People who find themselves with severe stomach aches or on the toilet dealing with diarrhea often scour the Internet to see if they have a stomach bug or food poisoning. Given that two gastrointestinal diseases share similar symptoms, it can be difficult to tell the difference. Knowing which infection you have can help provide guidance about how long your symptoms will last and how to manage your illness.
What is the difference between stomach flu and food poisoning?
At a high level, stomach flu and food poisoning fall under the broad category of gastroenteritis, which is a medical term to describe any inflammation (irritation) in the intestines.
The source of infection is the main difference between stomach flu and food poisoning. In most cases, stomach flu is caused by a viral infection, while food poisoning is caused by bacteria or parasites.
Another major difference is the onset of symptoms – food poisoning can occur within hours after eating contaminated food. On the other hand, stomach flu can take several days to cause symptoms after infection.
The terms stomach flu and stomach bug are both used interchangeably to describe viral gastroenteritis, a viral infection that causes inflammation and swelling in the lower part of the digestive system — the stomach, small intestine, and large intestine. Some people can get sick from bacteria, parasites, or toxins, although viruses are the most common cause of stomach flu.
It should be noted that stomach flu has nothing to do with influenza that causes the upper respiratory tract.
Here are the most common viruses that cause stomach flu:
- Norovirus: The most common cause of viral gastroenteritis in adults, symptoms may not begin until a day or two after infection. Norovirus can last for up to three days.
- rotavirusMore common in children than adults, rotavirus symptoms begin two days after infection. Symptoms may go away in a few days but may also last up to a week. Children can receive the rotavirus vaccine to prevent infection.
- Adenovirus: The adenovirus has a longer incubation period than the other three viruses listed, as it can take up to 10 days for symptoms to appear. From there, symptoms can last one to two weeks.
- Astrovirus: This type of virus usually produces symptoms four to five days after infection and lasts a few days.
Diarrhea is the main symptom of stomach flu, and people also experience nausea, vomiting, stomach cramps, fever, headache, and dizzy spells. The virus does not allow your digestive system to absorb water from the foods you eat, so your bowel movements become more fluid than usual.
A combination of diarrhea and vomiting causes dehydration in some people with stomach flu. Loss of body fluids and electrolytes leads to dehydration and can cause dry mouth, dizziness, decreased urine output, dark-colored urine or tiredness.
Food poisoning occurs when you eat food or water contaminated with viruses, bacteria, or parasites. There are more than 250 types of food poisoning, and they affect about 48 million people annually, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
Symptoms include diarrhea, stomach cramps, fatigue, fever, chills, muscle aches, and excessive sweating. Like the stomach flu, dehydration is a common complication of food poisoning. In some cases, a bacterial infection from Escherichia coli can cause hemolytic uremic syndrome, a condition in which destroyed red blood cells damage the kidneys.
Viruses that cause food poisoning:
Bacteria that cause food poisoning:
- Clostridium (C. purpurea and Clostridium botulinum)
- Escherichia coli (E. coli)
- Listeria monocytogenes (Listeria monocytogenes)
- Salmonella External Link to the National Institutes of Health
- Staphylococcus aureus (Staphylococcus)
- Vibrio (Paraemolyticus and Vulnificus)
Parasites that cause food poisoning:
Many of the most common causes of food poisoning have a short incubation period, including staph (30 minutes to 8 hours), salmonella (6 to 48 hours) and Clostridium perfringens (8 to 16 hours).
Is food poisoning contagious?
Food poisoning is not usually contagious because it is spread through food. However, there are some cases in which food poisoning may spread from person to person. This includes the spread of microorganisms in food or drinks by infected people who do not wash their hands after using the bathroom.
However, in most cases, harmful microorganisms are already found in foods such as raw fruits, vegetables and meat.
How does stomach flu spread?
On the other hand, viral gastroenteritis is highly contagious. Infection is spread by close contact, such as sharing items with an infected person or touching your mouth after touching a contaminated surface (doorknobs, handles, work surfaces, etc.).
Norovirus is the most common way stomach flu is spread. In most cases, the virus spreads in restaurants or food distribution centers where workers improperly handle ready-to-eat food. Buffets, such as those at resorts or cruise ships, tend to be most affected as workers can touch food with their bare hands and unknowingly spread the virus.
What do you eat when you have food poisoning or stomach flu?
Whether you have an upset stomach or have food poisoning, here are some tips to follow.
One of the first things associated with viral gastroenteritis or food poisoning is anorexia. But with the loss of fluids and electrolytes, eating and drinking is still critical when fighting digestive ailments.
For starters, you can follow the BRAT diet, which stands for bananas, rice, applesauce and toast. These foods won’t help your symptoms, but are gentle enough that they don’t upset your stomach any more.
Other foods that may be nice to your stomach include cereal (without milk), pretzels, oatmeal, or broth. Pretzel cookies are good for saving calories and salt lost from dehydration. However, you should not eat these foods for more than a day or two, as they lack the nutrients your body needs for energy and for other daily routine tasks.
Regarding fluids, drink plenty of water to help replace any lost fluids. Sports drinks are a good source of electrolytes, but many types are full of added sugars.
While bland foods can help provide energy while your body fights infection, some foods may make symptoms worse. For example, caffeine is a stimulant and can lead to more frequent bowel movements, while foods high in fat can disrupt the digestive system. Even milk can be difficult to digest when you are sick due to the presence of lactose and can worsen your problem.
While an upset stomach is not fun to deal with in the short term, most cases are mild and will resolve within 24 to 48 hours by treating it with rest and plenty of fluids. However, some cases are more severe and may lead to severe dehydration. Watch for your symptoms, and if you feel tired, excessively thirsty and have decreased urine output, call your doctor or go to your nearest urgent care.