu include washing your hands, avoiding sharing utensils and food with other people, engaging in exercise, and eating a healthy diet full of fruits and vegetables.