|1. Chemical structure.
2. Absorption mechanisms.
3. Bioavailability established by internationally recognized procedures.
4. Effectiveness as measured by field and clinical trials, using the compound as a supplement or in food fortification.
5. Acute, sub chronic and chronic toxicity studies.
6. Acceptability. No gastric problems. No organoleptic changes in foods.
7. Regulation of absorption by body reserves.
9. Registered by International quality assurance organizations.
The Compounds to be included in the Food Fortification Programme
The DOH and their advisors, selected and recommended the following compounds to be used as fortificants:
|Vitamin A Palmitate||Vitamin (B1) Thiamin Mononitrate|
|Vitamin (B2) Riboflavin||Vitamin (B3) Nicotinamide|
|Vitamin (B6) Pyridoxine HCl||Folic Acid|
|Reduced Iron (Electrolytic Manufactured, min 98% activity )||Zinc Oxide (min 80% activity)|
|Calcium Carbonate as carrier ( min 40% activity )|
Although the levels of the RDA have been recommended to be applied at 33% of the RDA, in a draft proposal dated 29th November 2001 (Regulations Governing the Fortification of Foodstuffs) the following dosage levels of nutrients per 200 g dry maize flour have been recommended;
Vitamin A 25% Vitamin B1 25% Vitamin B2 17% Vitamin B3 25% Vitamin B6 25% Folic Acid 17% Iron 50% Zinc 20%
Additional feed back on Folic Acid dosage levels is still outstanding
The portion sizes to be fortified of dry maize & wheat flour have been recommended to be 200g. Maize flour has a swell factor of 2.5 = 500 g cooked maize porridge. Wheat flour converted to bread will = ± 333g or 11 slices at 30 g each.
*Due to the instability of vitamin A when added to a premix and losses of the vitamin over the shelf life of the product and general losses when heated, for reconstitution, overages of vitamin A, at 142% have been included in maize flour to attain the desired dosage levels upon consumption, namely 25% of the RDA. ( please note the RDA values are based on adult requirements ) Thus theoretically the dosage of vitamin A delivered per 500g cooked maize flour will be 250 RE.
On evaluation of vitamin A needs for children in the age group 1 - 3 years old, the RDA requirements are 400 RE, thus in theory a child consuming 200g dry maize porridge a day will obtain 62.5% of their vitamin A needs.
The CSIR " Division of Food Science and Technology; Report; Storage Test of Fortified Maize Meal and Bread Flour, October 2000 " L Kyper Reported losses of vitamin A in storage conditions (shelf life of maize flour) and after cooking (reconstitution) at values of 142%.
The DOH are recommending the addition of 1,920 RE vitamin A per kg of maize flour. 5 portion sizes per kg of maize flour will yield a total of 384 RE per 200g dry maize flour. The reported losses of 142% vitamin A activity in maize flour, must be deducted to equate to vitamin A levels upon consumption, i.e. 200g of dry maize flour will contribute ± 40% of the RDA or 158 RE vitamin A. This equates to ± 40% of the RDA values for children 1 - 3 years of age, if they consume 500g of cooked maize porridge a day?
If the dietary adequacy of vitamin A is still less than 50% of the RDA amongst the most vulnerable group of children, it is unlikely to have the desired effect of preventing or curing vitamin A deficiency, as levels of vitamin A repleteness and vitamin A stores will not be maintained.
The choice of iron compound for the DOH food fortification program is "Reduced Iron ". It is electrolyticaly manufactured and has extremely poor bioavailability factors, especially with particle sizes as stipulated by the DOH to be in the region of 45 micrometers in diameter. (2) Reduced Iron, commercial food grade, is absorbed at only 0.2% in foods. The recommended dosage level is 7.4mg per 200g dry maize flour. The RDA, needs for children aged 1 - 3 years old is 10mg. Taking the bioavailability factor of 0.2% in a 200g dry maize flour portion size, 500g cooked maize porridge, a child will receive only 0.0014mg Fe a day!
The use of Reduced Iron of smaller particle sizes may offer an improvement, but still does not reach bioavailability of a more suitable alternative, ferrous sulphate. Studies using " Reduced Iron " ( Electrolytically Manufactured ) with particle sizes of 10 micrometers in diameter or less show that absorption was still only half that of Ferrous Sulphate. Ferrous Sulphate has a bioavailability factor of 2% in a diet rich in phytates. Thus, even at a bioavailability factor of 1% using smaller particle sizes of reduced iron, it will still only deliver 0.074mg, as a contribution to the child's daily needs of 10mg, and only if 500g of maize porridge can be consumed a day.
We are unable to find any bioavailability studies on Zinc Oxide in maize flour or wheat flour.
Metal to metal antagonsim/interference can not be intentionally ignored. (3) If calcium carbonate will be used as the carrier of the nutrients, it is most likely to interfere with the absorption of iron. (4) Ratios of non-heme iron to zinc of 2:1 and 3:1 have been shown to inhibit zinc absorption. It is also known that phytates inhibit the absorption of iron and zinc.
Parasitic infestation is also known to contribute to blood and iron loss. (5) A. duodenale, N. americanus, T.trichiura can have a negative impact on the iron status of children in South Africa, if not addressed prior to the implementation of a fortification program.
The DOH have shown a great vision to address malnutrition and must be admired for their efforts and endeavours. All parties concerned that have a true desire to address the scourge of poverty and malnutrition should assist the DOH in obtaining its objective without losing sight of delivering a cost effective fortification program together with a myriad of other interventions that will run parallel towards the upliftment and improvement in nutrient density of staple foods, supplementation programs, education and communication programs, mass dosage vitamin A, deparasitising programs etc for a better, brighter future of the targeted population most in need.
*(Please note, due to the home baking method used by the CSIR, Food Science and Technology Division, in the baking of breads for sensory and stability tests, we are unable to use the results as a reference.)
Gary Klugman Director CELANEM. Regional Office For Africa Latin American Center For Nutrition And Metabolic Studies Consultants in Biochemistry, Nutrition and Applied Nutrition.
Contact Gary Klugman at +27 (0) 21 981 7600 or at email@example.com
(1) David L. Yeung; Iron and micronutrients; complimentary food fortification;
(2) Bioavailability of different iron compounds in food; Brise & Halberg, Acda Med Scand 1960; supp. 368. Pineda, et al, J Appl Nutr 1984;46:2-13; Martinez-Torres, et al, 1986 J Nutr 116: 1720-25; Kalwasser, et al, 1987;37:122-29
(3) Intestinal Absorption of metal ions and chelates;1985 Charles C Thomas. Publisher; H. DeWayne Ashmead, Ph.D.; Darrell J. Graff, PH.d.; Harvey H. Ashmead, Ph.D.
(4) Solomons NW, Jacob RA. Studies on the bioavailability of zinc in humans; Effects of heme and nonheme iron on the absorption of zinc. Am J Clin Nutr, 1981;34:475-482
(5)Holland, Clin Nutr, 1989;8239-50
Copyright 2002 Janice Limson. All Rights Reserved