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True or False – Cracking your knuckles leads to arthritis?

Posted on May 15, 2013

False.

Some children start cracking their knuckles because they like the cool sound it makes, some because they say it feels good, and others do it just because they know it annoys their parents. So what causes the “crack” or “pop” anyway? In basic terms, it’s caused by air or gas bubbles being released in a joint. A more detailed explanation is offered by Castellanos & Axelrod (1990). They write “Cracking of the knuckles results in a rapid increase of intrasynovial tension. This increased tension results in synovial fluid cavitation, which causes rapid separation of the joint and collapse of the vapour phase of the formed cavity. The consequent release of vibratory energy provides the cracking noise.” No matter what causes the sound, parents have long been warning kids against knuckle cracking for fear it will lead to arthritis in old age. Only a few studies have examined whether habitual knuckle cracking leaves the “crackers” disfigured and suffering from painful arthritis in old age. The results of these studies suggest that there is no relationship or association between cracking knuckles and arthritis. It seems reasonable to think that cracking your knuckles would lead to damage of the cartilage that covers the ends of the bones in your fingers and hands (think of the awful sound cracking your knuckles makes), but it is not true. The above mentioned authors conducted a study in which they compared knuckle crackers vs. non-crackers and found the crackers didn’t have increased rates of arthritis in old age. They did find however, that those who did habitually crack their knuckles were more likely to have hand swelling and decreased grip strength and they suggest that habitual knuckle cracking should be avoided.

Reference:
Castellanos J & Axelrod D: Effect of habitual knuckle cracking on hand function. Annals of the Rheumatic Diseases (1990), Vol. 49, pps. 308-309.

Categories: Myths

True or False – Having a slow metabolism is a major cause of obesity?

Posted on May 7, 2013

False.

As an individual who has worked in the area of health and wellness for many years, I’ve frequently heard people grumble about how thin people can eat lots of food and not gain weight, and how others (usually themselves) simply need to look at something like a piece of chocolate cake and they start to gain weight and inches. Many times overweight or obese individuals blame their weight status on their “slow metabolism”. However, research doesn’t support the idea that being overweight or obese is the result of a slow metabolism. Dr. Donald Hensrud on MayoClinic.com states, “Yes, there is such a thing as a slow metabolism. But it’s rare and it’s usually not what’s behind being overweight or obese – that’s usually a matter of diet and exercise.” In addition, Dr. Hensrud says things like genetics, family history, certain medications, lack of sleep, and unhealthy habits like skipping breakfast are more likely contributors to weight gain. Your metabolism (sometimes referred to as resting metabolic rate or basal metabolic rate) refers to the number of calories you burn just to keep your body working or functioning properly. Bodily functions such as your heart beating, breathing, digestion, and muscle contractions all require energy (calories). Research has also shown that overweight or obese individuals usually have a higher absolute metabolic rate as compared to thin or lean individuals, simply because heavier individuals have a greater amount of body mass. When body size is taken into account, metabolic rates of obese and non-obese individuals is usually very similar. In an article entitled Energy metabolism and obesity published in the Medical Clinics of North America, Dr. Michael Goran states “Some longitudinal studies support the idea that reduced energy expenditure is a risk factor for the development of obesity, but most do not.”

Reference:
Goran M: Energy metabolism and obesity. Medical Clinics of North America (2000), Vol. 84, pps. 347-362.

Categories: Myths

True or False – A cut will heal faster if you keep it covered at night?

Posted on May 1, 2013

True.

I have the opportunity to travel a fair amount and give many talks and presentations on health myths and misconceptions. I routinely ask participants in those talks if they think it is best to uncover a wound and let it air out at certain times (e.g., when going to bed). I would say that 95% of those I ask think it is a good practice to uncover wounds and let them dry out as they think this promotes healing. It’s no surprise so many people have this misconception, as mothers and fathers have been telling their children this for years. Before researching this topic, I actually told my children the same thing. Keeping a wound covered will keep the area moist and promote new tissue (cell) growth. Not covering a wound, and having it dry out, usually results in increased scab formation, which can lead to increased scarring. Scabs also slow the rate of healing as healthy regenerative tissue has a more difficult time covering a wound if it is scabbed over. Keeping a wound covered also decreases the risk of infection as a covering will help keep dirt and bacteria out of the wound. Finally, a covering will help reduce the risk of re-injury. Most of us have had the unpleasant experience of having a scab break open or tear off or have a wound re-open because it gets bumped or scrapped up against something, a covering can help prevent this from happening. Well designed research studies have shown that covering a wound usually increases healing rates by 3 to 4 days. Dr. Joel Beam (2008) did a study where he created abrasions with sandpaper on research participants (doesn’t that sound like fun). Dr. Beam covered some wounds but also left some uncovered and concluded that covering wounds significantly increases healing rates. So, tell your children to keep those wounds covered, even when they go to bed!

Reference:
Beam J: Occlusive dressings and the healing of standardized abrasions. Journal of Athletic Training (2008), Vol. 43, pps. 600-607.

Categories: Myths

True or False – Reading in low light damages vision?

Posted on April 23, 2013

False.

I wasn’t much of a reader when I was growing up, but my children devour books like they are Willy Wonka chocolate bars. On more than one occasion I’ve quietly snuck up to my children’s bedrooms (after the time they were supposed to be sleeping) and have discovered them reading in practical darkness next to a small nightlight, or reading under their covers with flashlights. Such discoveries can worry parents. Many kids have been admonished for reading in low light conditions because their parents believe that it can damage vision. However, this has never been supported by research. In an article entitled Myopia: the nature versus nurture debate goes on published in the Journal Investigative Ophthalmology & Visual Science (1996), the authors note some environmental factors that can lead to myopia, but reading in low light conditions was not one of them. When you think about it, people used to read by candlelight by necessity, and there is no evidence that it damaged their eyesight. Reading in low light, like sitting too close to the television, can lead to eyestrain, where the eyes can become red, irritated, watery, blurry, and dry. But eyestrain usually only lasts for a short period of time and doesn’t result in vision damage. Our eyes are pretty incredible and allow us to see in a variety of environments. When in low light conditions, our eyes make a variety of adjustments to help us see better. These adjustments include pupil dilation, the production of certain chemicals to make our eyes more sensitive to light, as well as the nerves on the retina becoming more receptive to light. If you have to read in low light conditions, take breaks every 15 to 30 minutes and try to remember to blink often as this will likely help reduce the chances of your eyes getting tired and irritated.

Reference:
Mutti D, Zadnick K, Adams A: Myopia: The nature versus nurture debate goes on. Investigative Ophthalmology & Visual Science (1996), Vol 37, 952-957.

Categories: Myths

True or False – Sitting too close to the TV can damage your vision

Posted on April 16, 2013

False.

I would almost be willing to wager that every single person reading this post has at one point in their childhood been instructed by their mother or father to back away from the television set, or risk going blind. It has long been thought that sitting too close to the television can damage vision. Turns out mothers and fathers aren’t the only ones who believe this falsehood. I came across one study that reported even teachers and school children in Pakistan believed that watching television can damage vision. It is true that many years ago some referred to the television as the radiation box. Prior to 1968 televisions did emit low levels of x-rays, but I couldn’t find any studies linking television watching, even back then, to eye damage. The television sets of today do not emit x-rays or any radiation. So, watching SpongeBob up close on Saturday morning won’t damage your child’s vision, but most eye experts agree that it can cause eyestrain. Signs and symptoms of eyestrain can include red, itchy, burning, watery eyes, as wells as blurred vision. These signs and symptoms may be uncomfortable, but will usually subside or disappear in an hour if one stops watching television. Think about adults who stare at a computer screen up close for far too many hours a day. I’ve found no evidence that would suggest this cause’s eye damage either. The American Academy of Ophthalmology even reports that many kids can focus on close items better than adults. Watching television doesn’t damage vision, but research has shown (Toyran et. al, 2002) that too much television viewing contributes to obesity, headaches, back pain, and sleep problems. It’s probably a good idea to stay at least 5 feet back when watching television, and if you notice your child inching closer to the set take them in for an eye exam as that could be an indicator of nearsightedness.

Reference:
Toyran M, Ozmert E, Yurdakok K: Television viewing and its effect on physical health of schoolage children. The Turkish Journal of Pediatrics (2002), Vol. 44, pps 194-203.

Categories: Myths

True or False – Marijuana gives you the munchies?

Posted on April 9, 2013

True.

Marijuana (also known as Cannabis) has been grown and consumed for thousands of years. There are reports that marijuana was used as early as 300 AD in India to help stimulate the appetite in individuals who for whatever reason had lost the desire to eat. Keep in mind that using marijuana is illegal, unless prescribed by a physician (currently 13 states have legalized medical marijuana use). Marijuana has been shown to be an analgesic (pain reducer), has been used in the treatment of glaucoma (lowers intraocular pressure), and helps relieve nausea and vomiting. Early studies that were conducted in the 1930’s which examined whether marijuana stimulated appetite, were not always high quality studies. However, as the recreational use of marijuana increased in the 1960’s so did the interest in conducting high quality studies (e.g., studies that used control groups and attempted to standardize the doses of marijuana consumed). Most of the studies conducted support the idea that marijuana does in fact give you the munchies (stimulates appetite). The authors of one study (Cota et. al., 2003), which was published in the International Journal of Obesity state “Despite the public concern related to the abuse of marijuana and its derivates, scientific studies have pointed to therapeutic potentials of Cannabinoid compounds and have highlighted their ability to stimulate appetite, especially for sweet and palatable food”. This may be why marijuana use is thought to be helpful for patients with decreased appetites due to illnesses such as AIDS or late stage cancer, and it may be the reason people joke about taking late night runs to Taco John’s after consuming marijuana. It is believed that the active ingredient in marijuana (THC) is similar to chemicals in the body which are released when your stomach is empty with the purpose of telling the brain it is time to eat.

Reference:
Cota D, Marsicano G, Lutz B, Vicennati V, Stalla G, Pasquali R, & Pagotta U: Endogenous cannabinoid system as a modulator of food intake. International Journal of Obesity (2003), Vol 27, pp. 289-301.

Categories: Myths

True or False – Pesticide residue on foods cause cancer?

Posted on April 1, 2013

False.

There is no question that pesticides are dangerous. After all, the purpose of pesticides is to kill pests. Millions of people each year get sick from pesticide exposure and thousands are killed. However, most of those who get sick do so because they work with (e.g., produce, transport, apply) pesticides and not because they are exposed to pesticides on the foods they eat. Some people take the idea of pesticide residue on foods very seriously. I realized this one afternoon as I watched a woman at a park rinse and carefully wipe off grapes one by one before she ate them. Survey research tells us that many people believe that pesticide residue on food increases their risk for cancer. Pesticides are strictly regulated. The Environmental Protection Agency sets safety standards, known as tolerances, for how much pesticide residue can be on foods. The California Department of Pesticide Regulation (CDPR) reports that most crops are treated with pesticides. Those pesticides not only allow farmers to grow crops in areas that might not otherwise be suitable, they also result in higher crop yields, and extend shelf life of products. The CDPR also report that there is no pesticide residue on about 60% of the produce they test and that only about 1% of their test samples have pesticide residue levels that are too high. They also state that years of monitoring show that most fruits and vegetables have little or no detectable residue by the time they reach market, and even less by the time they are washed and served. Lois Gold and colleagues (1997) in an article titled Pesticide residues in food: investigation of disparities in cancer risk estimates state “Using standard methodology and measured dietary residues in the total diet study, the estimate of excess cancer risk from average lifetime exposure to synthetic pesticide residues in the diet appears to be less than one-in-a-million for each of the ten pesticides for which adequate data were available.”

Reference:
Gold L, Stern B, Slone T, Brown J, Manley N & Ames B: Pesticide residues in food: investigation of disparities in cancer risk estimates. Cancer Letters (1997), Vol 117, pps 195-207.

Categories: Myths

True or False – Going outside with wet hair increases your chance of catching a cold

Posted on March 25, 2013

False.

Mothers and fathers routinely scold their children for doing things like going out in the cold without their hats and mittens on, for having their jackets unzipped, and especially for going outside with wet hair. Many well-meaning parents still believe that going outside or going to sleep with wet hair will increase the likelihood of catching a cold. Research going back to the 1950’s has shown that just is not the case. Studies in which participants were exposed to cold viruses or even had viruses put in their nose, and then where placed in chilled or wet environments didn’t come down with more colds than participants who were exposed to viruses in the same manner but were kept in warm or normal environments. In an article titled “Acute cooling of the body surface and the common cold” published in the journal Rhinology, R. Eccles writes, “There is a widely held belief that acute viral respiratory infections are the result of a chill and that the onset of a respiratory infection such as the common cold is often associated with acute cooling of the body surface, especially as the result of wet clothes and hair. However, experiments involving inoculation of common cold viruses into the nose, and periods of cold exposure, have failed to demonstrate any effect of cold exposure on susceptibility to infection with common cold viruses.” Experts do agree that in order to get sick or to catch a cold, you must be exposed to a virus that causes the cold. There are roughly 200 such viruses, with rhinovirus being the culprit in the majority of cases. People often come in contact with the virus that causes a cold by breathing in viral particles after someone has sneezed or coughed or by picking up the virus from a door knob or hand rail and then touching their nose or mouth. Colds are also more common in the winter months as people tend to stay inside more and be in closer contact with one another.

Reference:
Eccles R: Acute cooling of the body surface and the common cold. Rhinology (2002), Vol. 40, pps. 109-114.

Categories: Myths

True or False – You should not eat after 9 P.M. because the calories are usually stored as fat

Posted on March 18, 2013

False.

In past generations many families held to a consistent dinnertime. Now, the typical evening of the American family is much more complicated. It often involves parents chauffeuring one or more of their children to extracurricular activities and events, making it difficult to eat at the traditional dinner hour. In an article entitled “Impact of the daily meal pattern on energy balance”, France Bellisle states “The development of the obesity epidemic has coincided with the loosening of traditional meal patterns, and it seems legitimate to ask whether this has any impact on the energy balance of individuals and their ability to control weight”. Specifically, there is a question of whether eating late at night contributes to weight gain because of how the body treats those calories. There is a common misconception among many that calories eaten in the evening (say at 9:00 or 10:00 pm) are more readily stored as fat. It seems completely logical that food eaten in the morning will be burned up by our daily activities, while calories consumed just before bedtime will not have the same opportunity, and therefore be turned into fat. There are times when even health professionals have perpetuated this popular myth. However, I could find no evidence in the medical or nutritional literature that would suggest that the body digests and stores calories any differently in the morning or at night. Most nutrition experts agree that what is important is the number of total calories eaten per 24 hour period, regardless of at what time of day they are eaten. The question may not be when are we eating, but how much are we eating? It really gets down to calories in vs. calories out. Simply put, if you consume more calories than you burn, you will gain weight. If you burn more calories than you consume, you will lose weight. It is a simple equation, but certainly a challenge to accomplish.

Reference:
Bellisle F: Impact of the Daily Meal Pattern on Energy Balance. Scandinavian Journal of Nutrition (2004), Vol 48, pp. 114-118.

Categories: Myths

True or False – Swallowing gum is dangerous as it can stay in your stomach for months or even years

Posted on March 12, 2013

False.

Many were told never to do it, most did it anyway, that is they swallowed a piece of chewing gum. This maybe the most perpetuated health myth of all time. The parental information that is usually shared with young children to deter them from swallowing gum is that gum is not digestible (which for the most part is true) and remains in the stomach or intestines where it can turn into a huge ball of sticky goo and plug up the digestive system (which for the most part is not true). People have chewed gum type substances, usually resin from trees, for thousands and thousands of years. It wasn’t until the 1840’s that a businessman noticed loggers chewing tree resin and tried to mass produce and market the resin as gum, but ultimately couldn’t find adequate supplies of the resin. Then in the 1860’s a Mexican general with the help of a New York inventor, identified a chewing gum base that became very popular. It is this gum base that makes gum chewy, which is not broken down in the system, but ultimately passes through the digestive system in about the same amount of time as other ingested materials. It is reported that swallowing gum can result in adverse effects such as diarrhea, gas, and stomach discomfort (Milov et. al., 1998). These authors even reported the cases of three children who had masses of gum removed from their digestive system. However, in one case a 1 ½ year old girl had swallowed a number of coins that was entangled with the gum, and the two other cases were of four year old children who habitually swallowed 5 or more pieces of gum a day. So, even though there are reported cases of masses of gum being removed from the intestinal tract of children, these cases are extremely rare and usually involve large quantities of gum swallowed.

Reference:
Milov D, Andres J, Erhart N, Bailey D: Chewing Gum Bezoars of the Gastrointestinal Tract. Pediatrics (1998), Vol 102, pp. e22.

Categories: Myths