National fortification of staple foods can make a significant contribution to micronutrient intake of South African adults.
BACKGROUND
A national survey found that micronutrient deficiencies are prevalent in South African children, particularly calcium, iron, zinc, riboflavin, niacin, vitamin B6, folate, vitamin A, E and C. Mandatory fortification of maize meal and wheat flour were introduced in 2003 to combat some of the deficiencies found in children. To date however, there has not been a national survey on dietary intake in adults.


OBJECTIVE
The main objectives of this study were to evaluate the micronutrient intake of the diet consumed by the average adult South African by means of secondary data analyses and secondly to evaluate the effects of fortification on selected nutrient intakes.


METHODS
Secondary data analysis was carried out with numerous dietary surveys on adults to create a database that included sampling (and weighting) according to ethnic/urban-rural residence in line with the population census, of which 79% were black Africans and the majority resided in rural areas. The effect of fortification was evaluated by substituting fortified foods in the diet for the unfortified products.


METHODS
The combined database used in this study comprised 3229 adults.


RESULTS
Mean calcium, iron, folate and vitamin B6 intakes were very low particularly in women. Mean intakes of most micronutrients were lower in rural areas. Fortification of maize meal and wheat flour (bread) raised mean levels of thiamine, riboflavin, niacin, vitamin B6 and folate above the recommended nutrient intakes (RNIs). In women, despite fortification, mean iron intakes remained below the RNIs, as did calcium since it was not in the fortification mix.


CONCLUSIONS
The average dietary intake of adults was of poor nutrient density, particularly in rural areas. Fortification of maize meal and wheat flour (bread) considerably improved mean vitamin B6, thiamine, riboflavin, niacin, folate and iron intakes as well as the overall mean adequacy ratio of the diet.
Steyn
Nelia P
NP
Chronic Diseases of Lifestyle, Medical Research Council, P Bag 19070, Tygerberg 7505, Cape Town, South Africa. nelia.steyn@mrc.ac.za
Wolmarans
Petro
P
Nel
Johanna H
JH
Bourne
Lesley T
LT
D000328:Adult; D000367:Age Factors; D004034:Diet Surveys; D005260:Female; D005433:Flour / Q000032:analysis; D005527:Food, Fortified; D006801:Humans; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage* / Q000172:deficiency*; D008875:Middle Aged; D008903:Minerals / Q000008:administration & dosage; D009753:Nutritive Value; D012424:Rural Population; D012737:Sex Factors; D013019:South Africa; D014908:Triticum; D014505:Urban Population; D014815:Vitamins / Q000008:administration & dosage; D003313:Zea mays
D018977:Micronutrients; D008903:Minerals; D014815:Vitamins