The Role of Sugar in ADHD
By Anthony Kane, MD
How sugar influences ADHD is one of those controversial areas in medicine. There are two sides to the debate. On one side, there is the official medical establishment that claims numerous scientific studies show that children do not react to sugar and that sugar does not play a role in ADHD. On the other side, there are all the mothers who have personally witnessed that when they give their children sugar, within a few minutes, their children are bouncing off the walls. So, the question is with whom does the truth lie.
Evidence for the Medical Establishment
In 1985, Dr. Mark Wolraich published the most influential study demonstrating that sugar plays no role in ADHD. Wolraich's team examined 16 hyperactive children for three days. The researchers manipulated the sugar content of their diet, but found no effects on behavior or learning. The same group later published a review article and concluded "the few studies that have found effects have been as likely to find sugar improving behavior as making it worse."
In 1994, Dr. Richard Milich examined thirty-one children whose mothers felt they were sugar sensitive. He gave all thirty-one children a sugar-free drink. However, he told half of the mothers that their child's drink contained sugar. The mothers who thought that their child had received the sugar drink all rated their child as being more hyperactive. These mothers also were more critical of their children and hovered over them more. Milich concluded that the parental expectations about the affects of sugar are the cause of the perception that sugar makes children more hyperactive. These expectations also influence the way the parents interact with their children.
There are a few more articles about sugar, but they are mostly a rehashing of earlier studies. The general consensus of the scientific literature is that sugar does not lead to hyperactivity. Unfortunately, some of us have children who have not read these studies.
Wolraich's study was quite thorough. Thirty-seven different measurements of behavior and learning were taken. They intensively studied 16 boys in a hospital setting for three days. So what could be the flaw of this study? I just said it. "16 boys," "hospital setting," "three days." Sixteen boys is a very small sample size. If even 10% of the ADHD population is sugar sensitive, and the number is very likely much less, a sample of 16 boys may not contain a single child who was sugar sensitive.
A "hospital setting" is not a normal environment. Just because a child can maintain himself in a controlled environment like a hospital, doesn't mean that he would function the same way at school or at home. "Three days" is a very short time. If the effects of sugar were additive, say over the course of a week, then the study would miss this. This is still a very good study, but it is premature to conclude from it that sugar plays no role in ADHD.
Dr. Milich concluded that it was the mother's expectations that affected how they viewed the effects of sugar on her child. Even if true, the results of this study are still insignificant. We have known for a long time that expectations influence perception. This is basis of the placebo effect. All that this study proved was that parents, who expect their children to behave hyperactively, perceive their children behaving hyperactively. We knew that before the study.
As for Wolraich's review article, although it is a very good article it has the basic flaw inherent in all survey studies. The author must choose which studies to include and which to exclude in his review. To put it another way, review articles are highly susceptible to bias on the part of the authors. Therefore, although Wolraich's review article is very good and seems to be very thorough it is not the final word, like many believe it to be.
Evidence Implicating the Role of Sugar in ADHD
Now for the Side of Motherhood
Wender and Solanto tried to link an increase in aggressive behavior in ADHD children to sugar ingestion. They compared 17 ADHD children with 9 age-matched normal children to assess the affects of sugar ingestion. They gave sugar or placebo challenges as part of a high carbohydrate breakfast. They did not find a relationship between sugar and aggression. Although the children with attention deficit disorder with hyperactivity were significantly more aggressive than the control subjects, eating sugar did not elicit this behavior.
However, they did find something else. Inattention, as measured by a continuous performance task, increased only in the ADHD group following sugar ingestion. The ADHD children showed no change following placebo, and the control group showed no change at all. So, according to this study, sugar ingestion as part of a high carbohydrate meal will exacerbate inattentiveness in some ADHD children.
Langseth and Dowd found that 74% of 261 hyperactive children in their study had abnormal sugar metabolism. These children displayed reactive hypoglycemia after eating refined sugar. What happened metabolically was that the large ingestion of sugar caused a surge of insulin to be released by the pancreas. This caused, in reaction, a significant decrease in blood sugar levels accompanied by a surge in the epinephrine levels.
Girardi found that sugar ingestion triggered other metabolic abnormalities in ADHD children. His team at Yale gave a standardized oral glucose challenge to 17 children with ADHD and 11 control children and compared the results. Baseline and oral glucose-stimulated plasma glucose and insulin levels were similar in both groups, including the glucose level bottoming out at 3-5 hours after oral glucose ingestion. This drop in glucose stimulated a rise in plasma epinephrine and norepinephrine in both groups. However, the rise in the ADHD children was nearly 50% lower than in the control children.
Both groups showed deterioration on the continuous performance test in association with the late fall in glucose and rise in epinephrine. However, the drop in test scores in ADHD children was significantly greater. ADHD children also had quicker reaction times than normal children, corresponding with impulsivity. This study suggests that children with ADHD have a general impairment of hormone regulation. It appears that sugar may accentuate this defect.
Sugar and Nutrition
There is another effect of eating refined sugar. You have probably heard that table sugar is called "empty calories." This is a true, but not complete picture. Table sugar is a nutrient vacuum. It provides no nutritional benefit other than calories, but it requires a lot of other nutrients to process it. It depletes the child's nutritional base. That means that if a child's ADHD is caused or exacerbated by the lack of certain nutrients, having a high sugar meal may drain these nutrients and push him into a nutrient deficiency state. And this would not necessarily happen during a three-day test in the hospital, as in Wolraich's study, where the children were receiving adequate nutrition.
We have studies that show children who don't eat breakfast don't perform as well in school. We also have studies showing that children who eat sugar with a high carbohydrate meal do poorly on tasks requiring concentration. There are also claims that some children display increased aggressive behavior.
What do we make of all this? Most researchers say that sugar doesn't make children hyperactive. Yet, everyone has seen children go crazy on sugar. How do we resolve this contradiction? What do we conclude from all this?
There is no concrete evidence that sugar causes ADHD. However, the evidence against this notion is also not very strong. We know that ADHD children frequently have abnormal sugar metabolism. We know that eating sugar does affect learning and behavior negatively, particularly after a low protein carbohydrate meal. This occurs even in normal children. We know that the metabolism of sugar drains the body's reserve of other vital nutrients. What should we conclude?
Basically, it is very likely that the medical researchers are correct in saying that sugar ingestion does not cause ADHD. All that means is that if you give a normal child too much sugar, he will not develop ADHD. However, it is clear that refined sugar does exacerbate some of the ADHD symptoms such as inattentiveness and possibly aggression in many children. There are mixed results as to whether or not it affects normal children in a similar but less pronounced way.
So, after examining all the evidence, I would recommend that you should try to give your children protein-containing meals for breakfast and lunch during the school year. You should try to keep all your children and yourself away from refined sugar.
Does this mean that I am saying sugar makes children hyperactive? Not exactly. I feel that the medical research is not conclusive either way.
You will have to judge for yourself the affect of sugar on your own child. However, even if refined sugar does not exacerbate your child's ADHD symptoms, I have yet to see one study that shows that refined sugar does anything positive.