Editorial
Do we need more food fortification?

The science of nutrition went through a tremendous phase of expansion in the first half of the twentieth century with the discovery that some diseases could be treated and pre-vented by ingesting sufficient amounts of bioactive substances vitamins and minerals largely derived from
food. This work encouraged a great effort to determine essential nutrient requirements and to use this knowledge to establish recommended nutrient intakes that would provide direction to eliminate nutrient deficiency diseases. So successful was the work of nutritional scientists that nutrient
deficiencies were thought to have been largely eliminated in economically developed countries by the second half of the last century. Over the last two decades research focus has shifted emphasis from essential nutrient
requirements to learning whether intakes of essential nutrients higher than those needed to prevent deficiency diseases can reduce the risk of chronic disease such as cancer and heart disease, improve cognition, or enhance immune function. Not only have these new areas of research engaged traditional nutritional scientists working in the public and academic arenas but industry has become an active and important participant by providing research funding opportunities for producing value added novel and functional foods. So prominent has this area of research become that the importance of nutrients in pre-venting classic nutrient insufficiencies may have been overlooked. It is perhaps not surprising, therefore, that there is an accumulating body of evidence that nutritional
deficiencies, far from being defeated, are once again emerging as a public health concern.

Of recent note are the results of the 2002 National Children’s Nutrition Survey (CNS02) in New Zealand indicating that mild iodine deficiency exists among school-aged children (1). Median urinary iodine concentration was 66 µg/L and 28% of children had a urinary iodine concentration below 50 µg/L. Both of these conditions meet the International Council for the Control of Iodine Deficiency Disorders definition of mild iodine deficiency: median urinary iodine between 50–100 µg/L and more than 20% of population with values less than 50 µg/L. These results, based on a large representative sample of New Zealand children (n = 1800), are not surprising because they confirm results of smaller representative surveys of school children in Dunedin and Wellington (2), as well as Melbourne (3) and Tasmania (4).

Reports on Vitamin D are still pending final approval from the New Zealand Ministry of Health. It has been assumed for some time that dietary intakes of vitamin D among Australians and New Zealanders were of little con-cern
because sun exposure ensured adequate cutaneous synthesis of the vitamin. This assumption has been drawn into question by studies indicating that vitamin D status is low—assessed using serum 25 hydroxyvitamin D concentrations— in small volunteer samples of several Australian population groups such as the elderly, veiled women, as well as children and adolescents (5). More recently, results from the CNS02 showed that vitamin D status of New Zealand children is poor. The prevalence of insufficiency, defined as a serum 25 hydroxyvitamin D concentration less than 37.5 nmol/L, was 31% and the prevalence of
deficiency (< 17.5 nmol/L) was 4%. There were 14% of Pacific females, 11 to 14 years, who had serum 25 hydroxyvitamin D concentration indicative of deficiency. Preliminary results from the National Nutrition Survey
1997 of New Zealanders 15 years or older suggests equally low serum concentrations of 25 hydroxyvitamin D. The high prevalence of insufficient vitamin D concentrations raises immediate concerns about the potential
public health consequences of low vitamin D status and the need to devise strategies to improve this. Other well-described examples of nutrient deficiencies include iron in women and vitamin B 12 in the elderly and results from the CNS02 suggest zinc may also be of concern.

Unfortunately, the quality of information about the nutritional status of Australians lags behind that of New Zealanders. The reason for this stems largely from the fact that biological samples were collected from participants in the last two New Zealand nutrition surveys (1,6) but were
not in the Australian National Nutrition Survey 1995 (7). Determining the extent of nutrient deficiencies using bio-chemical markers of nutritional status is far superior to relying solely on the results of dietary assessment. Dietary assessment without biochemical indicators is of minimal value in assessing the iodine and vitamin D status of a population.

The presence of mild iodine deficiency and the high prevalence of insufficient vitamin D concentrations raises immediate concerns about the potential public health con-sequences of the compromised nutritional status of a significant proportion of the New Zealand and probably
the Australian populations. It also demands an immediate response to considering and devising strategies to improve the iodine and vitamin D status of each population. Food fortification must surely rank as the strategy most likely to succeed. It seems fortuitous that the Food Regulation Standing Committee is currently considering policy
guidelines for the Fortification of the Food Supply with Vitamins and Minerals (http://www.nzfsa.govt.nz/policy-law/ consultation/archive/fortification-of-the-food-sup-ply/ index.htm). Should these be adopted, food standards will need to be developed and these will guide the method of any mandatory or voluntary fortification strategies.

There is a sense that new discoveries are waiting to be translated into fortification strategies that will benefit public health by reducing the burden of chronic disease. There have been many instances of observational epide-miological evidence linking increased intakes or high blood levels of a vitamin or mineral with decreased risk of cancer or heart disease (8–10). Unfortunately, with few exceptions the results of randomised controlled trials of vitamin and mineral supplements for the prevention of these diseases have been rather disappointing (11–12). The evidence that vitamin and mineral deficiencies exist in our populations does not necessitate an abandonment of the ‘health optimisation’ concept rather it demands a refocusing of attention onto the essentials of maintaining
adequate nutritional status of the population through pro-vision of adequate vitamin and mineral intakes.

The recent discovery that our food supply does not provide all the necessary vitamins and minerals to prevent deficiency (e.g. iodine and vitamin D) will challenge many nutritionists and dietitians who have long argued that a varied diet provides all the nutrient requirements we need. Clearly, a re-evaluation of this assumption needed. Food fortification is not a panacea. The fact that its history of use to improve nutritional status contains examples with greatly varying degrees of success, demands that the appropriate modelling, testing, and monitoring steps be carefully and thoroughly undertaken.

Murray Skeaff PhD
Tim Green PhD
Department of Human Nutrition
University of Otago
New Zealand

Leading articles
Food allergens and food allergy—complex relationships and responsibilities
(See paper by Palmer et al., pages 76–81)

Scientific and medical perspectives
The gaps in knowledge surrounding development of food
allergy in infants have lead to clinical practices with a poor level of evidential substantiation. This situation arises because of the significant population of infants affected: up to 3% of infants generally (1) and at least 0.5% of exclusively breastfed infants (2), and because of the need for medical support and advice to address their symptoms. Classical allergy presumes that the immediacy of adverse reactions to foods reflects IgE-mediated inflammatory processes. However, diagnostic tests for
IgE-mediated allergy such as skin-prick testing and measurement
of antigen-specific levels of circulating IgE are well known for false positive and false negative results depending on the antigen (3). Hence, studies using these biomarkers ideally require confirmation of allergy with
double-blind, placebo-controlled food challenge trials. The lack of reliable correlation between antigen-specific IgE and allergy symptoms indicates that non-IgE-mediated pathways are also involved in allergic responses to
foods. Non-IgE-mediated inflammatory responses to food antigens that are driven by T cells and other immune cell types have been implicated in delayed hypersensitivity reactions affecting both babies and adults (1,4). The role of the effect or T cells in allergy and intolerance is further
implicated from the benefits associated with probiotics, which are thought to restore tolerance to an allergenic Th2-skewed system by inducing a counterbalancing Th1- type response (5).

The immunological processes involved in the development and regulation of oral tolerance to foods are currently the subjects of intense scientific scrutiny, but as yet, the mechanisms at a molecular and cellular level
remain unresolved. Hence, key biomarkers for respective pathways are not yet established for diagnostic use. In the absence of suitable diagnostic biomarkers to identify all pathways of food hypersensitivity, medical practitioners are severely limited in their ability to diagnose food allergen
sensitivities, and to subsequently determine if an intervention strategy, such as maternal dietary restriction, is effective. Hence, there is a need for the development of models to account for the development of food tolerance and aberrant responses such as allergy.

The lack of high quality evidence for benefits of dietary exclusion of major food allergens in breastfeeding mothers in order to avoid development of atopic disease in infants (2), reflects the incomplete understanding of the
causal links between diet (infant and maternal) and manifestations of allergic symptoms. The natural recovery from food hypersensitivity in the majority of allergic babies with age suggests that immunemediated reactions resulting from immature digestion, gut integrity and mucosal immune tolerance are reversible as the infant gut matures. Furthermore, it appears that dietary immune modulators such as components of colostrum (6), whey and probiotics can reprogram an aberrant immune response to one of tolerance. If the mechanisms of food tolerance can be fully elucidated, then strategies for controlling exposure risk to infants that are not based on maternal dietary exclusion might be envisaged. Models should be developed from establishment of causative relationships between key immune cell and humoral immunological biomarkers and challenge related symptoms. Physiological factors that should also be
systematically considered include the integrity of the gut barrier and digestive function. Such information could assist in the development of improved strategies for intervention that address the complex regulatory framework of food tolerance and not just IgE-mediated reactions.

The supply of antigen to infants via breast milk brings further unknowns to the diagnostic equation (2). In particular, how does the antigen supply in breast milk affect the development of food tolerance in the infant? For example, what role does the host play in modulating the immunogenicity
of food proteins? Is the digestive function of the mother and survival of epitopes in her milk important for regulation of tolerance by the infant, analogous to the superior effect of partial versus fully hydrolysed infant
formulae for promoting food tolerance (7)? Furthermore, what is the relative importance of co-delivery in breast milk of serum IgA for antigen exclusion and regulatory cytokines for promoting maturation of the infant gut, as
opposed to presumption that reactions are related exclusively to the delivery of antigen via breast milk per se? A final challenge for researchers of food allergy is to determine the precise effect or molecules responsible for respective gut and skin symptoms. The dependence of the dose response and associated thresholds for reactivity represent crucial information required to assist the food industry in addressing and managing risk for allergic members of the public.

Perspectives of allergic individuals and the community

Valuable information has been collated from the EU Framework study ‘Protall’, which has shown that allergens known to trigger acute reactions following contact and processing along the gastrointestinal tract have structural features in common and belong almost exclusively to the prolamin, cupin and cysteine protease protein families (8). Many of these food proteins are of interest as targets for genetically modified expression systems incorporating improved production and technological efficiencies. It is also possible that GM technology can silence genes responsible for expression of allergenic epitopes, as has been demonstrated for soy protein (9). However, this strategy is not desirable if technological properties of food proteins are adversely affected (10). Immunotherapies for acute IgE-mediated allergy are based on therapeutic administration of structurally modified antigens, usually produced through genetic modification, and which induce favorable modulation of immune responses. Hence, recombinant forms of allergenic and hypo-allergenic proteins have been developed for the purpose of their use for immunotherapy, but not as hypo-allergenic food products per se. Nevertheless, until a substantiated model for the development and intervention of food allergy is available, it is risky to propose that ‘hypo-allergenic’ analogues of the major allergenic food proteins will be innocuous for all as the removal or modification of common epitopes may not guarantee hypo-allergenicity of the product for all allergic individuals. This is supported by the admission that factors leading to loss of allergenicity are not understood and that development of hypo-allergenic analogues of potent food allergens was undertaken through trial and error modification of known epitopes (11). Other factors associated with allergenic food proteins in relation to IgE-mediated allergy include resistance to digestion, stability in peptic and gastric fluids and the presence of post-translational modifications (12), which represent additional strategic targets for genetic modification. From the viewpoint of hypersensitive individuals, undeclared food allergens represent a full spectrum of risk, from mild discomfort to life threatening, depending on the individual and the type of allergen. For the latter category of individuals, this represents an imposition requiring vigilant attention that is typically nutritionally and socially compromising. In the case of breastfeeding mothers, it is desirable that the merits of dietary restriction in relation to treatment of food allergy symptoms be established with sound evidence before recommending dietary modification.

Food industry perspectives

It has been speculated that the apparent rise in the incidence of food allergy may be related to the practices of food processors over the last few decades with the introduction of processing technologies that modify the molecular properties of food allergens (13). While in some cases processing can increase allergenic potency, processing technologies can also help to reduce food allergenicity. Many allergens exhibit reduced allergenicity following standard cooking procedures. One demonstration has been the significant reduction in oral allergy syndrome reported following the treatment of apples with high pressure (14). This offers some evidence that processing may induce structural modification of epitopes that are unlike modifications associated with traditional processes, and may thereby offer alternative strategies for modulating the allergenicity of foods. In addition to investigating process based interventions for reducing the allergenicity of foods, the food industry is responding to the increasing concern regarding allergen traceability in processed products, through the new regulations surrounding mandatory labelling. The onus of managing risk for susceptible individuals has thus been transferred to the manufacturer in recent times, which has far reaching implications for the food processing industry, its suppliers and stakeholders. The implementation of risk management practices is also applicable to the food service industry, with increasing regulation of the information supplied to consumers at the point of purchase and consumption. This development has brought a completely new range of supply chain controls in an attempt to inform allergic individuals about potential exposure to allergens. The new Australian Food Safety Centre of Excellence, an initiative of the National Food Industry Strategy, has recently established an Allergen Forum in support of the issues affecting the Australian food industry. The aims of the forum are to identify and document allergen issues, provide industry with a means to establish and champion priorities, to develop networks and communicate with regulatory bodies. Currently, the combination of unknowns, including the threshold for reaction of an individual, together with the unknown immunogenicity of processed antigens and unknown residual concentration of a potential allergen in food products on a per serve basis, generates a very large opening for risk management, and requires a practical and reasonable approach that serves the needs of all stakeholders.

A related outcome from the attention of the food industry to the issues which face hypersensitive individuals has been to develop hypo-allergenic food products using strategies such as substitution of non allergenic for allergenic food proteins, and also in the marketing of products with ‘free-from’ allergenic protein labelling. These trends are fuelled both by the marketing push and consumer pull for foods with individualised attributes and apparent benefits. On the face of it, this appears to be a win-win situation for the industry and consumers alike. However, in the absence of adequate clinical diagnostic tools, the food industry may have unwittingly released a growing consumer trend towards associating a range of unrelated symptoms with food ingredients, and consumers who modify their diets accordingly. This trend is reflected in the wide discrepancy between individuals with challenge confirmed versus perceived food allergy (15). By complying with the new labelling regulations, the food industry is addressing the risk management of hypersensitive individuals who are susceptible to acute and life threatening reactions, and is simultaneously informing others who exercise choices based on perceived allergy-related symptoms. However, in the continuing absence of diagnostic tools relevant to proven biological processes of symptom elicitation, claims by consumers regarding liability of the food industry for their perceived symptoms may be legitimised by the industries’ provision of a growing range of alternative food products. In other words, the marketing of hypo-allergenic food products for individuals who do not need them may be lucrative in the short term, but this may backfire in the longer term by apparently validating the link between food components and a plethora of unrelated reactions. Hence, the apparent short-term benefits to the food industry and consumers surrounding the increasing marketing of hypo-allergenic food products without evidential substantiation, may actually reflect poor long-term management of relationships and responsibilities of the industry towards its customers.

Louise E. Bennett
Senior Research Scientist
Ingredient Functionality
Food Science Australia Malcolm Riley

Original research
General nutrition-related knowledge and beliefs of post-partum women
Madeleine Nowak, Simone L. Harrison and Petra G. Büttner

Abstract (Nutr Diet 2004;61:82–87)
Objective: To examine the general food and nutrition-related beliefs and knowledge of post-partum women in Brisbane and Canberra.
Design: Cross-sectional survey using self-administered mail or email delivered questionnaire.
Subjects: One hundred and sixty-eight post-partum women, who gave birth to a live infant in Brisbane or Canberra.
Setting: Subjects were drawn from three maternity hospitals in Canberra and one in Brisbane and were inter-viewed during a seven-day sampling period at each hospital.
Main outcome measures: Outcome measures were: beliefs, opinions and intentions relating to food, nutrition and weight; knowledge of requirements of core foods; and sources of nutrition information.
Statistical analysis: Standard statistical tests were used to assess bivariate relationships and multivariate analyses were performed using multiple logistic regression.
Results: Almost all the women (97%) were confident they could feed their families a healthy diet but their knowledge of core food requirements was inadequate with only 1.9% correctly answering four food intake questions, 10.5% correctly answering three food intake questions, 67.3% correctly answering two food intake questions and 20.4% correctly answering one food intake question. The major sources of nutrition information cited by these women were: reading (44.0%), education (36.9%), family (22.0%, particularly mothers), the media (13.1%), weight loss diets and organisations (4.8%) and health professionals (4.2%).
Conclusions: There is a need to provide pregnant and post-partum women with information about core foods requirements for health, so that they can better guide their families to healthful eating habits. Further research should explore ways in which this can be achieved.

Key words: post-partum women, food, nutrition, beliefs, knowledge

Original research
Treatment and prevention of food allergies in breastfed infants: practice and evidence
Debra J. Palmer, Michael S. Gold and Maria Makrides

Abstract (Nutr Diet 2004;61:76–81)
Objective: To determine whether current Australian dietetic practice is consistent with research relating to maternal dietary restrictions for treatment and prevention of food allergy in breastfed infants.
Design: Mail survey to benchmark practice and a systematic review of relevant studies and trials.
Subjects and Settings: All 15 Australian specialist paediatric allergy dietitians were surveyed. The systematic review was confined to studies involving maternal dietary intervention followed by maternal dietary challenge for the treatment of breastfed infants with food allergy, trials investigating maternal dietary restriction during lactation for allergy prevention, and studies where food proteins have been detected in human milk after the ingestion of a specific food challenge.
Main outcome measures: Assessment of current practice in relation to the level and quality of evidence on food allergy treatment and prevention in breastfed infants.
Results: The majority of dietitians (13 out of 15) surveyed follow recommendations of expert committees that breastfed infants with food allergy symptoms are trialled on maternal dietary restriction. However, the
strength of published evidence in this area is limited and high quality randomised controlled trials are required to test the validity of current practice and recommendations. Maternal dietary restrictions to prevent food allergy were used by six of the 15 dietitians surveyed. No clinical trials have investigated maternal dietary restriction during breastfeeding with the specific outcome of reducing the development of food allergy.
Conclusions: Insufficient high quality evidence exists to determine the extent of benefit offered by maternal food avoidance diets to breastfed infants for the treatment and prevention of food allergy.

Key words: food allergy, human milk, food proteins, maternal diet, practice survey

Original research
Comparison of fruit and vegetable frequency data from two Australian national surveys
Dorothy Mackerras, Jeremy Levy, Jonathan Shaw and Paul Zimmet

Abstract (Nutr Diet 2004;61:88–97)
Objective: To compare the fruit and vegetable intakes reported in the 1995 National Nutrition Survey and the 1999–2000 Australian Diabetes, Obesity and Lifestyle Study.
Design: Two national cross-sectional surveys.
Setting: All states and territories of Australia.
Subjects: 5604 and 11 041 adults aged 25 years and older.
Main outcome Measures: Frequency of intake of a range of fruit and vegetables, total frequency of fruit and of vegetable consumption and agreement between total frequency and responses to global questions about fruit and vegetable intakes. Comparisons between surveys are justified because the Apparent Consumption data showed little change in availability between the surveys.
Statistical Analyses: The proportion eating individual fruit and vegetable items at least once per week, the population distributions of the total fruit and vegetable frequencies and responses to the global questions were
calculated for each survey allowing for sampling strategies. Agreement between the total frequency and the global questions within each survey was examined using weighted kappa.
Result: The proportion reporting eating individual items at least weekly was similar (within 4%) between surveys for most commonly eaten foods. Population distributions of fruit intake derived from the total frequency
and global questions were broadly similar in the two surveys. However, within each survey, the frequency sum and global question showed only moderate agreement (kappa = 0.5). The population distributions of vegetable intake derived from total frequency were similar in the two surveys after excluding items which may have been reported twice in the National Nutrition Survey. However, the distribution from the global vegetable question was different in the two surveys. The agreement between the total frequency and global question for vegetables within each survey was poor to fair (kappa = 0.2 or 0.3). Using the frequency totals,
the top quintile of vegetable consumption in both surveys is six or more serves per day but only four or more serves per day by the global question.
Conclusions: In the absence of formal comparisons between the two surveys, this study indicates that many of the individual fruit and vegetable items are reported with reasonable consistency across time. However, there is enough variation that small changes across time in different surveys may not be due to true population change in intake. The global questions should not be compared to quantitative criteria until more work showing that they are valid for this purpose has been done.

Key words: fruit, vegetables, questionnaires, validity, nutritional epidemiology, surveillance

Original research
Resistant starch in the Australian diet
Jocelyn Roberts, Gwyn P. Jones, Ingrid H.E. Rutishauser, Anne Birkett and Carl Gibbons

Abstract (Nutr Diet 2004;61:98–104)
We set out to estimate resistant starch (RS) intakes using the 24-hour food intake data from the 1995 National Nutrition Survey (NNS) database of 13 858 Australians. As there are often significant differences in the RS
content of foods reported by various authors, we calculated intakes based on both published maximum and minimum values for individual foods. RS intakes (mean and SEM) for all persons were in the range 3.4 ± 0.03 g/d (minimum estimate) to 9.4 ± 0.07 g/d (maximum estimate). Adult males (19+ years) consumed more RS (10.7 ± 0.11 g/day maximum estimate) than adult females (19+ years) (8.2 g ± 0.08 g/day maximum estimate). RS comprised a greater proportion of the total starch intake in the very young and in the older age groups. Across the population, foods contributing most to RS intake were potatoes, bananas and white bread.

Key words: resistant starch, dietary intake, Australian population, food

Original research
Employers’ expectations of core functions, credentials and competencies of the community and public health nutrition workforce in Australia
Roger Hughes

Abstract (Nutr Diet 2004;61:105–11)
Objective: To review position descriptions of the community and public health nutrition workforce in order to assess employers’ expectations of workforce functions and competency requirements.
Design: Qualitative content analysis of job descriptions obtained from a sample of the known community and public health nutrition workforce in Australia and collation of position descriptions advertised in the February
2002 to August 2002 period.
Subjects and Setting: Community and public health nutritionists in the Australian health system.
Main outcome measures: Descriptive qualitative data about employers’ expectations of the core functions, competencies and credentials of community and public health nutritionists, as expressed by position
descriptions.
Results: From a total of 64 position descriptions obtained, 46 were included in the analysis. This sample consisted of 35 existing (occupied) positions and 11 new (advertised) positions. These were distributed across 29 entry-level and 17 advanced-level positions. The most consistent core function domains, as represented by duty statements, were community-based nutrition intervention management (planning, strategy development,
implementation and evaluation), capacity building and nutrition-related research and evaluation. Entry-level positions were more likely to have direct-care or clinical dietetics functions and there was a stronger emphasis on coordination, capacity building and research in the advanced-level positions. Competency expectations, as represented by key selection criteria, focused on experience of intervention management, knowledge of public health nutrition issues and strategies, interpersonal communication skills and the ability to adopt a multidisciplinary working style. Almost all of the entry-level positions required mandatory dietetic qualifications.
Conclusion: As a proxy of employers’ expectations, analysis of workforce position descriptions by duties (functions) and selection criteria (credentials and competencies), provide an alternative and complementary
method to inform workforce development. Position description development may be an important organizational response to facilitate progressive workforce development and re-orientation.

Key words:employers’ expectations, workforce development, core functions, competencies, public health nutrition, position descriptions