The effects of cooking utensils on the iron content of staple foods


Globally, over 600million people particularly in developing countries were affected by iron deficiency. Iron deficiency is the most common cause of anemia and insufficient dietary intake. However, infants, children and adults of reproductive age were the most vulnerable to this disease (Kennedy, Guy & Prakash, 2003; Unified Standing Communities on Nutrition, 2004).

Iron deficiency anemia among women is associated with an estimated 11,000 maternal death worldwide yearly. The prevalence among this group in Nigeria ranges between 24 to 48% (Federal Ministry of Health,2005;Food and Agricultural Organization, 2003). The deficiency is usually not due to the absolute lack of iron in their diet but rather to the processing methods adopted and poor bio availability of iron in these staple foods (Latunde, 2003). Even food staples that have adequate amount of these nutrients were either affected by losses during processing or increase from processing surfaces. Thus predisposing individuals to unhealthy risk factors to disease conditions from iron deficiency or iron overdose (Wardlor & Haupl, 2007; Chalton, Bothweel& Saftle, 2003). The majority of the population of most developing countries such as Nigeria relies on plant foods to provide their nutrient needs.  Staple foods such as maize, millet and sorghum tubers only supply 24%. However, the availability of non from these plant staples is very low (Hallberg, 2001; Loe &Clydesdale, 2007).

 Definition of staple food

A staple food, sometimes simply referred to as a staple, is a food that is eaten routinely and in such quantities that it constitutes a dominant potion of a standard diet in a given people, supplying a large, fraction of the needs for energy rich materials and generally a significant portion of the intake of other nutrients as well (Wikipedia, 2015).

Staple foods may from place to place, but typically they are inexpensive in readily available foods that supply one or more of the three organic micro nutrients needed for survival and health, carbohydrates, protein and fat.

Typical examples include:

  • Tuber or rest crops: yam, cassava.
  • Cereals: wheat, maize, rice.
  • Legumes and other seeds: cowpea.
  • Plantains

On the other hand, iron is a mineral that is naturally present in many foods, added to some food products and available as a dietary supplement. The cooking utensil includes stainless steel pots, clay pots and cast iron pots.

Recommended Dietary Allowances (RDAs) for Iron

Age                                        Male              Female                      Pregnancy   Lactation

Birth to6months                   0.27mg          0.27mg


7-12months                          11mg                        11mg

1-3years                                7mg                           7mg

4-5years                                10mg                         10mg

9-13years                              8mg                           8mg

14-18years                            11mg                         15mg                      27mg             10mg

19-50years                            8mg                           18mg                    27mg             9mg

51 + years                             8mg                           8mg


Cooking utensils and their effect on iron content in mg (100g) of staple foods

                            WhiteYam             Maize        Cowpea                        Plantain
Raw foods           0.46mg                      2.50mg            4.08mg                         3.14mg
Cooked on

Stainless pot        0.41mg                    2.48mg            3.31mg                         2.60mg

Cooked in

cast Iron pot        0.47mg                  2.54mg               4.13mg                      3.21mg

Cooked in

Clay pots                  0.45mg                   2.45mg          3.5mg                        2.81mg


Discussion of results presented in table I

Presented in table 1 above are the iron content of four staple foods cooked in stainless steel pot, cast iron pot and clay pot. From the table, it was found that iron content of raw foods were: 0.48mg (yam), 2.50mg (maize), 4.0mg (cowpea) and 3.14mg (plantain).

Also, the iron content of these four staple food was said to have reduced when cooked in stainless pots and compared with its raw contents. It read as 0.41mg (yam), 2.18mg (maize), 3.31mg (cowpea) and 2.60mg (plantain).

In addition, the iron content of these four staple foods was said to have increased when cooked in cast iron pots and compared with its raw content, it was as o.41mg (yam), 2.54mg (maize), 4.13mg (cowpea) and 3.21mg (plantain).

Finally, the iron content of these staple foods was said to have decreased when cooked in clay pots and compared   with its content. It read as 0.45mg (yam), 2.45mg 9maize), 3.54mg (cowpea) and 2.81mg (plantain).

Iron content of all these food varied from values obtained in food composition tables (platt, 2005; FAO, 2008). This may probably be due to variety of the various foods composition tables (platt, 2005; FAO, 2008). This may probably be due to variety of the foods that were analyzed, soil conditions and maturity at harvest of the various food samples. The result also shows that cowpea has the highest amount of iron at raw and after cooking. Although appreciable amount was found in maize and plantain.

This means that adequate intake of these three staples can supply over 40% RDA of the needed iron per day by an adult. However, irons from food of plant origin are less bio available to human nutrition, compared to iron from animal food source. It shows that consumers of foods cooked in these types of utensil are likely to be prone to iron deficiency anemia. This finding is consistent with (Henget al., 2001) results. It was found that the processes like washing, peeling and dicing had less significant effect on iron contents of edible portions of the staple food cooked in the three utensils.

However, it was reported by Latunde (2003) that significant losses of iron occur during the process of blanching and squeeze. Washing of vegetables which are common among Nigeria household food handlers. Therefore peeling and dehulling food staples may have a negative effect on iron and other micro nutrients content during cooking. Recently, a significant result was obtained from the study of Geerling et a.l (2003).

Iron and aluminum cooking pots were used in cooking foods to determine their effect on consumers’ hemoglobin status of rural adults Malawian with malaria infection. Result shows that mean hemoglobin change was significantly increased after six weeks of consumption of foods from the iron pots in Nigeria clay pots, stainless steel pots, aluminum pots and iron cooking pots were the most widely used utensils both in urban and rural communities. Information on the effect of iron content on food cooked in some of these utensils are minimal and inadequate.


In conclusion it is shown that some cooking pots contribute to iron content of staple foods cooked in this utensils. Therefore, good cooking utensils will go a long way to conserve iron loss during cooking and improve iron intake from the staples, thereby reducing iron deficiency anemia among the various vulnerable group in the population.

Also, Nigeria women at household level need to be encouraged to use utensils that will promote adequate iron intake and not utensils that can cause an overload to the consumer of those food cooked in them. Food handlers also need education on the effect of various processing procedure employed in the preparation of food that will lead to losses or conservation of micro nutrient. Rural peasant women should be educated on the use of cast range of iron cooking pots and avoid practices that reduce iron and other micro nutrients loss from food. More so awareness should be created on the need to bio fortify some foods with micro nutrients that can easily leach into water through utensil inner surface like clay pot during the cooking period. Good cooking utensil will go a long way to conserve iron during the cooking and improve iron intake the staples, thereby reducing iron deficiency anemia among the vulnerable in the population.


  • There is need for in-depth research to further probe into this area of study so as throw more light in this micro nutrient which is of high importance to human health.
  • Nigerian women at household level need to be encourage on the utensil that will promote adequate iron intake and not utensils that can curse iron overload to the consumer of those food cooked in them..
  • Food handlers also need education on the effect of various processing procedures employed in the preparation of food that will lead to losses.
  • Women of reproductive age need to be educated on cooking practices that affect micro-nutrients loss and should be encourage on the important of regular intake of iron supplement.


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Food and Agricultural Organization (2003).Food consumption table for use in Africa. United States Department of Health and Education and Welfare Public Health Service.

Federal Ministry of Health(2005).National guideline on micronutrient deficiencies control in Nigeria, Abuja: Department of Community Development and Population.

Geerling, P.P., Brabin, B., Mkumbina, A., Broadlead, R. &Guera, L.E. (2003). Effect of hemoglobin on the use of iron cooking pots in rural Malaria household on an area with high malaria prevalence.

Gordon, M. Wardlaw & Hampl, J.S. (2007). contemporary nutrition issue and insight .water  and minerals (7th ed).United Statesof America: McGraw Hill.

Hallberg, L. (2001).Bio availability of dietary iron in man.Ann Rev. Nutrition, 1,123 – 147.

Kennedy, G., Guy N. &Prakash, S.  (2003). The scourge of “Hidden Hunger”. Global dimension of micro nutrient deficiencies food nutrition and Agriculture no 32

Latunde, D. (2003).Iron contents and some physical components of twelve cowpea varieties. Food science nutrition, 43, 193-197.

Lee,K.& Clydesdale, F.M. (2007).Effect of thermal processing in endogenous and added iron in canned spinach. Food science, 46,1064-1068.

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United Nations Standing Committee on Nutrition (2004). 5th report on the world nutrition’s situation. Nutrition for improved development outcomes.

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