Sharp Brains: Brain Fitness and Cognitive Health News

Neuroplasticity, Brain Fitness and Cognitive Health News


Western’ Style Diet Increases Risk of ADHD

I recent­ly report­ed on an intrigu­ing study exam­in­ing the impact of an herbal treat­ment for youth with ADHD. Results from this ran­dom­ized-con­trolled tri­al were quite promis­ing and con­sis­tent with the idea that some indi­vid­u­als with ADHD have defi­cien­cies in essen­tial nutri­ents that com­pro­mise healthy brain devel­op­ment and result in ADHD symp­toms. This idea has sparked the long-stand­ing debate about whether dietary fac­tors play an impor­tant role in the devel­op­ment of ADHD, at least for some chil­dren, and led to many stud­ies of this issue.
Although results of these stud­ies elude any sim­ple con­clu­sions, dietary fac­tors do appear to con­tribute to ADHD symp­toms in some indi­vid­u­als.

Some have argued that research on the rela­tion­ship between diet and ADHD is more impor­tant than ever because the diets of chil­dren in West­ern coun­tries have shown steady increas­es in the amounts of heav­i­ly processed foods rich in sat­u­rat­ed fats, salt, and sug­ars accom­pa­nied by decreas­es in omega‑3 fat­ty acids, fiber, and folate. Is it pos­si­ble that such ‘West­ern’ style diets are asso­ci­at­ed with an increased risk of ADHD, and per­haps a con­tribut­ing fac­tor to the high preva­lence of the dis­or­der?

This impor­tant ques­tion was exam­ined in a study pub­lished recent­ly online in the Jour­nal of Atten­tion Dis­or­ders [Howard et. al. (2010). ADHD is asso­ci­at­ed with a “West­ern” dietary pat­tern in ado­les­cents. Jour­nal of Atten­tion Dis­or­ders]. Par­tic­i­pants were 1172 14 year-old Aus­tralian ado­les­cents and their par­ents who had been recruit­ed into the study and fol­lowed since the moth­ers were between 16 and 20 weeks preg­nant. The data col­lect­ed in this study was part of a large-scale lon­gi­tu­di­nal inves­ti­ga­tion focused on a vari­ety of issues relat­ed to under­stand­ing healthy and mal­adap­tive devel­op­ment.

When youth were 14, par­ents were asked whether their child had ever been diag­nosed with ADHD by a qual­i­fied health pro­fes­sion­al. One hun­dred and fif­teen — near­ly 10% — had been diag­nosed, includ­ing 91 boys and 24 girls. These diag­noses were con­firmed by review­ing chil­dren’s med­ical records. Pri­ma­ry care­givers also com­plet­ed the Food Fre­quen­cy Ques­tion­naire (FFQ) in which they rat­ed the typ­i­cal intake by their child of over 200 dif­fer­ent foods from near­ly 40 dif­fer­ent food groups.

Based on respons­es to the FFQ, 2 major dietary pat­terns were iden­ti­fied.

  • The ‘West­ern’ pat­tern was pos­i­tive­ly asso­ci­at­ed with high­er intakes of total fat, sat­u­rat­ed fat, refined sug­ars, and sodi­um. Spe­cif­ic food types promi­nent in the West­ern diet includ­ed ‘take­away’ foods (I believe this refers to ‘fast’ food’) red meat, processed meats, soft drinks, full fat dairy prod­ucts, soft drinks, sug­ary foods, and fried foods.
  • The ‘Healthy’ pat­tern (these labels were assigned by the inves­ti­ga­tors) was pos­i­tive­ly asso­ci­at­ed with omega‑3 fat­ty acids, fiber, and folate. Promi­nent foods in the healthy diet includ­ed all types of veg­eta­bles, fresh fruit, whole grains, legumes, and fish.

Ado­les­cents received scores on both diet pat­terns based on par­ents’ respons­es about their typ­i­cal food intake. Those above the mean were clas­si­fied as ‘high’ for that pat­tern and those below the mean were clas­si­fied as ‘low’. Thus, each ado­les­cent was placed in a high or low group for both the West­erns style and Healthy diets. By clas­si­fy­ing par­tic­i­pants in this way, the researchers could exam­ine whether being high vs. low for a West­ern diet and a Healthy diet was asso­ci­at­ed with an increased like­li­hood of being diag­nosed with ADHD.

Because many fac­tors besides diet may increase risk of ADHD, the researchers mea­sured a num­ber of oth­er vari­ables that could poten­tial­ly con­found the results. These includ­ed mater­nal age at con­cep­tion, mater­nal edu­ca­tion, mater­nal smok­ing dur­ing preg­nan­cy, pres­ence of bio­log­i­cal father in the home dur­ing preg­nan­cy, fam­i­ly income dur­ing preg­nan­cy, and the num­ber of stress­ful life events expe­ri­enced by the moth­er dur­ing preg­nan­cy. In addi­tion, data was col­lect­ed on ado­les­cents’ typ­i­cal week­ly lev­el of phys­i­cal activ­i­ty and the num­ber of hours they spent each day watch­ing tele­vi­sion, play­ing video games, or using the com­put­er.

- Results -
After con­trol­ling for all the oth­er vari­ables not­ed above, ado­les­cents in the ‘high’ group for the West­ern dietary pat­tern were more than twice as like­ly as those in the ‘low’ group to have been diag­nosed with ADHD.
These results were con­sis­tent for boys and girls. A high score for the Healthy dietary pat­tern, how­ev­er, was not asso­ci­at­ed with reduced risk of hav­ing a diag­no­sis.

When the authors looked at spe­cif­ic food groups, high con­sump­tion of fast food, red meat, processed meats, and high-fat dairy prod­ucts, pota­to chips, and soft drinks were all asso­ci­at­ed with increased risk of an ADHD diag­no­sis.

Increased like­li­hood of an ADHD diag­no­sis was also relat­ed to moth­ers hav­ing expe­ri­enced mul­ti­ple stress­ful events dur­ing preg­nan­cy. The only vari­able asso­ci­at­ed with low­er odds of diag­no­sis was phys­i­cal activ­i­ty, as youth who exer­cised at least 2 hours per week out­side of school were less like­ly than oth­ers to be diag­nosed.

- Sum­ma­ry and Impli­ca­tions -
Results from this study based on a large com­mu­ni­ty sam­ple of youth clear­ly indi­cate that a West­ern-style dietary pat­tern is asso­ci­at­ed with greater odds of hav­ing ADHD. This was true for both boys and girls. The West­ern-style diet iden­ti­fied in this study was one that was high in total fat, sat­u­rat­ed fats, refined sug­ars, and sodi­um.

One pos­si­ble inter­pre­ta­tion of these find­ings is that diets high in these food ele­ments play a direct causal role in the devel­op­ment of ADHD. How­ev­er, there was no evi­dence that adher­ing to a healthy diet, i.e., one high in veg­eta­bles, fresh fruit, whole grains, and fish, reduced the odds of being diag­nosed. Thus, while West­ern style diets may increase risk for ADHD, the find­ings do not sup­port the notion that adher­ing to a health­i­er diet reduces such risk. This does not mean that the healthy dietary pat­tern may not have had oth­er ben­e­fits, but only that it did not alter the risk for ADHD beyond what could be explained by being high vs. low for the West­ern-style pat­tern.

While it is tempt­ing to con­clude that the West­ern dietary pat­tern direct­ly con­tributed to the devel­op­ment of ADHD in some youth, the authors are care­ful to note that the design of their study does not allow causal con­clu­sions to be made. For exam­ple, although the con­sump­tion of a more ‘West­ern’ style diet may have “…pro­mot­ed the expres­sion of atten­tion deficits” it is also pos­si­ble that “…diag­nosed atten­tion deficits led to poor­er food choic­es and a more ‘West­ern’ style diet.” For exam­ple, the authors sug­gest that their results “…could be explained by the ten­den­cy for ado­les­cents expe­ri­enc­ing emo­tion­al dis­tress to crave fat-rich snack foods as a self-sooth­ing strat­e­gy.” It is also worth
not­ing that this study did not exam­ine whether dietary changes can reduce ADHD symp­toms and that the find­ings should not be inter­pret­ed in that way.

While no sin­gle study can ful­ly answer com­pli­cat­ed ques­tions per­tain­ing to the role of diet and nutri­tion­al fac­tors in the eti­ol­o­gy of ADHD, this research clear­ly high­lights that a West­ern-style dietary pat­tern is asso­ci­at­ed with increased odds of hav­ing an ADHD diag­no­sis. This sug­gests, but does not prove, that dietary pat­terns may be impli­cat­ed in the devel­op­ment of ADHD, and high­lights the need for addi­tion­al study so that a more defin­i­tive under­stand­ing of this impor­tant issue can be obtained.

These find­ings also pro­vide an reminder that although risk for ADHD has been strong­ly linked to genet­ic fac­tors, it is impor­tant to con­tin­ue the explo­ration of oth­er fac­tors that may increase risk. Such explo­ration should ulti­mate­ly lead to a rich­er under­stand­ing of the dis­or­der and how it devel­ops, and hope­ful­ly to the devel­op­ment of more effec­tive treat­ments.

Rabiner_David– Dr. David Rabin­er is a child clin­i­cal psy­chol­o­gist and Direc­tor of Under­grad­u­ate Stud­ies in the Depart­ment of Psy­chol­ogy and Neu­ro­science at Duke Uni­ver­sity. He pub­lishes Atten­tion Research Update, an online newslet­ter that helps par­ents, pro­fes­sion­als, and edu­ca­tors keep up with the lat­est research on ADHD, and teach­es the online course  How to Nav­i­gate Con­ven­tion­al and Com­ple­men­tary ADHD Treat­ments for Healthy Brain Devel­op­ment.

Leave a Reply...

Loading Facebook Comments ...

3 Responses

  1. james says:

    It is also worth not­ing that this study did not exam­ine whether dietary changes can reduce ADHD symp­toms and that the find­ings should not be inter­pret­ed in that way.”

    I would like to add an obser­va­tion on this point. We have two sets friends each with a child that has been diag­nosed with ADHD. A few years ago we sug­gest­ed to them that they try the “elim­i­na­tion diet”, which is used to iden­ti­fy food aller­gies. The diet removes all preser­v­a­tives, arti­fi­cial col­ors and fla­vors, and foods that are high in nat­ur­al food chem­i­cals. In both cas­es the symp­toms remit­ted spon­ta­neous­ly and they have enjoyed good health since.

    This is not to say that the change in diet reduced ADHD symp­toms. My own pet the­o­ry is that food intol­er­ance is often mis­di­ag­nosed as ADHD, because the symp­toms in chil­dren can be very sim­i­lar.

  2. Anon says:

    It would real­ly take lit­tle to con­vince me that this is true. In 2002 I suf­fered a rup­tured cere­bral aneurysm on the ante­ri­or com­mu­ni­cat­ing artery fol­lowed by the clip­ping surgery to repair the bleed. While, for the most part, I emerged phys­i­cal­ly intact I did have deficits relat­ed to the expe­ri­ence. I suf­fered extreme fatigue (both phys­i­cal and men­tal), was very dis­or­ga­nized, for­get­ful and could not remain focused on any­thing for any length of time. Pri­or to the rup­ture my weight had been increas­ing and in the months after­ward I real­ly bal­looned up. As my weight had reached a point that it was threat­en­ing my health I did make attempts at diet­ing. My girl­friend took a very crit­i­cal look at my diet and noticed that I was con­sum­ing huge amounts of fats and sug­ars. I con­cen­trat­ed on reduc­ing these, no deep fried foods, no fast food, no soda, and ate a bal­anced healthy diet. The weight begin quick­ly drop­ping off and I noticed a def­i­nite improve­ment in my thought process­es. Now, some eight years post rup­ture, it is even more appar­ent, to me, how much this diet improved me and not just my car­dio­vas­cu­lar health.

    James, you pose a good ques­tion. In my opin­ion, based sole­ly on my own expe­ri­ence, I would think that dietary changes could well reduce ADHD symp­toms.

  3. Anon says:

    James, are refer­ring to nat­ur­al whole food intol­er­ance or processed foods?

Leave a Reply

Categories: Attention and ADD/ADHD, Cognitive Neuroscience, Health & Wellness

Tags: , , , , ,

Search in our archives

About SharpBrains

As seen in The New York Times, The Wall Street Journal, BBC News, CNN, Reuters,  SharpBrains is an independent market research firm tracking how brain science can improve our health and our lives.

Follow us and Engage via…

RSS Feed

Watch All Recordings Now (40+ Speakers, 12+ Hours)