Don't Cross Your Eyes...They'll Get Stuck That Way!: And 75 Other Health Myths Debunked (4 page)

Don’t vow to stay in your house and shun other people forever! Even though antibiotics are not going to protect you from their coughs, colds, and crud, it is also important to realize that many illnesses are not contagious at all—even some very serious infections. Ear infections, sinus infections, and urinary tract infections happen as a result of a passageway or tube being blocked by an overgrowth of bacteria. These types of infections are usually not contagious. You need antibiotics to kill off the bacteria growing in your ear or in your bladder for you to feel better, but you are not going to pass this infection to someone else if you do not have an antibiotic. Other serious infections, such as infections of your bloodstream or pneumonias, are not very contagious to other people. Most often, these infections come about because of something else that was going on in your body first, and so healthy people around you are unlikely to get infected by the same thing. For other infections, like most sexually transmitted diseases, you will not get infected unless you have sexual contact with the person infected or have some other very close contact with them.

Clearly, though, there are bacterial infections that can spread from one person to another. In these cases, you do want the sick person to be on an antibiotic so that they do not infect you. One of the bacteria that causes meningitis,
Neisseria meningitidis
, is contagious, and if one person becomes sick with infection from this bug, that sick person needs an antibiotic, plus close family members exposed to that person need to take antibiotics themselves to prevent infection. In the case of
Neisseria,
it is very good news to know that the infected person is on an antibiotic. Strep throat is another example where having the person on antibiotics may or may not help you. Strep throat is caused by a bacterium,
Streptococcus pyogenes
, and it is contagious. This bug rapidly colonizes the family members and close contacts of the person who has the first infection. When one person in the family has strep throat, the risk that someone else in the family will get strep throat is at least 10 percent. Using an antibiotic may help decrease how the bacteria colonize your throat and thus prevent other people from getting infected. The real reason we use antibiotics for strep throat is to prevent other complications to your heart or kidneys that can result without treatment. In contrast to strep throat, another form of the strep bug,
Streptococcus pneumoniae,
which can cause bad pneumonias, is not as contagious as the bug that causes strep throat. While you would certainly need antibiotics to help with one of these strep infections, the antibiotics would not have much of an effect on how contagious you were.

You may have noticed that we said antibiotics “might” make you less contagious, even with contagious bacterial infections like strep throat. The truth is that there are very few scientific studies giving clear data about just how long you remain contagious. Parents are typically told that their child is no longer contagious after they have been on antibiotics for twenty-four hours or sometimes after forty-eight hours. These figures are very roughly based on how fast the antibiotics decrease the load of bacteria within the body. For some conditions, a person might still be contagious with only a small amount of the bacteria around and after they have been on an antibiotic for a while. For other conditions, the person may never have been very contagious or the period of being contagious might have passed even before you started the antibiotic. Some infections are still contagious as long as you have a rash or have a cough, whereas others are not. Often, doctors really do not know just how long you will be contagious. While it is important to take antibiotics for certain medical problems and to take them as directed by your physician, this is not a guaranteed way to know whether someone is contagious.

Whenever you have an infection, you should talk with your doctor about how contagious this infection is, how long it will be contagious, and what, if anything, you need to do to prevent other people from being infected.

Apples

An apple a day keeps the doctor away

Rachel loves apples and has eaten an apple a day for most of her life. She may have become an apple aficionado in her early days because of all of the orchards where she grew up in Grand Rapids, Michigan. Despite this love of apples, Rachel hasn’t managed to keep the doctor(s) away. Seriously though—the belief that “an apple a day will keep the doctor away” might not be something to laugh at. Scientists have done a lot of research to determine what is in apples and how they might benefit us. While an apple a day is not going to cure or prevent all of your medical problems, it turns out that apples are a good part of a healthy diet.

Food science examines many potential ways in which apples can help you. In general, there is plenty of evidence to suggest that eating fruits and vegetables is good for you. People who eat diets that are high in fruits and vegetables have less cancer and less heart disease. Scientists generally explain this because fruits and vegetables have certain chemicals, such as phenolics, flavonoids, and carotenoids, all of which are thought to reduce your chances of developing certain chronic diseases. People who eat lots of fruits and vegetables also tend to be slimmer, and that lowers your chances of developing other diseases as well.

What is the evidence for eating an apple a day? Researchers have looked at a lot of epidemiologic studies (studies of large groups of people) to see whether apple eaters might do better than apple scorners. In these studies, eating apples was associated with fewer cases of certain cancers, as well as fewer cases of heart disease, asthma, and diabetes. In a study of 77,000 women and 47,000 men surveyed through the Nurses’ Health Study, people who ate one serving a day of apples and pears had fewer instances of lung cancer. In a Finnish study of 10,000 men and women, those who ate the most flavonoids (which were mostly coming from apples and onions) also had the lowest rates of lung cancer. An apple plus a pear plus an onion keeps the doctor away? These are big studies, which are always good, but they do not really test if apples “work” to keep you healthy. It is possible that people who choose to eat apples also choose to do other healthy things that keep them in good shape.

A number of case-control studies have also tried to look at the apple question. In these studies, researchers take people with cancer and people without cancer and ask them about what they have eaten. In a study of patients with and without lung cancer, those who remembered eating the most apples, onions, and white grapefruit had the lowest risk of lung cancer. In a study of patients with and without colorectal cancer, those who ate more than one apple a day (one apple a day was not good enough) had fewer instances of colorectal cancer. These studies suggest that there might be benefit to eating a bunch of apples, but it is also important to remember that the cancer patients’ recall of what they ate might be skewed by the fact that they have been diagnosed with cancer. It’s easy for people who have cancer to start worrying that they were not healthy enough before their diagnosis; that they didn’t eat enough fruits and vegetables, for example, and blame those bad habits for their cancer. This can throw off our understanding of the studies’ reports.

There is also some evidence that apples are good for your heart. In the Women’s Health Study, which surveyed 40,000 people, eating flavonoids (which are contained in apples) was tied to having fewer “cardiovascular events” even though how many flavonoids you ate did not decrease how many strokes, heart attacks, or deaths from cardiac problems you had. In a study from Finland, women who reported eating fewer apples and onions (combining the apples and onions again!) also had lower rates of type 2 diabetes and more deaths from heart issues, though there was no difference for men. In a study from Iowa, women who ate more apples and drank more wine had lower risks of death from coronary artery disease. (Combining apples and wine sounds much better than combining apples and onions!)

Of course, apples are not the only good-for-you foods out there. Bran, pears, wine, grapefruit, strawberries, and chocolate are also high-flavonoid foods, and eating more of them is also associated with less heart disease and/or lower death rates. Apples might even be good for your lungs if you
also
eat pears. In a study of 1,601 adults in Australia, eating more fruits and vegetables in total was not connected with having or not having asthma. However, the people who ate more apples and pears in specific had lower rates of asthma and wheezing problems. Studies from the Netherlands and Britain also found better pulmonary function among Dutch people who ate more apples and pears, and among British people who ate five apples a week.

There are some scientific reasons why apples might be connected to lower rates of disease. Apples do have lots of chemicals that scientists think are healthy for your body. When researchers analyze apples, they find that apples have lots of good antioxidants, which have names you might not recognize: flavonoid, quercetin, catechin, phloridzin, and chlorogenic. The apple peel has the highest level of these chemicals. Those of us who are not nutritionists may not know what to think of these chemicals, but in the laboratory these chemicals from apples have been shown to be good antioxidants and can even be used to inhibit the growth of some kinds of cancer cells. When food scientists test apple chemicals or apple juice in rats, they can reduce the cholesterol in fat rats, and rats with a disease that is kind of like Alzheimer’s do better in running through a maze. (It is important to point out that these studies were, not surprisingly, commissioned by the apple industry.) This evidence all sounds great. Apples contain good things, and they seem to do good things for rats. Are apples really the key to health?

The science lab also offers some evidence that apples are not the perfect cure for human beings. Even though apples have all of these great antioxidant chemicals, your body may not be able to absorb and process them the way it would need for the apple to make a big difference. Some of the chemicals in apples do not seem to be absorbed well by the body (in other words, the chemicals are not very bioavailable). In more than one study of the apple antioxidant called quercetin, they could not find the antioxidant in volunteers’ plasma even after they drank 1.1 liters of apple cider or ate a whole apple. Quercetin is mostly found in the apple peel, however, and one study did find this antioxidant in the subjects’ plasma after they ate a serving of applesauce plus the apple peel. An antioxidant like quercetin may look great in the laboratory, but if you do not actually absorb it into your bloodstream, it probably will not do you much good. Apples and onions both contain a decent amount of quercetin, but stinky onions might be the better way to get this antioxidant. The amount of quercetin available from apples is only 30 percent of what is available from onions. The other apple all-star chemicals are not absorbed so well either. In a study in rats, the researchers could not find any phloridzin in the rats’ plasma after eating apples, even though apples have plenty of this chemical.

The bottom line is that apples are a great fruit; they are healthy to eat and may even have some added benefits for staying well. But you should not think of the apple as a clear-cut way to stay healthy or to improve your health. The studies connecting eating apples with having fewer cancer or heart disease risks are a bit difficult to interpret because the same people choosing to eat more apples are usually also making other healthy choices, such as exercising or not smoking. Plus, people may not remember exactly how much fruit they ate and might inflate the number of apples they report. Ultimately, if you like apples, eat more of them! If you are not an apple fan, do what you can to increase the amount of fruits and vegetables you eat in a day. Other fruits and vegetables and other healthy diet choices might help to keep the doctor away. Onion anyone?

Artificial Sweeteners

Artificial sweeteners will give you cancer

This one will undoubtedly inspire a lot of hate mail. It’s one of those myths that has left the realm of science and entered the realm of faith. We take on this chapter knowing that for many of you, no matter what we say, you are going to remain convinced that artificial sweeteners are linked to cancer. However, as we mentioned in the introduction, we do not want you to waste time being needlessly worried about things that are harmless.

Not all artificial sweeteners are the same. Saccharin is one of the oldest. There have been more than fifty studies about the effect of saccharin on rats. About twenty of them involved rats consuming saccharin for at least one and a half years. Nineteen of these studies found no relationship between saccharin and cancer. One study found an increased rate of bladder cancer, but it was in a type of rat that easily gets infected with a bladder parasite that can leave it more susceptible to disease.

Scientists then moved on to see if giving two generations of rats saccharin would do anything. They fed rats, and then their children, lots of saccharin. They found that male rats in the second generation got more bladder cancer. As a result, some countries banned saccharin, and others—like the U.S.—started labeling products with warnings. There was one problem: the link between saccharin and cancer couldn’t be found in humans. Later work found that often cancer induced in rats doesn’t equal cancer in humans. For instance, if you give rats vitamin C in the same doses as they used for saccharin in the other studies, vitamin C causes bladder cancer in rats too. Yet no one is attempting to ban vitamin C.

Cyclamate is another kind of artificial sweetener that was approved by the FDA for use in the United States in 1950. Almost twenty years later, a landmark study found that cyclamate also increased the rate of bladder cancer in rats. This led to cyclamate being banned in a number of countries. Later, the ban was lifted pretty much everywhere but in the United States. In one of those studies you can’t believe they actually did, some scientists fed thirty-seven monkeys either no cyclamate, 100 mg/kg of cyclamate, or 500 mg/kg a cyclamate every day for twenty-four years. Twenty-four years! By the way, 500 mg/kg is like drinking thirty cans of diet soda a day. That’s a lot of cyclamate! At the end of the study, they killed the monkeys who had not yet died and autopsied all of them. Three animals that had been given cyclamate had cancers, but they were different types of cancer in different parts of the body, and they were common cancers in monkeys. The conclusion from this long research study was that there was no apparent increased risk of developing cancer—even after consuming that much cyclamate.