Holford Watch: Patrick Holford, nutritionism and bad science

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). This is the second of three Holford Watch posts in which we 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. Part 1 discussed the claims relating to supplements and children’s diet. Part 2 examines the claims made for the benefit of a balanced glycaemic load diet for children.

A brief summary of the detail for Part 2. Holford and Fobbester refer to the truism that children’s nutrition affects their learning and behaviour. The FFTB authors draw our attention to studies that involve children with clinical disorders or do not address the topic (e.g., the references for the glycaemic load (GL) assertions do not discuss glycaemic load); the results or observations from such studies may not be generalisable to a wider population. Unless the references have more relevance than is immediately apparent, this looks like a list of assertions for which the authors feel the truthiness, and attempt to create the necessary scienciness through referenciness.

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.

Holford Watch has heard a surprising rumour that this report is being proposed as the scientific foundation for a project to validate a ‘psychonutrimetric’ questionnaire. After Holford Watch has finished publishing this multi-part exploration of the report, including the data and statistical analyses, it should be readily apparent that this report can not serve as the scientific foundation or justification for a diagnostic or descriptive tool. We shall update this section when we learn whether or not there is truth to this rumour.

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^[1]
• 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^[2] 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^[10]

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.]

If any other brace of authors were to introduce the concept of “a diet with a balanced glycemic load” and then refer to three papers, none of which explicitly refers to GL, Holford Watch might be surprised rather than resigned. However, none of these papers addresses the issue of a ‘balanced GL diet’ and children.

Haapalahti et al⁵ is a study of the food habits in 10-11-year-old children with functional gastrointestinal disorders (FGID) in a rural town in Finland. The authors administered and collated a food frequency questionnaire, GI-symptoms questionnaire and the Child Behaviour Check List (CBCL), all of which were filled in by parents together with their child. The authors asked for a 24-h dietary recall and anthropometric measurements (e.g., height and weight) and a blood test. There were 49 children with FGID and 78 children in the control group.

The authors report that children with FGID (primarily a disorder that is attributed to psychosocial factors) were less likely to have a daily family dinner or to eat vegetables and fruit than children in the control group. Children with FGID had a higher sucrose intake and lower lactose intake that the control group. As might be expected for children with a psychosocial disorder that manifests in gastrointestinal distress, the children with FGID had higher total problem scores in CBCL and the behavioural/emotional problems associated with FGID. The results were significant albeit not compelling with low reported odds ratios. This was an observational report; there is no suggestion that this reflects behaviour modification through dietary modification or that these findings are applicable to a wider population of children without FGID.

Haapalahti et al conclude the following (note the absence of any reference to GL or any suggestion that this is relevant to a wider population of children than those with FGID):

[t]his population-based study suggests that school-aged children with FGIDs have less-organized food habits and higher milk avoidance, and they display internalizing psychological characteristics.

Children who have been diagnosed with a psychosocial disorder that manifests in gastrointestinal symptoms display emotional differences and some differences of food habits when compared to children without that diagnosis. The nearest that the FFTB report has to offer is the question about symptoms of “belly aches, bloating or flatulence”; these symptoms might have several plausible aetiologies other than FGID and the FFTB report shows a reported incidence of 16% of the children experience these ‘frequently’ or ‘always’. It is difficult to understand why this is relevant to this FFTB study that does not include specific data about FGID or similar psychosocial disorders.

Holford and Fobbester presumably referenced Haapalahti et al to support their assertions but this paper does not provide explicit support for those assertions.

Benton⁶ is a short review that emphasises the importance of breakfast consumption and its impact on later mood and performance. Benton reports that eating breakfast is associated with improved mood, particularly when it provides high blood sugar later in the morning. Benton does not explicitly discuss GL. He does report a (then) unpublished) study which found that:

[e]ating a larger breakfast was associated with poorer mood late in the morning; eating a snack reversed this.

References to ‘high blood sugar’ do not lend necessarily lend support to the notion of a ‘balanced GL diet’. Benton does say that:

[i]mproved glycemic control is associated with improvements in cognition.

However, Benton is explictly referring to elderly patients with diabetes in that context;¹¹ it is not a discussion of GL diets. The Benton reference might be contorted into lending lip-service support to the notion of eating at regular intervals but there is no reference to the types of food involved: ironically, given the assertions it is introduced to support, Benton spends some time discussing the impact of a glucose drink on cognitive function in young adults.

[T]hose with a low initial level of blood glucose, and only slowly increasing levels of blood glucose, had a poorer memory than individuals whose blood glucose levels increased rapidly after consuming a glucose-containing drink. It appears that individual differences in glucose tolerance are important. This series of studies can be explained by the known equilibrium that develops between plasma and brain glucose. Those with higher levels of blood glucose develop higher levels of brain glucose…A limited supply of glucose can be overcome if your physiology allows the rapid transport of glucose from the gut to the blood stream. [pg. S20.]

There is a need for future research to elaborate the impact of carbohydrate on mood in groups of people who have been identified for their pre-existing psychological and physiological functioning. There are limited data on the topic of carbohydrate snacks to improve blood glucose availability and improve both mood and mental performance; however, few of these studies distinguish low or high GL carbohydrates or the GL of a meal. The only (weak) support that this review offers is the standard closing:

[w]e should further consider the possibility that the nature and schedule of meals may influence the cognitive functioning of sections of the population. [pg. S21]

Holford and Fobbester presumably referenced Benton to support their assertions but this paper does not provide explicit support for those assertions.

Lien et al⁷ is an observational study that analysed data about the consumption of soft drinks and the incidence of hyperactivity, mental distress and conduct problems in adolescents in Norway. This paper does not describe a trial in which the authors experimented with the administration of soft drinks and recorded the outcome. Lien et al report correlations only; they do not claim causation. There is no explicit indication that if some of the more distressed or aggressive adolescents were to reduce their consumption of soft drinks that this would change these observations. At present, this paper provides an interesting correlation but no indication of causation.

The highest adjusted odds ratios were observed for conduct problems among boys and girls who consumed 4 or more glasses of sugar-containing soft drinks per day.

Conclusions. High consumption levels of sugar-containing soft drinks were associated with mental health problems among adolescents even after adjustment for possible confounders.

Holford and Fobbester presumably referenced Lien et al to support their assertions but this paper does not provide explicit support for those assertions.

Holford Watch does not consider that Holford and Fobbester have made their case with this literature overview; in Parts 1 and 2, the references are mostly irrelevant or refer to such a specialised population that the results should not be readily generalised to a wider population of schoolchildren. To reiterate our position, this report should not be promoted as the scientific foundation or justification for a diagnostic or descriptive tool based on its contents or findings, far less the basis for a change in public policy. So far, the reports reads more like an impressionistic argument based on your grandmother’s aphorisms relating to eating breakfast and eating regularly. The reader does not have the strong impression that this report is objective, verifiable or the result of a rigorously-conducted research process.

Review Part 3 examines the report’s claims for chemical and food sensitivities with particular reference to gluten sensitivity.

References

[1] Benton D, Micro-nutrient supplementation and the intelligence of children. Neurosci Biobehav Rev. 2001 Jun;25(4):297-309.
[2] Richardson AJ, Long-chain polyunsaturated fatty acids in childhood developmental and psychiatric disorders. Lipids. 2004 Dec;39(12):1215-22.
[3] 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.]
[4] 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.
[5] 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.
[6] 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
[7] 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.
[8] 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.
[9] 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.
[10] 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.
[11] Meneilly GS, Cheung E, Tessier D, Yakura C, Tuokko H. The effect of improved glycemic control on cognitive functions in the elderly patient with diabetes. J Gerontol. 1993 Jul;48(4):M117-21.

Further Reading

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