Folic acid fortification of foods : Estimated intake of folate from different fortification scenarios in Norwegian population groups

Abstract

Clinical deficiency of micronutrients is uncommon in the developed world, but interest has increasingly focused on non-clinical deficiencies, or suboptimal status of micronutrients and the effect such deficiencies may have on risk of chronic disease. The focus on folate has greatly evolved over the past two decades from the prevention of anaemia to the prevention of neural tube defects (NTD). Folate also appears to have a lot of other health benefits; accumulating evidence suggests that folate may play a role in the prevention of cardiovascular disease and cancer. This expanding role of folate in prevention has major public health implications Public health policies have developed in two ways: some American and developing countries have chosen mandatory fortification of staple foods with folic acid (FA), while most western European countries so far have decided not to do so. In most Western European countries, voluntary fortification is nevertheless allowed, and some specific products are available. In this thesis the main aim was to: “determine a level of mandatory fortification that maximised folic acid (FA) intake for women of fertile age, to assist in achieving their recommended intake of 400 ìg FA/day, whilst preventing a significant proportion of people in the target and non-target groups to exceed the upper safe levels of intake. In considering mandatory fortification of food with FA, flour and bread were selected as the food vehicles. Breakfast cereals, juice, nectar, yoghurt and milk were selected as possible products for voluntary fortification. The effect of various fortification and supplementation scenarios have been studied for children 4, 9 and 13 years old, adult men, women of child-bearing age and pregnant women from. Norkost II (1997), Ungkost II (2000-2001) and the Norwegian Mother and Child Cohort Study. According to the results it is impossible with mandatory fortification of food with FA in Norway at a level that ensures the majority of women in the target group will consume 400 ìg folate/day, without other population groups exceeding upper safe level for FA. If mandatory fortification of flour with FA would be 140 µg FA/100 g flour, 41% of the fertile women and 29% of the pregnant women would reach the recommended intake. In the same scenario almost 20% of the children aged 4 and 9 years would exceed upper level. The scenario where least persons got an intake over upper level was when bread was fortified with 100 ìg FA/100 g. In this scenario 19% of the children aged 4 years and 15% aged 9 years reaches upper level, whereas over 50% of the fertile and pregnant women did not reach the recommended intake. With intake of voluntary fortified foods 83% of the fertile women and pregnant women would reach the recommendations, if taking FA supplement with 200 ìg/day in addition to dietary folate. In the fortification scenarios for those taking supplements with 200 ìg FA in addition to the five voluntary products and dietary folate show that 99% of children aged 4 years and 75% aged 13 years received total folate over UL. The fact that some of the supplements designed for children contain 200 ìg FA should be questioned, especial if Norway goes for mandatory fortification but also with regards to voluntary fortification. It might be a good decision to limit the content of FA in supplements designed for children. Data on the long term effects of increased folate intake are limited. The effects of long term exposure to high concentrations of FA are unknown, but antimetabolite effects are theoretically possible. We need to know more about the effects of chronic exposure to FA before instituting mandatory fortification. The strategy of universal fortification of staple foodstuffs with folic acid also presents the possibility of life-long exposure to unmetabolized FA. Therefore Norway should wait for new knowledge before starting mandatory fortification