Chapters 9.1/9.2

9.1/9.2 - Improving iron absorption

Michael Parmentier-Luzar, University of Guelph, Canada

Suggested citation for this chapter.

Parmentier-Luzar,M (2022) title of chapter. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

Introduction

Iron deficiency and related cases of anaemia constitute a global health risk of epidemic proportions. Iron deficiency reduces individuals’ work capacities, negatively affecting their ability to make a living and, in cases where it is widespread, severely hampering national economic development. This is especially apparent in developing countries (WHO, N.D). This chapter outlines a simple, low-cost set of practices for enhancing people’s abilities to absorb iron, with the goal of reducing the prevalence of iron deficiency. It is recommended that people increaes their ascorbic acid (vitamin C) intake around mealtimes, while simultaneously reducing caffeine intake.

Role of Iron in the Body

Iron is an essential element for most organisms and is critical to a number of human bodily functions. It is required for hemoglobin, the protein found in red blood cells that carries oxygen from the lungs to rest of the body (FAO & WHO, 2002). Iron can be classified under two primary subtypes:

-Heme Iron: primarily found in blood and muscles (meat) and is more easily absorbed by humans than the non-heme iron found in plants.

-Non-Heme Iron: found primarily in non-meat sources (plants and carbohydrates) and is not as easily absorbed by humans as heme iron (Hurrell & Egli, 2010

Consequences of Iron Deficiency

Anaemia is a condition where a deficiency in hemoglobin prevents red blood cells from providing adequate amounts of oxygen to the body (UNICEF & WHO, 1999). This can decrease an individual’s ability to work, contributes to overall poor health, and can lead to death over time. Physical symptoms include fatigue, shortness of breath, feelings of irritability, dizziness, headaches, and feeling cold, among others. Iron deficiency is responsible for approximately half of the cases of anaemia in developing countries. The other half of cases are generally attributable to disease, blood loss, and other nutrient deficiencies (Abbaspour et. al, 2014). Iron plays a crucial role in hemoglobin and red blood cell functionality (FAO & WHO, 2002), making proper intake and absorption important in reducing incidents of anaemia.

Who is most at risk for anaemia

Anaemia affects approximately 1.62 billion people globally (WHO, 2008). Low iron intake and absorption, rapid growth, pregnancy and menstruation are the primary causes of iron deficiency (Abbaspour et. al, 2014) relevant to this chapter. Correspondingly, growing children, pregnant and menstruating women are highly vulnerable to iron deficiency and related cases of anaemia (Abbaspour et. al, 2014; CDC, 2015). Iron deficiency is the leading single-nutrient deficiency among children and infants (Zlotkin et. al, 2003), presenting a challenge to solve a significant worldwide problem. Table 1 illustrates the prevalence of anaemia among subgroups globally, and specifically in Africa and India. The table displays a clear trend that anaemia rates in India and Africa, proportional to population, are considerably higher than the global standard.

The Effect of Caffeine on Iron Absorption

Caffeine does not have a marked effect on heme iron absorption, but it impinges on the body’s ability to absorb non-heme iron significantly. As discussed, heme iron is typically found in meat, while non-meat foods provide non-heme iron (Hurrell & Egli, 2010). Many diets in developing countries are based around grains and/or vegetables, often comprising relatively little – if any – meat. In some cases this is the result of a lack of availability, and in others is a matter of culture and/or religious choice. Considering that subsistence farmers in developing countries, and in many African countries specifically, rely primarily on non-heme iron, impaired absorption is highly problematic.

Effect of Citrus on Iron Absorption

Citrus fruits are rich in ascorbic acid (vitamin C), which significantly improves the body’s ability to absorb iron. Ascorbic acid is the most potent enhancer for humans when it comes to non-heme iron absorption (FAO & WHO, 2001). It exists in a number of fruits, making it an excellent option for improving iron bioavailability from grain and vegetable based diets.

Description of Practice: Reducing Caffeine and Adding Citrus

A simple and cost-effective method to help mitigate iron-absorption impairment is to limit caffeine intake. It must be noted that it is beyond the scope of this chapter to comment on the potential overall effects, both positive and negative, of completely eliminating caffeine from one’s diet. As a best practice, nutritional experts recommend limiting caffeine intake, specifically around meal times.

Tea and coffee are popular dietary sources of caffeine. In addition to caffeine, tea and coffee contain tannins that have also been observed as major inhibitors to iron absorption (Aldrian et. al, 1997). To avoid caffeine and tannin inhibition, one should allow a two-hour window between main meals and consumption of coffee or tea (FAO & WHO, 2001).

Nutritional experts second primary recommendation is to increase ascorbic acid consumption, particularly by pairing it with non-heme iron sources to enhance absorption. As noted, citrus fruits are an excellent source of ascorbic acid, and represent a natural, low-cost intervention to boost non-heme iron absorption.

A variety of different citrus fruits can be used for enhancing iron absorption. Individuals’ choices may be based on local availability, cultural preferences, or environmental factors (for example, soil type). When feasible, it may be advisable for subsistence farmers to plant multiple types of citrus fruit to better mitigate the risks posed by disease, pests, fungi and drought. The following table outlines approximate ascorbic acid content values for a number of citrus fruits

:

From the table, it can be deduced that the most potent source of dietary ascorbic acid is in consuming raw, whole oranges. Juicing is generally not recommended because, except in the case of grapefruit, it appears to lessen the ascorbic acid content gram-for-gram, and may be more labour intensive than eating the fruit whole.

It is worth noting here that adding lemon and lime to foods is already a traditional practice in many cultures. Because ascorbic acid is water-soluble and destroyed by heat (U.S Department of Health and Human Services, 2016) however, it is best that citrus be added to meals after the food has been cooked; for example, adding lemon zest to the top of a plated meal, as opposed to during the cooking process. This simple practice can be promoted where it is already common, and encouraged where it is not.

Additional Practices: Iron Fortification and Adding Meat to Vegetarian Meals

In addition to enhancing the body’s ability to absorb iron, it can be beneficial to increase overall iron intake when feasible. Nutritional experts recommend adding small amounts of meat to meals (FAO & WHO, 2001) when available and culturally appropriate, and fortifying other foods with iron as best practices.

The iron-related benefits of adding small amounts of meat to otherwise vegetarian meals is two-fold. Meats are rich in heme iron that is resistant to the impairing effects of tannin and caffeine, providing a more bioavailable source to the body. Furthermore, heme iron also enhances the body’s ability to absorb non-heme iron (WHO, 1999), indirectly improving iron bioavailability from non-meat sources. The following table outlines the iron content of a number of raw meats and meat products:

It is important to note that Table 3 was constructed using data on commercially available meats in the United States, and therefore may not reflect the iron content of locally available foods. A full analysis of iron content in meat is beyond the scope of this chapter, but this data suggests generally that red meat is the most potent provider of iron, followed by eggs and chicken. Based on this information, further research ought to look into the viability of raising chickens for egg harvest as a sustainable source of heme iron.

Where adding meat and/or meat products are not feasible or culturally appropriate, an alternative method of fortifying foods with iron can be beneficial. Iron fortification is beyond the scope of this chapter, but it should be noted that a number of low-cost, accessible options are being developed in this area (see Food Fortification and Sprinkles, p. 140 in Micronutrients, Macro Impact: The story of vitamins and a hungry world. Obtained from http://www.sightandlife.org/fileadmin/data/Books/Micronutrients_Macro_Impact.pdf).

Benefits of Enhanced Iron Absorption

Enhancing iron absorption through the reduction of caffeine and addition of ascorbic acid has a number of tangible benefits. As an essential micronutrient (CDC, 2015), better iron absorption can contribute to increased physical and mental development in children, and to higher development levels for future generations (WHO, N.D). In addition, improving iron absorption can allow for higher work productivity by allowing more oxygen to reach the muscles from the lungs. This can allow people to work longer and harder without tiring, and generally enjoy life to a fuller extent (WHO, N.D). Finally, by enhancing cognitive/labour capacity and morale, these benefits can manifest in higher yields and profits for subsistence farmers.

Critical Analysis

Coffee and tea are two primary sources of caffeine, and may be staple beverages in many areas and to certain groups. With this in mind, it may be unrealistic and unwelcome to recommend complete elimination of these beverages from local diets. It is important to remember that we ought not make recommendations to people that we would not personally follow. Furthermore, as previously mentioned, it is beyond the scope of this article to assess the overall effects, whether positive or negative, of caffeine elimination. Beyond the personal health effects, there is also the potential that farmers in certain locales rely on coffee/tea as cash crops. Recommending that locals eliminate caffeine in their diets may have the unwanted effect of alienating these farmers, and potentially affect their livelihoods. For these reasons, it is imperative that we recommend a targeted reduction in caffeine consumption around mealtimes as opposed to complete dietary elimination.

In regards to the recommendation that meat be added to meals to increase iron intake, it is important to consider individual local contexts. Beyond the issues of livestock and fish availability, many people adhere to vegetarian diets based on cultural and/or religious beliefs. Many practitioners of Hinduism and Buddhism, for example, abstain from meat consumption entirely. In these cases, incorporating meat into the diet is simply not feasible, and therefore should not be recommended as an intervention option.

Further Reading

For further reading on this topic, see the following resources:

1.World Health Organization: Micronutrient Deficiencies. http://www.who.int/nutrition/topics/ida/en/

2.United States Department of Agriculture: USDA Food Composition Databases. https://ndb.nal.usda.gov/ndb/search/list

3.Center for Disease Control: Micronutrient Facts. http://www.cdc.gov/immpact/micronutrients/index.html

4.Food and Agriculture Organization of the United Nations: Humani Vitamin and Mineral Requirements. ftp://ftp.fao.org/docrep/fao/004/y2809e/y2809e00.pdf

References

1. Abbaspour, N., Hurrell, R., & Kelishadi, R. (2014, February). Review on iron and its importance for human health. International Journal of Research in Medical Sciences, 19(2), 164-174. Retrieved from US National Library of Medicine National Institutes of Health.

2. Aldrian, P., Keen, C., Lonnerdal, B., Dewey, K. (1997). Effects of coffee consumption on iron, zinc and copper status in nonpregnant and pregnant Sprague-Dawley Rats. International Journal of Food Sciences and Nutrition. 48: 177-189.

3. Hallberg, L., & Rossander, L. (1982, April). Effect of different drinks on the absorption of non-heme iron from composite meals. Human Nutrition Applied Nutrition, 36(2), 116-123. Retrieved from US National Library of Medicine National Institutes of Health.

4. Hurrell, R., & Egli, I. (2010). Iron bioavailability and dietary reference values. American Journal of Clinical Nutrition. 91: 1461S – 7S.

5. Mascitelli, L., Pezzetta, F., & Sullivan, JL. (2007). Inhibition of Iron Absorption by Coffee and the Reduced Risk of Type 2 Diabetes Mellitus. Arch Intern Med. 167(2):204-205.

6. World Health Organization, Food and Agriculture Organization of the United Nations (2002). Human vitamin and mineral requirements. Report of a Joint FAO/WHO Consultation – Bangkok, Thailand. Retrieved November 23rd, 2016, from http://www.fao.org/docrep/004/Y2809E/y2809e00.htm#Contents.

7. World Health Organization. Micronutrient deficiencies: Iron deficiency anaemia. (n.d.). Retrieved October 4, 2016, from http://www.who.int/nutrition/topics/ida/en/

8. World Health Organization. Vitamin and Mineral Nutrition Information System: Summary tables and maps on worldwide prevalence of anaemia. Retrieved November 29, 2016, from http://www.who.int/vmnis/database/anaemia/anaemia_data_status/en/.

9. World Health Organization, Benoist, B., McLean, E., Egli, I., Cogswell, M. Worldwide prevalence of anaemia 1993 – 2005. WHO Global Database on Anaemia. Retrieved November 30th, 2016, from http://apps.who.int/iris/bitstream/10665/43894/1/9789241596657_eng.pdf

10. UNICEF, World Health Organization (February, 1999). Prevention and Control of Iron Deficiency Anaemia in Women and Children. Report of the UNICEF/WHO Regional Consultation. Retrieved November 23rd, 2016, from http://www.who.int/nutrition/publications/micronutrients/anaemia_iron_deficiency/UNICEF_WHO_ida_consutlation_report.pdf.

11. U.S Department of Health and Human Services: National Institutes of Health (February, 2016). Vitamin C Fact Sheet for Health Professionals. Retrieved November 23rd, 2016, from https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/#en6.

12. Zlotkin, S., Arthur, P., Schauer, C., Antwi KY., Yeung, G., Piekarz, A. (April, 2003). Home-fortification with iron and zinc sprinkles or iron sprinkles alone successfully treats anemia in infants and young children. The Journal of Nutrition. 133(4): 1075-1080