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 many decades. However, arterial stiffening can be seen even in children who are obese, and aortic fatty streaks are visible in some teenagers and young adults.1 Yet, most cardiovascular events do not manifest until after the age of 60 years. The general perception is thus of a slow process that will therefore only reverse slowly, if at all. However, this perception is wrong. Extensive empirical and trial evidence reveals that substantial reductions in mortality can occur within months of quitting smoking, or making healthy dietary changes. These reductions apply to both individuals and to entire populations. In one American hospital, admissions for acute coronary syndromes decreased by 40% within 6 months of the introduction of local smoke free legislation.2 When the law was rescinded, coronary admissions rapidly returned to previous levels. The introduction of smoke-free legislation in Scotland in 2006 was soon followed by a 6% decrease in out of hospital cardiac deaths and a 17% decrease in hospital admissions within a year.3Even 30 min of secondhand smoke exposure has been proven to increase platelet activity and hence elevate cardiovascular risk.4
Similarly, changes in diet can rapidly improve outcomes of cardiovascular disease (CVD), as demonstrated by several randomised trials. In the DART trial, 2033 survivors of myocardial infarction who were advised to eat fatty fish had a significant 29% reduction in all-cause mortality compared with control patients, with survival curves separating within months. Likewise, in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarcto Miocardico (GISSI)-Prevention trial, 1 g of Ω-3 fatty acids significantly reduced all-cause mortality and cardiovascular mortality in 11 324 myocardial infarction survivors. Moreover, survival curves separated early, with a significant reduction in total mortality after just 3 months of treatment (p=0.037).5
The PREvencion con DIeta MEDiterranea (PREDIMED) primary prevention randomised controlled trial found that an energy unrestricted diet supplemented with extra virgin olive oil or nuts achieved an impressive 30% reduction in major cardiovascular events (NNT=61) in over 7500 high risk individuals initially free of CVD. This reduction occurred within 3 months.6 Furthermore, this solid RCT evidence builds on a wealth of existing data from observational, cohort and secondary prevention intervention studies.7 ,8 It also provides further strong causal evidence that simple diet interventions can rapidly and powerfully reduce CVD outcomes. In comparison with an American Heart Association recommended ‘low fat’ diet, a Mediterranean diet post myocardial infarction is a more powerful coronary intervention tool for mortality than aspirin, statins, or coronary stents, but without any significant difference in total cholesterol, triglycerides or HDL between the two groups.9 It is the abundant α-linoleic acid, polyphenols and Ω-3 fatty acids found in nuts, olive oil, oily fish and vegetables, that rapidly exert positive health effects by attenuating inflammation, atherosclerosis and thrombosis.10 Conversely, the consumption of trans-fats commonly found in fast food can rapidly increase C reactive protein and other inflammatory markers within weeks.11
Strategies that prevent excessive weight gain in children and adults through curbing the consumption of the amounts of unhealthful foods should also be welcomed. However, simply focusing on weight loss in obese subjects misses a key finding from analysis of PREDIMED subgroups: dietary intervention achieved consistently large reductions in CVD risk irrespective of weight. Furthermore, weight loss interventions are rarely sustained. The weight loss industry, which emphasises calorie restriction over good nutrition, generates $58 billion in revenue annually in the USA, even though long-term follow-up studies reveal that the majority of individuals regain virtually all of the weight that was lost during treatment irrespective of whether they maintain their diet or exercise programme.12 Shifting focus away from calories and emphasising a dietary pattern that focuses on food quality rather than quantity will help to rapidly reduce obesity, related diseases and cardiovascular risk.13 ,14 Rapid weight loss and regain that can occur from fad dieting is actually detrimental to health. Such ‘weight cycling’ contributes to hypertension, insulin resistance and dyslipidaemia resulting in increased mortality risk and worse cardiovascular outcomes.15 The look AHEAD (Action for Health in Diabetes) trial found no reduction in the composite endpoint (ie, death from cardiovascular causes, non-fatal myocardial infarction, non-fatal stroke, or hospitalisation for angina) with a low calorie diet (on top of increased physical activity) in patients with type 2 diabetes despite a maximum follow-up of 13.5 years and despite significant weight loss in the intervention group.
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