Myth: I can change my body’s pH by eating certain foods.

Answer: Busted!

Some fad diets claim that you can make the pH of your body less acidic (in other words, more alkaline) by consuming more fruits, vegetables, and milk and less meat, fish, eggs and grains. This diet is based on some studies showing that cancer cells growing in test tubes will grow faster in an acidic environment and some anti-cancer drugs work better in an alkaline environment. Supporters of the diet argue that your urine, and therefore your body as a whole, will become more alkaline by following this diet. They believe that the more alkaline your body is, the better it can protect itself against cancer.

Unfortunately, there are several major flaws in the alkaline diet theory. First, following an “alkaline diet” will make your urine more alkaline, but it doesn’t change your blood pH. Urine is contained in the bladder and is not the same as blood. The kidneys are constantly working to keep blood pH from ever changing significantly; a condition that can make a person extremely sick and even result in death if untreated. Additionally, numerous studies show that no human cells can survive in an alkaline environment, regardless of whether they are healthy cells or cancer cells.

Eating a diet rich in fruits and vegetables is a good way to help prevent cancer because of the many nutrients that fruits and vegetables contain. Don’t be fooled into cutting out other food groups, especially whole grains and heart-healthy fish, which can also protect against some cancers.

Contributor: Mary Wissmann, MS, RD, LD, Nutrition and Health Education Specialist, St. Louis County, University of Missouri Extension, WissmannM@missouri.edu

MYTH: Drinking cold water after meals can cause cancer.

Answer: Busted!

As the myth goes, drinking cold water after meals will cause the oils and fats that you have just consumed to become solid. This "sludge" is supposed to react with the acid in your digestive system, line the intestines, turn into fat, and cause cancer.

This myth is busted on several accounts, starting with the entire premise that drinking cold water will turn oil into solid sludge. Our internal body temperature is a steamy 98.1 degrees, and it typically takes 2 to 3 hours for a meal to empty from the stomach and move into the small intestines. This is plenty of time for all of the liquids and solids in your stomach to become the same warm temperature. Additionally, during these 2 to 3 hours of digestion, the stomach mixes and churns it contents until everything is a similar consistency. Once in the small intestines, food is broken down further into carbohydrates, protein, and fats and absorbed through the wall of the intestine and into the blood stream. Fat does not remain in the intestine for an extended period of time.

While it is true that an accumulation of a large amount of body fat can put you at a higher risk for certain types of cancers, this has nothing to do with the temperature of the water you drink before, after, or during meals.