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What Causes Hemorrhoids?
About half of the people in the U.S. will suffer from hemorrhoids at some point in life; for most, this will happen between ages 20 and 50. Researchers are not certain what causes hemorrhoids. "Weak" veins -- leading to hemorrhoids and other varicose veins -- may be inherited.
It's likely that extreme abdominal pressure causes the veins to swell and become susceptible to irritation. The pressure can be caused by obesity, pregnancy, standing or sitting for long periods, straining on the toilet, coughing, sneezing, vomiting, and holding your breath while straining to do physical labor.
Diet has a pivotal role in causing -- and preventing -- hemorrhoids. People who consistently eat a high-fiber diet are less likely to get hemorrhoids, but those who prefer a diet high in processed foods can expect them. A low-fiber diet or inadequate fluid intake can cause constipation, which can contribute to hemorrhoids in two ways: It promotes straining on the toilet and it also aggravates the hemorrhoids by producing hard stools that further irritate the swollen veins.