Debunking medical myths just in time for the holidays. (Kevin Maloney for The New York Times, Ting-Li Wang and Damon Winter/The New York Times)Last year, the British medical journal BMJ reported on a series of medical myths that even doctors believe. Among them: Turkey makes you drowsy. Dim light ruins your eyes. Drink at last eight glasses of water a day.
This year, the same researchers, Dr. Aaron Carroll and Dr. Rachel Vreeman of the Indiana University School of Medicine, offer six new medical myths for the holiday season. The latest set of myths, published this month in BMJ, are commonly believed by the general public and many doctors, said the researchers. However, a search of the medical literature shows these myths aren’t true or lack evidence to support them.
“Even widely held medical beliefs require examination or re-examination,” the study authors wrote. “Both physicians and non-physicians sometimes believe things about our bodies that just are not true.”
Here are the six new commonly believed medical myths they’ve identified.
1. Sugar makes kids hyperactive.
The researchers cite 12 controlled studies that couldn’t detect any differences in behavior between children who had sugar and those who did not. Even when kids had a diagnosis of hyperactivity problems or were said to be more sensitive to sugar, they did not behave differently whether they ate sugar-laden or sugar-free diets. In fact, the biggest effect of sugar may be on parents. Parents rate their children as being more hyperactive if they are told the child has consumed sugar — even when the child hasn’t really had any sweets.
2. Suicide increases over the holidays.
Suicides are more common during warm and sunny times of the year, studies show. There is no evidence of a holiday peak in suicides.
3. Poinsettias are toxic.
Among 22,793 poinsettia exposures reported to the American Association of Poison Control Centers, there were no deaths or significant poisonings. A study of poinsettia ingestion found that when rats were given doses equal to a person consuming 500 to 600 poinsettia leaves, the plant wasn’t toxic.
4. You lose most of your body heat through your head.
This is the myth that Dr. Carroll and Dr. Vreeman believed to be true. They found out that the belief likely originated with an old military study where subjects wearing arctic survival suits lost most of their body heat through their heads. But that was because the head was the only bare part of their bodies. Typically, we don’t lose more than 10 percent of body heat through our heads. The bottom line is that any uncovered part of the body will lose heat, which is why wearing a hat, even when you’re bundled up everywhere else, is important.
5. Night eating makes you fat.
Studies show an association between obesity and eating more meals late in the day, but that doesn’t mean eating at night causes obesity, the doctors point out. Eating more at any time of day will cause weight gain if it results in ingesting more calories than you need.
6. Hangovers can be cured.
The researchers found no scientific evidence supporting any type of cure for alcohol hangovers. Because hangovers are caused by drinking too much alcohol, the only way to avoid one is to drink very little or not at all.
Next year, the doctors plan to provide more research on medical myths in their new book, “Don’t Swallow Your Gum: Myths, Half-Truths, and Outright Lies About Your Body and Health,” to be published by St. Martin’s Press.
Healthy living doesn't happen at the doctor's office. The road to better health is paved with the small decisions we make every day. It's about the choices we make when we buy groceries, drive our cars and hang out with our kids. Join columnist Tara Parker-Pope as she sifts through medical research and expert opinions for practical advice to help readers take control of their health and live well every day. You can reach Ms. Parker-Pope at 
The easiest and most pleasurable way to eat well is to cook. Recipes for Health offers recipes with an eye towards empowering you to cook healthy meals every day. 
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Thanks, Tara. I especially like the one that debunks that “night eating makes you fat.” Did people start to say this because we keep hearing that breakfast is the most important meal of the day; that we must eat breakfast if we hope to lose weight?
I wonder if some people just extrapolated in the wrong way to conclude that night eating made us pack on the pounds.
— ShanaYeah, I always wondered about #5. Mediterraneans consume huge dinners late at night and skimpy breakfasts and on the average, don’t look fatter to me than anybody else.
The old saw of dieting says that you have to have a big breakfast and avoid eating anything after 6 PM. But in the real world, it’s often difficult to achieve. You may only be back home way after 6 PM. You may want to meet friends at a restaurant or there may be receptions you have to attend as part of your work.
In real life, I’ve found it way easier to accommodate a system where I have the obligatory 5 portions of fruits and vegetables early in the day and save the heftier eating for later in the evening.
— SusannaI think some of these arguments are convoluted and misleading. Night eating may not make you “fat”, but eating late at night will make weight gain more likely as your metabolism slows down when you sleep. And you may not be able to “cure” a hangover, but you can sure make it less severe by chugging water before going to bed. Sounds like they were stretching for a 5th and 6th myth…
— KellyI remember when Oprah refused a dinner invitation from Tom Cruise because of her guru (Bob Greene) insisting on no eating after 7:30 p.m. Just look at how that helped her.
As for poinsettias, the paragraph says there were no deaths or significant poisonings. What is an insignificant poisoning if it happens to you?
— marlyDoes the lack of scientific support for any hangover cure indicate that hangovers cannot be cured or does it suggest that there isn’t much investigation into the matter?
— P. FlowersTo my mind, this “myth debunking” only proves the failure of study methodology to account for everything. Science can only measure so much.
— MattRe: 6. Hangovers can be cured.
There is a way to help prevent hangovers, however: B-vitamins.
If you take a few B-vitamins BEFORE you drink, it will really help. Even after you drink, the B vitamins help speed up the alcohol metabolism and reduce your hangover.
I recommend either a B-complex (no need to worry about B12 vs B6 etc.), or 1-2 packets of Emergen-C. For those who have used Emergen-C, the amazing powder mix which helps both when you are sick and when you have drunk, look at the ingredients: the main one is B vitamins.
Of course, NOT drinking is the only sure way to avoid a hangover… But for those practical people among us, the B-vitamin is a very useful supplement.
Bonus: take 2 advil before going to sleep with 1-2 glasses of water.
These tricks have helped me avoid hangovers for years.
— Sanjay“The researchers found no scientific evidence supporting any type of cure for alcohol hangovers. Because hangovers are caused by drinking too much alcohol, the only way to avoid one is to drink very little or not at all.”
It was my understanding that most “hangovers” are caused by some combination of dehydration and alcohol withdrawal, and thus are best “cured” by some combination of water and a little hair of the dog.
— Megan BThat might not have been clear. Science has failed to “measure” the correlation between immunizations and autism; try telling that to the mothers of children with autism who showed no symptoms of autism before the injection.
And try telling any parent that sugar doesn’t REALLY make their children hyper. Sorry, what? I’m not a dullard, I understand parents seeing what they think they should see, but honestly.
— MattIt’s not about WHEN you eat, per se, it’s about HOW MUCH you eat. Typically, eating a healthy breakfast leads to eating less throughout the day because you’re not starving all day and then load up on food when you finally get the chance to eat. But it’s ok to eat dessert or a snack at night - even after you’ve already had dinner - as long as it enables you to stay within your calorie limit for the day. The gaining weight at night myth developed because sometimes people pig out on junk food after dinner while mindlessly watching TV, etc., leading them to consume extra calories that pack on the pounds over time.
— ErikaHangovers can’t be “cured” with some magical remedy but they can be treated and prevented. Alcohol is a sugar. All sugars require water to be broken down into molecules the body can use and energy. Furthermore, alcohol also acts as a diuretic, or a chemical compound which tells your kidneys to take water out of your blood and put it into your urine. Thus, a hangover is merely extreme dehydration, due in part to the water used to break down the alcohol as well as the water lost in urine. In order to prevent a hangover drink lots of water before you start drinking, drink a large glass of water before you go to bed, and continue drinking water the next morning.
— VincentIt is a shame that we can’t get the information on sugar and hyperactivity out to all the children of the world.
I can see the family discussions that that one would provoke.
— Wonks AnonymousThere is actually one cure for a hangover: more booze.
Works like a charm.
Bloody Marys all around! Sip a couple of those slowly - over the morning - not enough to get drunk again…just to blunt the hangover. Taper off by afternoon & you’ll likely be through the worst of it.
Repeat until January 2nd.
— BacchusLike most myths, people will let them be dispelled for only so long before they go back to believing them.
— BillWell, I still chose not to have Poinsettias in my house because I have cats. I don’t want to risk it. The sugar thing I find a little hard to believe because I remember being a kid on a sugar high and it was.. um.. interesting. My daughter is the same way. The late night eating/hangover thing I already knew. Didn’t know about the suicide or hats though.
— StevieThe saying “breakfast is the most important meal of the day” originates back to the farming days, where farmers would wake early and often have a quick lunch or skip it. All that manual labor requires a lot of energy, so a big breakfast was needed if work was to get done.
— andrew#10 is exactly right. It’s all (or mostly) about portion size. We’ve so completely lost track of what a normal, sufficient amount of food is that we can’t conceive of something so simple being so central.
And in response to #2: Mediterraneans do eat late, but it’s not quite accurate to say they eat “huge” dinners. My experience living in Greece was that evening meals would go on for 3-4 hours, but the amount of food consumed was still far less than what people will shovel down in just 20 minutes here.
Plus, obviously, the ratio of vegetables and grains to meat is much higher in that diet.
— JHoThe “logic” behind “eating at night causes one to gain weight” is that you eat a meal, then immediatley get very inactive (go to sleep) so the food is stored as fat. I have argued with people about the falsehood of this many times, my argument being that calories are calories. Now I can at least point to this study.
— Dr.R.P.I don’t really think the night eating myth was debunked … yes, calories are calories regardless of the time, but I think what the ‘myth’ refers to people who add meals at night or snack until they sleep without cutting back elsewhere. Changing the times you eat may not cause you to gain or lose weight - but adding late night meals without cutting back at other times surely will.
I found cutting myself off from the kitchen after 8 had a significant impact on my weight.
— AThere might, however, be an indirect correlation between eating late and gaining weight. If you have already eaten all you need at the 3 regular meals, and eat an ADDITIONAL meal at night, you might gain weight you would otherwise not gain.
— Dr.R.P.The body’s metabolism slows down while sleeping, causing a higher percentage of the processed calories to be stored as fat. Number 5 is misleading because other habits “outweigh” eating late at night. For instance if you eat 8000 calories a day it does not matter when you eat them, you will become obese. A more fitting and true description would be night eating does not make you fat, it makes you fatter.
— LewisThese holiday axioms are myths? You can’t be serious! Are you next going to tell me that Santa Claus is a myth? Good Grief!
— NickI suspect that parents correctly observe that certain foods make their kids more hyper, but mistakenly attribute this to sugar. If you read the research on the glycemic index, it appears likely that what is causing the whipsaw in blood glucose levels (sharp spike followed by rapid insulin release followed by low sugar) is other quickly-processed carbs such as cake, pretzels, crackers, and cookies.
If you want to check this out, I strongly suggest reading the material only by the original research team, as it is complex, often counter-intuitive , and therefore often misrepresented when summarized. Ideally, see “The New Glucose Revolution” by J. Brand-Miller; or else http://www.glycemicindex.com/.
Interestingly, some of the foods highest in the glycemic index (i.e., provoking the worst reaction) are bagels, rice cakes, pretzels: the things many educated parents give their kids as what they hope will be healthy snacks. If you want to feed these to your kids, just don’t give them solo: always accompany with an apple, glass of milk, piece of cheese, a few nuts or peanuts if tolerated.
regards, Diana
— DianaMy comment to #17 is: eating for 3-4 hours? I hardly have time to spend 30min at each meal. I need to move to Greece!
— Dr.R.P.drinking a glass of water in between drinking alcoholic drinks will drastically reduce the hangover symptoms
— peterg