expert opinion

Improving the micronutrient status of population groups at risk

July 1, 2012

file

Professor David P. Richardson, Nutrition and Food Scientist, United Kingdom

“Eating a healthy, balanced diet is the best way to achieve appropriate intakes of vitamins, minerals and other essential nutrients. However, areas of nutritional concern and population groups at risk include the elderly, women at various life stages, children and adolescents, and people trying to lose weight. Even mild micronutrient deficiencies can lead to general fatigue, reduced resistance to infections, and impaired concentration and alertness. Inadequate micronutrient intake may take several weeks to develop, and once it occurs, it may take an equally long time to replenish body stores. Messages about the importance of a varied and balanced diet and a healthy lifestyle should continue to underpin nutrition advice given to the public, especially to vulnerable groups.

Social, demographic, economic and lifestyle changes determine our nutritional status and nutrition is now recognized to be a major contributor to morbidity and mortality rates and to the development of the chronic, non-communicable diseases including cardiovascular diseases and cancers. Healthcare costs are expected to rise dramatically in the next two decades, and much more attention needs to be focused on how they can be controlled. Key questions are whether nutritional interventions such as food supplements and fortification can contribute beneficially to help control costs of healthcare and promote the health, wellbeing and quality of life of people globally.

All women of childbearing age who are capable of being pregnant have special requirements, especially to reduce the risk of a pregnancy affected with spina bifida and other neural tube defects (NTDs). Folic acid supplements taken periconceptionally have been definitely proven to reduce significantly the risk of NTDs. The decisive evidence that supplements reduce the risk of NTDs resulted in the recommendation that all women of reproductive age, or capable of becoming pregnant should consume 400 µg/day folic acid from supplements or fortified foods. Several other vitamins and minerals can have important influences on the health and wellbeing of pregnant women and the growing fetus and newborn (1).

Anemia, most of which is related to iron deficiency, is one of the most common and widespread disorders in the world and it is a public health problem in both industrialized and non-industrialized countries. Research provided current global and regional estimates of anemia prevalence and the number of persons affected in the total population and by population subgroup (2). The estimated global anemia prevalence is 24.8%, affecting 1.62 billion people. Estimated anemia prevalence is 47.4% in preschool-aged children, 41.8% in pregnant women and 30.2% in non-pregnant women. These estimates, that one in four persons globally suffer from anemia and that pregnant women and young children are at greatest risk, illustrate the magnitude of the problem and highlight the need for action.

Vitamin A plays a vital role in visual perception, and a deficiency is the leading cause of childhood blindness in developing countries. It has been estimated that 127 million preschool children and 7 million pregnant women were vitamin A deficient in developing countries in 2003 (3). Vitamin A also plays a major role in growth and cell differentiation, the immune system and reproduction. Vitamin A is particularly important during periods of rapid growth and is significantly involved in the healthy development of the fetus and the newborn, especially with lung development and maturation. Provitamin A (beta-carotene), found in plant foods, plays an important role in meeting vitamin A requirements from the diet, in particular, those that have low intakes or exclude the consumption of meat, liver, milk and eggs (4).

Specific nutrients such as iron, calcium, magnesium, zinc and iodine, vitamin A and vitamin D and the water-soluble vitamin B group can be in short supply among the adolescent population as a result of individual, sociological, cultural and economic factors. To date, insufficient attention has been paid internationally to improving nutrition and the nutrient density of the diet around and just after puberty but before young women become pregnant.

Although lifespan is increasing, the quality of life for the elderly has not necessarily improved, leading to unhealthy aging and increased morbidity. A key objective is to increase lifespan and to minimize the time between the onset of illness and death. The evidence indicates that there is a high prevalence of several micronutrient deficiencies in this age group that will impair immune responses (5). Subclinical levels of micronutrients have been associated with impaired immune function in people over 60 years of age, and it has been shown that improved nutrition and micronutrient supplementation can enhance immune responses. Nutrient supplementation studies including those with vitamins B6, C, A, D and E and the mineral zinc, have been shown to be involved in immune responses of the elderly (6). Improvements in nutritional status of the elderly could achieve benefits to their health status and quality of life as well as significant savings of healthcare resources in countries around the world.

The past decade has seen a renewed interest and a proliferation of published papers related to the functions of vitamin D in growth and development, including regulation of cellular differentiation and apoptosis, immune system development, brain development, potential benefits for cardiovascular function, diabetes mellitus, cancer, multiple sclerosis, allergy, asthma, infection, depression and pain. An assessment of the level of evidence for the various potential benefits has been undertaken recently (7). For example, the evidence for skeletal benefits is strong, especially for the prevention of fractures and falls in older people. Vitamin D is an important determinant of bone health at all ages (8). Vitamin D deficiency is common and insufficiency very common in non-pregnant women, children and adolescents (9). The most serious concern and consequence of vitamin D deficiency and insufficiency centers around the adverse consequences for women’s health and in particular, poor vitamin status in pregnant and lactating women and decreased fetal and childhood bone mineral accretion.

Governments around the world already recognize the need for the use of food supplements and fortified foods in certain population groups. For example, in the UK, the Department of Health recommended that children between the ages of six months and five years take a supplement containing vitamins A and D. Iron supplementation is recommended for women with heavy periods, and women who are pregnant or planning to become so are advised to take folic acid. Older people, people who rarely get outdoors or who cover their bodies and Asian people are advised to consider a vitamin D supplement (10).

However, it is evident that the people already targeted by governments around the world for food supple-ments and fortified foods are not the only ones with poor micronutrient intake and nutritional status. Signifi-cant proportions of the general population are failing to achieve adequate intakes of several vitamins and minerals. Currently, many of the people already taking food supplements are often the ones who already have adequate intakes of micronutrients from food. The people who could benefit most from the use of food supplements are those that are most likely not taking them.”

References

  1. King J. C. et al. Maternal nutrition: new developments and implications. Proceedings of a symposium held in Paris, France, June 11–12, 1998. Am J Clin Nutr. 2011; 71:1217–1379.
  2. McClean E. et al. Worldwide prevalence of anaemia, WHO Vitamin and Mineral Nutrition Information System, 1993–2005. Public Health Nutr. 2008; 12:444–454.
  3. West K. P. Vitamin A deficiency disorders in children and women. Food Nutr Bull. 2003; 24(4):78–90.
  4. Strobel M. The importance of β-carotene as a source of vitamin A with special regard to pregnant and breastfeeding women. Eur J Nutr. 2007; 46(1):1–20.
  5. Calder P. C. and Jackson A. A. Undernutrition, infection and immune function. Nutr Res Rev. 2000; 13: 1–29.
  6. Dao M. C. and Meydani S. N. Micronutrient status, immune response and infectious disease in elderly of less developed countries. Sight and Life Magazine. 2009; 3:6–15.
  7. Thacher T. D. and Clarke B. L. Vitamin D insufficiency. Mayo Clin Proc. 2011; 86:50–60.
  8. Brannon P. M. et al. Overview of the conference Vitamin D and Health in the 21st Century: an Update. Am J Clin Nutr. 2008; 88:483–490.
  9. Hill T. R. et al. Vitamin D status and its determinants in adolescents from the Northern Ireland Young Hearts 2000 cohort. Brit J Nutr. 2008; 99:1061–1067.
  10. UK Department of Health. Vitamin D: advice on supplements for at-risk groups. 2012; www.dh.gov.uk.