When people buy nuts to snack on, they choose peanuts more often than any other kind, reports the National Peanut Board. Peanuts are actually legumes that grow underground, and they're nutritionally similar to nuts that grow on trees. Just like the other nuts, peanuts may help lower your risk of heart disease, as long as you keep calorie intake under control by limiting portions. But peanuts have a downside: For some people, they can be hard to digest, and they may cause side effects such as gas and diarrhea.
Allergies Versus Intolerance
Peanut allergies are one of the most common food allergies, and they’re on the rise in the United States, according to a July 2014 report from the American Academy of Allergy, Asthma and Immunology. If you’re allergic, you have to eliminate peanuts from your diet to avoid serious reactions. However, it's also possible to be intolerant to peanuts. For some people, that means they're difficult to digest. Depending on the severity of your intolerance, you may still eat peanuts occasionally without problems, or you may experience stomach pain, cramping, nausea, vomiting, diarrhea and excessive gas.
High Fiber Effect
A handful of dry-roasted peanuts, which is about 1 ounce, contains 2 grams of dietary fiber. Fiber is great for your digestive tract -- it keeps you regular and slows down the absorption of nutrients. But if you’re not used to eating that much fiber at once, or if you consume it too quickly, fiber can cause digestive problems. The most common side effects are bloating, gas and diarrhea. If you increase your fiber gradually, it gives your intestines time to adjust, and you’ll lower the risk of developing side effects. The Institute of Medicine recommends women get 25 grams of total fiber daily, while men need 38 grams.
Interference From Phytate
Peanuts contain phytic acid or phytate, which stores phosphorus the plant needs to grow. The amount of phytate in peanuts varies, but they have the potential to be one of the top sources. Phytate can have some unwanted side effects in your digestive tract. For starters, it isn’t digested well. It inhibits digestive enzymes, so you may not properly break down and absorb protein and carbs, according to a report in the September 2010 issue of "Toxins." Depending on the amount of phytate and other carbs you eat, you may end up with gas and bloating. Phytate also interferes with the absorption of iron, magnesium, calcium and zinc.
Despite any potential digestive problems, peanuts are rich in unsaturated fats that help lower cholesterol. They’re also good sources of protein, folate, vitamin E, magnesium, potassium and zinc. Peanuts are so beneficial they’re allowed to carry a health claim from the U.S. Food and Drug Administration -- eating 1.5 ounces daily may lower your risk of heart disease, as long as the rest of your diet is low in saturated fat and cholesterol. You can get too much of a good thing: 1 ounce of peanuts has 166 calories, reports the USDA National Nutrient Database.