Holford Watch: Patrick Holford, nutritionism and bad science

The Times had an article today on Food for Thought. Lots of decent stuff here: they quote a proper dietitian and everything. Sadly, though, they also use Holford as an expert commentator. Fay Schopen writes that:

Patrick Holford, the author of several books on nutrition and a visiting professor at the University of Teesside, says that there is good evidence for some supplements, especially omega-3. “It’s hard to do a randomised mackerel trial,” he points out, but he says that six studies have suggested that omega-3 supplements are effective in reducing depression, details of which can be found on his Food for the Brain website. “There’s an ever-increasing incidence of mental health problems in the workplace,” he says, pointing to stress, anxiety, depression, insomnia and memory decline. “Our world has speeded up immensely with the internet and e-mails, and we have to process much more information, I believe part of the reason for mental health problems is that we need much better nutrition.”

On the plus side, hopefully this means that The Times have realised that calling Holford a ‘nutritionist’ does not mean much. However, I’m still not sure that “the author of several books on nutrition” is a good descriptor for Holford: given the significant amounts of money he has made from the supplement industry, perhaps something like ‘nutritional entrepeneur’ would be more fitting.

Of course, if Holford provided good quality evidence for his claims, I wouldn’t particularly mind about his competing financial interests. Sadly, he doesn’t. Holford states that “six studies have suggested that omega-3 supplements are effective in reducing depression, details of which can be found on his Food for the Brain website”. Sounds fair enough - and, of course, in a quality paper like The Times a journalist would always check this type of thing, right? They would, wouldn’t they…?

Well, apparently not. Being picky about these things, I looked at ‘the evidence‘ on the Food for the Brain (FFTB) website. It listed twenty studies. Sounds good, doesn’t it - even better than the six Holford mentioned. Well, it would be good - except only two of these twenty studies focus on omega 3 fats and depression. One might also note that one of these studies focuses on bipolar depression - and results therefore may not map well across to typical depression.

Here’s one of the two articles that does focus on omega 3s and depression - Frangou et al’s Efficacy of ethyl-eicosapentaenoic acid in bipolar depression: randomised double-blind placebo-controlled study. FFTB did thus manage to pick out a somewhat relevent article that does indicate a statistically significant benefit from omega 3s in depression (though it does not show a benefit of more than 1g of EPA per day).

However, the article is a relatively small trial (only 75 participants, nine of whom did not complete the trial). The article is pretty explicit about its own limitations, too:

# This small study only assessed short-term efficacy and tolerability of ethyl-EPA treatment in bipolar disorders; its value in long-term treatment is unknown.
# This study only assessed the efficacy and tolerability of ethyl-EPA as adjunctive treatment in bipolar disorder; its value as monotherapy is unknown.
# This study did not assess the efficacy of ethyl-EPA in severe bipolar depression.

This is an interesting study, but one cannot use it to conclude that “omega-3 supplements are effective in reducing depression”.

The Drugs review of the evidence on Omega-3 fatty acids in the treatment of psychiatric disorders comes to a broader conclusion, but is still far from definitive: this review states that:

The evidence to date supports the adjunctive use of omega-3 fatty acids in the management of treatment unresponsive depression…However, as the clinical research evidence is preliminary, large, and definitive randomised controlled trials similar to those required for the licensing of any new pharmacological treatment are needed.

In other words, there is some promising evidence and - given that including some omega 3 fats in your diet is likely to have other health benefits - they are worth a try. However, more substantial trials are needed.

I could look over some more of the studies and reviews that provide evidence for and against the efficacy of omega 3 fats for depression - however, I’m inclined to think that we at Holford Watch should not do Holford’s (or The Times’) homework. If Holford wants to learn about the evidence for/against omega 3 fats for depression, he should read the evidence himself; it would be nice if he could upload a literature review to the FFTB site, too.

The point to take away here is that - speaking to The Times - Holford claimed that the FFTB site had details of 6 trials to prove his point re. omega 3 and depression. However, it actually listed only two trials that support (but certainly do not prove) Holford’s point. Holford got his ‘evidence’ wrong, and The Times did not spot this prior to publication.

To make matters worse, while Holford may joke about how “It’s hard to do a randomised mackerel trial”, it is actually perfectly straightforward to do a randomised, double-blind placebo-controlled trial of fish oil pills. FFTB could have done this in their ’schools projects’, but for some reason they chose not to. Here at Holford Watch, we much prefer eating fish to taking pills - but given that Holford favours fish oil pills, he has no excuse to complain about the difficulties of doing a randomised trial of such pills. I am not sure why The Times let this statement pass unchallenged.

Especially given that The Times published Simon Crompton’s excellent review of Holford’s Food is Better Medicine than Drugs last year, I can’t get my head around why they managed to make so many mistakes this time. Maybe the problem is that they haven’t been eating enough brain-boosting omega 3 fats. I think we ought to be told! In fact, to be safe, I think it’s imperative to drop several tonnes of kippers on The Times’ offices as soon as possible - for God’s sake, won’t someone please think of the children!

FFTB papers cited as ‘the evidence’

If you’ve got some time to kill - and to make clear that I’m not misrepresenting FFTB - I may as well end by listing all the papers that FFTB cite as ‘the evidence’ (the results of my search for ‘omega and depression’). Let me know if you see anything interesting…

1. A. Richardson & B. Puri, ‘Essential fats reduce ADHD-related symptoms in children with specific learning difficulties.’ Prog Neuropsychopharmacol Biol Psychiatry, 26(2), 233-9, 2002
2. B.M. van Gelder et al, ‘Higher intakes of fish oil from diet associated with slower rates of cognitive decline in elderly men.’ Am J Clin Nutr, 85(4):1142-47, 2007
3. Coppen & Bailey, ‘Supplementation with folic acid enhances effect of antidepressant medication’ J Affect Disord, 60(2):121-30, 2000
4. Davidson et al, ‘Chromium improves atypical depression’ Biol Psychiatry, 53(3):261-4, 2003
5. Dietary intake of omega-3 fatty acids and weekly consumption of fish may reduce the risk of Alzheimer’s Disease. Morris, Arch Neurol., 60(7):940-6, 2003
6. Emsley, ‘Omega-3 fatty acid EPA helps schizophrenia symptoms’ Am J Psychiatry, 159(9):1596-8, 2002
7. Frangou, ‘Omega-3 fatty acid EPA improves depression in people with bipolar alongside their existing medication’ Br J Psychiatry. 188:46-50, 2006
8. Godfrey P et al, ‘Folic acid improves recovery in major depression and schizophrenia’ Lancet, 336(8712):392-5, 1990
9. J. G. Bell et al, ‘An autistic patient has abnormal red blood cell fatty acid composition compared to control subjects.’ Prostaglandins Leukot Essent Fatty Acids, 63(1-2), 21-5, 2000
10. Joy C et al, ‘Cochrane Review of essential fatty acids for schizophrenia inconclusive but recommends more research needed’ Cochrane Database Syst Rev. 19;3:CD001257 Jul 2006

1. L J Stevens et al, ‘Essential fat levels lower in boys with ADHD compared to ‘healthy’ controls.’ Am J Clin Nutr, 62(4), 761-8, 1995
2. M H Jorgenson et al, ‘Fish-eating mothers’ milk highest in DHA. High DHA in breast milk may improve infants vision’ J Pediatr Gastroenterol Nutr.32(3):293-6, 2001
3. M. Morris et al. ‘Consumption of fish and n-3 fatty acids and risk of incident Alzheimer disease.’ Arch Neurol, vol 60, pp. 940-946 (2003)
4. M.A. Beydoun, ‘Elderly people with the highest blood levels of omega-3 fatty acids had the least decline in verbal fluency’. American Journal of Clinical Nutrition, 85(4), 1103-1111 2007
5. N. Sinn, ‘Supplementation of fatty acids improved ADHD symptoms in children aged 7 to 12 years.’ J Dev Behav Pediatr. 28(2):82-91, 2007
6. Peet & Stokes, ‘A review of the current evidence (2005) suggests that essential fatty acids, particularly EPA and DHA may benefit a variety of mental health conditions’ Drugs, 65(8):1051-9, 2005
7. Richardson & Montgomery, ‘Supplements of omega-3 and omega-6 improve reading, spelling and behaviour in children ages 5-12 years with Developmental Coordination Disorder’ Pediatrics, 115(5):1360-6, 2005
8. S Vancassel et al, ‘Autistic children show possible imbalance of fatty acids.’ Prostaglandins Leukot Essent Fatty Acids 65(1), 1-7, 2001
9. Taylor et al, ‘Review of research suggests folate may be effective for depression’ J Psychopharmacol., 18(2):251-6, 2004
10. Vahdat Shariatpanaahi et al, ‘Low Iron may contribute to depression in women who are not anaemic.’ European Journal of Clinical Nutrition, 61; 532-535 2007