Can Grape Juice Prevent or Fight a Stomach Flu or Bug?

Grape juice is a popular beverage that contains vitamins, minerals, and other nutrients. Grape juice is said to have antiviral properties, which prevent viruses from growing in the gut.

Grape juice is a popular beverage that contains vitamins, minerals, and other nutrients. It has many potential health benefits. Some people say that grape juice even fights stomach bugs and prevents stomach flu. Here’s all you need to know about grape juice and stomach bugs, including whether or not grape juice cures stomach flu.

Stomach flu (viral gastroenteritis) is a viral infection affecting your gut. It is commonly called stomach flu, but it is not caused by the influenza virus or flu virus and doesn’t actually affect the stomach: Instead, it is an infection of the intestines.

Stomach flu is an acute infection — it occurs suddenly and lasts for less than a week. Most people with stomach flu get better quickly without medical treatment. However, in some, this illness may cause severe symptoms and dehydration.

Symptoms of stomach flu

Symptoms of stomach flu include:

• Watery stools or diarrhea
• Abdominal pain or cramps 
• Nausea or vomiting
• Fever

Causes of stomach flu

Stomach flu can spread from person to person. You can get it if you come in contact with infected stool or vomit or nearby surfaces. This is more likely if you don’t wash your hands after using the bathroom and touch nearby surfaces and objects or shake hands with others. 

Bugs that cause stomach flu include cases of norovirus, rotavirus, adenovirus, and astrovirus. Norovirus is the most common cause of stomach flu. It affects people of all ages. In contrast, adenoviruses, rotaviruses, and astroviruses specifically infect babies and young children more often. 

In the U.S., rotavirus, norovirus, and astrovirus commonly cause infections in the winter.

Many people believe that the nutrients in grape juice help fight stomach bugs and stomach flu. Grape juice is said to have antiviral properties, which prevent viruses from growing in the gut.

What are the nutrients in grape juice?

One cup (253 grams) of unsweetened grape juice with added vitamin C contains the following nutrients:

• 214 grams of water
• 152 calories
• 0.936 grams of proteins
• 0.329 grams of fats
• 37.4 grams of carbohydrates
• 0.506 grams of fiber
• 35.9 grams of sugar
• 63.2 milligrams of vitamin C (i.e., ascorbic acid)

Grape juice also contains minerals like calcium, iron, magnesium, phosphorus, potassium, sodium, zinc, copper, and manganese. It also contains thiamine, riboflavin, niacin, pantothenic acid, vitamin B6, choline, and vitamin A, in addition to antioxidants like beta-carotene, lutein, and zeaxanthin.

Grape juice, stomach bugs, and the cure for stomach flu

There are some theories about grape juice’s potential effect on stomach bugs.

Grape juice pH. Research suggests that grape juice stops the growth of germs like bacteria and viruses in your body because of its acidity. It contains ascorbic acid or vitamin C, which makes it acidic. It has a pH of 3.3, and this high acidity level may kill germs in the stomach. However, researchers have only tested the antimicrobial activity of grape juice in a test tube and in animals.

Additionally, the change in acidity in your stomach after drinking grape juice is mild and may not last long enough to fight viruses before they enter your gut. So, grape juice acidity may not be able to cure stomach flu.

Vitamin C. Another theory is that grape juice can kill stomach bugs because it has high antioxidant levels. Vitamin C is one such antioxidant that can kill stomach bugs and prevent infection. Vitamin C also benefits symbiotic gut microbes (including beneficial gut bacteria), which may improve your immune system and fight against stomach bugs.

However, vitamin C is absorbed in the intestines, so if you have 30 to 180 milligrams of vitamin C daily, 70% to 90% of that gets absorbed by your body, and only a fraction might reach the gut microbes. Even when vitamin C  is added, a cup of grape juice typically contains only 63.2 milligrams, which may not be enough to cure or prevent stomach flu.

Still, old lab studies show that the ascorbic acid present in grape juice can eliminate intestinal viruses or enteroviruses like poliovirus. Another lab study suggests that vitamin C and sodium bisulfate deactivate enteroviruses. That being said, researchers haven’t studied the effects of grape juice on stomach flu in natural environments.

Vitamin A. Grape juice is rich in vitamin A. This is a natural antioxidant that promotes the growth of beneficial gut bacteria. A study in mice shows that vitamin A increases the levels of the gut bacteria Lactobacillus in the intestines. That may help control norovirus growth and prevent stomach flu. However, more studies are required to confirm whether grape juice is actually an effective cure for stomach flu in humans.

To date, there’s a lack of conclusive evidence to back the theories people believe about grape juice and its effect on stomach bugs. 

Most of the time, stomach flu resolves on its own. If you have unusually severe symptoms, stomach flu treatment includes drinking lots of liquids and electrolytes. This prevents dehydration and replaces the fluids you may lose due to diarrhea or vomiting. Your doctor will ask you to drink lots of water, fruit juices, and sports drinks. Children are usually also given oral rehydration solutions like Pedialyte. These contain sugar and electrolytes that replenish the body. 

Your doctor may also prescribe over-the-counter medicines such as loperamide (Imodium) and bismuth subsalicylate (Pepto-Bismol) to treat diarrhea caused by the stomach flu. They may prescribe other medications to control vomiting. Some doctors may even recommend taking probiotics, which partially consist of beneficial gut bacteria. These probiotics help improve your immune system, fighting stomach bugs and reducing diarrhea. 

You can prevent the stomach flu by washing your hands properly after using the bathroom, changing diapers, or preparing and eating food. If you come in contact with stool or vomit, sanitize surrounding surfaces and wash your hands thoroughly. 

Norovirus can also spread through contaminated food like fruits, vegetables, or oysters, so wash fruits and vegetables properly and cook oysters and shellfish thoroughly before eating them. 

You can’t prevent stomach flu by getting regular flu vaccines, but rotavirus vaccines are available to protect babies from that variety of the stomach flu.