Micronutrient deficiency is a lack of essential vitamins and minerals required in small amounts by the body for proper growth & development.
Worldwide most common micronutrient deficiency consists of:
– Vitamin A
– Folic Acid
Widely associated with the cause-effect of malnutrition, micronutrient deficiency is a huge contributor to the global burden of disease through increased rates of illness and death from infectious diseases and disabilities such as mental impairment. Deficiencies of some micronutrients are highly prevalent in low and middle-income countries and may affect the risk of illness or death from infectious diseases by reducing immune systems. and by compromising normal physiology or development. While deficiencies in any of the essential micronutrients can result in health problems, there are a few that are particularly important.
? A significant issue in terms of being a main contributor to high rates of morbidity & mortality amongst infants, children and mothers in developing countries
? Deficiencies in Vitamin A, iron, iodine and zinc exacerbate the burden of disease resulting in multiple health implications
? Leads to multiple significant consequences such as death during childbirth, mental retardation, lower educational attainment, decreased work capacity
? Vicious cycle of micronutrient deficiency extends beyond a single generation with far-reaching consequences on future populations
? Focus upon the measures that are taken to tackle the issue of micronutrient deficiency and stop it from becoming beyond a global epidemic
Several factors contribute to the rampant wide-spread reach of micronutrient deficiency. However, the most basic cause of this problem is poverty. The low and middle-income settings of the world are unable to obtain basic nutrition due to a lack of finances and education in terms of health and nutrition. Coupled with infectious disease and less-than-sanitary environments, the lack of access to health services too contributes to the rise in micronutrient deficiency. In addition, developed countries serve as a hurdle as they have the privilege of obtaining a greater amount of food in terms of using wealth to obtain what is required, leaving poorer countries with very little left to choose for their populace.
Box 1. Impact of Common Deficiencies
The result of micronutrient deficiency can be devastating and, in addition to these top MND’s deemed most prevalent, according to Micronutrient Initiative, Vitamin C, Thiamin and Niacin should also be considered as a global health concern.
Leading cause of blindness worldwide and impairs immune function and cell differentiation. Nearly 800,000 deaths among women ; children worldwide can be attributed to this. In addition, 20% of maternal deaths worldwide is also attributed to this cause.
Rated as the most common micronutrient deficiency worldwide and this leads to microcytic anaemia. If untreated, can result in damage to internal organs, as well as impaired immune and endocrine function. Contributes to 18.4% of total maternal deaths and 23.5% of perinatal deaths globally.
Results in goitre, mental retardation and or cognitive function, abortion and still birth. 28.5% is the estimated percentage of people worldwide who are iodine deficient.
Adequate zinc is necessary for optimal immune system function and this deficiency is associated with an increased incidence in diarrhoea and acute respiratory infections. A major cause of death to those younger than 5 years old. Estimated global prevalence of zinc deficiency is 31%.
Folate is essential for DNA synthesis and repaid. Deficiency results in macrocytic anaemia and neural tube defects. It affects up to 5 new borns per 1000 live births worldwide (95% of pregnancy).
? With the double constituent of protein-energy malnutrition and micronutrient deficiency, it continues to be a major health burden, with the emphasis on developing countries. Interventions to prevent protein–energy malnutrition range from promoting breast-feeding to food supplementation schemes, whereas micronutrient deficiency would best be addressed through food-based strategies such as dietary diversification through crop harvesting and livestock. Fortification of salt with iodine has been an international sensation, but other micronutrient supplementation schemes have yet to reach vulnerable populations sufficiently.
Malnutrition continues to be a major health problem throughout the developing world, particularly in southern Asia and sub-Saharan Africa. Diets in populations there are frequently deficient in macronutrients (protein, carbohydrates and fat, leading to protein–energy malnutrition), micronutrients (electrolytes, minerals and vitamins, leading to specific micronutrient deficiencies) or both
? The high prevalence of bacterial and parasitic diseases in developing countries contributes greatly to malnutrition there. In addition, this increases the susceptibility to disease, and is therefore a major component of illness and death. Malnutrition is consequently the most important risk factor for the burden of disease in developing countries. It is the direct cause of an estimated 300, 000 deaths per year and is indirectly responsible for about half of all deaths in young children. The risk of death is directly correlated with the extent of malnutrition.
Poverty is the main underlying cause of malnutrition and its determinants. The degree and distribution of protein–energy malnutrition and micronutrient deficiencies in a given population depends on many factors: the political and economic situation, the level of education and sanitation, the season and climate conditions, food production, cultural and religious food customs, breast-feeding habits, prevalence of infectious diseases, the existence and effectiveness of nutrition programs and the availability and quality of health services.
? Globally, approximately 852 million people were undernourished in 2000–2002, with most (815 million) living in developing countries. The complete number of cases has changed little over the last decade.
? In children, protein–energy malnutrition is defined by measurements that fall below 2 standard deviations under the normal weight for age (underweight), height for age (stunting) and weight for height (wasting). Wasting indicates recent weight loss, whereas stunting usually results from chronic weight loss.
? Protein–energy malnutrition usually manifests early, in children between 6 months and 2 years of age and is associated with early weaning, delayed introduction of complementary foods, a low-protein diet and severe or frequent infections.
Box 2. Stunting
Short stature – Low-height for age. Stunting is the impaired growth and development that children experience from poor nutrition, repeated infection, and inadequate psychosocial stimulation. Children are defined as stunted if their height-for-age is more than two standard deviations below the WHO Child Growth Standards median (WHO).
– Result of long-term under nutrition, chronic lack of sufficient macronutrients to sustain normal growth
– Also result of repeated infections in infancy
– 20% of stunting begins in utero-under nutrition and anaemia in pregnancy leads to low birth-weight
– Low-birth weight babies more likely to be stunted
– Failure to reach full potential height
– Impaired brain development
– Severely weakened immunity
– Predisposed to obesity in adulthood
– Pregnancy complications, delivering low birth weight babies
– Affects productivity (Overall economic growth of the country), reducing the ability to contribute to nutritional status of community
Micronutrient Deficiency (Epidemiology)
Deficiencies in iron, iodine, vitamin A and zinc are still major public health problems in developing countries, but vitamins C, D and B deficiencies have declined considerably in recent decades. Micronutrient deficiencies affect at least 2 billion people worldwide. As there are often no reliable biochemical indices of marginal micronutrient status, randomized controlled trials of supplementation are the best method to study the relation between micronutrient deficiencies and health parameters in human populations.
Globally, 740 million people are deficient in iodine, including up to 300 million with goitre and 20 million with brain damage from maternal iodine deficiency during their foetal development. About 2 billion people are deficient in zinc; 1 billion have iron-deficiency anaemia. Vitamin A deficiency affects some 250 million, mainly young children and pregnant women in developing countries.
Pathophysiology ; Clinical Features
? Protein–energy malnutrition and micronutrient deficiencies overlap, and the lack of 1 micronutrient is typically associated with deficiencies of others. Iron is an important component of haemoglobin, myoglobin and various enzymes. Hence, this leads mainly to anaemia, but also several other adverse effects. A lack of iodine reduces the production of thyroid hormone and increases that of thyroid-stimulating hormone. As a result, the thyroid gland becomes goitrous, and hypothyroidism develops.
? Vitamin A deficiency contributes to anaemia by immobilizing iron in the reticuloendothelial system and increasing susceptibility to infections. It is essential for functioning of eyes and the immune system. Although diarrhoea and related mortality has clearly been shown to be associated with vitamin A deficiency, evidence for associations with acute infections of the lower respiratory tract and with malaria is much weaker.
? Essential for the functioning of many enzymes is zinc. Thus, it is involved in a large number of metabolic processes, like RNA and DNA synthesis. Furthermore, zinc deficiency interferes with a variety of biological functions, such as gene expression, protein synthesis, skeletal growth, gonad development, appetite and immunity. Zinc deficiency is a major cause for diarrhoea and pneumonia, but evidence about its role in malaria and growth retardation is conflicting.
? Management ; Control
? Food containing high contents of absorbable micronutrients are considered the best means for preventing micronutrient deficiencies. In communities where supplies of such foods are sparse, specific preventive and curative interventions are needed.
? There is growing unanimity on the importance of multiple micronutrient interventions in populations with a high prevalence of malnutrition. However, compatible and incompatible interactions between micronutrients have to be taken into consideration during the development of appropriate formulations.
? The introduction of World Health Assembly’s Global Nutrition Target, where several aims at the reduction of symptoms of micronutrient deficiencies, were implemented in a bid to tackle the public health problem.
? Targets included 50% reduction of anaemia in women of reproductive age (pregnant/non-pregnant) and 30% reduction in low birth weight, amongst other factors.
? “Scaling Up Nutrition” launched in 2010 aims to promote action at all levels to build on existing structures and policies – and implement new ones – all with a clearly defined nutritional focus. Approaches include Nutrition-Specific aims which pinpoint obvious nutritional targets and Nutrition-Sensitive, which aims to target areas that influence nutritional status but are not themselves nutritional targets (i.e Education, Child-care, sanitation and hygiene)
? Progress towards goals requires action at all levels:
UNICEF report on 4 programme areas where this approach has had significant results (Annual
– Infant and Young Child Feeding (IYCF)
– Nutrition in emergencies and treatment of severe acute malnutrition
– General nutrition
Optimal IYCF practices include:
– Early initiation of breastfeeding (within an hour of life)
– Exclusive breastfeeding for 6 months
– Continued breastfeeding to 2 years or beyond
– Introduction of safe and nutritionally adequate complementary foods after 6 months (weaning)
– Ensuring adequate nutritional intake of breastfeeding mothers
These practices are paramount to prevention of all forms of child malnutrition including stunting
and wasting, as well as obesity.
Micronutrient supplementation is usually provided through the existing health services and can be taken orally or by injection.
Priority should be given to vulnerable populations, such as pregnant women and children. Supplementation is mandated in cases of a specific deficiency when other approaches are too slow. Although some micronutrients must be taken daily or weekly (e.g., iron and zinc), others can be stored in the body and need only be taken at intervals of months to years (e.g., vitamin A and iodine).
Nevertheless, modes of delivery, patient compliance and potential toxicity all need to be considered
Diet-based techniques are probably the most promising approach for a sustainable control of micronutrient deficiencies. Increasing dietary variation through consumption of a broad diversity of foods, preferably from home gardens and livestock production, is effective. Families must undergo education and receive supported to increase production of dark-green leafy vegetables, yellow and orange fruits, poultry, eggs, fish and milk.
Possible future strategies to prevent micronutrient deficiency include the harvesting of micronutrient-rich crops, through either conventional farming techniques or genetic modification of existing crops. Thus far however, the micronutrient concentrations achieved are very low. Furthermore, iron concentrations in bioengineered rice are no higher than those in natural varieties such as basmati or jasmine rice.