First, thank you for organising such an excellent conference (Secrets of a Healthy Heart, November 1999). For a layman such as myself, the range of expertise and information on the possible causes of atherosclerosis was very impressive. However, there were two omissions which I would have loved the panellists to have discussed: lack of sunlight and excess milk consumption.
Evidence for the role of sunlight in protecting against CHD is contained in a delightful paper by Grimes et al in Q J Med, 1996; 89: 579-89. The paper posits not only that sunlight is important for vitamin D production (a fact long known, of course), but also that, in its absence, the precursor chemical squalene is converted into cholesterol instead. If these researchers are right, the statin drugs used to lower cholesterol levels may also lower vitamin D levels by inhibiting the production of squalene. This cries out for further study. The paper also elegantly brings in the possible roles of microorganisms such as Chlamydia (another of the rare omissions of the conference) and antioxidants.
The hypothesis that adult milk consumption (which has grown radically since WWII) may cause CHD is put forward at some length by Stephen Seeley in The Health Hazards of Milk, edited by David Freed (Bailliere Tindall, 1984). Indeed, several authors in the book make this connection. Seeley uses 1983 data to show that the incidence of CHD in OECD (Organisation of Economic Cooperation and Development) countries is very highly correlated with milk consumption. I have often wondered what happened to this line of enquiry (there have been rumours of strong arm tactics by the dairy industry to prevent further research), so I was pleased to see a recent Lancet item in WDDTY vol 10 no 8, which suggests that it is still alive. David Crowther, Cambridge.....