It is simply taken as fact that swimming after eating will cause you to cramp up and drown. And everyone knows that sitting too close to the TV ruins your eyesight. Superstitious in nature, old wives’ tales like these get passed down through generations of family and friends, sometimes becoming so rooted that nobody questions their validity. These legends, which often concern health and nutrition, vary from completely absurd to somewhat plausible. Here are some old wives’ tales and the truths behind them.
Swimming Less than an Hour after You Eat Causes Cramps and Leads to Drowning: Most children have probably heard from their parents that they must wait at least an hour after eating before hopping into the water for a swim. Otherwise, they could suffer cramps and drown. The theory behind this tale is actually pretty sound and has to do with a shift in blood flow in the body.
When you eat something, your body increases the blood flow to your stomach muscles to help with digestion. The larger the meal you scarf down, the more oxygenated blood your stomach needs for digestion. But this means less oxygen available for your arms and legs, which require an increased amount during exercise (whether you’re swimming, running, or cycling). Depriving your muscles of vital oxygen can lead to cramps, conceivably increasing your risk of drowning. The real danger lies with those who eat huge meals before vigorous, triathlon-level exercise. Such cases can indeed lead to cramps and even vomiting. But even then, the medical consensus has long been that it’s unlikely to result in drowning; that is, unless the swimmer all-out panics and forgets how to float.
Cows Lie Down When It’s About to Rain: How can you accurately predict if it’s going to rain? Just check a cow pasture. If all the cows are lying down, a rainstorm is coming — or so this old wives’ tale claims.
Believers have schemed up several different explanations for why our bovine friends would hit the ground in anticipation of a storm, and many of them sound equally plausible. The simplest is that cows can sense increasing air moisture and will plop down to preserve a dry patch of grass. Another theory states that cows lie down to ease their stomachs, which are supposedly sensitive to changes in atmospheric pressure brought on by rainfall.
The most complicated explanation suggests that cow legs are micro-porous structures that rapidly absorb moisture. As the relative humidity builds from an oncoming downpour, the cow’s legs will absorb more and more moisture from the air, softening until they can no longer support the weight of the cow. But is there any weight behind this tale? Not likely – cows lie down for many reasons, and there’s no scientific evidence that rain is one of them. As the Farmer’s Almanac says, “Cows lying down in a field more often means they’re chewing their cud, rather than preparing for raindrops.” And just think: If weather predictions were made based on the actions of cows, the forecast would always be grim.
Gum Stays in Your Intestines for Seven Years: Thankfully the legend is false.
As gastroenterologist Dr. Rodger Liddle of the Duke University School of Medicine explained to Scientific American: “Nothing would reside that long unless it was so large it couldn’t get out of the stomach or it was trapped in the intestine.” Chewing gum passes through the digestive system like any other food. Your body is able to break down some of the gum’s components, such as sweeteners and oil derivatives, but the gum’s rubber or latex base gets churned out in a matter of days.
However, this doesn’t mean you should start swallowing your chewing gum regularly — in several reported cases, doctors had to remove taffylike wads of gum from children’s bowels. Swallowing a lot of chewing gum in a relatively short amount of time, it seems, can cause the pieces to accumulate and stuff up the digestive tract, causing constipation.
Spicy Food Causes Ulcers: For decades, doctors thought eating a lot of spicy food caused stomach ulcers, or painful sores on the lining of the esophagus, stomach or upper area of the small intestine. It certainly made sense, as patients would often complain of burning stomach pains after eating spicy food. The treatment: a strict diet of bland food (which didn’t actually get rid of the ulcer pain).
But in the 1980s, scientists put this old wives’ tale to rest (at least in the medical community — a lot of people still believe this one). Studies showed that spicy food doesn’t cause ulcers, though it can irritate existing ulcers, which explains the misunderstanding.
The real culprit behind the majority of ulcers, researchers found, was the bacterium Helicobacter pylori. When H. pylori enters the body, it heads for the stomach, excreting protective enzymes to shield it from the stomach’s harmful digestive acids. H. pylori then burrows into the stomach’s mucosal lining, which partially protects it from white blood cells, the immune system’s main weapon against bacterial intruders. Ulcers then develop as the bacteria colonize the stomach.
