Outdated. Doctors once believed that eating a lot of “roughage” kept the colon free of cancer-causing toxins. Several large studies found, however, that neither high-fiber diets nor fiber supplements prevented colon cancer.
2. Everyone should drink eight glasses of water each day.
Outdated. There is no scientific basis for this common recommendation. According to the Institute of Medicine, a man needs about 125 ounces (15 to 16 cups) of water daily, while a woman requires 91 ounces (a little over 11 cups). That amount is easily gotten from a normal diet, since all beverages and many foods contain water. To stay well hydrated, simply drink when you're thirsty.
3. A “broken heart” is a genuine medical condition.
True. Doctors have shown that people who experience severe emotional trauma, such as losing a loved one, sometimes develop a condition known as stress cardiomyopathy, also called broken-heart syndrome. The condition causes a ventricle, or cavity, in the heart to expand, though it is rarely fatal.
Outdated. Infections caused by bacteria called Helicobacter pylori cause 80% – 90% of stomach and intestinal ulcers. Treatment with antibiotics and Pepto-Bismol is usually successful. Most other ulcers are caused by sensitivity to aspirin and other nonsteroidal anti-inflammatory pain relievers, such as ibuprofen.
5. Washing your hands with antibacterial soaps helps prevent colds.
Outdated. Washing your hands frequently is always a great idea, especially during cold season; the rhinovirus, which causes the common cold, can live on your skin for up to three hours. However, since antibacterial soaps don't destroy viruses, they offer no advantage over other soaps.
6. Foods that are high in cholesterol are the main cause of clogged arteries.
Outdated. Cholesterol is a waxy substance found in all animal foods. Studies show, however, that eating modest servings of high-cholesterol foods does not raise blood levels of cholesterol. Saturated fat in meat and dairy foods, as well as the trans fats found in many commercial baked goods, are much greater threats to your arteries.
True. Many population studies have suggested that people who regularly engage in activities that require the brain to process information—whether reading, going to museums, or playing checkers—are less likely to develop Alzheimer's and other neurological diseases that lead to loss of mental clarity.