Can dietary changes rapidly decrease cardiovascular mortality rates?

Abstract

The UK National Institute for Health and Clinical Excellence (NICE) recently published guidance on the prevention of cardiovascular disease (CVD) in whole populations.1 The lukewarm government response demonstrated a surprising ignorance of the scale and rapidity of the potential benefits. Most heart attacks and ischaemic strokes are caused by complicated atheroma, usually compounded by thrombosis suddenly reducing blood flow in a critical artery. Extensive evidence suggests that this atheroma silently builds up over decades. Thus, early atheroma streaks were seen in classical autopsy studies on Korean war casualties and teenage traffic fatalities.2 Hence, the emerging paradigm describing the temporal relationship between risk factor change and the corresponding change in CVD mortality. The time scales for this paradigm are generally perceived in terms of decades. Thus, Rose thought the ‘incubation period’ was a decade or more,3 whereas Law et al .4 proposed a three-decade lag time to explain the paradoxically low French CVD rates. Reversing the CVD process following reductions in major cardiovascular risk factors has therefore also been assumed to require decades. However, this is wrong. ### Evidence from clinical trials Evidence in individuals and in populations actually suggests that decreases in fatal and non-fatal CVD events can rapidly follow reductions in risk. Thus, individual patients in therapeutic randomized trials often demonstrate mortality reductions within 1 or 2 years of blood pressure or cholesterol lowering.5 Trials in diet and lifestyle interventions also demonstrate rapid and substantial changes in multiple risk factors, notably DASH, DASH-Sodium, OMNI-Heart, and PREMIER. Even more importantly, several randomized controlled trials showed that diet interventions could have relatively rapid effects on CVD outcomes.6 The rapid reduction in diabetes incidence achieved with lifestyle interventions is also relevant, meaning subsequent reductions in costly diabetic care, as well …