Oysters are a delicious seafood treat that many people enjoy However, some people report feeling gassy or bloated after eating them. So, do oysters really make you gassy?
The short answer is – sometimes Let’s take a closer look
Why Oysters Can Cause Gas
Because of a few things, oysters may make some people gassy or bloated:
1. High Fiber Content
Oysters contain a type of carbohydrate fiber called oligosaccharides Our bodies can’t fully break down oligosaccharides during digestion. So when they reach the large intestine, they get fermented by gut bacteria This fermentation process results in gas as a byproduct.
For the same reason, other high-fiber foods like broccoli, cabbage, beans, and lentils can give you gas.
2. Individual Sensitivity
We all have slightly different populations of gut bacteria. Some people naturally produce more gas from certain foods than others.
If your personal mix of gut bacteria is efficient at fermenting oligosaccharides, oysters may make you gassier. People with irritable bowel syndrome (IBS) also tend to be more sensitive to gas-producing foods.
3. Contamination Risk
Raw oysters can sometimes be contaminated with bacteria, especially Vibrio species. Consuming contaminated raw oysters can lead to food poisoning, causing diarrhea and gas.
Cooking oysters thoroughly eliminates this risk.
4. Allergies
Some people have true allergies to oysters and other shellfish. An allergic reaction can also cause digestive symptoms like gas, cramping or diarrhea after eating only a small amount.
Tips to Prevent Oyster-Induced Gas
If you want to keep enjoying oysters without the unwanted side effect of gas, here are some tips:
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Cook oysters thoroughly – Raw oysters are more likely to cause foodborne illness. Cooking destroys any harmful bacteria.
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Limit portion size – Stick to 4-6 medium oysters. Large servings are more likely to cause issues if you’re sensitive.
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Take a digestive enzyme – A supplement containing alpha-galactosidase can help break down the oligosaccharides in oysters to prevent gas. Take it just before or with your meal.
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Try probiotics – Probiotic supplements can help populate your gut with bacteria that process oligosaccharides more efficiently and produce less gas.
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Avoid pairing with other gas-producing foods – Don’t have oysters with beans, broccoli, cabbage, soda, etc. in the same meal. Combining multiple gassy foods increases the chances of gas and bloating.
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Check for shellfish allergy – See an allergist if you experience coughing, hives, swelling or other severe reactions after eating oysters. You may need to avoid them entirely.
What Causes Gas After Eating?
Oysters are just one of many common culprits that can lead to gas and bloating. Here are some of the main dietary causes of intestinal gas:
Fiber
Soluble fiber from foods like beans, lentils, oats, fruits, vegetables and whole grains can’t be digested by your small intestine. In the large intestine, fiber gets fermented by bacteria, producing hydrogen, methane and carbon dioxide as byproducts – aka gas.
Lactose
People with lactose intolerance lack enough of the enzyme lactase to properly digest lactose – the sugar found in dairy products. Undigested lactose also gets fermented in the colon, causing gas and bloating.
Fructose
Foods high in fructose (like fruits, juices and soda) can exceed the capacity of the small intestine to absorb the sugar. Unabsorbed fructose travels to the colon where it gets rapidly fermented by bacteria, causing gas.
Sugar Alcohols
Sugar substitutes like xylitol, sorbitol and mannitol found in sugar-free foods and gums act as fiber in the gut. Most pass through undigested, and get fermented in the colon – again, producing excess gas.
Starches
Starchy carbohydrates like potatoes, wheat, oats and corn may also cause gas. Some starches can’t be broken down by enzymes in the small intestine, so they reach the colon and get fermented.
Sulfur-Rich Foods
Foods containing sulfur compounds like eggs, meat, Brussels sprouts, broccoli, cabbage, and beer
What You Need to Know
- If you eat oysters that are raw or not fully cooked, they can make you sick with Vibrio bacteria.
- Some kinds of Vibrio bacteria cause the illness vibriosis.
- There is no difference in how an oyster with Vibrio looks, smells, or tastes from any other oyster.
- Cooking oysters properly can kill Vibrio and other harmful germs.
Many people enjoy eating raw oysters. But you can get vibriosis and other foodborne illnesses if you eat oysters and other shellfish that are raw or not cooked enough.
Vibriosis is an illness caused by some kinds of Vibrio bacteria. Vibrio naturally live in coastal waters where oysters live. Because oysters feed by filtering water, Vibrio and other harmful germs can concentrate in an oyster’s tissues. If you eat raw or undercooked oysters, germs that might be in the oyster can make you sick.
CDC estimates that about 80,000 people get vibriosis—and 100 people die from it—in the United States every year. Most of these illnesses happen from May through October when water temperatures are warmer. However, you can get sick from eating raw or undercooked oysters during any month. Raw oysters from typically colder waters also can cause vibriosis.
An oyster that contains Vibrio doesn’t look, smell, or even taste different from any other oyster. You can kill Vibrio in oysters and other shellfish by cooking them properly.
Most Vibrio infections from oysters result in mild illness, including diarrhea and vomiting. However, people with a Vibrio vulnificus infection can get very sick. As many as 1 in 5 people with a Vibrio vulnificus infection die. This is because Vibrio vulnificus infection can lead to bloodstream infections, severe skin blistering, and limb amputations.
If you get vibriosis, you should tell your doctor if you recently ate or touched raw oysters or other raw shellfish or if you were in salt water or brackish water. Brackish water is a mixture of salt water and fresh water. It is often found where rivers meet the ocean.
Vibriosis can happen to anyone, but you may be more likely to get an infection or stay sick if you:
- Having liver disease, cancer, diabetes, HIV, or thalassemia in their blood
- Receive immune-suppressing therapy for the treatment of disease
- Take medicine to lower stomach acid levels
- Have had recent stomach surgery
- Are 65 years or older
Most people become infected by eating raw or undercooked shellfish, particularly oysters. Some people become infected by:
- When you swim, wade, fish, or go swimming, getting brackish or salt water in a wound
- People who cut themselves on something that has been in brackish or salt water, like a rock or pier
- Getting raw seafood juices or drippings in a wound.
If you want to lower your risk of getting sick when you eat or touch shellfish and other seafood, do these things:
- Don’t eat raw or undercooked oysters or other shellfish. Before you eat them, make sure they are fully cooked, and only order fully cooked oysters at restaurants. These germs can’t be killed by hot sauce, lemon juice, or alcohol. Some oysters are treated for safety after they are harvested. Oysters may have less Vibrio after this treatment, but it doesn’t get rid of all harmful germs.
- To keep raw seafood and its juices away from cooked seafood, keep them separate.
- If you touch raw seafood, wash your hands with soap and water.
- Avoid salty and brackish water if you have a wound, even if it’s from surgery, a piercing, or a tattoo that happened not long ago. If your wounds could touch raw seafood or raw seafood juices, or if you think you might get brackish or salt water on them, you should cover them.
- If you get salt water, brackish water, raw seafood, or raw seafood juices or drippings on an open wound or cut, wash it well with soap and water.
Oysters…Aphrodisiac or Placebo Effect?
FAQ
What are the side effects of eating oysters?
Are oysters bad for your gut?
What will happen if you eat too much oysters?
What to do if your stomach hurts after eating oysters?
Are oysters bad for You?
Understanding the risks of eating oysters can help you avoid reactions. Oysters may be a regular part of your summer, but an upset stomach after eating oysters can put a real damper on your warm weather fun. While it’s possible that your oyster side effects could indicate an allergy, if you’ve been eating raw oysters, it may be food poisoning.
Are oysters bad for cholesterol levels?
No, on the contrary, studies show that frequent consumption of oysters manages to lower cholesterol levels, due to the high content of essential fatty acids (omega-3 and omega-6).
What are some gassy foods to avoid?
These include beans, lentils, asparagus, broccoli, Brussels sprouts, cabbage, onions, garlic, wheat, dairy products, and carbonated drinks . If you are looking to avoid gassy foods, you may want to
Can you have an upset stomach after eating oysters?
Shellfish, such as oysters, are one of the most common food allergens. If you have an upset stomach after eating oysters, whether raw or cooked, it may be an allergic reaction. You can develop an allergy to shellfish at any age, but it most often develops in adults, according to Mayo Clinic.