Micronutrient Deficiencies in the First Months of Life

Public health decisions are seldom straightforward. An example of the complexities that may surface when a potentially beneficial intervention has been identified, is the recent experience of attempts to introduce flour fortification with folic acid in the UK.

From a purely biochemical and mechanistic viewpoint, normal growth and development of the infant depends upon a program that is orchestrated by the genome and initiated through transduction mechanisms by signals originating outside the cell.

Iodine is a micronutrient present in minute amounts (15–20 mg) in the human body, almost exclusively in the thyroid gland. Iodine is an essential component of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3), comprising 65 and 59% of their respective weights.

Iron deficiency in its most severe form results in anemia (iron deficiency anemia, IDA) and since anemia (Hb concentration or Hct below established cutoff levels) is relatively easy to diagnose, the prevalence of anemia has often been used as a proxy for IDA.

Typically nutritional rickets and osteomalacia are problems associated with the extremes of life. In both groups they are the consequence of an inability to obtain adequate exposure to ultraviolet radiation as a result of their dependence on others to get out of doors into sunlight.

Based on a WHO Expert Consultation, the World Health Assembly recommends that infants should be exclusively breast-fed for about the first 6 months of life [1]. Additional foods or fluids are considered to be contraindicated, except in rare cases.

Vitamin A is required for normal human growth and development, with nuclear receptors for this nutritional ligand detectable in embryonic life.

Observational studies over the past 30 years document a strong association between maternal anemia and birth outcomes such as low birth weight (LBW), prematurity, infant anemia, and mortality for either mother or infant.

The importance of zinc as a nutrient essential for growth, tissue repair, neural and cognitive development, development and functionality of the immune system has been known for a long time [1].

Infectious diseases (respiratory and diarrheal) are among the leading causes of death in children around the world. The immune system in children is not developed and is different from that of adults.

The classical role of vitamin K is as an antihemorrhagic factor which is needed for the synthesis in the liver of functional forms of prothrombin (factor II) together with factors VII, IX and X [1, 2].

Strategies to lower the rates of low birth weight and perinatal and neonatal mortality in the Third World have had limited success. In south Asia alone, 10–15% of infants are stillborn, die within 7 days of birth, or are born alive but fail to survive beyond the 1st month of life.

There are a number of features specific to the infant born prematurely that challenge the caregiver to achieve appropriate goals for growth, nutrient accretion and mental and physiologic development.

Human immunodeficiency virus (HIV) infection is one of the major public health challenges worldwide. According to most recent estimates, approximately 40 million persons are HIV-infected, among them 2.7 million children under 15 years of age [1].

Birth defects (the World Health Organization prefers the term congenital anomalies) represent a particular category of pathological conditions. As figure 1 shows births defects have a wide spectrum of developmental disturbances, however, we are interested in structural birth defects, i.e. congenital abnormalities (CAs), in this presentation.

Spectacular progress has been made in the last decades in the global fight against deficiencies of iodine and vitamin A [1]. As a result, the number of people suffering from iodine deficiency has been reduced from about 1.5 billion in 1990 to about 0.5 billion now, almost entirely due to the introduction in many countries of what has been termed ‘universal salt iodization’.

This brings our workshop to a close but we have hardly brought the challenges facing us to a close: to understand the depths and breadth of micronutrient nutrition as it effects infant health in the first 6 months of life.

Subject Index