Minimal Minimalisation for Minimal Change
Sometimes in General Practice we have to wait years to find out that we helped someone. Once people are well, and given that contacting the doctor isn’t that easy, there are higher priorities than getting in touch so say "I'm feeling fine".
Just the other day an ex-patient of mine stopped me in the street and thanked me for recommending a plant-based diet for her Crohn’s Disease several years previously I had recommended a plant based diet on the basis of a broad range of research about diet and inflammation, and specifically having been particularly impressed with this paper which had shown a near-abolition of relapses with a well-designed Japanese version of a plant-based diet over a 3 year follow up period.
“Oh” I said “did you find that helpful?” “Yes, she replied “it really did help”. Now this was a car-park conversation so we didn’t get into more medical detail, but this chance meeting was fresh in my mind when I saw this headline in my Trusted Medical Reference news feed:
Intrigued, I looked up the new research. It is really important to check that one is on the right track so this could be important new information. Yet I read the paper without being able to discover what the patients in the study had actually been eating. This, in terms of a trial of a drug, would be like reading the paper without knowing what the medicine was, or what doses were given. It is pretty frustrating. Eventually I found what I was looking for in the supplementary data; a breakdown of what the patients were eating in the “minimising meat” group, compared to the “control” group who carried on as usual.
The answer was that there were only very modest differences.
What stood out particularly was that the "low meat" diet did not appear to be higher in vegetables, fruits or whole plant foods, and intake of fibre was the same between the two groups. This is important because it is beleived the benefits of plant-based diets are partly to do with the extra fibre and other plant nutrients that appear in the diet when meat is sensibly replaced with these options. In this study the only differences were in fresh red meat intake (patients in the “minimising meat” group ate about half the quantity of the controls) and processed red meat products (where the “minimisers” ate about a third less).
So, even though the study set out in part to re-test the result of the impressive Japanese study (which was cited), this was simply a trial of a modest reduction in red meat intake with intakes of all other food groups apparently remaining unaltered. It is hardly surprising it had no effect. What is surprising is the idea that this study was worth performing in the first place. Anyone who has spent any time exploring food as a treatment in practice will know that small shifts away from Western dietary patterns only produce measurable effects in very large populations. “Cutting down a bit” on harmful food groups is unlikely to yield noticeable benefits for patients.
But the real harm done by this paper is that due to the way it is presented. Look at the headline. It suggests that the balance of evidence shifts away from the idea that plant-based diets may help many Crohns sufferers. Whilst plant-based whole-food diet is highly unlikely to be the whole solution (yeast may for instance be important for some patients, and some forms of fibre may make symptoms worse), this paper will not alter my feeling that a plant-based diet is well is worth a try for patients in remission with inflammatory bowel disease who are willing to give it a go.