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Nutritional transition: a determinant of global health
  1. Stephen J Genuis
  1. Correspondence to:
 Dr S Genuis
 2935-66 Street, Edmonton, Alberta, Canada T6K 4C1; sgenuisualberta.ca

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Much of the world’s disease burden results from faulty nutrition, which is a largely preventable risk factor. It is now time for a global diet strategy.

Perhaps more than ever before in recorded history there is a huge gap between health as it could be and health as it really is. The management of patients with persistent affliction and unremitting pain increasingly dominates medical practice1,2 and it is apparent that individual and public dietary habits are an important determinant in the mounting load of chronic suffering and illness.3 Exorbitant rates of adult onset diabetes as well as an epidemic of paediatric and adult obesity have triggered a careful re-examination of national food guidelines and population dietary practices. In recognition of the health ramifications of faulty dietary intake, the World Health Organisation in May 2004 implemented a global diet strategy,3–5 a move branded as a “landmark achievement in global public health policy.”5

Distinct challenges related to nutrition and health in developing countries, such as food shortage and inequitable distribution of resources, often result from political, economic, and social factors. Even within developed nations enjoying prosperity, cutting edge medical technology, and accessible health care, however, it is increasingly evident that rates of chronic illness are mounting,6–9 thus threatening the sustainability of health care systems in many jurisdictions. The Centers for Disease Control and other groups have provided substantial research data confirming that the rise in illness and chronic pain are, in part, attributable to nutritional choices.3,10–12 As early as 1988, the US Surgeon General’s Report on Nutrition and Health concluded that illness related to modern dietary habits had risen so noticeably that faulty nutrition significantly contributed to most deaths in the USA.13

The integrity of the physical body is determined, to a great degree, by the quality of consumed nutrients that continually nourish and rebuild the human structure. Deficiencies of ordinary micronutrients can be associated with a range of illnesses such as prostate cancer,14 miscarriage,15 and stroke,16 as well as an array of paediatric afflictions including widespread behavioural and learning disorders,17 certain congenital abnormalities,18 and even such common ailments as ear infections.19 The Canadian Journal of Psychiatry, for example, recently highlighted various psychiatric challenges including anxiety, depression, and hyperactivity problems associated with insufficient levels of essential fatty acids.20 Primary reasons for micronutrient insufficiency include the following: food is commonly grown in soil that has become nutritionally deficient; microwaving and prolonged cooking at high temperatures diminishes nutritional value21,22; produce is commonly harvested in advance of vine ripening, the stage at which many basic nutrients develop; and toxins including various herbicides and pesticides may have an adverse effect on nutrients. Furthermore, fast food with its questionable nutritional status has become a dietary staple for many families.23,24 As well as nutritional deficiency, exposures to potential toxins in foods are also a cause for concern.

Potentially toxic and allergenic agents in common foods are becoming more prevalent and, although much of the research on toxic effect remains at an early stage, there are increasing data that evoke concern.25 To expedite rapid and maximal growth, many farm animals destined for human consumption are injected with potent hormones including oestrogens, as well as being fed potentially toxic growth promoting feed additives.26–29 It is noteworthy that because of safety concerns, the European Union has steadfastly banned beef treated with growth hormones.28 In North America, dietary analysis by public agencies has showed that some ordinary foods consumed by many families now contain pesticide residue, antibiotics, heavy metals, industrial chemicals, and untested genetically engineered ingredients.26,30–35 Routinely consumed synthetic additives, such as artificial colours, flavours, and preservatives may provoke untoward reactions and long term effects of eating irradiated food have not been adequately studied. Toxins in food are also an important concern in obstetrical care: just as drugs and alcohol can affect the developing fetus, recent warnings that caution pregnant women to limit consumption of seafood because of teratogenic contaminants36 give evidence of potential in utero impact of food toxins.

An accumulating body of evidence has pointed to hyperinsulinaemia resulting from dietary choices as an aetiological factor in the development of many chronic medical problems.37–39 Hypertension, dyslipidaemia, coronary artery disease, and type 2 diabetes are among the most common chronic conditions seen by family physicians in western cultures, yet remain rare in less westernised societies. For example, 50 million Americans are hypertensive, 10 million have type 2 diabetes, and 72 million adults have dyslipidaemia.38 Habitual consumption of high glycaemic food carbohydrates such as refined sugar and many common cereals promotes the development of insulin resistance and compensatory hyperinsulinaemia.38 Awareness of the impact of raised insulin concentrations resulting from dietary challenges is increasing; research has implicated this physiological change with other common conditions such as acne and hair loss,38 polycystic ovarian disease,40 pre-eclamptic toxaemia,41 as well as prostate, breast, and colon cancer.38,42,43 As increased insulin concentrations also have a significant growth promoting hormone effect, higher fetal insulin concentrations in response to high glycaemic loads provided to the mother may be accounting for larger fetal growth. With high rates of cephalopelvic disproportion and associated caesarean section figures of 24% in the USA and 21% in Canada,44,45 the issue of diet in pregnancy needs to be carefully considered. The myriad health sequelae associated with habitual high glycaemic consumption and mounting western type illness in developing nations adopting western dietary behaviours, explain the high glycaemic caution (in addition to the fruit and vegetable promotion) in the WHO “Global strategy on diet, physical activity and health.”3

While the medical discipline of nutrition is emerging as an area of primary health importance, this domain has not been a focus for medical training and continuing medical education.46,47 It would be outlandish for a building contractor or architect to complete training in construction without an all embracing knowledge of structural materials, yet most physicians have received limited instruction about dietary nutrients, the building materials of the human frame. As a result, consideration of nutritional causation for medical problems occurs infrequently in everyday clinical practice48 and the underlying aetiology of various health difficulties is commonly unexplored.

What this paper adds

It is my desire that this commentary will bring attention to the contribution of nutritional factors to the escalating problem of chronic disease. Many people consider health and illness to be entirely independent of their own behaviour and voluntary choices, and regardless of unhealthy practices, perceive that health can be purchased in a medicine or vitamin bottle. Much of the general public now expects to consume medical services in much the same fashion that they consume fast food: rapid service, brief encounters, and immediate satisfication. As there is mounting evidence of the close relation between nutritional transition and disease, physicians need to be advocates for health promotion and prevention, in part, through dietary assessment and intervention.

Despite ample evidence confirming the need for good nutrition as a prerequisite for optimal health,10 dietary habits have changed substantially over the past few decades with accumulating research showing that many contemporary foods are nutritionally inadequate and that some contain potentially harmful substances. Study of “nutritional transition”,25 the changing nature of food consumed by the average person, and its relation to human health, is an area of intense investigation that requires careful consideration when exploring the health status of individual patients as well as health trends within populations. With the realisation that much of the world’s disease burden results from faulty nutrition, a largely preventable risk factor, the WHO has recently unveiled a global diet strategy, emphasising the inextricable relation between nutrition and human health.

Policy implications

The recent World Health Assembly strategy to introduce a new dietary initiative is an important first step in the commitment to improve global nutritional practices. However, there is much literature to confirm that most physicians are not trained in nutrition and do not consider this important field when managing illness. This paper will hopefully contribute to increasing physician awareness and facilitate the introduction of policies and programmes to educate the public about the need for prevention and promotion of community health, in part, through diet.

Much of the world’s disease burden results from faulty nutrition, which is a largely preventable risk factor. It is now time for a global diet strategy.

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