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I was searching around the British Medical Journal for some material by Brian Deer, the investigative journalist who exposed Andrew Wakefield as the complete fraud that he is, when I stumbled upon an article entitled “Festive Medical Myths.” As the holiday season is almost upon us and we love busting myths here at SBL, I thought I would share the contents of the article with you here. You can find the source and study references at the bottom of the post.

The material below has been slightly edited for length, but appears mostly verbatim.

Festive Medical Myths

Myth: Sugar causes hyperactivity in children

Regardless of what parents might believe, however, sugar is not to blame for out of control little ones. At least 12 double-blind randomized controlled trials have examined how children react to diets containing different levels of sugar.

None of these studies, not even studies looking specifically at children with attention-deficit/hyperactivity disorder, could detect any differences in behaviour between the children who had sugar and those who did not.

This includes sugar from sweets, chocolate, and natural sources. Even in studies of those who were considered “sensitive” to sugar, children did not behave differently after eating sugar full or sugar-free diets.

Scientists have even studied how parents react to the sugar myth. When parents think their children have been given a drink containing sugar (even if it is really sugar-free), they rate their children’s behaviour as more hyperactive. The differences in the children’s behaviour were all in the parents’ minds.

Myth: Suicides increase over the holidays

Holidays can bring out the worst in us. The combined stresses of family dysfunction, exacerbations in loneliness, and more depression over the cold dark winter months are commonly thought to increase the number of suicides. While the holidays might, indeed, be a difficult time for some, there is no good scientific evidence to suggest a holiday peak in suicides.

In a study from the United States of suicides over a 35 year period, there was no increase before, during, or after holidays. Indeed, people might actually experience increased emotional and social support during holidays. In the US, rates of psychiatric visits decrease before Christmas and increase again afterwards.

Further debunking myths about suicide, people are not more likely to commit suicide during the dark winter months. Around the world, suicides peak in warmer months and are actually lowest in the winter.

Of course, none of this evidence suggests that suicides do not happen over the holidays. The epidemiological evidence just does not support that the holidays are a time of increased risk.

Myth: Poinsettia toxicity

With flowers and leaves of red, green, and white, poinsettias are widely used in holiday decorations. Even though public health officials have reported that poinsettias are safe, many continue to believe this is a poisonous plant.

In an analysis of 849, 575 plant exposures reported to the American Association of Poison Control Centers, none of the 22 793 cases involving poinsettia resulted in considerable poisoning. No one died from exposure to or ingestion of poinsettia, and most (96%) did not even require medical treatment.

In 92 of the cases, children ingested substantial quantities of poinsettias, but none needed medical treatment, and toxicologists concluded that poinsettia exposures and ingestions can be treated without referral to a healthcare facility.

Another study, looking at poinsettia ingestion by rats, could not find a toxic amount of poinsettia, even at amounts that would be the equivalent of 500-600 poinsettia leaves or nearly a kilogram of sap.

Myth: Excess heat loss in the hatless

Even the US Army Field manual for survival recommends covering your head in cold weather because “40 to 45 percent of body heat” is lost through the head. If this were true, humans would be just as cold if they went without trousers as if they went without a hat. But patently this is just not the case.

This myth probably originated with an old military study in which scientists put subjects in arctic survival suits (but no hats) and measured their heat loss in extremely cold temperatures. Because it was the only part of the subjects’ bodies that was exposed to the cold, they lost the most heat through their heads. Experts say, however, that had this experiment been performed with subjects wearing only swimsuits, they would not have lost more than 10% of their body heat through their heads. A more recent study confirms that there is nothing special about the head and heat loss.

Myth: Nocturnal feasting makes you fat

A common suggestion to avoid unwanted weight gain is to avoid eating at night, and at first glance, some scientific studies seem to support this. In a study of 83 obese and 94 non-obese women in Sweden, the obese women reported eating more meals, and their meals were shifted to the afternoon, evening, or night. But just because obesity and eating more meals at night are associated, it does not mean that one causes the other. People gain weight because they take in more calories overall than they burn up. The obese women were not just night eaters, they were also eating more meals, and taking in more calories makes you gain weight regardless of when calories are consumed.

Other studies found no link at all between eating at night and weight gain. In a study of 86 obese and 61 normal weight men, there were no differences in the timing of when they ate. Another study of 15 obese people found that the timing of meals did not change the circadian rhythm pattern of energy expenditure.

In a study of over 2500 patients, eating at night was not associated with weight gain, but eating more than three times a day was linked to being overweight or obese.

Myth: You can cure a hangover

From aspirin and bananas to Vegemite and water, internet searches present seemingly endless options for preventing or treating alcohol hangovers. Even medical experts offer suggestions.

No scientific evidence, however, supports any cure or effective prevention for alcohol hangovers. A systematic review of randomized trials evaluating medical interventions for preventing or treating hangovers found no effective interventions in either traditional or complementary medicine.

A hangover is caused by excess alcohol consumption. Thus, the most effective way to avoid a hangover is to consume alcohol only in moderation or not at all.


In the spirit of skepticism, the authors conclude:

Examining common medical myths reminds us to be aware of when evidence supports our advice, and when we operate based on unexamined beliefs…Only by investigation, discussion, and debate can we reveal the existence of such myths and move the field of medicine forward.

Source and Citation:

You can find the article online here.Vreeman, R.C. & Carroll, A.E. (2008) Festive medical myths. BMJ, 337. doi: 10.1136/bmj.a2769