Don’t go outside in the cold without a jacket. Drink eight glasses of water a day. Breakfast is the most important meal.

You may have grown up believing these are proven medical facts. But the reality is that they are more myth than fact, handed down by moms and granddads who were sure you were going to starve or catch a cold if you didn’t listen to them.

“There are many common myths about health care that people refuse to stop believing,” said Dr. Derek Robinson, an emergency medicine doctor and a Blue Cross and Blue Shield Plan vice president. “Sometimes it’s a remedy from your grandma, or it might be advice from an article on the internet. Always check with your doctor to make sure the advice you’re getting is right for you.”

Let’s look at (and debunk) six of the most common health care myths:

Drink eight glasses of water per day. For most people, it isn’t necessary to try hard to get in eight cups of water, research shows. That’s because your body gets hydration throughout the day from beverages (about 80 percent, including caffeinated drinks) and food (the remaining 20 percent). Unless you live in a very hot climate or have a specific medical need, you can let your thirst be your guide. Also watch the color of your urine. It should be a very pale yellow; if it’s darker, increase your fluid intake.

You can get a cold from being cold. Going outside in the cold without a coat, hat and gloves can give you frostbite, but it can’t give you a cold. Colds are caused by viruses spread from one person to another. The best way to prevent a cold is to avoid people who are sick and wash your hands often. Be sure not to touch your eyes, nose and mouth with unwashed hands.

Eggs are bad for your heart. Eggs have cholesterol, but not enough to take them off the menu completely. The Mayo Clinic says most people can safely eat up to seven eggs per week. If you are diabetic or have heart disease, be sure to check with your doctor to see if you need to limit eggs in your diet.

The real breakfast culprit is what people tend to eat with eggs — the sodium in the bacon and the fat to fry eggs and hash browns. If you are concerned about your cholesterol, skip the frying and eat only the egg whites — all the cholesterol is found in the yolk.

You must eat breakfast to lose weight. Dieters have been told for years that they must eat breakfast to keep from overeating the rest of the day. Research shows that isn’t true. While skipping breakfast may make people feel very hungry by lunch, they still didn’t make up those breakfast calories at another meal. So if you’re not hungry in the morning, don’t eat.

Sugar makes kids hyperactive. There are a lot of reasons kids shouldn’t eat much sugar — obesity and tooth decay, for example. But hyperactivity isn’t one of them. There is no reliable proof linking sugary foods and drinks to behavior in children. Instead, kids may be excited about a birthday or a holiday simply because of the event, not the sugary treats.

Flu vaccine causes the flu. This is one of the most common — and potentially most dangerous — health care myths. Despite what you may read on the internet or hear from your well-meaning but uninformed friend, the flu vaccine does not cause the flu. The shots contain the virus, or a copy of it, in a form that won’t make you sick. Believing this myth can be dangerous to your health because the flu can cause serious complications, especially for older people, babies and people who suffer from another illness.

“Every year, patients and friends tell me — convincingly — that the flu vaccine will cause you to get the flu,” Robinson said. “We know that this is a myth and not true. But every year, too many people still avoid getting the flu vaccine and put themselves and their families at risk for infection.”

magnifying_glassWhen in doubt, check it out!

If you aren’t sure whether to believe a piece of health advice, check it out. Ask your doctor or check a reliable website, like a hospital or medical association.