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Vitamin D and Folate fortification of foods - April 2012

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Vitaminfood fortification today

Maria de Lourdes Samaniego-Vaesken,Elena Alonso-Aperte and Gregorio Varela-Moreiras*

Departmentof Pharmaceutical and Food Sciences, Faculty of Pharmacy, CEU SanPablo University, Madrid, Spain

Abstract

Historically,food fortification has served as a tool to address population-widenutrient deficiencies such as rickets by vitamin D fortified milk.This article discusses the different policy strategies to be usedtoday. Mandatory or voluntary fortification and fortified foods,which the consumer needs, also have to comply with nutritional,regulatory, food safety and technical issues. The ‘worldwidemap of vitamin fortification’ is analysed, includingdifferences between developed and developing countries. The vitamins,folate and vitamin D, are taken as practical examples in the reviewof the beneficial effect of different strategies on public health.The importance of the risk–benefit aspect, as well as how toidentify the risk groups, and the food vehicles for fortification isdiscussed.

Keywords: foodfortification; folic acid; vitamin D; policies; deficiencies

Published:2 April 2012

Food& Nutrition Research 2012. © 2012M de Lourdes Samaniego-Vaesken et al. This is an OpenAccess article distributed under the terms of the Creative CommonsAttribution-Noncommercial 3.0 Unported License(http://creativecommons.org/licenses/by-nc/3.0/),permitting all non-commercial use, distribution, and reproduction inany medium, provided the original work is properly cited.

Citation:Food & Nutrition Research 2012. 56: 5459 - DOI:10.3402/fnr.v56i0.5459

Inthe past, food fortification along with nutritional education and thedecrease in foodcosts relativeto income have been of great success in eliminating the commonnutritional deficiencies. These deficiencies, such as goiter,rickets, beriberi and pellagra, have since been replaced with anotherset of ‘emergent deficiencies’ that were not previouslyconsidered a problem (e.g. folate and neural tube defects, zinc andchild growth and selenium and cancer). In addition, the differentnutrition surveys in the so-called affluent countries have identified‘shortfall’ nutrients specific to various age and/orphysiological status. Complex, multiple lifestyle diseases, such asatherosclerosis, diabetes, cancer and obesity, have emerged. It iswidely known that these are not simply deficiency diseases, butrather conditions that are present in a relatively well-nourishedsociety. Food fortification was proven an effective tool for tacklingnutritional deficiencies among population; but today, a morereasonable approach is to use food fortification as a mean to supportbut not replace dietary improvement strategies (i.e. nutritionaleducation campaigns) (1).

Themain goal of the present article is to review the past record and itseffect on public health including a look into the future.

Anexample of success in food fortification programmes can be found inthe United States, where great efforts have been made within publichealth officials and educators, the private industry andepidemiological evaluation (2).In the early 1920s, medical researchers announced that iodine couldprevent goiter that was widespread at that time (2).Through this was a successful fortification programme. Thereafter in1932, milk was fortified with vitamin D, and again, this was heavilysupported by the medical community because of the prevalence ofrickets in children (2).This was followed by the 1941 fortification of flour and bread withthe B vitamins, which was ‘presented as insurance againstnutritional deficiencies’, when B vitamin deficiencies wereprevalent in the United States and most of Europe (3).Cooperation between the private and public sectors was essential toaddress public health needs. That said, are the products that arecurrently on the market serving the nutritional needs of thepopulation? It is clear that nowadays is a differentworld.What began in the 1920s of the last century as a response to a publichealth need has escalated into an industry-driven fortification withfrequent conflicts of interests with the public health campaign. Oneof the main issues today is that consumers are seeking foods withhealth benefits, in an era of complex diseases. Currently,international organisations and the public sector are activelyworking on this field (4).

Foodfortification in today's world

Historically,food fortification, such as iodised salt or vitamin D-fortified milk,served as a public health measure to address population-wide nutrientdeficiencies. By means of restoring nutrients removed during foodprocessing or replacing nutrients in substitute foods, today's foodfortification comprises several initiatives, where foods must meetnot only consumer needs and preferences but also comply withnutritional, regulatory, food safety and technical constraints.Previous fortification policies were great successes, but authoritiesare facing other problems in developed countries that seem to beinhabited by well-nourished people.

Morethan 67 countries require fortification of certain staple foods. Themain examples are folic acid fortified wheat or maize flour to reducethe risk of neural tube defects (NTD) and limitation of fortificationof foods with certain nutrients such as vitamin D. The first questionto consider is whether these approaches are aligned with nutritionalneeds, as nutritionaldeficiencies are often limited to a subset of the population (5).And secondly, if all food ingredients are safe at the level ofaddition when used as intended, or in other words: whichis the right dose of the fortificant so that it is effective but nottoxic? (5).

Internationally,the Codex Alimentarius of the Food and Agriculture Organization (FAO)and the World Health Organization (WHO) have established generalprinciples for the addition of vitamins and minerals to foods. Forexample, the guidelines on food fortification with micronutrientspublished in 2006 (6)outline FAO/WHO initiatives for folic acid. However, each countrydetermines its own policy or regulations, and fortificationapproaches can vary widely throughout the world.

Inthe past few years, food industry made calcium and vitaminD-fortified juices, breads fortified with omega-3 fatty acids andvegetable oil spreads with plant sterols available for consumerssearching for foods with additional health benefits (7).This is the basis of voluntary fortification, the practice by whichdifferent concentrations of vitamins, mineral and other nutrients areadded to processed foods, and decisions about which products and howto fortify them are made by food manufacturers. Harmonisation of thispractice is essential as it is common in many countries. Therefore,it is expected that Europe will be under a unique regulation in thenear future. This regulation will control the addition of nutrientsto foods and the nutritional claims stated on their labels(Regulation (EC) No 1924/2006 of the European Parliament and of theCouncil of 20 December 2006 on nutrition and health claims made onfoods).

Remarkably,the indiscriminate addition of nutrients to foods and thefortification of fresh products are not allowed by the US Government,and fortification of unprocessed foods is prohibited in Europeancountries. Furthermore, fortification of certain types of foods, suchas sugars and some snack foods (e.g. candies and carbonatedbeverages), is discouraged. Importantly, food has to taste good andbe appealing to consumers, so fortification is often self-limiting.

Whoare the usual consumers of supplements and fortified foods?

Fortifiedfoods and multivitamin supplements are frequently included in thedaily diets of many populations from western developed countries.Amongst frequent users are women and their relatives, the elderly andchronic patients but especially people who are well educated or froma high socio-economic background (8).This group are considered the ‘healthy and active people’,who paradoxically may not necessarily present any nutritionaldeficiency. Recent publications from the US National Health andNutrition Examination Survey (NHANES) reported a high proportion ofseniors (9, 10)and also of children 1–13 years (11)who were frequent consumers of these products. A new era in nutritionhas clearly evolved very recently with unknown expected results atpopulation level in the future.

Vitamincontent and stability in processed and ready-to-eat foods

Vitamincontent of foods is susceptible to losses and/or can be destroyedduring technological/cooking processes induced by a number offactors. Most losses are because of their solubility in water that isdependent on the cooking method used. However, some vitamins aresubject to additional losses: B vitamins are more labile totemperature and light, whereas fat-soluble vitamins are labile tooxygen (12, 13).Losses depend on the type of food and its process: for example,thiamine, natural folates and vitamin C can reach up to 100% losswhen different concomitant cooking and processing conditions aregiven (12, 14).

Althoughthe availability of processed foods containing added vitamins andother nutrients is increasing, food tables and databases show a lackof accurate and updated data on their composition. This is the casefor not only critical nutrients such as folic acid and iron but alsofor many other nutrients and non-nutritive compounds (15–17).To overcome these difficulties, the EuroFIR project is making a greatcontribution in unifying and harmonising food composition databasesacross Europe (18).

Isit possible to follow the Mediterranean diet adherence in a‘fortified world’?

TheMediterranean diet model is based on a high consumption of ‘fresh’products, including vegetables, fruits, legumes and fish, with oliveoil as the main source of fat. Recent publications underline theconcern that Mediterranean countries are drifting away from thishealthy model (19, 20),moving towards a higher intake of meat, processed, high-fat,high-salt and sugary foods (21).These ‘new’ patterns affect the nutritional status ofdifferent population groups living in these countries, particularlyas vitamin recommended intakes are not met by a high percentage ofthe population (22).

Inaddition, serving/portion size is an untargeted issue infortification of staples. Recommended and/or standard serving sizesare the basis for intake assessments, but it should be taken intoaccount that they will vary depending on the population–age–gendergroup: they each have specific requirements and recommended intakes.Manufacturers normally include fixed serving sizes in the nutritionlabel of their products, but how realistic are these? In a pilotstudy, Whittaker et al. (16)found that regular adult breakfast cereal consumers ate nearly twicethe recommended serving found on the product's label, meaning thatthey also consumed twice the intended vitamin/mineral content perserving of cereal. This fact is of great importance for monitoringand assessing nutrient intakes, especially for children andadolescents. Moreover, nutrient contents/levels in fortified foodlabels do not always match label information. Different studies,including those from our group, found overages in fortified products,showing that manufacturers may add higher quantities of the nutrientto ensure its presence at declared levels throughout shelf life(16, 23, 24).

Inthe Spanish market, we found a wide choice of fortified food groupsthat may contain different nutrient levels depending on product group(dairy, cereals, etc.), brand name and target population (i.e.children). However, there is a high proportion of products thatpresent no specific target population for consumption (Fig.1)(25).

Fig 1
Fig.1.  Distributionand main target consumption population groups of folic acid-fortifiedfoods available in the Spanish market.
Note: Adapted fromSamaniego-Vaesken et al. (25).

The‘big two’ in vitamin fortification today: folic acid andvitamin D

Folicacid

Folateis a general denomination that includes all vitamers with theactivity of the B vitamin pteroylglutamic acid. Folic acid is amonoglutamate synthetic compound added to food for fortification; itis a more chemically stable form than the natural vitamers (26).Several studies have found a higher bioavailability in men for folicacid, (27)and the result of these findings was the establishment and use of thedietary folate equivalents (DFE). The term DFE accounts for thehigher bioavailability of the synthetic form versus the naturalfolate vitamers, where DFE equals the micrograms of food folate plus1.7 times the micrograms of added folic acid. Then, use of DFE wasrecommended by the US Food and Nutrition Board of the Institute ofMedicine for planning and evaluating folate intakes (28).

Folicacid is an essential micronutrient involved in the prevention ofmacrocytic anaemia that acts as a co-factor in cellular developmentand homeostasis throughout all life stages (29).It has been identified as a potential factor in the aetiology ofvascular disease (30),certain types of cancer (31, 32),cognitive impairment in the elderly (33)and prevention of congenital abnormalities known as NTD (34, 35).As scientific evidence is still inconclusive (36, 37),the only established recommendations at present are aimed at women ofchildbearing age for reducing their risk of having a NTD affectedpregnancy.

Strategiesto improve folate status in the target population

Theevidence linking folic acid to NTD prevention led to the introductionof three potential strategies to improve folate status among targetpopulations: pharmacological supplementation, mandatory or voluntaryfortification of staple foods with folic acid and the advice toincrease intakes of natural folate food sources. The potentialstrengths and weaknesses of these approaches, summarised in Table1,have been widely evaluated, but questions remain regarding theireffectiveness.




Table 1.  Comparativeanalysis of strategies to improve folate intake

 

Strengths

Weaknesses

Nutritional advice: natural folate sources

Overall improvement of population's nutritional status Diet should provide all nutrients needed (38)

Difficulty to change dietary habits Low amounts in foods and limited number of food sources (legumes, green leaf vegetables, etc.) Bioavailability and chemical stability of folates is questioned (39, 40)

Pharmacological supplementation

Target population specificity (e.g. women at childbearing age) (41, 42) Better dosage

Lower adherence Depends on socio-economical status (9) Potentially higher risk of toxicity when combined with fortification practices (10)

Mandatory fortification

Reaches all population groups No need to change dietary habits Better cost-effectiveness (28, 40)

Dosage is a function of serving size Risk of high intakes in untargeted population Different fortification ranges and laws across countries (43)

Voluntary fortification

Target consumption with marketing of products (e.g. breakfast cereals for children) (25) Consumption is a matter of food choice

Different fortification levels depending on manufacturers and food groups (25) Higher costs Potentially high or insufficient intakes depending on consumption patterns/dietary habits (16)

Themain public health measure for primary prevention of NTD in manycountries is the recommendation of folic acid supplements takenpericonceptionally amongst women who are planning a pregnancy.Increasing awareness and knowledge of the role of periconceptionalfolate in women of childbearing age by educational campaigns isdifficult, as women do not generally plan their pregnancies, andthose at higher risk of NTD affected pregnancies (lowersocio-economic, education status) are not always reached by healthpromotion messages and are less likely to be supplement takers (9).

In1998, the US Food and Nutrition Board advised that all women capableof becoming pregnant should consume a daily dose of 400 µg ofsynthetic folic acid, either in the form of fortified foods orsupplements, in addition to naturally occurring folates from food(28).

Withregard to the advice to increase dietary intake of naturallyoccurring folate, efforts, such as health promotion campaigns toachieve dietary changes on a population basis, have been proven tohave limited success (21, 44).Not only does it require a behavioural change, but changes also needto be accessible, affordable and sustainable (21).In addition, some countries introduced mandatory fortification of astaple food and/or allowed manufacturers to voluntarily fortifycertain foodstuffs (17).

Voluntaryfortification requires women to know about and choose fortifiedfoods, or that commonly and regularly eaten staple foods arefortified (e.g. milk) and affordable. In other words, most women mustconsume the fortified foods whether or not they are aware of theirfolic acid content. In addition, variations in folic acid amountsadded by different manufacturers to different foodstuffs (25),or higher than expected content ‘overages’ (16, 24),add difficulty to monitoring folate intakes from these foods by thepopulation.

Mandatoryfortification seems to be the key to overcome many of the drawbacksdescribed above. Most women will consume fortified food regardless ofsocio-economic disparities or family planning. Many countries adoptedthis measure starting more than 10 years ago in the United States andCanada (28).So far, about 67 fortify either wheat or maize flour with folic acid(45).Conversely, other countries are still reluctant to implement thispopulation-wide strategy, as is the case in European countries thatonly allow addition of this vitamin on a voluntary basis (45).

Ina recent report on folic acid-preventable spina bifida andanencephaly, Bell and Oakley (41)estimated that 27% of the world's population now has access to folicacid-fortified flour. However, after 18 years of knowledge, only 10%of preventable birth defects are actually prevented by currentfortification programmes. The main lack is in developing countries(41).

Examinationof selected national policies towards mandatory folic acidfortification

Mandatoryfolic acid fortification raises a number of scientific, ethical andtechnical challenges (46).Lawrence et al. (43)summarised the implications of different folic acid fortificationpolicies worldwide to assess their nature and rationale, as well asthe lessons learned from their implementation. All of the reviewedcountries have identified the folic acid/NTD relationship asimportant and recommend the consumption of folic acid supplements(400 µg/day) and food folate for women of childbearing age.Despite having access to the same epidemiological evidence, theselected countries have diverse policy positions on mandatory folicacid fortification, which reflect different interpretations of thepotential risks and benefits. An example of two countries that applydifferent fortification policies are China and Finland. Differencesare, for instance, the high NTD rates in China in contrast to thosein Finland (43).

InChina, the recommendation states that all women of childbearing ageobtain health information and advice on folic acid supplementation of400 µg/day, for 3 months before and after conception. Thisadvice is given pre-maritally and at their periconceptional checkupthat is conducted through the maternal and infant health care system.In 2001, it was agreed to initiate a flour fortification pilotprogramme at 2 mg folic acid/kg of flour. The pilot trial offortified flour consumption was conducted during 2003–2006. In2004, fortified flour was introduced into the marketplace. Althoughcertain local government regions encouraged implementation of folicacid fortification of flour, in 2006, the State Grain Bureau drafteda national standard for fortified flour, which is still awaitinggovernment authorisation. The main lesson learned concerns the factthat China has a diverse consumption pattern of food staples and soit is difficult to assess the best food candidate for fortification.In addition, the NTD incidence is highest in remote and lessdeveloped regions of China. Generally, in these regions, peopleconsume homemade flour rather than commercial flour that has beenfortified with folic acid (43).

Incontrast, Finland does not allow mandatory fortification of staplefoods with folic acid, and there are no policy discussions at themoment. A balanced diet, rich in folate, is recommended for all womenplanning a pregnancy or in early pregnancy, to obtain at least 400 µgof folate daily. In addition, a daily supplement of 400 µgfolic acid is recommended for all women planning a pregnancy or inthe early stages of pregnancy. Nevertheless, voluntary fortificationof certain food products is allowed. In this country, between 37 and86% of pregnancies are planned, but the first pre-natal visit is fartoo late for NTD prevention. The major limitation for risk evaluationand monitoring of any fortification programme to be implemented isthe need for updated data on folate intake of the target group andthe population in general. This can be applied to most countrieswhether they adopt mandatory fortification or not. In summary,policies should be determined and assessed on a ‘fit forpurpose’ basis meaning each country has to address thepotential risks and benefits taking into consideration its uniquecircumstances and possibilities.

Concernsrelated to folic acid fortification today

Increasedfolic acid intakes in some population groups have raised specialconcerns about potential adverse effects, as scientific evidence hasstill not clarified if the benefits outweigh the risks, mainly inchildren and the elderly.

Becausehigh doses of folic acid are able to correct the anaemia associatedwith vitamin B12 deficiency,high intakes could delay the diagnosis of the latter vitamin bymasking its deficiency, which could lead to irreversible neurologicaldamage/higher risk of memory impairment (47).Scientific data are still inconclusive as to whether folic acidsupplementation accelerates or delays age-related cognitive decline(48).

Offurther and more recent concern is the association of folic acid witha potential increase in the risk of cancer, particularly colorectal(49).Folic acid has a role as a co-factor in nucleotide synthesis, and itsavailability can promote proliferation of rapidly dividing malignantcells. Observations from both animal and human studies have suggestedthe possibility of a ‘dual effect’ of this vitamin incancer development, depending on the timing and dose of theintervention (49).High intakes may suppress the development of early lesions in normaltissues, probably by maintaining genetic stability but may in turnincrease the progression of neoplasic cells. This complexrelationship that was referred to as the ‘double-edged sword’by Kim (50)is exerting a necessary halt/delay in the widespread folic acidfortification in many countries, although the safety of this policyis ensured for all population groups (51).Moreover, adequacy of other vitamin status, such as B2,B6 andB12,has to be taken into account, as they are interconnected and serve asco-factors for crucial enzymes of the one-carbon metabolism.

Aspreviously described, recently published results from the NHANESstudy in the United States estimated that in 2003–2006, 53% ofthe population used dietary supplements, and from these, 34.5% useddietary supplements that contained folic acid. Total folate intake(in DFE) was higher for men than for women and higher fornon-Hispanic whites than for Mexican Americans and non-Hispanicblacks. Total folate and folic acid intakes were highest for thoseaged 50 years, and 5% exceeded the tolerable upper intake level.Improved total folate intakes were observed in targeted populations(10).However, it is noteworthy that the authors specify that estimates offolic acid intakes from food sources and dietary supplements rely onthe product's label not analytical values and that those amountscould be higher than declared (23, 52)as is the case for fortified foods.

Toquantify the health and economic outcomes of mandatory folic acidfortification in the United States, Bentley et al. (53)conducted a cost-effectiveness analysis considering different healthoutcomes in four projected scenarios (including ‘nofortification’) and taking the adult population with folateintake distributions from the NHANES (1988–1992 and 1999–2000)as reference. The greatest benefits from fortification implementationwere predicted for myocardial infarction prevention. Allpost-fortification strategies provided quality-adjusted life yearsgains and cost savings for all sub-groups, much higher for theso-called 700 µg/100 g ‘strategy’. It was concludedthat health and economic gains could outweigh the losses for the USpopulation as a whole.

InSpain, where currently voluntary folic acid fortification is allowed,the food industry is offering a significant and increasing number offolic acid-fortified products from different food groups aimed at awide variety of populations (Fig.2)(25).Furthermore, overage seems to be a common practice, and there isstill a lack of reliable data to assess the impact of the increasingnumber of folic acid-fortified foods. In a recently published studyby our group, breakfast cereal products were analysed to evaluatefolic fortification levels. According to laboratory values, ‘lowfat’ (n=15)contained the highest total folate (445–630 µg/100 g),which represented almost twice the declared label values, but similarresults were obtained for fibre, muesli and corn flake categories(24).

Fig 2
Fig.2.  Distributionof main folic acid-fortified food groups available in Spain.
Note:Adapted from Samaniego-Vaesken et al. (25).

VitaminD

Background:how may whole nations become vitamin D deficient?

Theterm vitamin D is a generic term that comprises a family offat-soluble metabolites involved in calcium metabolism andhomeostasis and thus bone formation and resorption. Thephysiologically active form of vitamin D is the 1,25-dihydroxyvitaminD3.Without an adequate status of this metabolite, the small intestinecannot absorb more than 10%–15% of dietary calcium (54).Sun exposure (ultraviolet B radiation) is the main source of vitaminD3 tohumans as it can be synthesised in the skin. In fact, our apeancestors probably had adequate vitamin D status unlike the modernhuman: we cover about 95% of our skin surface, spend less time in thesun, wear sunscreen and are subjected to geographical differencesthat account for less sun hours per day. Awareness of the roleexcessive exposure plays in increasing risk of skin cancer has risen.In addition, nutritional sources of vitamin D are limited: oily fishis considered to be one of the best and its recommended intakes areof at least 3–4 times per week (55).But a question that has evolved recently is: ‘are there enoughfish in the sea?’ it seems not (55).Foods such as milk, orange juice, cereals and some breads arefortified with vitamin D, but contribution from diets is veryvariable (54).Human's requirements of vitamin D are met mostly by casual exposureto sun. During winter, storage of body fat can be utilised as theskin has a large synthesis capacity (54).

Epidemiologicalevidence shows that there is a high prevalence of vitamin Ddeficiency especially among elderly population groups. It is a knownfact that vitamin D production in the skin decreases about four timeswith age (55);in addition, this group is prone to avoid sun exposure and limittheir outdoor activities. The survey in Europe on nutrition and theelderly: a concerted action (SENECA) study revealed that there isscarce cutaneous vitamin D production from November to May in most ofEuropean seniors. This was primarily a consequence of avoiding thesun, and surprisingly, lowest levels were observed in theMediterranean seniors (56, 57).

Howmany are deficient? The SENECA study: vitamin D status in elderlypopulation

Vander Wielen et al. (56)measured 25-hydroxyvitamin D in serum (25(OH)-D), in adult populationacross 11 European countries during winter and found that free-livingelderly, regardless of geographical location, were at high risk ofinadequate vitamin D status. Thirty-six percent of men and 47% ofwomen had 25(OH)-D concentrations below 30 nmol/L; threshold with anincreased risk of osteomalacia (bone disease produced by severevitamin D deficiency i.e. 25(OH)-D≤25 nmol/L). Authors’recommended dietary enrichment or supplementation with vitamin Dshould be seriously considered during this season. In the studiedpopulation, major food sources of vitamin D were fish (62%), eggs(20%) and dairy products (8%) and intakes (µg/day),as well asserum 25(OH)-D levels (nmol/L) were lower for women. Assessment ofoverall vitamin D status was regarded as marginal in 62% of seniors.

Inthe Optimal Fortification with Vitamin D (OPTIFORD) European project,relative contribution of both sun exposure during summer and diet tovitamin D status were analysed across five European countries,comparing adolescents versus elderly women. When dietary intake ofvitamin D was assessed, authors found that elderly females consumed3.9±5.0 µg/day, whereas adolescent girls consumed2.8±2.7 µg/day with fish and eggs as the main foodsources. However, sun exposure, measured with an adhesive skindosimeter (J/m2),revealed that Spanish elderly women received less than half the sunexposure of their adolescent counterparts (58).This situation was not observed in the rest of the participatingcountries (i.e. Finland).

Whenvitamin D exposure and status, measured as 25(OH)-D in plasma inwinter versus summer, in a Spanish elderly women population werecompared, both were clearly higher in the latter. Nevertheless,vitamin D deficiency affected 28% of the women during summer time,although this percentage was doubled in winter. In addition, dietaryintakes of ≥ 95% of the population sample did not reach therecommended dietary intakes for vitamin D in the summer or winterseason (34.5 and 31.3%, respectively); with oily fish as the mainfood source (59).

VitaminD fortification and supplementation: implications and public healthpotential

Availableevidence found in meta-analyses of double-blinded trials indicatesthat supplemental vitamin D has dose-dependent beneficial effects onbone health and muscle strength. These are both related to preventionof falls and, therefore, hip and other non-vertebral fractures thatare the main causes of disability in the elderly (60).25(OH)-D serum concentrations of 75–110 nmol/L provide anadequate status for fall and fracture prevention (61).

Whatremains to be proven are other additional and not less important,public health benefits. In cancer prevention, vitamin D may have arole downregulating or inhibiting cell proliferation in colorectalcancer (62).It has also been shown to act as an important immune systemregulator: vitamin D receptors are present on T-cells, B-cells,macrophages and other immune cells, providing modulatory effects thatcould have benefits for the occurrence of autoimmune diseases such asType I diabetes, rheumatoid arthritis and asthma (63).

Basedon data of a benefit–risk assessment published in 2009 byBischoff-Ferrari et al. (61),it has been proposed that 800–1,000 IU of vitamin D per day maybe needed to achieve a satisfactory status in all adults of 75–100nmol/L of 25(OH)-D. However, as in the case of folic acid, authorsagree that larger trials are needed to confirm benefits and safety ofthese new and promising approaches.

VitaminD supplements use and adherence

Ina recent study that estimated the prevalence and patterns of use ofover-the-counter medications and dietary supplements in a sample ofadults aged 57–85 years (n =3,005), findings showed that 49% (95% CI, 46.2%–52.7%) used adietary supplement (64).Amongst the most popular supplements were multivitamins (28%),calcium (17%) and vitamin C (9%). Only 4.5% of the users declared adaily consumption of Vitamin D supplements.

Anotherstudy conducted in Italy investigated the global adherence toosteoporosis treatment in a nationwide survey carried out inpost-menopausal women (n=9,851) (65).They were referred to centres for osteoporosis management for afollow-up assessment, at least 1 year after having been prescribedeither a treatment with calcium+vitamin D alone or other drugs(hormone replacement therapy, etc.). Results showed that 19.1% of thepatients discontinued the prescribed drug before attending the bonemass re-evaluations. Most frequent reasons for discontinuation weredrug-related side effects, insufficient motivation to treatment andfear of side effects. Lack of motivation was the most common causefor poor compliance in the case of calcium+vitamin D supplements,whereas best treatment adherence was observed in patients with severeosteoporosis (65).

Fortificationtomorrow

Atpresent, it seems clear that ‘optimal nutrition’ remainsa moving target in the food fortification field: to appropriatelydesign a fortification programme, nutritional status of manymicronutrients has to be assessed. Furthermore, as nutrigenomicstudies identify individuals with higher, or at least differentnutrient requirements, nutrient fortification may help optimise anindividual's nutritional needs. The scientific evidence basecontinues to evolve, and discovery of new compounds withhealth-promoting effects will call for new strategies involving bothnutrition guidance and fortification with a focus on benefit–riskassessment.

Insummary, questions and issues to be fully addressed regarding whetherwe are targeting the most appropriate food vehicles with nutrientsand the levels needed by those who actually consume them arecurrently still under discussion. Further studies comprising themonitoring of population intakes in countries, where fortification isimplemented at different levels will grant greater insight intoimproved policies. What is clear is that harmonising foodfortification policies, within the scope of optimal and safe levels,will enable suitable competition in a global food supply with notrade barriers and possibly achieve the necessary right balance forvitamin food fortification.

Conflictof interest and funding

Theauthors have not received any funding or benefits from industry orelsewhere to conduct this study.

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*Gregorio Varela-Moreiras
Departmentof Pharmaceutical and Food Sciences
Faculty of Pharmacy
CEU SanPablo University
ES-28668 Boadilla del Monte (Madrid), Spain
Tel:+(0034) 913724726
Fax: +(0034) 913510496
Email: [email protected]


Vitamin D and Folate fortification of foods - April 2012        
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