Doctors and researchers have been at odds for many years as to whether long-chain polyunsaturated fatty acids have an effect on the behaviour and cognition of ADHD children. It is hoped that a study at Ulm University will bring more clarity to the debate and potentially come up with an alternative to the controversial psychostimulant therapy.
Previous data are contradictory and inconsistent, said the molecular biologist Katharina Müller from the Transfer Centre for Neurosciences and Learning at the University of Ulm. The 52-year-old scientist, working with the Centre of Social Paediatrics (SPZ) at the Children’s Hospital in Ulm (Prof. Harald Bode), is set to start a study as part of the BMBF-funded biomedical nutrition research programme as soon as she has received the green light from the project management organisation.
In Germany, two to seven percent of children and young adolescents between the age of four and 17 years of age suffer from attention deficit hyperactivity disorder (ADHD) with symptoms starting in early childhood. ADHD is considered to be a neurobehavioral development disorder and is one of the most common chronic diseases in children and young adolescents. The major symptoms are impulsiveness, inattention and hyperactivity.
The specific cause of ADHD is not known. According to Müller, a number of factors may contribute to its development, including environmental factors such as smoking and the consumption of alcohol during pregnancy; low birth weight; social factors such as family conflict or poor child-rearing practices as well as genetic factors involving the genes encoding the dopamine receptors D4 and D5, the dopamine transporter, the dopamine-beta-hydroxylase (DHB) and the serotonin transporter (5-HTT).
The brain of children suffering from ADHD matures normally, however its development lags slightly that of non-ADHD children. According to Müller, recent research has shown that this is particularly evident in the central prefrontal cortex, which lags about three years behind the development of normal brains. This area of the brain is considered to be the key centre for the control of situation-specific activities and is also strongly involved in the regulation of emotional processes.ADHD therapy involves mainly psychoeducational input, psychotherapy and drugs. In Germany, the psychostimulant methylphenidate (brand name Ritalin) is the most common drug used in the treatment of ADHD. Ritalin is the first choice due to its efficacy in treating the disorder. The drug generates an increase in dopamine in the synaptic cleft, which leads to the more efficient transfer of nerve signals.
Amphetamines (mainly prescribed for the treatment of ADHD in the USA), pemolin and atomoxetine are also considered to have significant effects. According to the German Medical Association (BÄK), there are hardly any damaging side effects associated with psychostimulant therapy when taken correctly (statement of the BÄK, 2005). However, many parents of ADHD children have a negative view of long-term treatment involving psychostimulants. An alternative with fewer associated risks, and which is currently being investigated in Ulm, is the nutritional and dietary treatment of ADHD.
Müller said that the lack of long-chain polyunsaturated fatty acids (LCPUFAs) has been regarded as a major cause of ADHD for more than 20 years. This seems quite plausible because the human brain has the highest proportion of fat of all the body’s organs. The brain’s dry mass consists of 50 to 60 percent lipids, of which around one third are LCPUFAs, necessary for structure and functionality of neuronal tissue.A recent scientific paper (Fröhlich, Döpfner) confirmed the correlation: “It seems that supplementing the diet with essential fatty acids might have a significant therapeutic use in ADHD patients with subclinical or moderate symptoms."
There is evidence that humans are able to learn better when they have sufficient quantities of such fats in their diet. Evidence, correlations, but not causalities. It is virtually certain that the concentration of essential fatty acids concentration falls in pregnant women because the lipids are preferentially given to the growing baby. The more babies at shorter intervals that a woman has, the lower the fatty acid level becomes, said the researcher from Ulm.
Where does the human organism get the fatty acids from which it cannot produce? There are two ways that the organism can do this. Either the fatty acids are assembled from small precursor molecules that are present in large quantities in rape or flax oil or they are taken up with the daily food intake. In humans, the indirect biochemical synthesis of valuable long-chain fatty acids (for example docosahexaenoic acid, DHA) from short precursor molecules only leads to a small amount of DHA, so DHA supplements from other sources are therefore recommended.
Natural sources of DHA are sea fish rich in fat such as herring, mackerel or salmon. Müller considers one portion per week to be enough as the long-chain fatty acids absorbed when eating such fish have a long half-life.
The German Society of Nutrition (DGE) recommends eating oily fish once or twice a week or, on medical advice, taking fish oil capsules containing the long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and DHA. (BASF is, for example, working on the development of synthetically produced alternatives for limited stocks of expensive fish oil using genetically modified rape plants to produce n-3 and n-6 fatty acids).
According to Müller there is growing evidence that the omega fatty acid metabolism is defective in one subgroup of ADHD patients. Many studies have attempted to provide further evidence for the assumption that the specific and supplementary consumption of long-chain polyunsaturated fatty acids reduces the symptoms of ADHD. However, many of the findings were contradictory.
The study being carried out by the Ulm researchers, which has a run time of two years, is seeking to clarify the contradictions and come up with unambiguous results. Müller believes that LCPUFA supplements will benefit some ADHD children. In order to come up with watertight results, ADHD must be diagnosed by a doctor who is part of the SPZ at the Ulm University Children’s Hospital, the intervention (placebo verum) must be in place and the adherence to medication must be confirmed. The study will involve 110 children between six and ten years of age and last for four months. The blood of the probands will be withdrawn before and after the four-month period to examine the fatty acid pattern. This is an additional biochemical control to monitor the uptake of the fatty acids given in concentrated form in pills. If the study confirms Müller’s assumption that LCPUFA supplements have an effect on the behaviour and cognition of ADHD patients, the fatty acid pattern in the blood of the patients in the supplement group would be a diagnostic criterion, enabling the targeted therapy of certain ADHD patients.
Sources: Weiland, U./Widenhorn-Müller, K.: Langkettige mehrfach ungesättigte Fettsäuren – eine zusätzliche Behandlungsmöglichkeit bei Kindern mit ADHS?, in: Nervenheilkunde 9/2008, p. 789ff.Frölich, J./Döpfner, M.: Treatment of attention-deficit/hyperactivity disorders with polyunsaturated fatty acids – an effective treatment alternative, doi:10.1024/1422-4918.104.22.168German Nutrition Society (DGE): Evidenzbasierte Leitlinie: Fettkonsum und Prävention ausgewählter ernährungsbedingter Krankheiten (November 2006)German Nutrition Society (DGE), 9 May 2006: Kein Zweifel an der Wirkung von n-3 FettsäurenGerman Medical Association (BÄK) (Ed.): Stellungnahme zur Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS)-Kurzfassung, 2005
BASF Plant Science, 15/16 September 2005: Lebertran ade – gesunde Fettsäuren aus Pflanzen
Jörg Blech, Dünger fürs Gehirn, in: Spiegel 52/2008, p. 112-114.