Lori Anderson: Many favourite myths soberly debunked

Popular notions about alcohol and pregnancy may not stand up, writes Lori Anderson

EMILY Oster would have made a great barrister had numbers not been her chosen profession. She can fillet a “fact” like the finest of fishwives, and sometimes all that is left of what was once considered the truth is a pile of bones and a bad smell.

For the author of the new book, Expecting Better, numbers run in the family. Her mother and father were economists at Yale, her husband is an economist and she is an associate professor of economics at the University of Chicago.

When she became pregnant and was told not to drink alcohol or coffee and to avoid a long list of foods, she decided to examine the statistical data on which such broad bans were based, with controversial results.

A study in a medical journal, Pediatrics, insisted that light drinking while pregnant was a problem and that women who took a single alcoholic drink a day could trigger behavioural problems in their child.

However, Oster concluded that the study was fatally flawed, as 18 per cent of those questioned did not drink at all while 45 per cent of those who reported having one drink a day also reported using cocaine during their pregnancy.

As Oster writes in her book: “Perhaps the problem is that cocaine, not the occasional glass of Chardonnay, makes your child more likely to have behaviour problems.”

After drilling through a mass of studies to the raw data below, she came to the conclusion that women should have no concern about enjoying one or two drinks a week during the first trimester and up to a maximum of one per day during the second and third trimesters.

She then switched her focus to coffee, which has been linked to higher rates of miscarriage, and once again she discovered serious concerns with the data.

She noticed that those who drank the most coffee tended to be older mothers, for whom miscarriages are more likely. A second crucial point was that nausea, which is a sign of a successful pregnancy, could prevent women from drinking coffee while those who did not suffer nausea, and so drank coffee, may have had different underlying problems that could lead to a miscarriage.

Her conclusion was that her cafetiere and Starbucks visits should not be uninterrupted by pregnancy and so she continued to sip between three and four coffees each day.

While striking down traditional bans, she came up with one: expectant mothers should avoid gardening as it exposes them to a greater risk of the toxoplasmosis parasite than in dirty cat litter which some pregnant women avoid.

Many a mother-to-be may question whom to trust: the medical establishment or economists? The latter is a profession whose reputation has been battered by their inability to accurately foresee the worst economic crisis since the 1930s, subsequently mothers may decide to err on the side of caution rather than reach for a cheeky beaujolais. After all, wasn’t it President Harry S Truman who said that his greatest wish was to have a one-armed economist and so restrict economic forecasts that concluded: “on one hand … but on the other”?

Reading Oster’s findings, however, led me to think of the range of other more definitively confirmed medical myths of which most are ignorant.

Following on from analysing the dos and don’ts of pre-natal care, mothers may be surprised to learn that sugar-rush among toddlers and young children is a myth. The idea that dosing up young children with fizzy drinks and sugary sweets will spin them into a whirlwind is largely accepted as fact despite the absence of any supporting evidence. A dozen double-blind randomised controlled trials found no proof that children who ate sugary sweets were any more rowdy that those who did not. Instead, scientists believe that since parents thought there to be a link they subsequently judge their children to be hyperactive after a sweetie binge.

The idea that we only use 10 per cent of our brains was first reported in 1907 but the most recent research among neuroscientists who have carried out metabolic studies is that there are no dormant areas of the brain and even the dimmest of us use all our grey matter.

If we stay above the neck, the idea that one loses most of one’s heat from the head is only because it is the part of the body most regularly uncovered. Once naked, we lose 10 per cent of our total body heat from the head and the remainder from the rest of our body.

Medical myths abound, and last month the Royal Society in London held a talk on medical myths and misconceptions in an attempt to illuminate our dark ignorance. So do not listen to anyone who insists that cracking your knuckles will cause arthritis in later life, though it may weaken one’s finger joints – and ignore the dietary fad that encourages you to sweat “toxins” out of the body. No one can sweat toxins out of their body, toxins such as mercury, alcohol and drugs are eliminated through the liver, intestines and kidneys.

There is, however, one that I’m ghoulishly disappointed to discover is nonsense. Sadly hair and fingernails do not continue to grow after death. Any appearance of growth is down to the skin dehydrating and retreating from the fingernails. Another darling of mine that has been murdered, one which I have solidly believed in since a child, is that the pain of a jellyfish sting can be relieved by – for want of a better phrase – a “golden shower” upon the affected area. All of these findings show that we often deal in assumptions and that we judge decisions by their results and not by factors at the time which influenced them.