It Can Cause Migraines
Some people have an allergic reaction to beans, though this isn't common. When these people eat beans it can trigger migraines for them. If this happens, it important to see a doctor and possibly eliminate it from your diet depending on what the doctor advises.
It Can Interfere With Vitamin Absorption
Some beans, like soy beans, contain substances that can interfere with the absorption of betacarotene, vitamins B12 and vitamins D. However, the heat from cooking renders most of these substances inactive which makes vitamin absorption more likely. Nevertheless, it is still advisable to compensate for potential vitamin loss by consuming fresh fruits, green vegetables and lean meat.
It Can Make You Gassy
Well this isn't exactly a health risk, but beans, especially dried beans, lentils and peas, can cause embarrassing flatulence (excessive gas) problems. You can reduce the gas production of beans by changing the water several times during the soaking and cooking process, and always rinse canned beans. It might seem like a lot of work but when you consider the potential embarrassment it might save you from, it might in fact be worth it. Adding herbs like lemon balm, fennel and caraway can also help to reduce the gas production of beans.
It Can Cause Cramping
Beans contains fiber and this component is not easily digested by the body. If you overdo the quantity of beans you consume, the fiber in the beans can temporarily slow down your bowels (because it is indigestible) and cause cramping.
It Can Cause Constipation
Typically, the fiber in beans is meant to help prevent constipation by moving food through your intestines. However, the flip side to this is that if you do not drink enough liquids after consuming beans, it can actually constipate you. This is because beans are high in both soluble and insoluble fiber, and soluble fibers need liquid to move through your system as it should.
The solution for most of the health risks or side effects of beans is simply water. Boiling beans well helps to soften its fiber content, and drinking plenty of liquid after consuming beans helps it to move around in your digestive tract more efficiently which helps to eliminate flatulence, cramping and constipation. You should ensure you eat beans in moderation too, don't overdo your quantities no matter how much you love beans.