Visiting Professor Patrick Holford has his own dedicated chapter in Ben Goldacre‘s Bad Science: Chapter 9; pp 161-80. Both HolfordWatch and Holford Myths have commented that the CV which Holford submitted to the University of Teesside is riddled with a remarkable number of errors, several of which involve implausible timelines. Today, an outraged reader has submitted more evidence of confusion about Holford’s understanding of time as well as the evidence-base for chromium supplementation to “to stabilise blood sugar levels”.
To be fair to the correspondent in question, the item was submitted in the hopes of confounding us and maybe reducing us to sobbing heaps of contrition at (the alleged) unfounded criticisms of one of the UK’s leading thinkers and scientists. Had the correspondent taken a few seconds to search this blog then we might never have learned about yet more Holford space-time distortion or his continuing special interpretation of the research literature involving chromium supplements for blood sugar management.
Patrick Holford’s Newsletter 100%health. No 48, November 2008, for which the subtitle should read, I reject your reality and substitute my own, opens as follows.
The reason I founded the Institute for Optimum Nutrition, back in 1984, was that the profession of dietetics was in complete denial about the therapeutic value of vitamins and minerals. At the time it claimed the moral high ground, calling itself ‘evidence based’, but blatantly failed to take into account the growing evidence for the ability of nutrients, above recommended daily allowance (RDA) levels, to prevent and reverse disease. Has anything changed?
Today I was flicking through the latest dietician’s bible, the Manual of Dietetic Practice (printed in 2007), and the answer is ‘no’…
Evidence for the mineral chromium, in amounts above 200mcg (no RDA exists) helping to stablilise blood sugar levels, especially in diabetics, has been growing since the 1980s. But the Manual of Dietetic Practice denies all this – “there is no evidence that chromium supplementation has any beneficial effects on glycaemia”. Last year a systematic review concluded “chromium supplementation significantly improved glycemia among patients with diabetes”. Time for an update. [Emphasis added.]
Where to start. There’s more but there is a limit as to how many canards one blog post can cover.[a] The major point, for which the remainder of this post is an elaboration is that Manual of Dietetic Practice was published June 18 2007 and the systematic review on August 30, 2007 (some 6 weeks later). More importantly, despite Holford’s very selective quotation, the systematic review would not have prompted an update, and even the authors of the review have some rather more nuanced interpretations than Holford implies.
Despite the provocation, we are actually rather more fair-minded than some people credit us. In May, 2008 we commented that Holford had just issued a Special Report on Natural Pain Killers that relied upon a study that shows “conclusively that fish oil supplementation can reduce the inflammation of arthritis”. We criticised Holford for failing to notice that that paper had been retracted and should not therefore have been included in the Special Report. However, we were scrupulous in not criticising Holford and Jerome Burne for including it in the first printings of Food Is Better Medicine Than Drugs.
it is quite extraordinary that Holford, who regularly boasts that he keep up to date with the literature in a dizzying array of specialities, should somehow have missed this. It’s bad enough that he mis-reported matters to the readers of FIBMTD but perhaps understandable, given the timing issues and the publication date (but there should perhaps have been an erratum slip in the later paperback edition or at least an acknowledgement on his website). It is lamentable that he is still disseminating this mis-information in a subscription service. What sort of research quality is this?
Ben Goldacre’s chapter on Holford is a meticulous examination of Holford’s references in Chapter 12 of New Optimum Nutrition Bible. Holford’s shoddy scholarship and low-quality references are not germane to this post but we would like to highlight one of Goldacre’s gracious observations.
[Holford refers] to a study by the great Dr R.K Chandra, a disgraced researcher whose papers have been discredited and retracted, who has been the subject of major articles on research fraud, including one by Dr Richard Smith in the British Medical Journal called ‘Investigating the previous studies of a fraudulent author’. There is an entire three-part investigative documentary series on his worrying career made by Canada’s CBC…[He] did, of course, patent his own multivitamin mixture, which he sells as an ‘evidence-based’ nutrition supplement for the elderly. The ‘evidence’ is largely derived from his own clinical trials.
In the name of scrupulous fairness, I am happy to clarify that much of this has come out since the first edition of Holford’s book, but there had been serious questions about Chandra’s research for some time, and nutrition academics were wary about citing it, simply because his findings seems to be so incredibly positive. In 2002 he had resigned his university post and failed to answer questions about his papers or to produce his data when challenged by his employers. The paper than Patrick Holford is referring to was finally fully retracted in 2005… [pg 167, Ben Goldacre, Bad Science; emphasis added.]
There are other examples where various commenters have been remarkably fair in giving Holford the benefit of the doubt when he overlooks retracted papers, or fails to provide updates etc. because of the acknowledged time lag between submitting a book manuscript, having it printed and distributed.[b]
You may need to refer to the quotation from Holford’s November 2008 newsletter again. Note the criticism that the “Manual of Dietetic Practice (printed in 2007)” fails to acknowledge the systematic review of chromium that was published “last year”. The publication dates for Manual of Dietetic Practice were: USA, Jul 2007; Rest of World, Jun 2007; Australia, Aug 2007. That systematic review was published August 30, 2007.
Your mileage may vary, but, under the circumstances, and assuming the authors are living in the same space-time continuum as the rest of us (bar Holford), it might seem a little unfair to expect them to include this reference, particularly when it is far from clear that the reference merits an update to the reference work.
We have repeatedly argued that there is too little good quality clinical research to justify the commercial recommendation of chromium supplementation for blood sugar management or diabetes. The studies and their results are too variable in quality to allow a definitive conclusion but the research findings show that there is no clear evidence to support chromium supplementation for diabetics: there is no ready support for the notion that chromium has an role in ‘stabilising blood sugar’ levels.
A number of researchers have investigated whether chromium supplementation has a beneficial effect for glucose or lipid metabolism: most of these studies or trials have involved people with Type 2 diabetes. Holford makes a rather selective quotation from Balk et al’s A systematic review of the relevant randomised controlled chromium supplementation trials We can quote from that paper as well, and the authors conclude that:
[n]o significant effect of chromium on lipid or glucose metabolism was found in people without diabetes.
The authors do add that:
[t]he evidence was limited by poor study quality, heterogeneity in methodology and results, and a lack of consensus on assessment of chromium status.
There was some interesting correspondence that followed-up the review by Balk et al. but Holford doesn’t seem to be interested in this.
Kleefstra et al commented on the inclusion of a study that involved a large number of people in China . The study in China skewed the results substantially because of the relatively large number of people in the trial when compared to other trials that were included. The disproportionate numbers of participants influenced the apparent effect size for chromium. Holford has repeatedly assigned undue significance to this study in his case for chromium although it is deprecated by a number of researchers for reasons that are mostly understood and accepted.
Kleefstra et al discuss the apparent consistency in various studies and argue that it may be more productive to look at outcomes for different groups rather than all diabetics. They highlight apparent differences between:
Western and non-Western patients, as it seems that the beneficial effects on A1C are for the most part found in studies in non-Western countries.
(A1C is the test that gives a longer-term, better insight into blood sugar control than the snapshot of the fasting blood glucose test.) Kleefstra et al argued that
chromium has no (relevant) effect on A1C, especially not in Western patients with type 2 diabetes.
Consequently, they expressed the belief that future trials should concentrate on assessing the impact of chromium supplementation on those who are known to be chromium deficient rather than all diabetics. They acknowledged the lack of consensus for a test to establish chromium deficiency.
A subanalysis of the chromium picolinate trials excluding Anderson et al. , because of its quality and its large effect, produced a smaller, though still statistically significant, summary estimate of the effect of chromium supplementation on A1C (–0.3% [95% CI –0.5 to –0.1]). However, such an approach toward meta-analysis is arguably arbitrary.
They restate their position that, “available trials on chromium supplementation are of poor quality and have heterogeneous results” which is not a good reason for including them. They go on to acknowledge again that:
[t]he overall poor quality of the evidence clearly limits any conclusions that are drawn about the effect of chromium supplementation.
They conclude by agreeing that there is a need for a consistent and reliable test to establish a individual’s chromium status and that:
well-conducted trials in clearly defined populations (preferably with an indicator of chromium status) are needed before definitive conclusions can be made about the value of chromium supplementation.
The discussion about the need to identify those with low chromium status before running any more trials of chromium supplementation if people with diabetes continues. Wang et al have been attempting to identify a practical, readily available tool[c] that would allow researchers to identify patients who might be responsive to chromium supplementation and those who are non-responders. Kleefstra et al have questioned the need to perform more chromium supplementation trials in the absence of a usable research tool to predict response.
We fully agree that it is important to be able to have some kind of parameter by which you can select patients who have a low chromium status, as there are no possibilities yet to define someone as chromium deficient . This would indeed be more appropriate than performing more and more randomized controlled trials in unselected patients in whom it seems that, in most high-quality trials, there were no beneficial effects . [Reference nos. altered to accord with those we give.]
There is considerable dispute about the efficacy and appropriateness of chromium supplementation for the general population of diabetics. Although Holford has a commercial interest in the matter, there is no consensus or groundswell of support for Holford’s optimism that:
chromium has been shown to dramatically decrease the need for medication in many diabetics and in some cases eliminate the need for drugs completely.
This extravagant claim is made under the heading: Chromium as an alternative to diabetic drugs. The reference for this claim is Rabinovitz et al who reported a small study of elderly people with Type II diabetes in rehabilitation following a stroke or hip fracture. It is only a 3 week study, and it involves a 1500 Kcal diet which might itself have an impact on blood glucose levels for this pool of participants. (We have commented previously on the studies that Holford cites to support the case for chromium supplementation.)
It is self-evident that Holford’s overview of the clinical evidence does not support the use of chromium to modify glucose metabolism in people without diabetes; more generally, as from Balk et al’s recent review and the subsequent discussion, the studies in this area are notoriously poor and may compromise their usefulness for any population that is considering supplemental chromium for the regulation of blood sugar management.
It is worthwhile mentioning that these trials involve different forms of chromium which may have a different bio-availability than the chromium polynicotinate in Holford’s formulation. Chromium polynicotinate has been the subject of even less research than other forms (we comment further on the quality of research on chromium elsewhere).
We appeal to Patrick Holford to update his assertions about chromium and its role in the management of blood sugar levels and diabetes. We see no strong reason as yet to second his self-serving advice on the matter of updates to the editors and authors of the Manual of Dietetic Practice.
We do not consider Holford to be a trustworthy source of advice on who needs to update their research monitoring or summaries, so it is not as if this episode has altered our opinion of him. He has not altered our relative appraisal of his own knowledge versus that of qualified dietitians. However, these remarks in his newsletter show a lack of generosity of spirit and it reinforces a sense of carelessness about rigorous research and a lack of regard for his (paying) audience. It also, like the CV that he submitted to Teesside University, emphasises a certain playful spirit about dates that suit his narrative.
Instead of “flicking through the latest dietician’s bible, the Manual of Dietetic Practice“, Holford should read it properly: there is a lot that he might learn about nutrition, appropriate standards of clinical evidence, accuracy and scholarship.
Nov 24: include refs 5 and 6 and material related to them.
[a] Perhaps when some dietitians recover from the homeric laughter provoked at Holford’s self-serving explanation for setting up his business and electing to teach students a discipline in which he lacks any qualifications, they may be kind enough to comment. I would also welcome anyone who would like to drop along with some of the fabulous history about the work of McCance and Widdowson, the sadly neglected Dame Harriette Chick or any other of the outstanding researchers that made the UK so respected for dietetic research in the twentieth century. I see no reason to accept Holford’s characterisation of that period.
[b] Many readers will be familiar with the brouhaha concerning Holford’s unwise assertions about the relative merits of AZT and Vitamin C in the treatment of Aids. As Ben Goldacre points out, Holford has published his correction on this matter in the chapter notes of his book, not in the main text.
Professor Holford did not change the main text in the book chapter. He added some text to the note at the back, in a small font, referencing some other papers where people did actually, at least, tip both AZT and vitamin C onto cells in a dish…To be fair, [Holford] did however once deliver my favourite line from five years of writing in this area: ‘Perhaps Goldacre, who purports to be the campaigner for evidence-based medicine, could provide some evidence that high-dose vitamin C has no effect against HIV AIDS.’ [pg. 332, Bad Science]
[c] Insulin clamp procedures are not run of the mill in standard, outpatient care for people with diabetes.
 Balk EM, Tatsioni A, Lichtenstein AH, Lau J, Pittas AG. Effect of chromium supplementation on glucose metabolism and lipids: a systematic review of randomized controlled trials. Diabetes Care. 2007 Aug;30(8):2154-63.
 Kleefstra N, Houweling ST, Bilo HJ Effect of chromium supplementation on glucose metabolism and lipids: a systematic review of randomized controlled trials. (Letter) Diabetes Care. 2007 Sep;30(9):e102.
 Anderson RA, Cheng N, Bryden NA, Polansky MM, Cheng N, Chi J, Feng J. Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes. Diabetes. 1997 Nov;46(11):1786-91.
 Balk E, Lichtenstein A, Pittas AG. Effect of chromium supplementation on glucose metabolism and lipids: a systematic review of randomized controlled trials. (Authors’ Response) Diabetes Care 2007 Sep 30(9):e103.
 Wang ZQ, Qin J, Martin J, Zhang XH, Sereda O, Anderson RA, Pinsonat P, Cefalu WT. Phenotype of subjects with type 2 diabetes mellitus may determine clinical response to chromium supplementation. Metabolism 2007;56:1652-5.
 Kleefstra N, Houweling ST, Groenier KH, Bilo HJ. Author reply: phenotype of subjects with type 2 diabetes mellitus may determine clinical response to chromium supplementation. Metabolism. 2008 Nov;57(11):1623-4.
 Rabinovitz H, Friedensohn A, Leibovitz A, Gabay G, Rocas C, Habot B: Effect of chromium supplementation on blood glucose and lipid levels in type 2 diabetes mellitus elderly patients. Int J Vitam Nutr Res. 2004;74:178–182.