In the 1960s and '70s, scientists linked blood cholesterol with heart disease and gave eggs a bad rap. More recent studies have found that saturated and trans fats in a diet are more likely to raise heart disease risk. An egg has only 1.6 grams of saturated fat, compared with about 3 grams in a cup of 2 per cent milk. At 213 milligrams of cholesterol, one egg slips under the recommendation of no more than 300 milligrams a day. Just watch the cholesterol levels in the other food you eat that day.

3. Myth: Cancer cannot be prevented.

As many as 50 per cent or more of cancer deaths are caused by social and environmental conditions and unhealthy choices, according to the Centres for Disease Control and Prevention. In general, you can help your body prevent cancer if you quit smoking, avoid second-hand smoke, avoid drinking too much alcohol, avoid weight gain, eat five or more servings of fruits and vegetables a day, eat a low-fat diet and be physically active.

4. Myth: Shaved hair grows back faster, coarser and darker.

A 1928 clinical trial compared hair growth in shaved patches to growth in nonshaved patches. The hair that replaced the shaved hair was no darker or thicker, and did not grow in faster, according to Indiana University School of Medicine researchers who debunked seven commonly held medical beliefs in a 2007 report. When hair first comes in after being shaved, it grows with a blunt edge on top. Over time, the blunt edge gets worn so it may seem thicker than it actually is. Hair that's just emerging can be darker too, because it hasn't been bleached by the sun.