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Research confirms winning 'eggs and C' combination

16/10/2008

A new research study presented this week (16 October) has confirmed that the amount of iron absorbed from eating eggs may be significantly increased by consuming food or drink containing Vitamin C at the same meal.

So a glass of orange juice with a breakfast egg, or an omelette and salad, could be on the menu for the millions of people in the UK suffering from low iron levels.

Iron deficiency is a relatively common nutritional disorder - it is estimated that about 8% of women in the UK have anaemia, the clinical symptom of iron deficiency, and many more have low iron stores [1]. Women of child-bearing age are most at risk, especially when pregnant.

Survey data also indicate that about a quarter of women have a low iron intake [2] and that the diets of young women are particularly low in iron, with 50% of 15-18 year olds having intakes below the lower reference nutrient intake (LRNI), the amount considered as inadequate [3].

Eggs are a useful source of iron, with 1mg per medium egg, and a two egg-meal contributes between 14-23% of an adult’s daily iron requirement [4].  However there has previously been uncertainty about the bioavailability - the degree to which a nutrient is available to the body - of the iron.

Using an in vitro technique, modified from the method used to screen iron availability in food crops [5], the study at the University of East Anglia, illustrated in a poster today at the first BBSRC Diet and Health Industry Research Club Dissemination meeting [6], measured iron availability in hard boiled eggs with and without foods containing vitamin C - orange juice or salad (lettuce, tomato and red pepper) - in ratios that would be found in a meal, using a Caco-2 cell model system that predicts how cells in the intestine will respond.

Meals were prepared and put through a process to simulate digestion in the gut, and iron uptake into the cells was measured.  When mixed with orange juice or salad, iron uptake from eggs was significantly increased.

“These findings, if confirmed in vivo, show that the iron in eggs has a higher bioavailability when consumed with food rich in vitamin C,” commented Sue Fairweather-Tait, who coordinated the research at the University of East Anglia, undertaken by a Master’s student from the University of Sheffield. “This is important information for the significant percentage of the UK population, in particular young women, suffering from iron deficiency.”

References

1.Ruston D, Hoare J, Henderson J, Bates CJ, Prentice A, Birch M, Swan G, Farron M. The National Diet & Nutrition Survey: adults aged 19 to 64 years. Volume 4: Nutritional status (anthropometry and blood analytes), blood pressure and physical activity. The Stationery Office (London, 2004)
2.Henderson L, Irving K, Gregory J, Bates CJ, Prentice. A, Perks J, Swan G, Farron M. The National Diet and Nutrition Survey: adults aged 19-64 years. Volume 3: Vitamin and mineral intake and urinary analytes. The Stationery Office (London, 2003)
3.Gregory J, Lowe S, Bates CJ, Prentice A, Jackson V, Smithers G, Wenlock R, Farron M.  The National Diet and Nutrition Survey: young people aged 4-18 years. Volume 1: Report of the diet and nutrition survey. The Stationery Office (London, 2000)
4.Department of Health. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. HMSO (London 1991)
5.Glahn RP, Lee OA, Yeung A, Goldman MI, Miller DD. Caco-2 ferritin formation predicts nonradiolabeled food iron availability in an in vitro digestion/Caco-2 cell culture model. J Nutr 1998;128:1555-61.
6.Thompson BAV, Al Mutairi S, Fairweather-Tait SJ. A modified simulated digestion/Caco-2 cell in vitro model to study iron availability. BBSRC DRINC Dissemination Meeting, 16th Oct, London.