What Role Does Nutrition Play in ADHD?

There's no evidence that the behavioral disorder ADHD is caused by diet.

However, research suggests that for some people, dietary changes can improve symptoms.

In fact, a substantial amount of research has examined how nutrition affects ADHD.

This article is an overview of these findings, discussing the foods, diets and supplements involved.

ADHD is a complicated behavioral disorder and common treatments include therapy and medication.

What Is ADHD?

Attention deficit hyperactivity disorder (ADHD) is a behavioral condition involving inattention, hyperactivity and impulsiveness (1, 2).

It's one of the most common disorders children can have, but also affects many adults (3, 4).

The exact cause of ADHD is unclear, but research shows that genetics play a major role. Other factors, such as environmental toxicity and poor nutrition during infancy, have also been implicated (5, 6, 7, 8).

ADHD is believed to originate from low levels of dopamine and noradrenaline in the region of the brain responsible for self-regulation (9, 10, 11).

When these functions are impaired, people struggle to complete tasks, perceive time, stay focused and curb inappropriate behavior (12, 13, 14).

This, in turn, affects the ability to work, do well in school and maintain appropriate relationships, which can decrease quality of life (15, 16, 17, 18, 19).

ADHD is not considered to be a curable disorder and treatment instead aims to reduce symptoms. Behavioral therapy and medication are mostly used (20, 21).

However, dietary changes may also help manage symptoms (1, 22).

Bottom Line: ADHD is a complicated behavioral disorder and common treatments include therapy and medication. Dietary changes may also be useful.

Nutrition and Behavior

The science behind food's effects on behavior is still quite new and controversial. However, everyone can agree that certain foods do affect behavior.

For example, caffeine can increase alertness, chocolate can affect mood and alcohol can totally change behavior (23).

Nutritional deficiencies can also affect behavior. One study concluded that taking a supplement of essential fatty acids, vitamins and minerals led to a significant reduction in antisocial behavior, compared to a placebo (24).

Vitamin and mineral supplements can also reduce antisocial behavior in children and poly-unsaturated fatty acids have been shown to decrease violence (25, 26).

Since foods and supplements have been shown to influence behavior, it seems plausible that they could also affect ADHD symptoms, which are largely behavioral.

For this reason, a good amount of nutrition research has looked into the effects of foods and supplements on ADHD.

Mostly, two types of studies have been performed:

  • Supplement studies: Supplementing with one or several nutrients.
  • Elimination studies: Eliminating one or several ingredients from the diet.

Bottom Line: Studies show that certain foods and supplements do affect behavior. For these reasons, quite a few studies have looked into how nutrition affects ADHD symptoms, which are mostly behavioral.

Supplement Studies: A Research Review

Many studies have shown that children with ADHD often have unhealthy eating habits or nutrient deficiencies (27, 28, 29, 30).

This caused researchers to speculate that supplements might help improve symptoms.

Nutrition studies have looked into the effects of several supplements on ADHD symptoms, including amino acids, vitamins, minerals and omega-3 fatty acids.

Amino Acid Supplements

Every cell in your body needs amino acids to function. Among other things, amino acids are used to make neurotransmitters or signaling molecules in the brain.

In particular, the amino acids phenylalanine, tyrosine and tryptophan are used to make the neurotransmitters dopamine, serotonin and norepinephrine.

People with ADHD have been shown to have problems with these neurotransmitters, as well as low blood and urine levels of these amino acids (31, 32).

For this reason, a few trials have examined how amino acid supplements affect ADHD symptoms in children.

Tyrosine and s-adenosylmethionine supplements have provided mixed results, with some studies showing no effects and others showing modest benefits (33, 34, 35).

Bottom Line: Amino acid supplements for ADHD show some promise, but more studies need to be done. For now, the results are mixed.

Read page 1

Vitamin and Mineral Supplements

Iron and zinc deficiencies can cause cognitive impairment in all children, whether or not they have ADHD (36, 37, 38).

However, lower levels of zinc, magnesium, calcium and phosphorous have repeatedly been reported in children with ADHD (39, 40, 41).

Several trials have looked into the effects of zinc supplements and all of them reported improvements in symptoms (42, 43, 44).

Another two trials assessed the effects of iron supplements on children with ADHD. They also found improvements, but again, more research is needed (45, 46).

The effects of mega-doses of vitamins B6, B5, B3 and C have also been examined, but no improvements to ADHD symptoms were reported (47, 48).

Nevertheless, a 2014 trial of a multivitamin and mineral supplement did find an effect. The adults taking the supplement showed a convincing improvement on ADHD rating scales after 8 weeks, compared to the placebo group (49, 50).

Bottom Line: The results from vitamin and mineral supplement studies have been mixed, but several show promise.

Omega-3 Fatty Acid Supplements

Omega-3 fatty acids play important roles in the brain.

Children with ADHD generally have lower levels of omega-3 fatty acids than children who don't have ADHD (51, 52).

What's more, the lower their omega-3 levels, the more learning and behavioral problems the ADHD children seem to have (53).

Therefore, it's not surprising that many studies have found omega-3 supplements to cause modest improvements to ADHD symptoms (54, 55, 56, 57, 58).

In studies, omega-3 fatty acids appear to help improve task completion and inattention. Additionally, they decreased aggression, restlessness, impulsiveness and hyperactivity (59, 60, 61, 62, 63, 64, 65).

Bottom Line: Numerous trials have found that omega-3 supplements can bring about modest improvements in ADHD symptoms.

Elimination Studies: A Research Review

People with ADHD are more likely to have adverse reactions to food, which caused speculation that eliminating problematic foods might help improve symptoms (30, 66).

Studies have examined the effects of eliminating many ingredients, including food additives, preservatives, sweeteners and allergenic foods.

Eliminating Salicylates and Food Additives

By accident, an allergist named Dr. Feingold discovered that food could affect behavior.

In the 1970s, he prescribed a diet for his patients that eliminated certain ingredients that produced a reaction for them.

The diet was free of salicylates, which are compounds found in many foods, medications and food additives.

While on the diet, some of Feingold's patients noted an improvement in their behavioral problems.

Soon after, Feingold started recruiting children diagnosed with hyperactivity for dietary experiments. He claimed that 30–50 percent of them improved on the diet (67).

His work was celebrated by many parents, who formed the still-existent Feingold Association of the U.S. (68).

Although reviews concluded the Feingold diet was not an effective intervention for hyperactivity, it stimulated further research into the effects of food and additive elimination on ADHD (69, 70, 71).

Bottom Line: The Feingold diet pioneered elimination diet research for ADHD. It improved symptoms in children with ADHD, although recent evidence is mixed.

Eliminating Artificial Colors and Preservatives

After the Feingold diet was no longer considered effective, researchers narrowed their focus to look at artificial food colors (AFCs) and preservatives.

This is because these substances seem to affect the behavior of children, regardless of whether or not they have ADHD (72, 73).

One study followed 800 children suspected of hyperactivity. 75 percent of them improved while on an AFC-free diet, but relapsed once given AFCs again (74).

Another study found that hyperactivity was increased when 1,873 children consumed AFCs and sodium benzoate, a preservative (75).

Yet even though these studies indicate that AFCs can increase hyperactivity, many people claim the evidence is not strong enough (1, 54, 76, 77, 78, 79).

Nonetheless, the Food and Drug Administration (FDA) requires certain AFCs to be listed on food packages. The EU, on the other hand, requires foods containing AFCs to have a label warning of adverse effects to children's attention and behavior (80, 81, 82, 83).

Bottom Line: AFCs may affect behavior in children, although some say the evidence is not strong enough. However, the FDA and the EU require food labels to list additives.

Eliminating Sugar and Artificial Sweeteners

Soft drinks have been linked to increased hyperactivity and low blood sugar is also common in those with ADHD (84, 85).

Furthermore, some observational studies have found sugar intake to be related to ADHD symptoms in children and adolescents (86, 87).

However, one review looking into sugar and behavior found no effects. Two trials studying the artificial sweetener aspartame also found no effects (88, 89, 90).

Theoretically, it's more likely that sugar causes inattention, rather than hyperactivity, as blood sugar imbalances can cause attention levels to drop.

Bottom Line: Sugar and artificial sweeteners have not been shown to directly affect ADHD. However, they may have indirect effects.

The Few Foods Elimination Diet

The Few Foods Elimination Diet is a method that tests how people with ADHD respond to foods. Here's how it works:

  • Elimination: Follow a very restricted diet of low-allergen foods that are unlikely to cause adverse effects. If symptoms get better, enter the next phase.
  • Reintroduction: Foods suspected of causing adverse effects are reintroduced every 3–7 days. If symptoms return, the food is identified as “sensitizing."
  • Treatment: A personal dietary protocol is prescribed. It avoids sensitizing foods as much as possible, in order to minimize symptoms.

Twelve different studies have tested this diet, each of which lasted 1–5 weeks and included 21–50 children.

Eleven of the studies found a statistically significant decrease in ADHD symptoms in 50–80 percent of the participants, while the other one found improvements in 24 percent of the children (91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102).

Of the children who responded to the diet, most reacted to more than one food. While this reaction varied by individual, cow's milk and wheat were the most common offenders (92, 94, 100).

The reason why this diet works for some children and not others is unknown.

Bottom Line: The Few Foods Elimination Diet is a diagnostic tool to rule out problems with food. All studies have found a favorable effect in a subgroup of children, usually more than half.

Take Home Message

Research about how food affects ADHD symptoms is far from conclusive.

Yet the studies mentioned here suggest that diet can definitely have powerful effects on behavior.

This article was reposted from our media associate Authority Nutrition.


10 Superfoods That Will Keep You Healthy This Winter

7 Foods That Keep You From Overeating

What You Should Eat to Balance Your pH and Alkalize Your Body

4 Foods That Age You Faster

Show Comments ()
South Carolina United Turtle Enthusiasts (S.C.U.T.E) unearthed three baby loggerheads after a nest inventory at Pawleys Island beach. Lorraine Chow

Sea Turtle Population Rebounding But Many Threats Remain

A new study published in Science Advances has found that most global sea turtles populations are recovering after historical declines.

The results from the analysis suggest that conservation programs actually work, and why we must defend the Endangered Species Act (ESA) that protects vulnerable plants and animals, and is currently under attack by political and business interests.

Keep reading... Show less

Baby Rhino Brings New Hope to India’s Manas National Park

A baby rhino spotted alongside its mother in Manas National Park, located in the northeastern Indian state of Assam, is an encouraging new sign that the rhino population in the protected area is on the upswing. The mother, named Jamuna, was rescued as a calf from Kaziranga National Park, located about 200 miles east of Manas and raised at the Center for Wildlife Rehabilitation and Conservation, a facility that cares for injured or orphaned wild animals run by Wildlife Trust of India/International Fund for Animal Welfare and the Assam Forest Department. She was moved to the Manas in 2008 as part of the country's rhino conservation efforts.

The calf is her second since 2013—a positive indication that despite concerns due to poaching of mature males, rhinos in Manas are reproducing.

Keep reading... Show less
Cedar Mesa Valley of the Gods in the Bears Ears National Monument in southeastern Utah. Bob Wick, BLM

Navajo Nation Readies Legal Action if Trump Shrinks Bears Ears National Monument

Interior Sec. Ryan Zinke's recommendation to reduce the size of the Bears Ears National Monument in Utah could spark a legal battle between the Navajo Nation and the Trump administration.

"We are prepared to challenge immediately whatever official action is taken to modify the monument or restructure any aspect of that, such as the Bears Ears Commission," Ethel Branch, Navajo Nation attorney general, told Reuters.

Keep reading... Show less
Jilson Tiu / Greenpeace

Nestlé, Unilever, P&G Among Worst Offenders for Plastic Pollution in Philippines Beach Audit

A week-long beach clean up and audit at Freedom Island in Manila Bay has exposed the companies most responsible for plastic pollution in the critical wetland habitat and Ramsar site—one of the worst locations for plastic pollution in the Philippines.

The Greenpeace Philippines and #breakfreefromplastic movement audit, the first of its kind in the country, revealed that Nestlé, Unilever and Indonesian company PT Torabika Mayora are the top three contributors of plastic waste discovered in the area, contributing to the 1.88 million metric tonnes of mismanaged plastic waste in the Philippines per year.

Keep reading... Show less

Arkansas Plant Board Backs Dicamba Ban Next Summer in Blow to Monsanto

The Arkansas Plant Board has approved new regulations that prohibit the use of dicamba from April 16 through Oct. 31, 2018 after receiving nearly 1,000 complaints of pesticide misuse in the state.

Arkansas, which temporarily banned the highly volatile weedkiller in July, could now face legal action from Monsanto, the developers of dicamba-resistant soybeans or cotton and the corresponding pesticide, aka the Xtend crop system.

Keep reading... Show less
Crews cleanup a spill from the Rover pipeline near the Tuscrawas River in southern Stark County. Ohio EPA

Ohio EPA Hikes Fines Against Rover Pipeline to $2.3 Million

The Ohio Environmental Protection Agency (EPA) asked the state attorney general's office Wednesday to hold the owners of the troubled Rover natural gas pipeline responsible for $2.3 million dollars in fines. Rover leaked more than 2 million gallons of drilling mud into protected Ohio wetlands this spring, leading the Federal Energy Regulatory Commission to order a halt to construction.

Keep reading... Show less
Diego Cambiaso / Flickr

White House Considers Green Rebrand

The White House convened a "big-picture" strategy meeting on climate and environment this week, Politico reported.

At the meeting, deputy-level White House officials and representatives from agencies discussed how to frame President Trump's larger environmental objectives beyond simply overturning Obama-era regulations. Per Politico, meeting attendees considered the possibility of highlighting job creation and new energy technology and "how to combat the public perception that the administration is out of touch with climate science."

Keep reading... Show less

How Trump Could Undermine the U.S. Solar Boom

By Llewelyn Hughes and Jonas Meckling

Tumbling prices for solar energy have helped stoke demand among U.S. homeowners, businesses and utilities for electricity powered by the sun. But that could soon change.

President Donald Trump—whose proposed 2018 budget would slash support for alternative energy—may get a new opportunity to undermine the solar power market by imposing duties that could increase the cost of solar power high enough to choke off the industry's growth.

Keep reading... Show less


Get EcoWatch in your inbox