Don't Cross Your Eyes...They'll Get Stuck That Way!: And 75 Other Health Myths Debunked (10 page)

Some of the studies examining whether echinacea treats colds have found a small improvement in the duration of cold symptoms when echinacea is used for adults. In these, echinacea led to slightly shorter colds in adults, but the results were mixed. For children, echinacea does not improve cold symptoms and can lead to side effects like a bad rash. Once again, when studies show only very small potential benefits, we have to temper our expectations. It is possible that echinacea has a small effect on the duration of the cold, but the effect is not powerful enough to consistently turn up in studies of the herb.

Compilations of studies that were done after the Cochrane review compilation have not provided any more convincing evidence in favor of echinacea. In 2007, a group of researchers claimed that the evidence from fourteen studies suggested that echinacea did shorten cold symptoms by a day or so. Unfortunately, other researchers claimed that those scientists did not combine the studies appropriately and that the results could not be trusted. Another group compiled studies where researchers put the cold virus right into the noses of study participants and then followed up to see if the herb did anything to stop the people with virus in their nose from getting sick.

This is a great way to design studies of whether something works for colds, but echinacea did not work. We know it can be confusing when the science does not agree on a particular topic. In this case, most of the science says that echinacea does not work. And if echinacea does work for helping cold symptoms, the results are not strong enough to produce consistent results. The bottom line is that echinacea does not prevent colds. While echinacea might make your cold linger for a little less time, that is pretty unlikely too.

Eggs

Eggs give you high cholesterol

For decades, eggs have been getting a bad rap. Everyone “knows” you shouldn’t eat a lot of eggs, and they all think they know why. The logic goes like this: eggs are high in cholesterol, people who eat a lot of cholesterol in their diet get high levels of cholesterol in their blood, and people with high levels of cholesterol in their blood are more likely to have heart disease. So, if you want to avoid heart disease, don’t eat eggs. That was easy.

Let’s look at this more closely. The first one is easy to acknowledge. Each egg contains about 212 mg of cholesterol. Of course, that assumes you eat the yolk, since egg whites have no cholesterol whatsoever, but we’ll assume you’re eating the whole egg. Since the daily recommended allowance for cholesterol is 300 mg, that egg does seem to contain a lot of cholesterol in it. But eggs are also a source of great nutrition. Eggs are a good source of protein. They also contain vitamins, minerals, and unsaturated fats (which your body needs). They also contain choline, lutein, and zeaxanthin, which sound odd but may also help to prevent eye and heart disease. So it’s not like eggs are empty cholesterol bombs.

The second leg of the argument is more complicated. Basically, the theory is that if you eat things high in cholesterol (like eggs), you get high cholesterol in your blood or high serum cholesterol. Serum cholesterol is the cholesterol level you (should) get checked at your doctor each year. And there is some truth to the theory. But the link between high dietary cholesterol and high serum cholesterol is not nearly as strong as you think. This theory that diet cholesterol increases serum cholesterol only occurs in hyperresponders. These are people who really respond to dietary cholesterol, and they are a minority. About 70 percent of people are what are known as hyporesponders. These people show no increase in their serum LDL—“bad” cholesterol—after eating three eggs a day for thirty days. For the majority of people, there is not a clear link between eating eggs and having really high bad cholesterol in their blood.

It gets worse (or better depending on your outlook). Good research estimates that even in hyperresponders, for every extra 100 mg of cholesterol in your diet, your serum cholesterol goes up about 2 mg per deciliter. That’s not nearly as much as you think. So adding a daily egg to your diet may increase your serum cholesterol by 4 mg/dl. That’s not the difference between a heart attack and no heart attack. This is especially true since other research shows that eggs preferentially cause an increase in large LDL molecules, which are less damaging than smaller ones. Additionally, an increase in HDL, or the “good” cholesterol, also occurs.

The final nail in the coffin of this argument comes when you look at studies of heart disease. A large study of male physicians found that eating up to six eggs a week did not increase the risk of heart failure. Eating more than seven eggs a week did. But this was a study of only male physicians. Another study, a bigger and better one looking at 120,000 men and women, showed no difference in the risk of heart attack or stroke over a fourteen-year period if you ate one or more eggs a day compared to eating an average of one egg per week. Eggs just don’t seem to lead to heart disease in otherwise healthy people.

We’re not advocating that people go right out and eat an unhealthy diet high in cholesterol. But the wholesale avoidance of eggs is an overreaction that has no basis in science. Eggs can be a part of a very healthy diet, and do not deserve the terrible reputation they seem to have developed.

Raw eggs will give you salmonella

Eggs get a bad rap all around. They are blamed for raising your cholesterol, and time and time again we hear about people getting terribly sick with salmonella from eggs. In the 1990s, U.S. government reports suggested that as many as 20 percent of all U.S. chickens were contaminated with salmonella, although later reports dropped that number to as low as 3 percent. Even with the lower numbers, you may worry that eggs are a dangerous food, at least when it comes to food poisoning! Raw eggs, in particular, may inspire panic. The fear of raw eggs is great enough that Rachel worries a little every time she sneaks a lick of the uncooked brownie or cookie batter.

The truth is that eggs, raw or cooked, are not the risky food that you might think. Eggs cause only a tiny percentage—0.5 percent—of all of the illnesses that people in the United States contract from food every year.

But even if it is a small risk, you might still be worried about eggs and salmonella. After all, salmonella are nasty bacteria that can cause bad diarrhea, fever, vomiting, and cramps and can even be fatal in some severe cases. Stories of egg recalls and egg farms being shut down because of salmonella are enough to make any of us scared. And it is true that eggs can be contaminated with salmonella.

Remember, though, that eggs get a bad rap. Despite what you may hear on the news, salmonella does not always come from eggs. It can come from eggs, but up to 85 percent of the cases of people sick with salmonella are unrelated to eggs. Moreover, current estimates are that only 1 in every 30,000 eggs is contaminated by salmonella.

The Centers for Disease Control (CDC) tells us that there are several simple steps to make sure that you do not get ill from any bacteria that might be contaminating your eggs. The first step is to keep your eggs refrigerated. If eggs are refrigerated, salmonella and other bacteria that may be present in or on the eggs should not grow. Second, you should cook the eggs until the yolks are firm and cook foods containing eggs thoroughly. Cooking eggs properly should destroy any salmonella that is present.

This advice about cooking eggs properly makes most of us think that the raw egg is to blame for the salmonella. This is not really true. If salmonella is lurking on the egg, it is actually on the shell of the egg, not inside the yolk or white. Usually, the egg’s shell protects the yolk and the egg white against contamination. The problem comes in when the eggshell is cracked open or if there are small cracks in the eggshell; cracking allows the salmonella to infect the rest of the egg. Because of the risk of salmonella coming in from the shell, people are also advised to wash eggs before cracking them open, and to throw out any eggs that have cracks in them. Washing the eggs, plus cooking them thoroughly to kill any salmonella that might have snuck in, should be a good protection against the bacteria.

We are not saying that you should eat raw eggs with wild abandon. Cooked eggs are definitely safer. While there is only a 1 in 30,000 chance that you will be coming across an egg with salmonella on the shell, it is still a risk and one that you can minimize through washing and cooking. Moreover, it always makes sense to use extra caution around people with immune systems that are not as strong, especially children and the elderly. But you should not be afraid of eggs! If you take basic steps to refrigerate, clean, and cook your eggs, they are a healthy protein source.

Exercise

If you stop exercising, your muscles will turn to fat

Aaron recently went on an exercise and diet program called P90X. With great zeal, he followed this workout routine and diet for ninety intense days, during which he sculpted his pale, soft body into a much more buff version. And it worked! At the pool, friends admired his newly defined muscles. We have been debunking a lot of health myths, but there are some good health truths to remember. Among the more important is that exercising and building up your muscles are great ways to help your body stay healthy.

Now that Aaron has his bulging P90X muscles, what will happen to them when he stops his crazy workout routine (which he did while writing this book)? Will his muscles soften into pudgy fat? Aaron is great at following diet and exercise plans, but even he might have difficulty finding a way to maintain these muscles.

Aaron can take comfort in one thing, though—it is a myth that muscle will turn into fat when you stop exercising. It is just not true. Fat cells and muscle cells are different things, and one cannot convert into the other. Cells are the smallest functional units in your body, the building blocks of how you are put together as a living creature. You have fat cells, muscle cells, blood cells, bone cells, and so on. These cells do not convert from one kind into another. Muscle cells and fat cells look very different and work in different ways. Muscle cells are mostly a bundle of fibers or filaments that are attached to each other and contract when electricity from the body’s nerves come into the cell. Muscle cells are like tiny ropes, powered by small engines and connected together to do the work of pulling your bones around. In contrast, fat cells do not seem like they do very much. Under a microscope, they look like motionless globs. These cells are focused on storing fat and making fat from things like sugar. Fat cells do have jobs; they provide your body with emergency food, they insulate your body, and they help facilitate hormonal activity in your body.

When Aaron stops his P90X program, his muscle cells will not go away. If he stops doing his pull-ups and starts eating food that has a bit more fat in it, he will not have any fewer muscle cells; however, Aaron’s muscle cells will get smaller and thinner. He will not develop any more fat cells, but the fat cells that his body has will get bigger and bigger as they store more fat inside them and use less. The muscle and fat cells will not change in number, and the muscle cells will not become fat cells. Instead, the muscle cells will be getting smaller while the fat cells are getting bigger. As the fat cells get bigger, it might look like Aaron’s muscles are turning into fat.

There are a few other dimensions to this idea of muscle turning into fat. If a person is really desperate for energy, such as a person who is starving and cannot get enough food, the body can break down some of your muscle fibers to use them for energy. If the muscle fibers are used for energy (by breaking them down through a process called catabolism into the body’s sugar source of glucose), and if this happens to such an extent that there is extra sugar left over that the body does not need, then the body will store that sugar as fat. This is pretty rare, as it requires you to need to use parts of your body as an energy source in the place of having food, and yet you need to do this to an extent where you have some leftover to store as fat. The scenario where you let your muscles get small and wasted (from not exercising them) while your fat cells store up more fat (because you are eating more calories than you burn up) is much more common. Interestingly enough, the number of fat cells in your body remains almost constant throughout your life. Some of the fat cells die, and others replace them, but you do not grow brand-new fat cells when you get fat. Instead, your fat cells get bigger and bigger as they store more and more fat.

Eyes

Don’t cross your eyes … they’ll get stuck that way!

You probably remember hearing this one from your mother. When you used to torment your younger sister with gruesome faces, your mother would catch a glimpse of your crossed eyes and scold you, “Don’t cross your eyes! They’ll get stuck that way!”

This is a case where your mother was just plain wrong (or she was lying to you). There is absolutely no medical or scientific evidence that crossing your eyes will make your eyes stay crossed. Experts in ophthalmology conclude that crossing your eyes voluntarily is absolutely not going to hurt them permanently.

Even though your mother was wrong about the dangers of your silly faces, eye-crossing can be a problem for other reasons. If someone has crossed eyes without trying to cross them, this is a medical condition that merits further investigation. Two to 4 percent of the population has strabismus, in which one or both eyes are not aligned properly and may look crossed. However, you do not develop strabismus as a result of crossing your eyes too often or for too long. Most of the time, babies are born with it. When strabismus or this improper alignment develops later in life, it is usually caused by serious infections or problems in the head such as certain types of brain tumors. If you notice that your child’s eyes seem to be crossed or aligned abnormally, you should definitely talk to your doctor about your concerns, but the child’s penchant for making silly faces should not be blamed.

The eye is a very complex thing. Eye movements are controlled by three pairs of muscles that work in concert. One muscle in the pair relaxes and one muscle contracts in order to move the eye in a particular way. Crossing the eyes, or bringing both eyes closer to the nose, is actually the normal movement of the eyes when you are focusing on something very close to your face. When you cross your eyes, you are just mimicking or exaggerating that natural movement. When there are problems in how the eye is moving, doctors need to evaluate which of the muscles in a pair are having difficulty.