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Food Poisoning vs Stomach Flu: Learn the Difference

If you’ve come down with a stomach bug or feel like you contracted food poisoning after eating something suspicious, you might not know how to tell food poisoning vs the stomach flu apart. They often have similar symptoms and similar durations, but it’s important to know if your illness is serious and when to see a doctor.

The stomach flu — also known as the stomach bug or viral gastroenteritis — is an intestinal infection that can result from contaminated food or water. It causes inflammation of the intestines and the stomach. A person can also contract gastroenteritis through contact with someone who already has the illness. The virus is present in stool and vomit, so the stomach flu can easily be carried on the hands, face, and body of an infected person.

Food poisoning is an illness caused by consuming something contaminated with a bacteria, parasite, or virus. The toxins of these microscopic organisms can also cause illness. Food can be contaminated when being grown, harvested, processed, packed, or handled at a store or at home.

Many of the symptoms of food poisoning and the stomach flu overlap, but they vary in severity and duration. The reaction you have to food poisoning and the stomach flu also depends on the strength of your immune system. Children, the elderly, and immunocompromised adults may be more severely affected by food poisoning and gastroenteritis.

Depending on how you contracted food poisoning, the onset of your symptoms and their severity will vary. Typically, however, people with food poisoning will experience:

  • Watery or bloody diarrhea
  • Nausea
  • Vomiting
  • Fever
  • Abdominal cramps

Symptoms of food poisoning can begin as soon as hours after eating or manifest days later. Food poisoning typically doesn’t last more than several days, sometimes only lasting a few hours, and improvements can be seen in a couple of days.

The symptoms of the stomach flu are gastrointestinal, even though normal flu symptoms are respiratory. This is because gastroenteritis isn’t really a form of influenza, which attacks the respiratory system. It’s actually a viral infection of the intestines. Its symptoms include:

  • Nausea and/or vomiting
  • Diarrhea
  • Muscle aches or headaches
  • Low fever
  • Fatigue

Symptoms can manifest one to three days after you’ve been infected, but it can be hard to tell when you were first in contact with the illness. Gastroenteritis is the most severe the first one to three days after symptoms appear and rapidly improves within a week.

Viral gastroenteritis doesn’t have the same symptoms in everyone. Having one of these symptoms doesn’t always mean you have a stomach bug, either. For example, some people who experience migraines also have nausea. If you’re unsure, consult with your doctor or visit an urgent care center or emergency room. 

Stomach flu and food poisoning are caused by different things. Specific viruses can cause the stomach flu and different types of bacteria, viruses, and parasites (or their toxins) lead to food poisoning.

Food poisoning is caused by food contaminated by toxic microscopic organisms. Salmonella, for example, is often found in raw or undercooked poultry and meat, as well as in undercooked eggs and raw milk. It can cause food poisoning when ingested. 

Other bacteria that cause food poisoning are E. coli and listeria. These can often be found in improperly handled food. For example, a total of 85 multistate outbreaks in the United States from 2010–2017 that were caused by E. coli, listeria, and salmonella were due to contaminated lettuce and other fruits and vegetables. Eating raw foods and ready-to-eat foods can increase your risk of contracting food poisoning because uncooked foods haven’t been exposed to high temperatures that can kill some bacteria.

Stomach flu can also be caused by contaminated foods and liquids. However, gastroenteritis is usually caused by strains of norovirus or rotavirus. Norovirus is highly contagious and often spread through food contaminated with the virus. Rotavirus affects children more than adults, but adults can carry it and unwittingly spread it to children. Foods are often contaminated because someone with the stomach flu prepares food with hands contaminated with fecal matter or vomit. 

Food poisoning can be treated with fluids and antibiotics. 

Treatment for food poisoning typically depends on the source of the illness, if known, and the severity of your symptoms. Most people feel better without any medication or treatment within a couple of days, provided they rest and avoid fatigue. Fatigue can exacerbate symptoms and make for a longer recovery.

More severe cases of food poisoning need to be treated with antibiotics, and in some cases intravenous antibiotics are administered during a hospital stay. Remember, though, that only bacterial food poisoning can be treated with antibiotics, so if your food poisoning is the result of a virus, you’ll simply have to wait it out. 

Fluids and electrolytes — minerals such as sodium, potassium, and calcium — lost to persistent diarrhea need to be replaced. Some children and adults with persistent diarrhea or vomiting may need hospitalization, so they can receive salts and fluids intravenously to prevent or treat dehydration.

Stomach flu is caused by a virus, so specific treatments aren’t available. Fortunately, it’s often short-lived, and treatments like hydration can be done at home. It’s very important to rest and give your body time to regain energy after an illness that results in dehydration and serious loss of fluids. If your symptoms don’t resolve after about a week, you may want to see a doctor to confirm your diagnosis and investigate other potential issues.

Doctors usually do not recommend antidiarrheal medications for gastroenteritis because they tend to prolong infection, especially in children.

The best thing to eat when you’re suffering from food poisoning is nothing. Your stomach will be unsettled and irritated, and you may vomit up anything you ingest. Helping your body rehydrate is the best course of action.

Diarrhea can lead to dehydration, so taking small sips of water when you can tolerate it can help your body. When your urine is clear or light-colored, you’re hydrated. You might experience loss of appetite for a while even after the worst of your symptoms are over. Foods that are low in fat and easy to digest — like toast, bananas, and rice — can restore your appetite and help you regain your strength. After an illness that causes diarrhea and vomiting, your body is likely to be low in vitamins and many nutrients. Slowly incorporate simple but healthy foods back into your diet.

As in cases of food poisoning, people with the stomach flu are better off avoiding many foods and slowly rehydrating themselves. Drinking plain water and water with electrolytes can replace lost nutrients like sodium and potassium. Plain chicken, rice, and gelatin can soothe an inflamed stomach.

The symptoms of the stomach flu vs food poisoning often overlap — they both can cause nausea, vomiting, stomach pain, and occasionally a fever. People with the stomach flu may also have headaches with their illness.

Food poisoning is caused by bacteria and viruses that have contaminated food or liquids. These include E. coli, listeria, and salmonella. People get a stomach bug or the stomach flu from viruses such as strains of the norovirus or rotavirus. These are spread from person to person by fecal matter or vomit.

Treating the stomach flu and food poisoning often doesn’t require medication. Many treatments for both involve replacing fluids and resting for the duration of the illness. However, when a person has a serious bacterial illness as a result of E. coli, listeria, or another dangerous bacteria, they need immediate medical attention (and medically prescribed antibiotics).

If you’re comparing the best foods for food poisoning and the stomach flu, the best food is often none at all. It’s most important to drink plenty of water to avoid dehydration. Eventually, foods with low fat that are easy to digest — such as rice, crackers, gelatin, bananas, and toast — can be reintroduced.

Neither the stomach flu nor food poisoning is usually serious. Most people see improvements within a few days. By avoiding possibly contaminated foods and people, you can avoid getting sick with gastroenteritis. If you’re eating at home, make sure to properly wash and cook all foods to prevent food poisoning.

https://www.niddk.nih.gov/health-information/digestive-diseases/viral-gastroenteritis/symptoms-causes#spread

https://my.clevelandclinic.org/health/diseases/12418-gastroenteritis/management-and-treatment

https://www.cdc.gov/foodsafety/symptoms.html

https://www.fda.gov/food/consumers/what-you-need-know-about-foodborne-illnesses

https://www.mayoclinic.org/diseases-conditions/viral-gastroenteritis/diagnosis-treatment/drc-20378852

https://www.mayoclinic.org/diseases-conditions/food-poisoning/diagnosis-treatment/drc-20356236

https://www.mayoclinic.org/diseases-conditions/viral-gastroenteritis/symptoms-causes/syc-20378847

https://www.mayoclinic.org/diseases-conditions/food-poisoning/symptoms-causes/syc-20356230

https://www.mayoclinic.org/diseases-conditions/food-poisoning/diagnosis-treatment/drc-20356236

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6883221/

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