DEAR DOCTOR K: I've heard that an alkaline diet can help prevent cancer. Is this true?
DEAR READER: I wish it were, but it's not. So-called alkaline diets do not fend off cancer. That's because it's nearly impossible to change your body's pH by changing what you eat. Let me back up for a minute. Every day our bodies perform any number of intricate balancing acts. One of them is to make sure the body's fluids, tissues and cells don't get too acidic or, at the other extreme, too alkaline. As you may remember from high school chemistry, acidity and alkalinity are measured as pH.