I Just Found Out That Raw Lima Beans Can Be Deadly—Here's What You Need to Know

Isadora Baum; Reviewed by Jess Ball, M.S., RD
·3 min read

Beans and legumes are among the healthiest foods you can eat, as they have protein, iron and fiber to keep you full and regular (they're called the magical fruit for a reason!). Lima beans are a type of legume, like chickpeas and lentils, and they pack some pretty impressive health benefits.

Ilyse Schapiro, M.S., RD, CDN, says, "Lima beans are great for diabetes control, as they are low [on the] glycemic index and rich in fiber, which helps to control blood sugar." That fiber keeps your gut in check, and eating beans can even help you live longer. Yet, I just learned that if you eat lima beans raw, it could be deadly. I was curious to find out why, so I asked the experts.

Why Is It Dangerous to Eat Raw Lima Beans?

Raw lima beans contain a compound called linamarin, which turns into cyanide when consumed. Though you're likely not sitting around eating raw lima beans, it's important to keep them away from children and to make sure that, when you are cooking them, you're doing it properly. Schapiro says cooking lima beans thoroughly is important because "when you cook lima beans, it destroys the enzymes that would release the cyanide."

It's also worth mentioning that where you buy your beans from may also play a role in how much linamarin they contain. "Lima beans in the U.S. tend to have lower levels of cyanide." Though commercially grown lima beans in the U.S. must have less than 200 mg/kg of cyanide, it's definitely better to err on the safe side and cook your beans thoroughly, since ingesting even small amounts of cyanide could cause unpleasant side effects such as headache, dizziness, nausea, vomiting, rapid breathing and increased heart rate, according to the CDC.

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How to Cook Raw Lima Beans So They're Safe

Before consuming lima beans, Schapiro recommends cooking them for at least 10 minutes, but you can cook them even longer if you want to stay on the safe side. Oregon State University says that cooking your lima beans in a large pot of water for at least 30 minutes will remove about 80% of the original cyanide, but also notes that cooking U.S. lima beans (which have low levels of linamarin) for 10 minutes will likely be sufficient.

As for cooking them, you can keep it simple and boil them like we do in our recipes for Stewed Lima Beans or Mediterranean Lima Beans. You can also boil them for 10 minutes before whirling them into a tasty Lima Bean Spread.

You can even cook lima beans in the pressure cooker! That makes meal prep easy, as you let the dish cook in the pressure cooker while you're out and about then find a meal ready to eat right when you get back home.

Here, Schapiro suggests an easy method. First, rinse the lima beans, then combine the lima beans, broth and water, the chopped onion, garlic, bay leaves, and kosher salt. Put the pressure cooker on high for about 25 minutes. When it is done, let the pressure release for 5 to 10 minutes.

"Enjoy as a side dish, or add ham, or sausage or bacon. You can also add different seasonings like rosemary, or different herbs," she says.

The Bottom Line

Lima beans are a delicious way to boost protein, iron, fiber and nutrients in your diet, but cooking them properly will ensure that they're safe to eat. So, the next time you pick up some raw lima beans, make sure to cook them for at least 10 minutes before consuming!