Human Nutrition Review – Roisin Mc Donagh 18428822 Introduction The RDA of iron differs depending on age and gender
Human Nutrition Review – Roisin Mc Donagh 18428822
The RDA of iron differs depending on age and gender. For adolescents the RDA is 14mg/day. (FSAI 1999) There are two types of iron haem and non-haem. Haem iron sources are mainly animal sources i.e. meat, poultry and fish. Non-haem is mostly from plant sources i.e. legumes, green leafy vegetables and fortified cereals. Iron is a component of haemoglobin which is a pigment in red blood cells that helps to transport oxygen around the body. It is a component of myoglobin. This is how oxygen is stored in muscles. It is a cofactor for many enzymes in DNA synthesis, energy metabolism and antioxidants. It is vital for cytochromes which are involved in the TCA cycle.
Iron deficiency anaemia is defined as a haemoglobin level below the cut off value for age and gender and at least two other irregular iron status measurements i.e. serum ferritin, transferrin saturation, RBC protoporphyrin and haemoglobin levels. (Gibney et al. 2010) Symptoms include fatigue, paleness, shortness of breath and cold hands and feet. This can result from less haemoglobin in the blood which means less oxygen is being transported, making the symptoms more prominent. Observational research shows that adolescents are not meeting iron requirements. However, boys are closer to reaching the requirements than girls. (Vandevijvere et al. 2013) have high iron requirements as they are growing rapidly, and girls need increased amounts for menstruation. (Wharton et al. 1987) This loss of blood and quick growth puts adolescents at greater risk of anaemia. The study observed the sources of iron. Haem iron sources are more bioavailable than non-haem sources. It contained a random group of over 3000 adolescents from Europe aged 12 to 18 conducted over 2 weeks. Dietary intake was noted using a 24-hour recall on two non-consecutive days. A self-recorded questionnaire was taken about the participants socio-economic backgrounds. The adolescents weight and height were recorded. It found that the total iron intake for boys was higher than for girls. Boys consumed 13.8mg/day and girls 11mg/day. 97.3% of boys met the requirements compared to 87.8% of girls. From this study we see girls are at a higher risk of developing anaemia than boys as less meet requirements. (Vandevijvere et al. 2013)
According to the National Teens’ Food Survey (2005-2006), 81% of teenagers consume ‘ready to eat’ breakfast cereals. Experimental research shows that the fortification of breakfast cereals has a positive impact on iron status. (Powers et al. 2016) In this trial 71 girls aged 16-19 who did not consume breakfast cereals more than four times a week were studied in a random, double blind, placebo-controlled intervention over a 12-week period. 55% of their iron intakes was lower than RNIs or DRIs. The study found that daily intake of iron increased from a mean of 8.9mg/day pre-invention to a mean of 13.1mg/day post-intervention when fortified cereals were consumed. This is a significant increase. Even though some girls were still below the sets of requirements none fell below the LRNIs for the UK. No haemoglobin increase was noticed and there was no difference in haemoglobin concentrations between the two groups afterwards. The transport of iron to the site of haemoglobin synthesis was never compromised. (Powers et al. 2016)
Iron is a mineral of major importance to teenagers as it is a component of haemoglobin and it supports muscle development during growth spurts. Research shows that changes, like increasing haem iron in the diet and the fortification of foods can improve iron intake among adolescence.
Food Safety Authority Ireland (1999). Recommended Dietary Allowances for Ireland. Food Safety Authority Ireland. Available at https://www.lenus.ie/handle/10147/44808 (Accessed on 18 November 2018)
Gibney, MJ. et al. (2010) Introduction to Human Nutrition Second Edition. Wiley-Blackwell.
Powers HJ. Et al. (2016) ‘Fortified breakfast cereals consumed daily for 12 wk leads to a significant improvement in micronutrient intake and micronutrient status in adolescent girls: a randomised controlled trial’, Nutrition Journal, 15, pp 69. Available at: https://doi.org/10.1186/s12937-016-0185-6. (Accessed on 7 November 2018)
Vandevijvere, S. et al. (2013) ‘Intake and dietary sources of haem and non-haem iron among European adolescents and their association with iron status and different lifestyle and socio-economic factors’, European Journal of Clinical Nutrition, 67, pp 765-772. Available at: https://doi.org/10/1038/ejcn.2013.100 (Accessed on 7 November 2018)
Wharton, B. et al. (1987) ‘Nutrition in Adolescence’, Nutrition and Health, 4(4), pp. 195–203. https://doi.org/10.1177/026010608700400403 (Accessed on 29 November 2018)