Obesity and Cardiovascular Diseases: The Risk Factor in African Diets

Introduction Once thought to be a problem of developed countries, the epidemic of obesity and its associated chronic diseases is now growing in the developing world as well. This is influenced by the dietary and lifestyle changes that accompany economic development which include less physically demanding manual labour, urbanization, rising purchasing power and modernized food marketing. These factors, as extensively discussed by Witkowski (2007), are further exacerbated by genetic predispositions and early life undernutrition. The consequence is that basic energy equation is altered, as both energy intake and expenditure are affected. The resulting overweight and obesity has been associated with an upsurge in the prevalence of chronic diseases such as cardiovascular disease (CVDs), hypertension, Diabetes mellitus, stroke and osteoporosis. Evidence is also building as regards the links with some forms of cancer (World Cancer Research Fund/ American Institute of Cancer Research 2007). The global burden of these chronic diseases is daunting, as they remain significant causes of disability and mortality worldwide. Deaths caused by chronic diseases dominate mortality statistics even in developing countries. In 2001, chronic diseases contributed approximately 60% of the 56.5 million total reported deaths in the world (WHO 2002). This amounted to 46% of the global burden of disease in that year, and this proportion is expected to increase to 57% by 2020. However, the locus of the burden will reside in the developing world, as it has been projected that, by 2020, about three-quarters of mortality due to Ischaemic Heart Disease, stroke and diabetes will occur in developing countries. One major underlying determinant of obesity is the dietary intake, in addition to genetics, intrauterine influences, physical activity and socio-cultural factors. In Africa, obesity is becoming a serious problem in some regions and among certain population groups, despite the widespread prevalence of undernutrition Since the diet has been recognized as a key player as a risk factor for obesity and CVDs, the question arises: what risk(s) does the African diet pose in this regard? What dietary patterns exist which have either positive or negative implications for obesity and CVDs? How and why are dietary habits changing, and what implications may these have on obesity and CVD risk? Understanding gained from these investigations will aid timely interventions and play a role in ensuring well being, and invariably quality of life for present and future generations in Africa. Obesity and cardiovascular diseases (CVDs) The health dangers of obesity are widely recognised, dominant among which is its role as an important determinant of CVDs. A large body of epidemiological studies of obesity have documented a relationship between obesity and risk of CVDs, especially in younger age groups. Both obesity--a body mass index (BMI) of 30 or greater and overweight (BMI of 25 to 30) confer elevated risks of CVDs. The Renfrew--Paisley study (Murphy et al. 2006), which was a 20-year follow-up of more than 15 000 middle-aged men and women underscored the long-term cardiovascular consequences of obesity, and demonstrated the association of obesity with an increase in a broad range of fatal and non-fatal cardiovascular events. A recent study also showed that higher BMI during childhood is associated with an increased risk of coronary heart disease in adulthood, suggesting that as children are becoming heavier worldwide, greater numbers of them are at risk of having coronary heart disease in adulthood (Baker et al. 2007). Existing literature reveal that risk factors for coronary heart disease, such as hypertension, dyslipidemia, impaired glucose tolerance, and vascular abnormalities, are already present in overweight children (Weiss et al. 2004; Viner et al. 2005). For adolescents, the (similar) picture as depicted in the study of Bibbins-Domingo et a. …