Peanuts are quite beneficial for human health at it is rich in Protein, Calcium, magnesium, Potassium, Phosphorus and Dietary fiber which all are good for human health.
But excessive intake can cause some problems because of which people try to avoid eating peanuts, seeing so many people avoiding it people become confused and start asking questions that are peanuts harmful for our health.
Peanuts grow underground and can be contaminated with a mold which creates aflatoxin which is dangerous for liver. If human is exposed to aflatoxin for a long period or eats a great amount it may cause liver failure or liver cancer.
Peanuts are also rich in Sodium which may increase the chances of heart attack, it also contains Saturated Fat which increases the LDL cholesterol or the bad cholesterol.
If you are not careful with the calorie intake it will result in weight gain, eating half cup of peanuts fulfills 1/5th of your calorie need, so excess intake will make you gain 27 pounds in few months.