believe it or not… it is a myth

Ever have a conversation with your friends and end up arguing about what’s true and what’s a myth? Well here are some cool facts I found on common mis-understandings… (myths)

Sugar causes hyperactivity in children

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 behavior 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 behavior as more hyperactive. The differences in the children’s behavior were all in the parents’ minds.

Suicides increase over the holidays

Holidays can bring out the worst in us. The combined stresses of family dysfunction, exacerbation 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.

One study from Japan that looked at suicides in 1979-94 showed that the rate of suicide was lowest in the days before a holiday and highest in the days after the holiday. In contrast, 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 afterward. A smaller study of adolescents showed a peak in suicide attempts at the end of the school year, possibly reflecting a decrease in social support. Data from Ireland on suicide in 1990- also failed to connect suicides with the holidays. While Irish women were no more likely to commit suicide on holidays than on any other days, Irish men were actually significantly less likely to do so.

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. In Finland, suicides peak in autumn and are lowest in the winter. In a 30 year study of suicides in Hungary, researchers again found the highest rates of suicides in the summer and the lowest in the winter. Studies of suicide rates from India also show peaks in April and May. Studies from the US reflect this pattern, with lower rates in November and December than in typically warmer months.

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.

Hair and fingernails continue to grow after death

Morbid information about the body captures the imagination and reinforces medical mythology. In All Quiet on the Western Front, the author describes a friend’s fingernails growing in corkscrews after the burial.Johnny Carson even perpetuated this myth with his joke, “For three days after death hair and fingernails continue to grow, but phone calls taper off.” To quote the expert opinion of forensic anthropologist William Maples, “It is a powerful, disturbing image, but it is pure moonshine. No such thing occurs.”

This myth does have a basis in a biological phenomenon that can occur after death. As Maples and numerous dermatologists explain, dehydration of the body after death and drying or desiccation may lead to retraction of the skin around the hair or nails. The skin’s retraction can create an appearance of increased length or of greater prominence because of the optical illusion created by contrasting the shrunken soft tissues with the nails or hair. The actual growth of hair and nails, however, requires a complex hormonal regulation not sustained after death.

Reading in dim light ruins your eyesight

The fearful idea that reading in dim light could ruin one’s eyesight probably has its origins in the physiological experience of eye strain. Suboptimal lighting can create a sensation of having difficulty in focusing. It also decreases the rate of blinking and leads to discomfort from drying, particularly in conditions of voluntary squinting. The important counterpoint is that these effects do not persist.

The majority consensus in ophthalmology, as outlined in a collection of educational material for patients, is that reading in dim light does not damage your eyes. Although it can cause eye strain with multiple temporary negative effects, it is unlikely to cause a permanent change on the function or structure of the eyes. Even in patients with Sjögren’s syndrome (an autoimmune disease that features inflammation in certain glands of the body), decreased functional visual acuity associated with strained reading improves when they stop reading.

One review article on myopia concludes that increased use of one’s eyes, such as reading in dim light or holding books too close to the face, could result in impaired ocular growth and refractive error. The primary evidence cited was epidemiological evidence of the increased prevalence of myopia and the high incidence of myopia in people with more academic experience. The author notes that this hypothesis is just beginning to “gain scientific credence.” In the past reading conditions involved even less light, relying on candles or lanterns, so increased rates of myopia over the past several centuries does not necessarily support that dim reading conditions are to blame. In contrast to that review, hundreds of online expert opinions conclude that reading in low light does not hurt your eyes.

Original articles can be found here and here.