Don't Cross Your Eyes...They'll Get Stuck That Way!: And 75 Other Health Myths Debunked (6 page)

Caffeine is a commonly used drug in the neonatal intensive care unit, where premature babies are cared for. We use it to stimulate them when their brains are immature; it helps them to breathe on their own. If there was any real evidence that caffeine would stunt their growth, we wouldn’t be using it there.

There are, of course, plenty of reasons not to give kids caffeine. Unlike sugar, caffeine can affect their behavior and even their sleep. But it won’t stunt their growth.

Cancer

Cancer is unpreventable

Cancer is scary. Many people don’t like to talk about it at all because they fear it so much. A lot of the fear comes from a belief that there’s nothing you can do to prevent cancer. That’s totally not true. And getting over this myth could actually save your life.

First of all, there are a number of things that people do that seriously increase their risk of getting cancer. Our advice: stop doing them. For instance, tobacco use is significantly associated with cancers of all types. The scary truth is that smoking cigarettes has been proven to be associated with cancer in the lungs, mouth, throat, kidney, bladder, stomach, pancreas, and cervix. It can also cause certain types of leukemia. Studies have shown that about 30 percent of all cancer deaths occurring in the United States are caused by smoking cigarettes. Don’t do it. Not smoking in the first place or quitting smoking if you do is probably the very best way to prevent cancer.

Another major cause of cancer is infection. Luckily, many of these infections are also preventable. For instance, human papillomavirus (HPV) is well established as the cause for cervical cancer. Luckily, there is now a vaccine for HPV, which can lead to a significant decrease in precancerous lesions. A vaccine to protect people against cancer is a great thing! Hepatitis B is also known to lead to liver cancers. There’s a vaccine for that too. Granted, some viruses that lead to cancer can’t be prevented by vaccine, but many types of cancer can be avoided by taking good care of your body.

Radiation exposure can also lead to cancer. Specifically, ultraviolet radiation from the sun is a major cause of skin cancer. So, cover up, or at least use sunblock. Ionizing radiation is even more of a concern in regard to cancer, because it actually rips electrons from their orbit, killing or irreparably harming components of some of your body’s cells. These cells can then go on to become cancer. Ionizing radiation can come from either medical sources, such as radiological scans, or from radon in homes. Most of the increase in radiation exposure in recent years is because of the increased use of CT scans in medical practice. Try to avoid these when you can.

There are a number of other things you can do to prevent cancer, although there is not as much evidence for them compared to what we’ve already discussed. A number of reviews have been conducted, and most point to the fact that fruits and nonstarchy vegetables are associated with a decrease in the risk of getting cancer. However, when these types of food are carefully studied in scientific randomized controlled trials, their protective effects are not clearly seen. Similarly, alcohol has been linked to some cancers. But no conclusive evidence exists. Since we always rely on evidence to make declarative statements, we can say with confidence that a diet high in fruits and nonstarchy vegetables, without alcohol abuse, may reduce your risk of cancer and definitely will result in better overall health.

Lots of people will tell you that vitamin and mineral supplements will prevent cancer. This, unfortunately, goes over the line into the myth category itself. No good evidence exists that they do any good. In fact, a prospective study of beta-carotene (vitamin A) found that it might actually increase your risk of lung cancer. Antioxidants like vitamin E or selenium have failed to show any significant results in studies. Vitamins C and E do not prevent prostate cancer. And the Women’s Antioxidant Cardiovascular Study could detect no protective effects for vitamins C, E, B
6
, B
12
, folic acid, or beta-carotene.

The problem with all this is that we often pin false hopes on things that don’t work and ignore the obvious things that do. It would be great if popping a few vitamin pills would prevent cancer. But they won’t. What will is avoiding tobacco and the sun, getting necessary vaccines, and, perhaps, eating more healthily.

Celery

Celery has negative calories

The key to weight loss or weight gain is simple: it is all a matter of how many calories you take in and how many calories you burn. If you burn more calories than you take in, then you will lose weight. If you burn the same number of calories as you take in, then you will maintain the same weight. In this equation, celery has come to hold a legendary role among dieters. In contrast to most foods, which add to the calories you take in, celery is reported to have “negative calories.” The idea is that you use up more calories in the act of eating the celery than are actually contained in the vegetable.

It is true that celery can be a great part of your diet when you’re trying to lose weight. An eight-inch stalk of celery contains only six calories. Not much at all, but it does contain
some
calories. Do we use up that many calories chewing up the celery? Probably not. The body burns roughly eighty-five calories per hour while eating (not so much more than the sixty calories per hour it uses when you are sleeping!). This means that in one minute of eating, you only use up 1.4 calories. It would have to take you several minutes of chewing to burn up the number of calories in a stick of celery, and even though those stringy stalks take some time, it probably does not take you four minutes to chew one piece.

However, you just might use up all those calories in the stick of celery from the process of digesting the celery. Much of celery is a substance called cellulose that the human body does not digest, and which passes through our system without being absorbed. Cellulose is not metabolized by humans, and so your body needs to pass it through to the other end. In the much longer time needed to pass that celery through your system, your body will have used more than the six calories in that piece of celery.

Does this mean that the celery will help you lose weight? Not necessarily. In order to lose a pound of body weight, you need to take in about 3,500 calories fewer than you use up. The six calories in celery and the small calorie deficit that you might get from your body digesting the celery are a far cry from 3,500 net calories used up. And in case you have heard that celery is a special negative calorie food that somehow boosts your metabolism and makes you burn other foods up faster, you should know that there is absolutely no evidence for this. So, the point we’re trying to make here is quite simple: there is nothing magical about celery. Losing weight still requires you to take in fewer calories than you burn. Celery might help you toward your goal, but it is likely to play only a very small role.

Cell Phones

Cell phones cause brain tumors

Let’s start with some facts. Cell phones are hugely popular. Worldwide estimates put their usage at more than three billion people. In the United States, more than 270 million people use cell phones, including about half of children age eight to twelve. We also know that exposure to radiation increases your risk of developing cancer (see the section on cancer). And cell phones do emit radiation. So it shouldn’t come as a surprise that there is an ongoing debate as to whether this widespread use of a device that emits radiation causes cancer—specifically brain tumors.

Many studies have been published in this area. The vast majority of them are what we call case-control studies: First, you gather a group of people with brain tumors. Then, you gather a group of people without brain tumors. Then you ask them about their day-to-day activities (such as the frequency of cell phone use) to see if there are differences between the two groups.

While this type of study can sometimes give us good information, it’s important to recognize that case-control studies are among the weaker types of scientific studies. Unlike randomized controlled trials, a case-control study will not prove that cell phones do or do not cause brain tumors. And, unlike in prospective cohort studies, which follow a group of people forward in time through the study, there is a real problem with recall bias. Recall bias happens when someone with a particular issue or disease (in this case, a brain tumor) is more likely to recall activities that might have caused their issue or disease than someone who does not. The danger with case-control studies is that people with brain tumors may have heard the theory that cell phones cause brain tumors, and therefore may be more apt to recall their cell phone use than people without brain tumors.

There are so many of these studies about cell phones that we won’t try to summarize them all. Luckily, that has already been done for us! In 2008, a scientist summarized data from thirty-three studies in the peer-reviewed scientific literature. This summary found major flaws in the research that make it difficult to draw solid conclusions from all of these studies.

Another group attempted a meta-analysis of the literature. They felt that twenty-three studies were good enough to be included in the analysis. All of them were case-control studies. They found overall that, compared to rarely or never using a cell phone, regularly using a cell phone did not cause malignant or benign brain tumors.

The studies point out some important issues contradicting the idea that cell phone use is connected to brain tumors: With so many people using cell phones, you could expect, if there was a major association between cell phones and brain tumors, the number of tumors would be through the roof. Three billion people use cell phones! Even if there is an association, it has to be very small. Moreover, the types of brain tumors that have been more common recently take decades to appear. Cell phones, on the other hand, are a relatively new invention. We know from previous work that there is usually a long time period between exposure to radiation and the development of slow-growing brain tumors. According to that timeline, even if there were a link, we shouldn’t see a jump in brain tumors caused by cell phones until the 2030s.

Let’s remember something else too: there are much greater risks to our lives than cell phones. That’s for sure. After all, the number one killer of children in the U.S. is car accidents, and yet how many people out there think cars should be banned? As a society, we accept that the quality of life derived from driving is greater than the risks having people die in car accidents. If you disagree, don’t drive. Almost no one does that. The risk of brain tumors is so low that, even if it exists, few would likely forgo their cell phone to reduce it.

Furthermore, although we talk about an increase in brain tumors, there has been no explosion of brain tumors recently in the population. A study published in the
Journal of the National Cancer Institute
in 2009 examined data for cancers in four countries with registries from 1974 to 2003. Over that time, almost 60,000 people in a population of 16 million adults between ten and seventy-nine years were diagnosed with brain tumors. While a slow increase in rates of gliomas and meningiomas (faster-growing tumors) was seen throughout the same time period, no changes in incidence were seen from 1998 to 2003, five years when cell phone use increased dramatically and when you would expect to see more brain tumors because of that increase.

Case-control studies are a reasonable measure for determining a link between the activities we undertake and the diseases we develop. But cell phones are so widely used that, honestly, if they were so dangerous, we’d be seeing that effect right now. That’s just not happening. Additional studies will be needed to see if they cause long-term harm, but as of now, this is a myth.

Cheese

Cheese makes you constipated

If you want to consider foods that get an unfair shake, it’s worth talking about cheese. Aaron’s son Noah loves cheese. He loves it almost as much as chicken nuggets and fries, which he would eat for three meals a day, seven days a week if permitted. It’s all part of his “beige food” diet, which someday he will turn into fame and fortune. Anyway, Aaron has been guilty of putting strict limits on Noah’s cheese intake because he, like many of you, has been told that cheese causes constipation. But is it true?

If you go to any number of Web sites dedicated to constipation, it sure seems like it’s true. (By the way, why are there so many Web sites dedicated to constipation?) These sites will tell you that both a low-fiber diet and too much dairy consumption (especially cheese), will lead to constipation.

But the science behind all of this is not nearly so cut-and-dry. The belief that dairy products cause constipation was born mostly from studies of constipation in babies. Parents are obsessed with babies’ pooping, as we detailed in our last book. So much so that parents constantly bring their children to the doctor to talk about the child’s poop. Constipation is the reason for about one in four visits to pediatric gastroenterology clinics. But baby constipation and childhood or adult constipation are two different issues.

If you look at the data from babies, there is some connection between dairy intake and firmer stools or constipation. The proteins in breast milk are easily digested, as they are designed to be. However, the proteins in baby formula are not the same as those in breast milk, and the proteins in formula most often come from cow’s milk. Infants who are fed formula (which is cow’s milk–based) have firmer stools and more frequently have problems with constipation. Other factors, like fat content, can also affect the consistency of infant stools.

But there are many problems with simply extrapolating this data about cow’s milk formula and applying it to children and adults. First of all, a lot of what those parents think is constipation is not really constipation. Second, the issues infants might have with cow’s milk formula are not the same as children or adults might have with cheese. They aren’t the same at all.