Richard G. Petty, MD

Non-pharmacological and Lifestyle Approaches to Attention-Deficit/Hyperactivity Disorder: 1. Diet


You can find some articles on Attention-Deficit/Hyperactivity Disorder (ADHD) here, and also some of the evidence that ADHD is a “real” illness and not just a label for socially unacceptable behavior. That being said, it is essential to take extra care when making the diagnosis. Mud sticks, and diagnostic mud sticks like glue. It can be hard to “unmake” a diagnosis.

As with any problem, the most effective way of helping it is to address the physical, psychological, social, subtle and spiritual aspects of the situation.

Medicines can definitely have a place in the management of ADHD, and the reason for treating ADHD is not so that people get better grades in school or do better at their jobs. It is to prevent the long term problems that may follow from inadequately treated ADHD.

There is a large and growing body of research on non-pharmacological approaches to treating ADHD. A literature search has turned up over two hundred papers, over half of which report some empirical research. Some of the research is summarized in a short paper aimed at health care professionals.

Research has shown that more than 50% of American families who receive care for ADHD in specialty clinics also use complementary or alternative medical (CAM) therapies, if you include things like modifying their diet or other aspects of their lifestyle. Despite that, only about 12% of families report their use of CAM to their clinician. Despite that low rate of families reporting the use of unorthodox therapies, a national survey of pediatricians showed that 92% of them had been asked by parents about complementary therapies for ADHD. The trouble is that many pediatricians have not been taught very much about the pros and cons of these approaches.

The most commonly used CAM therapies for ADHD are dietary changes (76%) and dietary supplements (> 59%). I have talked about food additives and one type of diet in the past. Now let’s look in a little more detail.

The 3 main dietary therapies for ADHD are:

  • The Feingold diet,
  • Sugar restriction, and
  • Avoiding suspected allergens.

Sometimes these diets are used in combination.

The Feingold Diet
The Feingold diet is the most well known dietary intervention for ADHD. It aims to eliminate 3 groups of synthetic food additives and 1 class of synthetic sweeteners:
Synthetic colors (petroleum-based certified FD&C and D&C colors);
Synthetic flavors;
BHA, BHT and TBHQ ; and
The artificial sweeteners Aspartame, Neotame, and Alitame.

Some artificial colorings such as titanium dioxide are allowed.

During the initial weeks of the Feingold program, foods containing salicylates (such as apples, almonds, and grapes) are removed and are later reintroduced one at a time so that the child can be tested for tolerance. Most of the problematic salicylate-rich foods are common temperate-zone fruits, as well as a few vegetables, spices, and one tree nut.

During phase 1 of the Feingold diet, foods like pears, cashews, and bananas are used instead of salicylate-containing fruits. These foods are slowly reintroduced into the diet as tolerated by the child.

The effectiveness of this diet is controversial. In an open trial from Australia, 40 out of 55 children with ADHD had significant improvements in behavior after a 6-week trial of the Feingold. 26 of the children – 47.3% – remained improved following liberalization of the diet over a period of 3-6 months.

In another study, 19 out of 26 of children responded favorably to an elimination diet. What is particularly interesting is that when the children were gradually put back on to a regular diet, all 19 of them reacted to many foods, dyes, and/or preservatives.

In yet another study, this one a double-blind, placebo-controlled food challenge in 16 children, there was a significant improvement on placebo days compared with days on which children were given possible problem foods. Children with allergies had better responses than children who had no allergies.

Despite this research many pediatricians, particularly in the United States, do not believe the evidence regarding the effectiveness of elimination diets or additive-free diets warrants this challenging therapy for most children.

There is an interesting difference in Europe. In 2004 a large randomized, blinded, cross-over trial of over 1800 three-year-old children was published. The results showed consistent, significant improvements in the children’s hyperactive behavior when they were on a diet free of benzoate-preservatives and artificial flavors. They had worsening behavior during the weeks when these items were reintroduced. On the basis of this and other studies, in 2004 schools in Wales banned foods containing additives from school lunches. It has been claimed that since the ban, there has been an improvement in the afternoon behavior of students.

The biggest problem with the Feingold and other elimination diets is that they are hard to follow and to maintain. But for some children and families, the inconvenience and stricter attention to food have worthwhile results.

It is also essential to ensure that children on any kind of diet maintain adequate nutrition: there have been many examples of that simple rule not being followed.

Sugar Restriction
The notion that sugar can make children “hyper” entered the mainstream over twenty years ago, and is now on the list of things that “everyone knows.” But happily it is not true. At least 12 double-blind studies have failed to show that sugar causes hyperactive behavior. Some researchers suggest that sugar or ingestion of high-carbohydrate “comfort foods” is actually calming, and that children who seek these foods may be attempting to “self-medicate.”

There are plenty of very good reasons for children to avoid candy, but hyperactivity is not one of them.

Food Allergies
There is clear evidence that children, and perhaps adults with ADHD are more likely to have allergies. That lead to the obvious question whether children with ADHD allergic or sensitive to certain foods. (It is useful to differentiate “allergies” that are the result of abnormal reactivity of the immune system to proteins in food, from “sensitivities” that are the direct result of substances in food: the two have different treatments.)

It is certainly true that food allergies and food sensitivities can generate a wide range of biological and behavioral effects. Gluten sensitivity (celiac disease) is known to be linked to an increased risk of ADHD and other symptoms.

In an open study of 78 children with ADHD referred to a nutrition clinic, 59 improved on a few foods trial that eliminated foods to which children are commonly sensitive. For the 19 children in this study who were able to participate in a double-blind cross-over trial of the suspected food, there was a significant effect for the provoking foods to worsen ratings of behavior and to impair psychological test performance.

For more than 30 years one of the tests used to track allergies has been the radioallergosorbent test (RAST). It is not much used these days since technology has moved on. In an allergy testing study of 43 food extracts 52% of 90 children with ADHD had an allergy to one or more of the foods tested. Over the next few years several researchers carried out open-label studies in which children with ADHD and food allergies were treated with a medicine called sodium cromoglycate, that prevents the release of inflammatory chemicals such as histamine from mast cells. Some of the reports suggested that it could help in some children.

Other popular dietary interventions include eating a low glycemic index diet to avoid large swings in blood sugar. Another strategy has been to “go organic” to reduce the burden of pesticides, hormones, antibiotics, and synthetic chemicals in the child’s system. These diets need more scientific study but they are probably safe if expensive.

There are plenty of practitioners and commercial entities who claim to be able to identify food sensitivities with all kinds of methods from blood and muscle testing to electrical and energetic techniques. Some may be helpful, but few have been proven to be effective.

What Should Parents do About Diet, Nutrition, Allergies and Sensitivities?
It is very difficult to predict whether an individual child will be helped by changes in diet. However, as long as the child’s needs for essential nutrients are met these diets should be safe.

It is an extremely good idea for parents to keep a diet diary for one to two weeks to see if anything obvious jumps out. Then trying an additive-free diet, low in sugar and avoiding foods that are suspected of exacerbating symptoms. You will normally find the answer – yes or no – within a few weeks.

What is the Evidence for Food Sensitivities and ADHD in Adults?
Not a lot!

There are plenty of people who have reported that dietary restrictions have helped them, but there is very little evidence. One of the problems about looking for food sensitivities is that there is a high placebo response rate. But if you have adult ADHD, it may be worth investigating. Just make sure that any diet that you use is nutritionally sound. And if you don’t find anything reconsider another approach.

Anti-inflammatories and Colon Cancer

I just had a very good question after I published my list of Twelve Tips to Reduce Your Risk of Colorectal Cancer.

Dear Dr. Petty,

“That’s a great list, but I am wondering why you haven’t included aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs)? I thought that they had been shown to reduce the risk of colon cancer.”

This is an excellent question, and I deliberately omitted mention of anti-inflammatories because the research suggests that they may cause more harm than good.

There is a report in today’s edition of the Annals of Internal Medicine from the United States Preventive Services Task Force, a highly regarded and independent panel of experts in primary care and prevention, that confirms that screening for colorectal cancer is still important and everyone over 50 should have it. But they urge caution on taking preventive drugs, saying that on balance the health risks of aspirin outweigh the benefits when it comes to preventing colon cancer. This advice holds even for those people with a family history of the disease, as long as they have only an average risk of colon cancer. (20 per cent of people who get colorectal cancer also have a close relative with the disease, with proportionally more cases among African Americans than other races.)

They found good evidence that high doses of aspirin (i.e. 300 mg a day or more) and possibly ibuprofen protect against colorectal cancer but this comes with increased risk of intestinal bleeding, stroke and kidney failure.

In low doses – under 100 mg a day – the Task Force says that good evidence supports the notion that aspirin protects against heart disease. However, at this dosage it will have no preventive effect on colorectal cancer.

The US Preventive Services Task Force regularly reviews the available research evidence and issues advice based on what they regard the strength of the evidence to be. They use a grades to help guide practice. For example a grade A recommendation is equal to "strongly recommends", while a B is just "recommends", and C is "no recommendation for or against".

In this case the Task Force has issued a grade D "recommends against" to the routine use of aspirin and NSAIDs to prevent colorectal cancer.

So for now I recommend following the Twelve Tips that I published yesterday.

Twelve Tips to Reduce Your Risk of Colorectal Cancer

Colon cancer, or, more accurately colorectal cancer, includes cancerous growths in the colon, rectum and appendix. It is the third most common form of cancer and the second leading cause of death among cancers in the Western world. Colorectal cancer surpasses breast and prostate cancers as a leading cause of cancer deaths in both men and women.

And the key point is that with early screening and a few simple dietary modifications, you can dramatically reduce your risk of getting it.

These are the 12 Tips to Slash Your Risk of Colorectal Cancer

  1. Receive regular colorectal cancer screenings beginning at age 50 if you are at normal risk
  2. If you are at higher risk due to a personal or family history of colorectal cancer, other cancers or inflammatory bowel disease have a discussion with your health care provider about screenings before age 50
  3. Eat between 25 and 30 grams of fiber each day from fruits, vegetables, whole grain breads and cereals, nuts, and beans
  4. Eat a low-fat diet: colorectal cancer has been associated with diets high in saturated fat, particularly fat from red meat
  5. Eat foods with folate, such as leafy green vegetables
  6. Try to drink at least 80 fluid ounces of pure water a day unless you have a medical reason for not doing so
  7. Drink alcohol in moderation: 2 units of alcohol or less each day
  8. If you smoke, here is another good reason for quitting. Alcohol and tobacco in combination are linked to colorectal cancer and other gastrointestinal cancers
  9. Exercise for at least 20 minutes three to four days a week. Moderate exercise such as walking, gardening or climbing stairs may help reduce your risk
  10. If you get any persistent symptoms such as blood in the stool, a change in bowel habits, weight loss, narrower-than-usual stools, abdominal pains or other gastrointestinal complaints, it is essential to report them to your health care provider
  11. Maintain a healthy weight. Obesity may increase the risk of colorectal cancer
  12. Maintain a good intake of calcium and vitamin D: this combination has been shown to reduce the risk of colorectal cancer

For more information, I recommend visiting the Web site of the American Cancer Society.

I keep their details in the “Resources” section on the left hand side of this blog.

Intestinal Microbes: A Hidden Cause of Obesity

It is no secret that many famous people swear by colonic irrigation. The late Princess Diana used to say that it helped her stay fit and keep her weight steady, though personally I always thought that good genes and regular exercise were the real explanations.

In previous posts I have talked about some of the emerging lines of evidence suggesting that there are at least four previously little recognized causes of obesity:

  1. Stress
  2. Salt intake
  3. Pesticides
  4. Viruses

Following a paper in today’s issue of the journal Nature, it looks as if we shall have to add a fifth: the intestinal microbes that are collectively known as “gut flora.”

We have within us vast communities of microbes that outnumber our own body’s cells by 10 to 1, and may contain 100 times more genes than our own human genome.

We have known for many years that we each contain pounds of these microbes and that they are doing a great deal more than simply sitting there. We have known since the 1950s that many of the microbes are involved in digestion, absorption and immune function. That is one of the reasons why most doctors worry about the unnecessary use of antibiotics: some can knock out the gut flora, sometimes with serious consequences.

It is the first of these – digestion and absorption – that has been attracting attention. Under normal circumstances our bacteria break down many complex molecules like polysaccharides into simple sugars that we absorb and use for energy.

Colleagues from the Washington University School of Medicine in St. Louis have made a remarkable discovery. It seems that the balance of two major families of intestinal bacteria: Firmicutes and Bacteroidetes have a major impact on digestion and obesity. Together these two families constitute 90 per cent of the bacteria in the intestines of humans, and, coincidentally, white mice.

The researchers conducted two parallel studies. In the first they found that as obese people lose weight, the balance between the Firmicutes and the Bacteroidetes changes – the latter increasing in abundance as an overweight person gets slimmer.

The second study used white mice. Here, researchers discovered that the bacteria in the lower intestines of obese white mice were more efficient at extracting calories from complex carbohydrates than the bacteria in the intestines of slimmer mice.

In an earlier study the researchers had shown that the intestines of obese mice had the same depletion of Bacteroidetes as found in the innards of obese humans.

The practical consequence of this finding is immense: it means that if two people are on the same diets and doing the same amount of exercise, one may gain weight and the other stay the same weight. Simply because the person who stayed the same had more Bacteroidetes in his large intestine, extracting fewer calories from the same amount of food. The main reason why his friend gains weight is because he has more Firmicutes and fewer Bacteroidetes.

The researchers suggest that intestinal bacteria could become “biomarkers, mediators and potential therapeutic targets” in the fight against obesity.

I find it impressive that some advocates of natural healing had predicted something along these lines in the early days of the 20th century. I am not too keen on colonic irrigation, though I have many colleagues who use it routinely. But there are many other ways of changing your intestinal flora, including probiotics and prebiotics. You may be interested to look back at a few words that I wrote about them in late August.

I would be happy to detail some other evidence-based strategies that we have used for normalizing intestinal flora.

“A man is not rightly conditioned until he is a happy, healthy, and prosperous being; and happiness, health, and prosperity are the result of a harmonious adjustment of the inner with the outer of the man with his surroundings.”
–James Allen (English Author and Mystic, 1864-1912)


“You cannot poison your body into health with drugs, chemo or radiation. “ Health” can only be achieved with healthful living.”

–T.C. Fry (American Writer on Natural Healing and Originator of the Life Science/Natural Hygiene Course, 1926-1996)

Probiotics: Caveat Emptor

You may well have heard the advice that we all need to keep the bacetria in our intestines healthy. Countless experts have recommended that, as long as we are not lactorse intolerant, we should regularly take some live yoghurt to "re-colonize" our intestines with nice friendly bacteria.

There has just been a briefing in London to warn the public that as many as half of the "probiotic" or "friendly bacteria" products on sale in the United Kingdom could be ineffective and some may even be harmful.

The experts on the panel included Professor Glen Gibson from the University of Reading who is an expert in food microbiology, and recommended sticking to products made by major manufacturers. Too many of the other productsmight not contain the numbers of bacteria advertised, and the icrobes might not survive long enough in the intestines to do much good.

The evidence that probiotics help is still far from settled, as discussed in a recent review. But there are enough reports to think that probiotics may be helpful for irritable bowel syndrome and perhaps inflammatory bowel disease.

An even newer area or interest in the use of "prebiotics:"  short-chain carbohydrates that alter the composition, or metabolism, of the intestinal organisms in a beneficial way.

Make sure that if you are using a product, it comes from a reputable manufacturer, and that it contains at least 10 million bacteria. And as I said in my title, "Caveat Emptor," "Let the buyer beware."

Toxoplasmosis, Behavior and Mental Illness

This title may seem odd, but this item may actually turn out to have enormous implications for all of us.

A couple of years ago I read a fascinating book: Parasites and the Behavior of Animals, in which the author – Janice Moore from Colorado State University – cataloged some of the extraordinary ways in which parasites can impact the behaviors of a vast array of animals. As difficult as it is to interpret studies of parasites in humans, I kept coming back to some odd observations about an illness with which I’ve been involved for more than 30 years: schizophrenia. I kept wondering if some of the odd observations made over the years could be explained by the parasites?

What kind of odd observations?

  1. Reports of mental illness have been found throughout history, yet this strange illness that we now call schizophrenia seems to have been very rare until about 1750, when it increased dramatically throughout Western Europe. I have had the privilege of working at the Bethlem Royal Hospital from which got the word “bedlam.” I know of the incredible records kept there. Something began to change in some of the types of patients being admitted at that time. I have also had the opportunity to look at some of the records at the Philip’s Hospital in Southern Germany, which has been in existence since 1533. Again the records show the sudden appearance of many cases of something that had been quite rare until then. 1750 marked the early years of the industrial revolution in Europe and the mass migration of people from the countryside to the new and very crowded cities
  2. There has been recent evidence that being born and raised in a city increases your chance of developing schizophrenia.
  3. There is increasing evidence that acute episodes of psychosis, mania and depression are associated with increases in circulating inflammatory mediators. There is also intriguing new data that both psychosis and depression can be improved by giving people COX2 inhibitors.
  4. There has also been the strange observation that bipolar disorder may have been becoming more common in recent years, over and above our greater ability to recognize the illness.

Several years ago the well-known psychiatrist E. Fuller Torrey first suggested that a small protozoal parasite called Toxoplasma gondii might be responsible for all of these observations. Cats can carry it, which is why pregnant mothers are advised not to pet their cats during pregnancy.

The idea that such a complex disease as schizophrenia might sometimes be caused by a parasite caught the media’s attention, but in recent years the story – but not the ongoing research – died down a bit.

There was an excellent and provocative blog item by Carl Zimmer about this almost three weeks ago, but I wanted to check everything out before responding. He gave a brief review of a new paper published in the Proceedings of the Royal Society, by Kevin Lafferty from the University of California in Santa Barbara. Lafferty has attempted to correlate the varying rates of Toxoplasma in different countries with predominant personality traits and therefore – since our societies are aggregates of all our personalities, cultural characteristics.

That may all sound far-fetched, but I don’t think that it is. And I don’t think that the Proceedings would have taken a completely half-baked proposition.

I have also found a report published in the journal the Proceedings of the Biological Society. Four eminent authors, including Torrey, revisited the while issue of Toxoplasmosis and mental illness. When the parasite gets into the nervous system it can alter behavior: Rats are normally programmed to avoid cats, but once infected they are attracted to cats. Over the last few days I’ve been plowing the world literature, and I’ve learned some very interesting things that support the idea that Toxoplasma may be playing a role in several different types of psychiatric illness.

There is strong evidence that schizophrenia, bipolar disorder and major depressive disorder lie on a spectrum. The illnesses are not the same, but people often switch from one type of clinical presentation to another. The precise type if illness would be determined by the interaction of genes, physical and Intrapsychic environment. Nobody would be sufficiently naïve to try and reduce the whole of psychiatric illness to a single bug. Mental illness is a great deal more than just a physical problem, and apart from anything else, the rates of Toxoplasma infections show remarkable variations around the globe, while the rates of major mental illness are much the same everywhere.

So what have I learned?

  1. There are a remarkable numbers of studies showing that many people with schizophrenia have antibodies to Toxoplasma, including people having their first attack of the illness
  2. Blood donors infected with Toxoplasma have decreased levels of novelty-seeking
  3. In women who become infected, there are some marked changes in personality.
  4. Toxoplasma affects the dopamine systems of the brain that we know are intimately involved in mood, cognition, movement and motivation.
  5. Some drugs used to treat psychosis (haloperidol) and mood disorder (valproic acid) inhibit the replication of Toxoplasma gondii. The valproic acid already does it at concentrations lower than we normally aim for when treating humans.
  6. There is some intriguing work going on into the use of antibiotics to kill Toxoplasma and reverse its behavioral effects.

In the last few years, so many illnesses have turned out to have infectious origins, from peptic ulcers to arteriosclerosis and some cancers. Perhaps some mental illnesses will be next.

Last year Barry Marshall and Robin Warren were awarded the Nobel Prize in Physiology or Medicine for their pioneering work on Helicobacter. I have a strong sense that there are more prizes to come on the interaction between infectious agents, inflammation, genes, the psyche and the environment.

Perhaps the reason that some antipsychotics and mood stablizers can reverse some of the neurological damage associated with schizophrenia and bipolar disorder is becuase they are killing off the causative agents and allowing the brain to repair itself.

I shall keep you posted!

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