Dress up your kids like Dracula or Frankenstein, and most likely they'll look more cute than scary.
Let them eat too much candy, and they'll turn into real little monsters.
That's the word, at least, from many parents who fear their trick-or-treaters' sweets success this Halloween will end in wild "sugar highs" -- with energy going through the roof -- followed by moody "sugar crashes" -- with that energy suddenly dropping through the floor.
"I have mothers tell me their child can ingest something sweet, and they know to the minute when the reaction is going to occur," says Jo Ann Hattner, a registered dietitian who teaches nutrition at the Stanford University School of Medicine.
Yet the truth is that experts disagree about whether the sugar high and sugar crash truly exist.
Many say the evidence contradicts such stories. "There is no scientific basis to the idea that sugar and/or candy has any major effect on children's behavior, particularly if they eat OK," says Dian Dooley, professor of human nutrition, food and animal sciences at the University of Hawaii at Manoa.
Others think sugar has plenty of skeletons in its closet. "The bottom line is that the ingestion of too much high-glycemic carbohydrate causes a rapid rise and then fall of blood sugar," says Dr. David Ludwig, professor of pediatrics at Harvard Medical School and director of the Optimal Weight for Life program at Children's Hospital Boston. "This triggers a series of metabolic and hormonal changes that can affect appetite and behavior for hours to come."
Still more experts think that the experience of a sugar high is real -- but only because parents are convinced it exists.
"I would never try to convince parents otherwise," says Dr. Thomas Robinson, professor of pediatrics at Stanford and director of the Center for Healthy Weight at Lucile Packard Children's Hospital. "You can't tell them it doesn't happen because, for them, it does happen."
A little basic physiology implies that sugar highs could happen. Glucose, a digestive byproduct of the sugar we eat, is one of the body's two main sources of energy (along with fat). So it seems feasible that eating a lot of sugar could give a person a quick energy boost.
That's the reasoning behind, say, marathoners eating candy bars en route. It's also the theory behind an old test doctors once got a kick out of: They'd give a pregnant woman a glass of orange juice, Hattner says, and in no time, if the woman's baby was healthy, it would be treating its mom like a soccer ball.
But the body is designed to keep glucose levels in the blood stable. When the levels increase, the pancreas releases insulin, which moves glucose out of the blood and into tissues throughout the body.
If levels have spiked steeply, the pancreas might overreact and release too much insulin, so the glucose level could end up dipping below where it should be. But then the pancreas releases another hormone, glucagon, which moves glucose stored as glycogen out of the liver to bring the levels back up again.
Things can go wrong with this regulatory system. Diabetics don't produce enough insulin, for example. And even in a healthy person, it can take a little time to restore the system to balance once it's gotten off kilter. If glucose levels get dramatically low, that's the physiological basis for a sugar crash. But here the neatness of the theory seems to end. If levels stay high for a while, instead of energizing a person as you'd expect, it actually makes a person sleepy, studies show.
Investigations into the topic date back decades. In the early 1970s, pediatric allergist Dr. Benjamin Feingold found that food additives were related to hyperactivity. His work is widely seen as jump-starting the study of how diet affects behavior, and that field of research soon became very active.
Early studies of sugar searched in vain for proof of the sugar highs that parents and teachers so often complained about. One such finding, published in the New England Journal of Medicine in 1994, compared sugar and the artificial sweetener aspartame -- both of which had been reported to cause hyperactivity and other behavioral problems.
Researchers tested two groups of children: 25 normal preschoolers, 3 to 5 years old, and 23 school-age children, 6 to 10 years old, who were described by their parents as sugar-sensitive.
Each of the children followed three different diets for three weeks each. One was high in sugar but had no artificial sweeteners. A second was low in sugar and used aspartame as a sweetener. And the third was low in sugar and used saccharin as a sweetener. (Because no hyperactivity problems with saccharin had been reported, saccharin was considered a placebo.)
The result: On 39 behavioral and cognitive measures, no significant differences in the three diets were found among the "sugar-sensitive" children. Some differences were found on four of 31 measures among preschoolers, but in no consistent pattern.
The researchers concluded that even at atypically high levels, neither sugar nor aspartame affects children's behavior or cognitive function.
Other studies came up short as well. In 1996, an article published in Critical Reviews in Food Science and Nutrition reviewed 12 studies and found no evidence that sugar had negative effects on the behavior of normal children or children with attention-deficit hyperactivity disorder. The authors also found no evidence of such effects in a number of studies of chocolate and other types of candy.
-- The opposite effect?
More recently, researchers testing sugar effects on adults found that, if anything, sugar makes people hypoactive -- that is, more lazy and sluggish. In a 2006 study (published in the journal Human Psychopharmacology: Clinical and Experimental), five healthy adults had an "energy drink" containing 42 grams of sugar and 30 milligrams of caffeine an hour after a light lunch. Five others had a sugar-free drink that tasted exactly the same. Then all 10 took a 90-minute performance test.
At first, both groups did equally well, but 50 minutes after having the drinks, the supposedly energized ones began going downhill, becoming slower to react and getting sleepier.
Some evidence does support the reality of sugar highs, however. In a survey of more than 5,000 Norwegian teenagers, researchers found higher rates of hyperactivity among those who habitually drank the most sugary sodas.
Of course, this study (which was published in 2006 in the American Journal of Public Health) did not show that the sugar in the sodas caused the hyperactivity. Any number of relationships could exist between the sodas and the teenagers' behavior. Another ingredient in the sodas might be to blame. It's also possible that hyperactivity makes teens more likely to drink sugary sodas, instead of vice versa.
Missing the link
Even though a great deal of evidence implies that sugar does not affect children's behavior -- and many experts seem to consider the issue settled -- some researchers think mistakes were made in the research and wrong conclusions reached as a result.
Harvard's Ludwig says that much of the research in this field has been looking for effects in the wrong way and in all the wrong places. ("If you lose your keys, and you don't happen to look where they actually are, you're not going to find them," he says.)
Ludwig says that many studies testing for a sugar-behavior link didn't find one because they compared sugar with other refined starches whose effects on the body are the same because they are broken down into sugar very quickly. "Your glucose level can rise as much after a bowl of plain Rice Krispies as after a bowl of sugar," he says.
With co-workers, he corrected for this problem in a 1999 study of 12 obese, but otherwise healthy, teenage boys that was published in the journal Pediatrics. The boys were evaluated on three occasions: when their breakfast and lunch had a low, medium or high glycemic index -- a ranking of carbohydrates according to how quickly they cause blood glucose levels to rise. All the meals for each subject had the same number of calories.
Ludwig's team measured how much the boys ate during the five hours after their lunches. After the high-index lunch, the boys ate 53% more calories than after the medium-index meal and 81% more than after the low-index meal -- indicating that the higher the glycemic index of a meal, the hungrier the boys were likely to get soon afterward.
More significant for the sugar-high question, the high-index meal led to lower levels of glucagon and higher levels of insulin and epinephrine -- a stress hormone that, among other things, increases heart rate and blood pressure.
"The results show that sugar and other refined starches can trigger counter-regulatory stress hormones that can affect hunger, mental functioning and behavior," Ludwig says.
Parents' reports on the effects of sugar vary widely -- even among children in the same family.
"Cameron gets nasty," says 42-year-old Diane O'Hagan of Pacific Grove, about her eldest son. "And Eric, he gets kind of moody. And Reece just gets wild, but then he's wild all the time, so it's hard to tell when he's having a sugar high."
Faith Shearin, a 38-year-old poet in Kittyhawk, N.C., says her 7-year-old daughter, Mavis, doesn't experience sugar highs. But, she says, "Some of my friends complain that their children consume candy or soda and begin to hop up and down like popcorn. I have witnessed this behavior but have never been sure if sugar was the cause."
If sugar is not responsible for the behavior so often labeled a sugar high, what might be?
Caffeine is one possibility, at least at Halloween, suggests Dr. Zhaoping Li, a professor of medicine at UCLA's Center for Human Nutrition. The stimulant is found in many soft drinks and candies, but usually not at a level to affect mood. Still, sugar reactions may occur when those foods are consumed in mega amounts: "Ordinarily, kids will eat one piece of candy, but at Halloween, maybe 30 or 40," Li says.
It's also possible, she says, that kids simply experience genuine excitement on the night. They look forward to Halloween for a long time -- plan their costumes, anticipate their goodies -- and they expect to have big fun.
If effects of sugar vary from child to child, it might be explained by differences in their insulin secretion, Ludwig suggests. For example, if the three O'Hagan boys each ate half a bag of Reese's Pieces, their three different pancreases might produce three different amounts of insulin, influencing how rapidly sugar rises in their blood and is removed from it.
No one knows yet how much insulin production should be considered normal, but a routine glucose tolerance test can measure its levels. (In a study reported in the May edition of the Journal of the American Medical Assn., "high" was anything above 57.5 micro-units per milliliter. Not that there's a ghost of a chance parents will have such tests at their disposal Wednesday night.)
All an illusion?
Here's one more spooky thing to think about. If the sugar-high-sugar-crash cycle exists, parents, not the kids, may lie at the root of it.
"It's due to parents' expectations of what behavior is likely to be after kids eat a lot of sugar," says Robinson of Stanford.
This can work in several ways. For one thing, if parents expect a child to be hyper after eating something full of sugar, then that's what they'll see. "Expectancies are very powerful in altering perceptions," Robinson says.
Parents may even conceivably act in subtly different ways toward their kids -- in ways that could make them get wilder.
Alternatively, if parents see their child behaving hyperactively they may try to figure out why that's happening and decide it's because of a sugary treat the child ate awhile before.
Audrey Vernick, 43, of Ocean, N.J., says she's found herself doing just that with her kids. "When they don't sleep at night . . . it's easy to think of the sugar they've eaten and try to blame that."
There's even science to back up the notion that the sugar effects that parents report might be based on the sugar effects they expect to see. A 1994 study published in the Journal of Abnormal Child Psychology tested the theory on 35 boys, ages 5 to 7, described by their mothers as sugar-sensitive. During the study, researchers told half the mothers that their sons had been given a lot of sugar. They told the other set of mothers that their sons had been given a placebo. In fact, though, all the boys received the placebo, which was the artificial sweetener aspartame.
Mothers and sons then spent awhile playing together, and then the mothers were interviewed about how their sons behaved. Those who believed their sons had eaten sugar rated them as more hyperactive than did those who believed their sons had eaten a placebo -- in direct support of the expectancy hypothesis. (To show how tricky these studies can be, recall that aspartame, too, has been blamed by parents on altering the mood of their kids, making it a less-than-ideal placebo.)
Sugar highs and lows may not do all that we think they do, but for some people they can definitely make themselves felt. "For some people it's an uncomfortable feeling to go up and then down within a couple of hours," says Carol Koprowski, a registered dietitian and a professor at USC.
But whether or not sugar makes your child go wild, it would be hard to find anyone who thinks a child should go wild eating sugar. It is implicated, after all, in other undesirables such as obesity and tooth decay.
Still, most experts do consider Halloween a special case.
And it is just one night.
(BEGIN TEXT OF INFOBOX)
Pork: the other Halloween treat?
We're eager to enlighten readers about all aspects of a healthful Halloween and so are grateful to the many dentists, dietitians and merchants who have sent timely news releases. Here's a taste of what we've learned:
* "Candy is a staple of the Halloween holiday," says Bryan Shirtliff, senior vice president of category management for Rite Aid. Don't believe him? Here are hard data from Joseph Cifelli, assistant professor of science education at Saint Joseph's University in Philadelphia. He took a survey of his undergraduate students and ranked their Halloween treat preferences as follows: Reese's Peanut Butter Cups, Snickers, Swedish Fish, Twix and Skittles.
"It's clear that our students reflect the national consumer trend, and candy is still the No. 1 Halloween treat," Cifelli reports. You heard it here first.
* The American Assn. of Orthodontics urges kids who wear braces to steer clear of the following treats: all hard candies, all chewy candies, caramel, nuts, licorice, taffy, jelly beans, bubblegum. But everything else is cool, right? Sweet!
* "With Halloween just around the corner, I thought you [might] be interested in the fact that October is national pork month," writes Victor Domine of Bender Hammerling Group, which handles public relations for French's mustard and french fried onions. Maybe this is what those kids who wear braces get to eat -- or is Domine suggesting that folks pig out Wednesday night? It's a policy we cannot in good conscience endorse.
* Halloween, it seems, is not just about pork. It's also about dairy. "We thought maybe a light and fun story that revolves around scary skeletons, building bones and calcium and vitamin D-fortified snack foods would be of interest to you," writes Kevin Hughes of Peacock Communications on behalf of Precious Cheese. Well, we guess this might go down better with the kids than the healthful celery-sticks-dipped-in-peanut-butter treat suggested by UT Southwestern Medical Center.
* "Celebrate the Fantasy-Filled Fun of Halloween with Candy Dynamics' Toxic Waste Hazardously Sour Candy, Toxic Waste Nuclear Sludge Chew Bars, and Valuable Safety Tips," offers the Candy Dynamics candy company. Will those tips tell us how to stay safe around toxic waste and nuclear sludge?
* Food allergies from nuts and eggs, skin irritation from make-up and masks, hand injuries from hazardous pumpkin-carving knives, trailing capes for little feet to trip on: There's plenty to be scared of -- and here's a little more. "Just in time for Halloween, researchers are releasing new data that show darkness increases the impact of social stress," says the scientific publishing house Elsevier. People can be afraid of the dark! Who knew?
-- Karen Ravn