Academics and health professionals gathered at the launch conference in London on 27th February 2019 to hear findings of a new Task Force report from the British Nutrition Foundation (BNF), entitled Cardiovascular Disease: Diet, Nutrition and Emerging Rask Factors: 2nd Edition. The Task Force report summarises emerging scientific evidence for the links between diet and lifestyle and risk factors for cardiovascular disease (CVD), and describes some of the changes in scientific thinking since the publication of the first edition in 2005.
CVD mortality rates have been falling in the UK for decades but heart disease remains one of the leading causes of death. In the UK, it is responsible for one death around every eight minutes. There are a number of treatments (such as lipid lowering agents, aspirin, ACE-inhibitors, beta blockers and other anti-hypertensive drugs) now available which have helped to reduce CVD mortality rates – in 2013 more than 307 million prescriptions were dispensed for CVD in England alone, which is six times higher than in 1981 – but CVD related morbidity remains high and could even be rising in older age groups.
Delegates at the BNF conference – Nutrition & CVD, the Heart of the Matter – heard that, although there is both an inherited and an environmental component to CVD risk, interactions between an individual’s psychosocial and physical environment and their unique genetic make-up are now known to play an important role in nearly all CVD conditions and underlying biological processes.
Professor Keith Frayn Emeritus Professor of Human Metabolism, University of Oxford and Chair of the Task Force opened the Conference by describing the remit of the Task Force. He said: “Conventional lifestyle-related risk factors for CVD include smoking, raised cholesterol, especially LDL cholesterol, raised blood pressure, lack of physical activity, obesity and diabetes. However, these ‘classical’ risk factors cannot fully explain differences in CVD risk and emerging evidence suggests that other novel risk factors may play an important role.”
Experts involved in the Task Force presented on the newer and more emerging risk factors highlighted in the Task Force report including foetal development, gut microbiome, inflammation and sedentary behaviour.
The Task Force report highlights that accumulating research has shown a link between restricted foetal growth, resulting in lower birthweight, and CVD, hypertension and type 2 diabetes in adulthood. These adverse effects of low birthweight are multiplied in people who cross the BMI centiles upwards (i.e. gain excess weight) during mid-late childhood or adolescence. The risks of adult CVD and type 2 diabetes are also greater in children with high birthweight caused by maternal gestational diabetes or obesity. The clear association between birthweight and adult disease led to the Developmental Origins of Health and Disease (DOHaD) hypothesis, which proposes that environmental disturbances such as under or overnutrition during critical periods of early development may cause permanent metabolic and structural changes, which can lead to disease like CVD in later life. The mechanisms for developmental programming are now thought to include tissue remodelling due to inadequate nutrients during critical periods of organogenesis, and epigenetic changes, which may occur very early in gestation.
Professor Caroline Fall, Professor of International Paediatric Epidemiology within Medicine, University of Southampton said: “Cohort studies have shown that adult risk factors like smoking and obesity add to, or even multiply, the effects of adverse early life exposures. But this evidence also suggests that people who are at risk because of poor intrauterine nutrition can lower their risk of CVD by maintaining a healthy body weight and avoiding smoking in adult life, even if the early life effects aren’t fully reversible.”
There has been growing interest in the importance of the gut microbiome in human health and disease in recent years. The Task Force report reiterates that dietary modification can positively or negatively influence microbial communities with evidence of specific benefits from dietary fibres on some cardiovascular and metabolic risk factors. These include reduced blood low density lipoprotein (LDL) cholesterol concentrations and positive influence on the immune response.
Professor Julie Lovegrove, Hugh Sinclair Professor of Human Nutrition, University of Reading said: “There is strong evidence that higher dietary fibre intake is associated with lower CVD mortality but as yet the mechanisms are not totally clear. The effect of fibre on the gut microbiota may well be an important contributor to its protective role.”
Chronic, low‐grade inflammation appears to underlie atherosclerosis, although the Task Force report concluded it isn’t clear whether it plays a causal role. However, drug treatments that lower levels of inflammation have been shown to reduce the risk of a second heart attack or stroke in people with heart disease.
Weight loss is a critical factor in reducing inflammation, but there is also a growing body of data describing the effects of dietary patterns on inflammatory markers, both in healthy people and those with CVD. Epidemiological evidence has demonstrated an association between poor micronutrient status and inflammation, but supplementing with these micronutrients does not appear to be beneficial.
Professor Parveen Yaqoob, Professor of Nutritional Physiology, University of Reading said: “There is some evidence that some dietary patterns, for example the Mediterranean diet and diets rich in the long chain n-3 fatty acids found primarily in oily fish, are associated with reductions in levels of inflammatory markers, but we need more research to determine whether these dietary patterns influence CVD risk in this way.”
It is widely recognised that physical activity and physical fitness help to keep the heart healthy and that people who don’t exercise are twice as likely to have a heart attack as those who exercise regularly. Physical activity has beneficial effects on a number of CVD risk factors including bodyweight and lean body mass, blood pressure, blood lipids, glucose control, haemostatic factors and endothelial function.
There is also now evidence, that being sedentary for long periods of time, even if a person is active at other times, can increase the risk of CVD. Time spent being sedentary is associated with poorer blood lipid profiles, high blood pressure and increased risk of type 2 diabetes. It has been suggested that frequent musculoskeletal contractions throughout the day may be help to counteract some of the negative effects of sedentary time.
Prof Marie Murphy, Professor of Exercise and Health, Ulster University, said: “We’ve known for some time how important being active and fit is for heart health but the effect of inactivity and sedentary behaviour warrants further research. We know that time spent in uninterrupted sedentary behaviour increases risk of CVD, what we don’t know is what pattern of activity has the greatest benefit for cardiovascular health.”
The conference ended with a presentation from BNF Director General Professor Judy Buttriss, who outlined the key public health implications of the Task Force report on cardiovascular disease, which include longstanding issues like replacing saturated with unsaturated fatty acids and increasing fibre intakes as well as more emerging issues such as the effects of sleep and stress.
Sara Stanner, Science Director at BNF and editor of the Task Force report, concluded: “The Task Force report supports existing UK dietary and lifestyle recommendations for CVD prevention and we now have more emerging evidence on how such factors influence CVD risk. For example, high intakes of saturated fatty acids may not only negatively affect blood cholesterol levels but also inflammation and endothelial function, and the beneficial effects of fibre for our hearts may, at least in part, be modulated by our gut bacteria.”