Professor Patrick Holford of Teesside University (and also Head of Science and Education at Biocare) and Drew Fobbester are joint researchers and authors of the Food for the Brain Child Survey, September 2007 (pdf). Holford Watch will use three posts to explain why the literature overview in the FFTB Child Survey is inadequate: some of the claims made in the review are not supported by relevant references or studies of sufficient quality.
A brief summary of the detail for Part 1. The authors refer to the truism that a child’s nutrition affects their learning and behaviour. They cite studies to argue that children with “sub-optimum nutrition” (an undefined term) have poor cognition and behaviour. The studies that the authors cite indicate that multi-supplements may be of benefit to a small sub-group of children. However, several reviewers have remarked that these are most effective for children who might have deficiencies that approach clinical levels; even appropriate supplementation is unlikely to promote a substantial difference in the absence of other supportive factors such as a stable homelife or stimulating education.
There is a buzz of excitement about the claimed benefits of Omega 3 supplements. However, it is unfortunate that the evidence in this area is currently of such poor quality that it weakens its probative value. The FFTB authors draw our attention to studies that involve children with clinical disorders; results of such studies may not be generalisable to a wider population.
It is premature, at best, to attempt to use the results of this FFTB report or its literature overview to argue that there is a robust scientific case for a change in public policy or dietary recommendations that affects the general population of children. The results are not even sufficient to sustain the authors’ animadversions about the current recommended RDAs. Ironically, when so few children in this survey of children (albeit, it is not a representative sample) adhere to the dietary recommendations that already exist (see, e.g., the publications of the Caroline Walker Trust), it would seem that this sample can not be used to comment on the adequacy or otherwise of RDAs.
Section 3.1 (pg 6) offers a short introduction and overview of the literature in this field:
A substantial and convincing body of scientific evidence, including many randomised-controlled trials, shows that a child’s nutrition has a profound effect on their learning and behaviour:
- Ten out of twelve randomised controlled trials (RCTs) assessing the impact of vitamin and mineral supplementation have illustrated significant improvement in non verbal IQ and concentration
- A diet high in essential fats, especially omega 3 essential fats, as well as supplementation improves attention and reading, and reduces anxiety and aggression. Numerous studies have been conducted in this area including two recent randomised controlled trials[3,4]
- A diet with a balanced glycemic load, incorporating more whole foods and slow-releasing sugars and less refined foods and fast-releasing sugars, eaten at regular intervals, may improve learning, attention and reduce anxiety and aggressive behaviour[5, 6, 7]
- A significant proportion of children with ADHD may have unidentified food and chemical sensitivities[8,9] Gluten sensitivity, for example, is far more common in children with behavioural problems than in those without
The evidence from what is now a large and growing body of broadly consistent research links sub-optimum nutrition with poor cognition and behaviour. While much is known about the kind of diet that provides Recommended Daily Allowances, little is known about the kind of diet that equates to optimal mental health, learning and behaviour. Since RDAs largely do not take into account recent research on nutrition and mental health there is no good reason to assume that these kinds of levels, if eaten, are optimal for mental health. [Too many errors to sic.]
Benton’s1 comprehensive review is the source for the 10/12 claim. It is a little irritating for a reader who checks the primary source to note that Benton reports positive findings for 10/13 studies. [Updateda : Holford Watch had assumed that Holford and Fobbester had noticed that not all of the studies discussed in Benton are RCTs and this accounted for a difference in the numbers. However, more than one of the studies is not an RCT so the 10/12 number is still not correct. Holford and Fobbester must be aware that RCTs and other forms of studies are not semantically equivalent or interchangeable.] Beyond that, the summary of the papers is puzzling. Benton reports:
[i]n 10 out of 13 studies a positive response has been reported, always with non-verbal measures, in at least a sub-section of the experimental sample.
The table that summarises the results shows significant results for only 8 of the reviewed studies and the status of one of those results is equivocal (the Schoenthaler et al11 reports a significant result for only 1 of the experimental groups). It seems that Benton is including some sub-group analyses (that are not pulled out or noted in the table summary) to produce 2 other positive outcomes although, to be fair, he mentions this in the abstract.
There are some null results from studies included in Benton’s summary for which various authors have (appropriately) criticised the methodology (as discussed in Benton). However, it seems as if re-analysing the data for some of these studies would still yield results that are not significant (see, e.g., Eysenck and Schoenthaler12). It would be helpful to understand why the authors of the FFTB report consider it acceptable to report that 10/12 of these studies illustrate “significant improvement” given the usual meaning of the word “significant” in such reports. Benton was careful to distinguish significant results and “positive response[s]” in the body of his paper; Holford and Fobbester must be aware that the two are not semantically equivalent or interchangeable.
Eysenck and Schoenthaler12 review many of the same studies and reach a more nuanced conclusion.
It would seem to follow that positive effects [of supplementation] would only be expected for a (possibly small) subsection of the population-namely, those children below the optimal level. It is unknown how large this subsection might be, and of course, it is likely to vary from country to country and from high to low socioeconomic groups. [pg 369.]
It is interesting to note that in the (then) absence of research on the impact of long-term supplementation, Eysenck and Schoenthaler12 argue that:
the optimal strength [of supplementation] for one child will differ from that of another, depending on the degree of deficiency. Perhaps the requirements of the more seriously deficient children should decide this issue, there being little chance of oversupply have a negative effect on the nondeficient children within the limits described. [pg. 371]
That was a reasonable assessment given the available knowledge at that time. However, recent research with adults indicates that we may need further research and observational data about the impact of long-term supplementation13:
The data presented in the article…suggest that …single supplement use produces worsened cholesterol indicators (p. 38) and worsened health outcomes for diabetes, coronary heart disease, heart attacks, angina, strokes and arthritis (pp. 40-1), when compared to no supplement usage at all.
It is attractive to assume that there are probably no adverse effects from administering a multi-supplement (the supplement that was used for most of the studies included in the literature review). However, in the light of recent observational reports involving adults (above and the Bjelakovic et al meta-analysis that reported increased mortality risks14), the long-term impact is an open question for the present and mandates a better understanding of possible confounds and the identification of sub-groups who may benefit disproportionately or be harmed disproportionately. We would reiterate that these studies involved adults rather than children so the reported outcomes may not be generalisable; nonetheless, they do suggest that we can not be sanguine that there are no adverse outcomes from an “oversupply”. Update Feb 11: A Cochrane Review has flagged some unexpected findings for vitamin A supplementation for preventing lower respiratory tract infections (LRTI) in young children who are otherwise well nourished. It is possible that vitamin A may reduce the incidence of acute LRTI with children with poor nutritional status or weight, but increase it in children of normal nutitional status and weight. This is just an example of unintended consequences that make it premature to assume that there are no consequences to providing supplements to children who don’t otherwise need them.15
In the absence of better information, we would argue that it may be optimistic to claim that there is a solid body of scientific evidence to support the beneficial effects of supplementation for a general population of children. We would further highlight that these studies are said to illustrate “significant improvement” for children with nutritional deficiencies that probably approach clinical rather than “sub-optimal” levels. Despite the reservations in the overview about the RDA levels (as above), Benton, for one, would seem to question the necessity of hypersupplemented nutritional levels for mental health.
Many parents will readily believe that diet can both cause and solve complex and worrying problems. In most cases this is an unreasonable expectation. There is no reason to expect a supplement to produce dramatic change in a child’s functioning, even if they have a low intake of micro-nutrients…Assuming that your child would in fact benefit from supplementation all that you can expect to improve is intellectual potential…Improved nutritional status of itself will bring no intellectual gain unless it takes place in a stimulating, emotionally secure environment. Even then the changes will take place gradually over a long period.
Eysenck and Schoenthaler concluded, “with a certain degree of confidence”, that “inadequate levels of vitamins and minerals in the blood reduce a child’s IQ” and “supplementation by vitamin and mineral pills can raise the child’s non-verbal IQ significantly”, although it “has no effect on children with an adequate level of vitamins and mineral”. The only non-controversial aspect of this summary is the final part. Nobody has suggested that those with an adequate vitamin status will respond to supplementation, it is not a way of achieving a level of supra-normal functioning. [Emphasis added.]
It is unfortunate that Holford and Fobbester chose to express these nuanced studies by using the word ‘significant’ as it is a word with a very specific implication when writing about statistics or analysis: Benton is clear that although some studies showed improvements for some groups and provide interesting pointers, the results were not statistically significant.
The assertions about Omega 3 are interesting but, given the state of the research, they do not have robust scientific evidence to support them. The woeful state of the research that underpins the claims of better education through fish oils is covered by Dr Ben Goldacre. Holford Watch will exercise unusual economy on this point.
Most of the trials have not involved a sample of children who are representative of the general population and the numbers involved in the trial are too small to be useful. Richardson mostly referred to trials involving children with developmental or psychiatric disorders. She acknowledges that:
[t]reatment with omega-3 FA appears most promising, but the few small studies published to date have involved different populations, study designs, treatments, and outcome measures. Large-scale studies are now needed to confirm the benefits reported. Further research is also required to assess the durability of such treatment effects, to determine optimal treatment compositions and dosages, and to develop reliable ways of identifying those individuals most likely to benefit from this kind of treatment. [Emphasis added.]
The recent trials3,4 also involve children with developmental or psychiatric disorders and are not therefore readily generalisable to the more general population of children. Even the ASA has had cause to review these papers when adjudicating against Equazen’s advertising claims and they dismissed them as inadequate to support the grandiose claims made for them. It is regrettable that the authors of the FFTB did not choose to acknowledge the deficiencies or special population of these studies before claiming them as an evidence-base for the general population of children. [Update Feb 5: for a good overview of the Fish Oil issues, BBC Radio 4’s You and Yours broadcast a well-received review 26.10.2006. Catherine Carr’s report won a special commendation at the Norwich Union Medical Journalism Awards: “this was a wonderfully assembled piece helping to protect the public from bad science”.]
Review Part 2 examines the report’s claims for glycaemic load and its impact on children’s mood and performance.
 Benton D, Micro-nutrient supplementation and the intelligence of children. Neurosci Biobehav Rev. 2001 Jun;25(4):297-309.
 Richardson AJ, Long-chain polyunsaturated fatty acids in childhood developmental and psychiatric disorders. Lipids. 2004 Dec;39(12):1215-22.
 Richardson AJ, Montgomery P. The Oxford-Durham study: a randomized, controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder. Pediatrics. 2005 May;115(5):1360-6. [The authors misquote the name in the FFTB Survey.]
 Sinn N, Bryan J. Effect of supplementation with polyunsaturated fatty acids and micronutrients on learning and behavior problems associated with child ADHD. J Dev Behav Pediatr. 2007 Apr;28(2):82-91.
 Haapalahti M, Mykkänen H, Tikkanen S, Kokkonen J. Food habits in 10-11-year-old children with functional gastrointestinal disorders. Eur J Clin Nutr. 2004 Jul;58(7):1016-21.
 Benton D. The impact of the supply of glucose to the brain on mood and memory. Nutr Rev. 2001 Jan;59(1 Pt 2):S20-1
 Lien L, Lien N, Heyerdahl S, Thoresen M, Bjertness E. Consumption of soft drinks and hyperactivity, mental distress, and conduct problems among adolescents in Oslo, Norway. Am J Public Health. 2006 Oct;96(10):1815-20.
 Carter CM, Urbanowicz M, Hemsley R, Mantilla L, Strobel S, Graham PJ, Taylor E. Effects of a few food diet in attention deficit disorder. Arch Dis Child. 1993 Nov;69(5):564-8.
 Egger J, Carter CM, Graham PJ, Gumley D, Soothill JF. Controlled trial of oligoantigenic treatment in the hyperkinetic syndrome. Lancet. 1985 Mar 9;1(8428):540-5.
 The FFTB Child Survey cites: Gerarduzzi T et al. Celiac disease in USA among risk groups and general population in USA. Journal of Pediatric Gastroenterology and Nutrition. Vol 31 (suppl) 2000: pp S29, Abst 104. [Having searched Jnl of Ped Gastro and Nutr, this paper doesn’t seem to exist as per this reference. It appears in Google Scholar as a citation only which might indicate an error.] Holford Watch has previously mentioned our difficulty with this reference: Running out of tolerance.
 Schoenthaler SJ, Amos SP, Eysenck HJ, Peritz B and Yudkin J. Controlled trial of vitamin-mineral supplementation: effects on intelligence and performance. Personal Indi Diff . 12 (1991), pp. 351–362.
 Eysenck HJ and Schoenthaler SJ. Raising IQ level by vitamin and mineral supplementation. In: Sternberg RJ and Grigorenko EL, (Eds), Intelligence heredity and environment, Cambridge University Press, Cambridge (1997), pp. 363–392.
 Block G, Jensen CD, Norkus EP, Dalvi TB, Wong LG, McManus JF, Hudes ML. Usage patterns, health, and nutritional status of long-term multiple dietary supplement users: a cross-sectional study. Nutr J. 2007 Oct 24;6:30.
 Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA. 2007 Feb 28;297(8):842-57
 Chen H, Zhuo Q, Yuan W, Wang J, Wu T. Vitamin A for preventing acute lower respiratory tract infections in children up to seven years of age. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD006090
[a] E.g., from the Benton Table that is reproduced above, neither the Kerimova, Aleskerova15 paper nor the Southon et al16 are RCTs. Benton is explicit about this, he labels the column ‘Study’. There was possibly a misunderstanding of the sort that would arise if somebody were to read the abstract rather than the full paper.
References for notes
 Kerimova MG, Aleskerova IR. Effect of supplementary intake of vitamins for 6 months on physical and mental work capacity of children beginning school education at the age of 6 years. Vopr Pitan. 1988 Jul-Aug;(4):38-41. Russian.
 Southon S, Wright AJ, Finglas PM, Bailey AL, Loughridge JM, Walker AD. Dietary intake and micronutrient status of adolescents: effect of vitamin and trace element supplementation on indices of status and performance in tests of verbal and non-verbal intelligence. Br J Nutr. 1994 Jun;71(6):897-918.
Food for the Brain Child Survey 2007: The Promotion
Holford Watch looks at the literature review:
Food for the Brain Child Survey 2007: Review Part 1
Food for the Brain Child Survey 2007: Review Part 2
Food for the Brain Child Survey 2007: Review Part 3
Food for the Brain Child Survey 2007: Review Part 4
Food for the Brain Child Survey 2007: Review Part 5
Holford Watch appeals for help to Professor Holford and two members of the Scientific Advisory Board who approved this report and then looks at the data and analyses:
Food for the Brain Child Survey 2007: Review Part 7
Food for the Brain Child Survey 2007: Review Part 8
Why Don’t Food for the Brain Report Their Survey Results on Supplement Pills Survey: Review Part 9
Food for the Brain Child Survey 2007: Review Part 10