Zinc is an essential mineral that we must consume in our diet. It is needed for the brain, digestion and the immune system. Recently, there has also been some interest in the role that Zinc might play in ADHD. However, research in this area is still in the early stages. NHS Highland does not recommend Zinc supplements as a routine treatment for ADHD. However, it is worth ensuring that the diet contains adequate amounts of Zinc rich foods. This information sheet summarizes this research and its implications for children with ADHD.
- Average intakes of Zinc among UK schoolchildren are below the “Reference Nutrient Intake” (Gregory, 2000). This means that some children may be at risk of “Marginal Zinc deficiency”.
- Severe Zinc deficiency affects growth and is common in developing countries. However, marginal Zinc deficiency appears to affect brain function and has been found in middle class populations in developed countries (Hambridge, 2000), (Prasad, 1996).
- Moderate Zinc deficiency in rats causes impaired learned behaviour and impaired cell maturation (Takeda, 2000), (Yeiser, 2002).
- Zinc deficiency may be more common in children with ADHD than in children without ADHD (P Toren, 1996), (Starobrat-Hermelin, 1998), (Kozielec, 1994), (Bekarolglu, 1996), (Arnold, 2005). This could be due to low intake of Zinc rich foods, poor absorption or increased Zinc excretion (Arnold, 2005).
- One study of American children showed a strong correlation between Zinc status and the degree of inattention in ADHD. However, they found no correlation between Zinc status and impulsivity or hyperactivity (Arnold, 2005).
- Zinc supplements on their own have been shown to reduce ADHD symptoms of hyperactivity and impulsivity compared to placebo. However this has only been shown at relatively high doses that may not be safe in the long term (Bilici, 2004).
- Stimulant medication may work better in children with good Zinc status than in those who have a poor Zinc status (Arnold, 2000).
- Zinc supplements can improve the effectiveness of stimulant medication. The effect was seen in both the parent and teacher rating of ADHD symptoms in a “blinded placebo controlled” study (Akhondzadeh, 2004).
- Two studies show that some artificial food colours increase ADHD symptoms and reduce Zinc status in children with ADHD, leaving the zinc status and behavior of children without ADHD unaffected (Ward, 1990), (Ward, 1997).
Zinc plays a role in the structure and function of the brain. It is needed for the production of long chain fatty acids that are used in brain cell membranes. Zinc also has a powerful antioxidant role and therefore is needed for the stabilization of cell membranes (in the brain and elsewhere). Zinc activates vitamin B6 to the active form which enables serotonin production. Zinc is also required for the production and modulation of melatonin. Serotonin and melatonin are important “brain chemicals” that affect mood and sleep patterns.
- We do not recommend Zinc supplements as a single routine therapy for ADHD. At present, there is not enough scientific evidence in favour of this.
- There may be some value in taking Zinc supplements alongside stimulant medication for ADHD. However, this should only be done under the supervision of your paediatrician.
- We do recommend that children include dietary sources of Zinc as part of a healthy balanced diet. Zinc is found mostly in protein rich foods.
- Very good sources of Zinc include beef (including mince) and lamb. Good sources of Zinc include pork, chicken, fish, shellfish, pumpkin seeds, chick peas, peas, beans, eggs, cheese, yoghurt and nuts.
- As a “rule of thumb” children who eat 2 or 3 portions of red meat a week are more likely to have a good Zinc status than those who eat no red meat. Children who eat very few protein rich foods are quite likely to be deficient in Zinc. This could exacerbate any symptoms of ADHD.
- Note that red meat is also a particularly good source of Iron. Iron is also an important mineral for the brain. More information on Iron is available in a separate NHS Highland information sheet.
- Remember that many children with ADHD have a perfectly adequate diet and are not deficient in Zinc or any other nutrient
Further information:
For further information, talk to you Community Paediatrician or to Children in the Highlands Information Point Plus (CHIP+) at the Birnie Child Development Centre.
Dave Rex, Child health Lead Dietitian, NHS Highland September 2008
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