Holford claims a study shows his recommendations reduce Alzheimer’s risk

We were interested to see Holford’s blog trumpeting a new study by Yian Bu et al, on Alzheimer Disease and dietary patterns: claiming that the study shows that “Holford diet reduces Alzheimer’s risk”. Holford’s blog argues that the
study

findings are completely consistent with out recent 100% Health Survey and the diet I recommend in the Alzheimers Prevention Plan book.

These principles are also incorporated into the Holford Diet which also factors in eating a low GL diet. In our 100% Health survey we found that the consumption of sugar-based snacks and sugar were strongly associated with worsening memory and concentration. All the other findings in this recent study, soon to be published in the Archives of Neurology (Arch Neurol. 2010;67[6]), are completely consistent with our survey results.

However, the study states that

We identified a DP [dietary pattern] strongly associated with lower AD risk: compared with subjects in the lowest tertile of adherence to this pattern, the AD hazard ratio (95% confidence interval) for subjects in the highest DP tertile was 0.62 (0.43-0.89) after multivariable adjustment (P for trend = .01). This DP was characterized by higher intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables and a lower intake of high-fat dairy products, red meat, organ meat, and butter.

This seems rather close to the advice of mainstream organisations such as the BDA (or to my Gran’s advice to ‘eat your greens’). As far as I can tell, the study doesn’t consider the benefits (or disbenefits) of a low glycaemic load diet. It certainly doesn’t show that Holford’s supplement recommendations are effective: instead, “nutrient intakes from foods and from supplements were separately estimated, and only the nutrient intake from foods was used in the RRR analysis.”

Certainly, we have no objection to some of Holford’s recommendations: for example, eating lots of green veg seems perfectly sensible. However, these good recommendations are not at all original and we have not seen any convincing evidence that his more novel recommendations are any good.

Holford: “Research has shown that women in particular tend to put on 7 pounds a year”

In the holiday season, people often worry about weight gain. I’m not sure that things quite add up with Holford’s blog’s contribution to the discussion, though. A contributor has blogged that

Research has shown that women in particular tend to put on 7 pounds a year. This steady weight gain is often linked to the excesses of the festive season, which are not discontinued come January, so more weight piles on year after year.

Assuming that a women starts out at 150lb at 18, a steady weight gain of 7lb/year would mean that she reached 500lb by her 68th birthday. This type of sustained weight gain is – clearly – unusual. While I am not sure on what research ‘has shown’ this level of weight gain, I suspect that things may be rather more complicated than the blog post suggests.

Holford Diet site’s interesting take on Cochrane Review

Holford has had varied engagements with Cochrane Reviews, so we were interested to see the Holford Diet site – which promotes a low glycaemic load (LGL) diet plus supplements – celebrating one Review’s alleged finding that

a low GL diet is more effective than any other diet for weight loss and improving overall health…’Overweight or obese people lost more weight on a low Glycemic Load diet and had more improvements in lipid profiles than those receiving conventional diets.’

However, on looking at the Review itself we noted that it did not distinguish between LGL and low glycaemic index (LGI) diets. This was a review of

Randomised controlled trials comparing a low glycaemic index or load diet (LGI) with a higher glycaemic index or load diet or other diet (Cdiet) in overweight or obese people.

The review found some evidence that LGI and LGL diets can be especially beneficial, but did not aim to find whether an LGI or LGL diet was best. Given that this was a review of only six trials involving only 202 participants, this seems a sensible decision.

While it is nice to see a Holford site referring to such good quality sources, it is a shame that the Review could not have been reported more accurately.