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Role of red meat in the diet for children and adolescents.

Article Excerpt
KEY POINTS

* Optimal nutrition during the first years of life is crucial for optimal growth and development and, possibly, the prevention of chronic disease of adulthood.

* Iron-deficiency anaemia in childhood and adolescence is associated with serious adverse outcomes that may not be reversible, making detection and early treatment an imperative.

* Zinc plays a major role in cellular growth.

* Vitamin A is essential for the functioning of the eyes and the immune system.

* Vitamin A is necessary for membrane stability, and zinc is essential for mobilisation of the beta-carotene. Vitamin A deficiency contributes to anaemia by immobilising iron in the reticuloendothelial system, reducing haemopoiesis and increasing susceptibility to infections.

* Like iron, iodine appears to be involved in myelin production and, hence, nerve conduction.

* Meat is a core food in the diet for children and adolescents because it provides significant amounts of these micronutrients.

INTRODUCTION

Over the first few years of postnatal life, an infant's body undergoes dramatic changes not only in physical attributes, but also in developmental milestones. By three years of age, an infant's head circumference and hence brain size will have reached 80% of what it will potentially achieve in adulthood, and its length will also have doubled in size. Therefore, it is not surprising that any adverse events occurring during these periods may have a negative impact upon psychomotor development.

In 1968, Dobbing (1) suggested that there were vulnerable periods of neurological development that coincided with times of maximal brain growth. These periods begin during foetal development at around the 25th week of gestation and continue for the first two years of postnatal life. Nutrient deficiencies occurring during these vulnerable periods may well have an impact upon brain growth and, hence, neurological and psychomotor development. (1) These nutrient deficits have subsequently been shown to result in more functional deficiencies rather than physical abnormalities. Not only is optimal nutrition essential for achieving optimal physical and psychosocial development, but it also appears to have significant disease implications for later in adult life. Barker and his epidemiology group in the UK proposed that not only intrauterine malnutrition, but also poor weight gain in the first year of life, was associated with an increased incidence of cardiovascular disease (particularly in adults aged >50 years), hypertension and glucose intolerance during adulthood. (2) Their retrospective, epidemiological report has been supported by several studies on the Netherlands famine during World War II, which affected women during early, mid and late stages of gestation. (3,4) Subsequently, animal and prospective human studies have suggested that either under- or over-nutrition in utero can be associated with epigenetic changes as well as intrauterine adverse programming of organ function. (5)

Development of functional activity may be associated with myelination. Many nerve fibres are covered with a whitish, fatty, segmented sheath called the myelin sheath. Myelin protects and electrically insulates fibres from one another and increases the speed of transmission of the nerve impulses. Myelinated fibres conduct nerve impulses rapidly, whereas unmyelinated fibres tend to conduct quite slowly. This acceleration of nerve conduction is essential for the function of the body and survival. In humans, the myelin sheath begins to appear around the fourth month of foetal development and first appears in the spinal cord...