The number of children with ADHD in Hong Kong is rising.

Four ways diet could help reduce ADHD symptoms in children

Cases of attention deficit hyperactivity disorder are rising in Hong Kong. A diet that is high in omega fatty acids and proteins, and low in processed sugars and junk food, may help treat it without resort to drugs

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental problems in children. Sufferers are usually hyperactive, impulsive, and have difficulty paying attention. The prevalence of ADHD among Hong Kong schoolchildren is similar to the figure internationally, which is from 5 per cent to 9 per cent, with boys more frequently affected than girls, according to Castle Peak Hospital’s Institute of Mental Health.

The number of cases handled by the Hospital Authority’s child and adolescent psychiatric teams rose more than 50 per cent, from 18,900 in 2011 to 28,800 in 2016, according to a Review on Mental Health published by the Legislative Council’s panel on health services in April. ADHD was among the major disorders in these children, making up almost half the caseload.

While the precise cause of the condition remains elusive, previous research has suggested that a poor diet may play a role. A study published in Nutrition Review in 2008 from the Nutritional Physiology Research Centre at the University of South Australia in Adelaide, found adverse reactions to specific foods and food additives, exposure to toxic food contaminants and low levels of micronutrients such as essential fatty acids, zinc, magnesium and iron in children with ADHD. Some studies have indicated that healthful diets could help to prevent or even treat ADHD, though other research has challenged this theory.

Drugs are often the first tool for treating ADHD and they have proven effective in controlling disruptive behaviour and inattention. Some parents are reluctant to medicate their children, as they are concerned about the long-term side effects and potential adverse reactions such as loss of appetite, stomach upset, sleeplessness, and weight loss. They prefer to use drug-free approaches, including nutritional interventions.
Following a Mediterranean diet and eating cold-water fish that are high in omega-3 fatty acids should help children with ADHD. Photo: Alamy

The Mediterranean diet – high in fruit, vegetables, fish, whole grains, nuts and legumes, and low in red meat, eggs, dairy products, and sweets – is celebrated for its positive effects on the brain, especially later in life. Physicians recommend it for preventing Alzheimer’s and protecting the brain from ageing. Recent research published in the journal Pediatrics has uncovered a link between low adherence to the Mediterranean diet and an increased risk of ADHD. Children with low adherence to the diet were seven times more likely to have ADHD than children who stuck to it, the study found.

The researchers also found that children with ADHD consumed more sugar and processed foods than their counterparts, and ate less fruit, vegetables and fish. The study showed only correlations and cannot conclude that a Mediterranean diet can ward off ADHD.

Researchers are uncertain whether these children suffer from ADHD due to an unhealthy diet, or whether they eat an excess of sugar and fat to balance impulsiveness or emotional distress caused by the disorder. It may even be the impulsiveness of children with ADHD triggering their unhealthy food choices.

So what are some dietary interventions for children with ADHD? Here are four food strategies aimed at helping children with ADHD:

Omega power

Essential fatty acids fuel basic cell function, improve overall immunity, and enhance heart health. Nutritional deficiencies, including deficiencies in fatty acids (EPA, DHA), the amino acid methionine, and the minerals zinc and selenium, have been shown to influence the neurons and cause defects in neuroplasticity – the brain’s ability to reorganise itself. These nutritional disturbances have been associated with behaviour typical of ADHD.

Omega-3 fatty acids (EPA, DHA, and ALA) can be obtained from salmon, tuna, other cold-water fish, and from some seeds and oils. Omega-6 fatty acids (especially linoleic acid) is obtained primarily from vegetable oils. According to the American Psychological Association subcommittee, children with ADHD are encouraged to consume levels of omega-3 fatty acids as part of a healthy diet. For children, that means having up to 340 grams (two average meals) a week of a variety of fish and shellfish such as shrimp, canned light tuna and salmon that are low in mercury, along with daily plant sources of unsaturated fats.

Simple sugars can have a negative effect on brain function. Photo: Alamy
Cut down simple sugars

An unhealthy, sugar-laden diet (includes sweets, corn syrup, products made from white flour, white rice) can have a negative effect on brain function and mood, so reducing the amount of sugar and junk food in a child’s diet should improve their learning and prevent causing the roller coaster blood-sugar response. A high-sugar diet also alters the composition of the microbe community in the gut.


A low-sugar, whole food diet supports a healthy community of gut bacterial, which may lead to improved brain function and mood. Replace simple sugars with complex carbohydrates such as vegetables and fruits such as grapefruit, apples, cherries, and oatmeal, bran, high-fibre cereals and pasta, which deliver a steady supply of sugar (and energy).

Try to eat a healthy protein-rich breakfast. Photo: Shutterstock
Eat a protein-rich breakfast

Protein affects brain performance by providing essential amino acids to awaken neurotransmitters, the biochemical messengers that carry signals from one brain cell to another. The better these messengers are fed, the more efficiently and accurately they deliver messages, allowing children with ADHD to be alert and focused. Since the body makes neurotransmitters when you eat protein, start your child’s day with a protein-rich breakfast and try to give them lean protein throughout the day.

A nutrition-packed breakfast should contain a balance of complex carbohydrates and protein (whole grains, dairy, and fruits: a vegetable omelette, bran muffin, fresh fruit with yogurt). Beans, cheese, eggs, lean meat and nuts are good sources of protein. Protein also helps keep blood-sugar levels steady.

Avoid “trigger” foods

Elimination diets, such as the Feingold diet, can help parents pinpoint foods that may be contributing to a child’s ADHD symptoms. Certain foods can cause headaches, gastrointestinal tract problems, and itchy skin. Eliminating foods with artificial colours, flavours, and preservatives from a diet for about three weeks and then reintroducing them one at a time can help parents identify problem ingredients. Gradual reintroduction of foods is important, in case a serious adverse reaction occurs with exposure to even a small amount of food. Many children on such a diet have improved gastrointestinal function, behaviour and concentration.

While there are thousands of chemical compounds in our foods, and still more in our water, air, soil, and everyday environments, there are dozens of nutritional components that might affect ADHD symptoms for better or worse. Until we know more about how both the presence and absence of various nutrients and chemicals affect our children’s cognition, behaviour and health, providing them with more fresh fruit and vegetables, wholegrains and lean meats, fish, nuts and beans may be the most assured nutritional interventions.

This article appeared in the South China Morning Post print edition as: Food for thought