Tuesday, October 06, 2009

The Candy-Crime Correllation-Causality Conundrum

A new study is out suggesting that daily candy consumption by young kids is related to committing crimes later in life. Crime and Consequences points out the apparent logical fallacy in this finding:
The classic example for the fundamental principle that correlation does not prove causation is the ice cream/crime connection. Daily spikes in the rates for aggravated assault are correlated with spikes in sales of ice cream. Therefore, ice cream causes crime and we should ban it, right? Wrong. Hot weather causes people prone to assault to commit more assaults and people who like ice cream to buy more ice cream.

The reason the example is classic is that the hypothesized direct causal connection (that ice cream causes crime) strikes us as so patently absurd (in jargon, lacking facial validity) that the students instantly know something is amiss. Where the causal connection is plausible, though, we see exactly the same fallacy put forth and accepted by too many too often. The correlation between poverty and crime "proves" that poverty is the root cause of crime, for example. Too many people see no need to probe further.

Now we see a serious proposal that comes close to the classic example.
I agree with Kent's critique of correlation vs. causation, yet I've had some personal experiences that warn me not to dismiss quite so quickly the candy-crime conundrum.

Many years ago now, Kathy and I became the guardian of a young 11-year old neighbor who we'd known since early childhood after her father died and her mother went to prison. The young lady (who today is grown with a child of her own) had run away from her relatives after her parents were gone, and she'd been either a runaway on the streets or locked up in juvie hall for months before we took her in.

To call this child's behavior atrocious when she first arrived in our home understates the case; on some days the task had more in common with taming a wild animal than what you'd typically think of as parenting. She suffered tremendous grief, pain and anger, and as a long-neglected kid would lash out and act up to get attention (negative attention is often as good as positive for neglected children), creating an ugly, self-perpetuating cycle.

We did everything we could to try and break that cycle and one thing we noticed that really made a difference was diet. Having basically fended for herself since early childhood, she'd consumed sugar 24-7, from sugar cereal in the morning to sugar soda at night, and it visibly affected her behavior whenever we could successfully reduce it. Many times we noted a direct correlation - nervous, hyper, willful behavior within just a short time after some big sugar rush. It was so predictable Kathy and I would openly discuss it while it occurred. You could also tell when she'd "come down" from a sugar high.

We were never able to completely wean the child from sugar, and when she was old enough to be out and about on her own she reverted to her bad eating habits. But we always adamantly believed it made a big difference.

Cut to the present day, when my goddaughter's own daughter is now three years old, calls me "Grandpa," and is enrolled in a delightful Spanish-language immersion daycare she began just this summer. She loves her school and especially the gal in charge of her age group, but not long after she began there they began reporting minor behavior problems - nothing too out of the ordinary for a child then still in the terrible twos, but enough to where they sought parental help to reduce it.

Conversation didn't cut it and her mom was becoming frustrated, until she and Kathy hit on the idea of reducing sugar intake. This has worked like a charm. It had an effect within just a few days after eliminating most refined sugar from her diet - especially candy, sugar-filled breakfasts and soda - and judging by daily reports from the daycare, it has all but completely resolved (knock wood!) the problems they were seeing. Nobody - her mom, us, her teacher, anybody - can identify anything but the change in diet that accounts for the altered behavior.

Indeed, we've already been discussing Halloween with some dread, fearing that a night that generates a sack full of candy could generate weeks worth of misbehavior in the aftermath. Plots are already being hatched by others to come up with a low-sugar Halloween workaround.

We've talked a lot in my household about this phenomenon. Kathy theorizes that many of the kids diagnosed with ADHD or whose behavior is controlled through Ritalin or other psychoactive drugs at an early age are really just ginned up on too much sugar and actually need a better diet more than medication. I recall her expressing that view once to a relative who's a schoolteacher, who replied with an anecdote about removing sugar-candy from the vending machines at her school because of its effects on student behavior. Clearly we're not the first ones to notice this relationship.

One also wonders if there's a sugar-candy relationship to research-based findings (discussed here on Grits) that "Treatment for kids with signs of hyperactivity, when it's delivered by age three, can decrease the chance they'll land in the juvenile justice system by 75 percent." Hyperactivity and aggression at that age, according to these studies, are statistically significant risk factors for kids later getting wrapped up in the juvenile justice system. Might some of those "hyperactive" kids just be ginned up on too much sugar? I have to wonder.

So in the end, I agree with those critiquing the instant study, but at the same time I think the relationship between sugar and juvenile behavior is strong and not especially positive. Is it as big a factor as crappy parenting? Probably not. But I'm convinced that reducing sugar in a kid's diet can make a big difference in juvenile behavior at the margins.

UPDATE: I knew I should have run this piece by Kathy before hitting "Publish"! She informs me that it's not just sugar she believes is the culprit but more specifically high-fructose corn syrup and perhaps most importantly, certain widely used dyes that are common in America but have been banned in the UK. She pointed me to this article calling dyes the "Secret Shame" of the US food industry and regulators:

Artificial dyes are particularly prevalent in the sugary cereals, candies, sodas, and snack foods pitched to kids. For instance, General Mills' Fruit Roll-ups and Fruit-by-the-Foot flavored snacks get their fruity colors from Yellow 5, Yellow 6, Red 40, and Blue 1. General Mills' Fruity Cheerios, Lucky Charms, and Trix also contain several of the problematic dyes, as do Kellogg's Froot Loops and Apple Jacks and Post's Fruity Pebbles.

More than a dozen American varieties of Kraft's Oscar Meyer Lunchables kids' meals contain artificial food dyes, but not so the British versions. Starburst Chews, Skittles, and M&M candies—all Mars products—contain the full spectrum of artificial colors in the U.S., but not in the U.K., where the company uses natural colorings. Even foods that aren't particularly brightly colored can contain dyes, including several varieties of macaroni and cheese and mashed potatoes. Betty Crocker's Au Gratin "100% Real" Potatoes are partly not real, colored as they are with Yellow 5 and Yellow 6, both derived from coal tar. Remarkably, in Britain, the color in McDonald's strawberry sauce for sundaes actually comes from strawberries; in the U.S. it comes from Red 40.

"The science shows that kids' behavior improves when these artificial colorings are removed from their diets and worsens when they’re added to the their diets," said Dr. David Schab, a psychiatrist at Columbia University Medical Center, who conducted the 2004 meta-analysis with his colleague Dr. Nhi-Ha T. Trinh. "While not all children seem to be sensitive to these chemicals, it's hard to justify their continued use in foods—especially those foods heavily marketed to young children."

Kathy said it's hard to tell whether reducing high-fructose corn syrup or artificial dyes has been the biggest contributor to our grandaughter's improved behavior, mostly because they're so often in all the same foods. Like these:


Bersi said...

My three year old gets what we call the "hunger grumps." He doesn't eat candy about the closest we get to sugar is apple juice.

I wonder if the sugar behavior and the hunger behavior are related? Perhaps dietary sugar reduces the sensations of hunger but doesn't help the hunger grumps. This an Ig Nobel prize just waiting to be won.

Anonymous said...

Damn! Ahd I was going ton have a Snickers for breakfast.

Doran said...

So, maybe the "Twinkie Defense" was not such a pile o' crap after all.

Seriously, I have to agree with just about everything you've said or suggested about sugar affecting behavior, especially the behavior of children, because they mostly haven't learned to control their behaviors.

Remember Calvin and the little sugar coated chocolate coca bombs cereal?

And, omigod! The blind munchies!

Diet in general is so, so important.

ckikerintulia said...

Grits, you certainly would have kudos from my daughter Nancy and my wife Patricia on this one. Yet the schools allow vending machines with high sugar soda and candy on site. It's an economic issue, the Amarillo school board claims.
Rev. Charles

Don Dickson said...

I read some of the news reports about that study, which was published in the journal Psychiatry, and my understanding of the findings is that the correlation, if there is one, is not centered on the sugar itself as much as the gratification which it represents. It's a very plausible theorem.

Forgive me if I've told this story here once before, but a few years ago I represented a young lady at Dobie Middle School who had been charged with assault for pushing another girl in the cafeteria. (This used to get you sent to the principal's office, now it gets you charged with a crime.)

This girl got good grades in school, but for three academic years had been on a "BIP," edu-babble for some sort of behavior modification plan. And it had not been working.

I met with the principal, and the teachers, and the parent, and AISD's lawyers, to discuss the girl's situation. I asked what kind of behavior problems she was displaying, and they included falling asleep in class, and irritability upon being awakened.

The girl was morbidly obese, and I asked if she'd been screened by the school dietician. "Ohh, we don't have a dietician." (In my day my schools had dieticians, but no police departments.)

Turns out the girl was most likely to fall asleep after lunch. What a surprise. "Lunch" was usually coming out of the vending machines, and not from the cafeteria line (not that the school chow was necessarily an improvement over the candy bars and soda).

I don't know whatever became of the girl....I was not optimistic for her future....but for any child of any age who is displaying problematic behaviors, an examination of the child's diet and sleep patters would be my first recommendation.

Anonymous said...

High Fructose Corn Syrup is the bane of the commercially produced food supply.

They claim that it is "nutritionally identical to sugar" which is a dead lie.

HFCS is at least 55% or more Fructose which is why it "takes less" to produce the desired sweetness. It keeps better because you've highly refined a sugar that bacteria have an issue digesting. However, it doesn't get to why it's a problem.

Sucrose, otherwise known as sugar, is a disaccaride, composed of Glucose and Fructose bound together. In order to digest Sucrose, you have to expend energy cracking it apart. In and of itself, too much of it is a bad thing because of the Fructose present.

But with HFCS, it's not bound up. It goes straight into your blood stream. That's problem one. There it lingers because it's NOT glucose and while it's metabolized by your body, the reason it's "low glycemic" is because it's processed by ONE and only one organ in your body- your liver.

Now, this has several dire consequences to people.

1) Your pancreas can't distinguish between Fructose and Glucose in the blood. So your body detects entirely too high levels of sugars in your system, it pumps more insulin into your blood- with the eventual and predictable result of becoming a Type II diabetic.

2) The metabolic pathway is through your liver. Just like Alcohol. With similar disastrous results with the high levels of Fructose in your system. Too much of it before your liver can process it and you end up with a Diabetic Sugar High- for which you know the results from the blog post.

3) Once your liver stores it's "day or so's reserve" of fuel in the form of glucogon (animal starch...), it promptly converts the rest as it can into fat. Some of which shows up where one would expect. Some of which forms as deposits in your liver with the same consequences as cirrhosis with Alcohol.

How to avoid this nasty substance?

Do without sodas. The jury's still out on Acesulfame and Sucralose, Stevia's not there yet and even though it's safer than the other solutions, it's still a good idea to get to drinking water. We won't get into what's bad about Nutrasweet (and there's quite a bit...).

Start reading packaging. I had to for my own well being- diabetes will do that for you. If you can afford the "organic" produced foods, you're vastly better off there because HFCS doesn't and can't meet the criteria for "certified organic" foods.

It doesn't at all surprise me that this is a partial cause for the problems we're seeing today. Get the kid ginned up on HFCS laiden food and they're like they're intoxicated- and actually they're very likely to be so.

Supermarket To The World said...

Hush you! If the market for High Fructose Corn Sytrup dries up the poor corn farming corporations will need even more corn subsidies to maintain their profit levels.

This is a matter of national security!

Anonymous said...

@Supermarket: Heh... Why worry about that- they'll use the corn in Ethanol for our cars, you know...

Anonymous said...

In England they've run a nutritional program for young offenders - full of yummy broccoli and fish oil. The kids hate it, of course, but apparently their behavior improved considerably. Here's a link to one such study:


Having represented more than a few young offenders, half the time the problem is that they were just plain hungry: their parents didn't give them an adequate diet and they would then grab any technicolor junk that came to hand. The misery and bad temper caused by being starved of nutrients (even tho' sometimes stuffed with calories) is painful to watch. I firmly believe that juvenile courts should offer kids a nutritious snack before they appear in court - their malnutrition has all kinds of ramifications for their ability to behave properly in court, and to assist counsel, make rational decisions etc. And proper school lunches are another area that needs work. Paternalistic? Liberal do-gooding? Perhaps. But a good deal cheaper than locking them up, let alone the societal damage caused by the kind of feral kids that neglect produces.

Anonymous said...

Feral kids? Neglect?

Oh, no, no, no...

Feral Kids these days are caused by CPS.

Mr. Anxiety said...

It's odd to have a topic beginning with correlation != causation and ending with wild speculation about food dyes and sugar.

I don't know anything about the study cited at the end of the article - except that a meta-analysis (which is a study in which they don't do any actual testing. They say "Ah - there have been x other studies done on this topic and y% of them have been positive, so therefore the effect must be true!") is only as good as the studies that went into it. If all of the source data wasn't from high quality double blind studies then it's worthless.

Regarding HFCS, I don't believe there is a significant difference between it and sugar, but I'm not going to argue the point without having studied the issue. I tend to go to http://www.theskepticsguide.org for such things.

Gritsforbreakfast said...

Mr. Anxiety, is it really "wild speculation" when the UK regulators banned those food dyes based on scientific research?

Anonymous said...

Excessive sugar consumption can cause unwanted/hyperactive behavior, as can excessive caffeine. This occurs in all people, regardless of age. I have always fed my children a balanced, healthy diet. Sodas are only allowed on special occasions, and snacks do not consist of candy bars or chips. However, as a parent with an ADD child, I can attest to the fact that genetics play a huge role in these undesirable behaviors. This 'child' is now 20, and he still struggles with disorganization, impulsivity, and gets easily distracted. Many years ago, 15 to be exact, I had tried special sugarless 'diets', positive behavioral techniques, placing charts all over the house-to keep him on track(among many other things). But, all these did not help, and I opted to place him on an approved medication for ADD. This decision produced much inner turmoil for me, but did help lessen his distractibility and impulsivity somewhat-which, in turn, lessened his negative feedback from school authorities. His self esteem and confidence improved, and in high school, he expressed interest and joined several extracurricular organizations. Lets not forget that lack of enough sleep, living in a home without consistent rules, and the presence of poor role models can create undesirable behaviors. Lets not judge those who have children with ADD/ADHD and place them on medication, for until one walks this path, it is unfamiliar territory.

sunray's wench said...

Tartrazine is another yellow food dye that we are suspicious of here in the UK. In fact, anything that has an "E number" is thought of the be not good for children.

Interestingly, the vending machines in the prisons only stock high-sugar, high-sodium snacks. And then TDCJ expect the visiting children to sit still and quiet for 2 hours with nothing to entertain them. Not to mention the inmates.

Anonymous said...

10:35, thank you. The sugar nazis seem to be a lot like recovering drug addicts, alcoholics and ex smokers in that upon giving up something they suddenly have the magical ability to diagnose everyone's problem. Never mind that none of them are doctors or clinical researchers. Yes, those foods in excess and especially as a substitute for a balanced diet will surely play havoc on your mental state, but not everyone suffering from the same symptoms is a "sugar junkie."

There are a lot of reasons our society is screwed up, and lack of knowledge about and the self discipline to implement healthy eating habits on a daily basis are a big part of it. But blaming it on sugar alone is just whacky.

I'm going to use one of his gimmicks and say: Having solved all of society's problems, Scott can now focus on outlawing Halloween.

Scott makes good sense most of the time but some days he acts like he's had too much sugar.

Anonymous said...

Oh yea I forgot to ask; Scott, how do you take your grits, straight up? Or do you sprinkle a little Imperial pure cane when no one is looking? Bahahahaha

Anonymous said...

a number of years ago, my wife, an elementary special education teacher in a predominantly catholic community, knew precisely one time of the year when the behavior of her kids would improve markedly and then when it would revert to "normal" Lent, when the kids gave up all sweets. every year, just like clockwork.