Vitamin D intake and status in Irish postmenopausal women

OBJECTIVE

The objective of this study was to assess vitamin D status during late-summer and late-winter/early-spring in postmenopausal Irish women, and whether it was influenced by vitamin D-containing supplement use.

DESIGN

A longitudinal observational study.

SETTING

Cork City, Ireland (51 degrees north).

SUBJECTS

A total of 59 apparently healthy, free-living, postmenopausal women aged between 51 and 69 y were sampled during February/March 2002. Of these, 48 and 47 returned during August/September 2002 and February/March 2003, respectively. None of the women were suffering from any medical condition likely to affect vitamin D status. Fasting serums were collected and analysed for 25-hydroxyvitamin D (25 (OH) D) and parathyroid hormone (PTH) by enzyme immunoassays.

RESULTS

Mean daily intake of vitamin D was 3.2 microg from food sources alone and 5.8 microg when vitamin D-containing supplements were included (P<0.01). Serum 25 (OH) D was significantly lower (P<0.001) during February/March 2002 than both August/September 2002 and February/March 2003. Serum 25 (OH) D was also significantly higher (P < or = 0.05) in women who were vitamin D-containing supplement users than nonusers during all three sampling points. Between 17 and 36% of women had inadequate vitamin D status (defined as serum 25 (OH) D <40 nmol/l) during late-winter, but only 4% had inadequate vitamin D status during late-summer. Serum 25 (OH) D was inversely related to serum PTH (r = -0.33; P = 0.028).

CONCLUSION

Suboptimal vitamin D status is common in postmenopausal Irish women during winter. Vitamin D supplementation is associated with improved vitamin D status, even during summertime.

Risk-benefit analysis of micronutrients

Traditionally, different approaches have been used to determine the recommended dietary allowances for micronutrients, above which there is a low risk of deficiency, and safe upper levels, below which there is a negligible risk of toxicity. The advice given to risk managers has been in the form of point estimates, such as the recommended dietary allowance (RDA) and the tolerable upper level (UL). In future, the gap between the two intake-response curves may become narrower, as more sensitive indicators of deficiency and toxicity are used, and as health benefits above the recommended daily allowance are taken into account. This paper reviews the traditional approaches and proposes a novel approach to compare beneficial and adverse effects across intake levels. This model can provide advice for risk managers in a form that will allow the risk of deficiency or the risk of not experiencing the benefit to be weighed against the risk of toxicity. The model extends the approach used to estimate recommended dietary allowances to make it applicable to both beneficial and adverse effects and to extend the intake-incidence data to provide a range of estimates that can be considered by the risk manager. The data-requirements of the model are the incidence of a response at one or more levels of intake, and a suitable coefficient of variation to represent the person-to-person variations within the human population. A coefficient of variation of 10% or 15% has been used for established recommended dietary allowances and a value of 15% is proposed as default for considerations of benefit. A coefficient of variation of 45% is proposed as default for considerations of toxicity, based on analyses of human variability in the fate and effects of therapeutic drugs. Using this approach risk managers, working closely with risk assessors, will be able to define ranges of intake based on a balance between the risks of deficiency (or lack of benefit) and toxicity.

Management of colorectal cancers

The management of colorectal cancers, published in a recent issue of Effective Health Care, is reviewed.

Prudent diet and the risk of insulin resistance

BACKGROUND AND AIM

Diet is a potentially modifiable risk factor for diabetes. Dietary patterns may exert greater effects on health than individual foods, nutrients or food groups. Data on associations between dietary patterns and the risk of insulin resistance and type 2 diabetes are sparse. The aim of the study was to examine associations between dietary patterns and the risk of insulin resistance.

METHODS AND RESULTS

We performed a cross sectional study involving a group of 1018 men and women, sampled from 17 general practice lists in the South of Ireland, with a response rate of 69%. Participants completed a detailed health and lifestyle questionnaire and provided fasting blood samples for analysis of glucose, insulin and lipids. Dietary intake was assessed using a food frequency questionnaire. The food frequency questionnaire was a modification of the UK arm of the European Prospective Investigation into cancer, EPIC study, which was based on that used in the US Nurses' Health Study. Dietary patterns were assessed by K cluster analysis. Insulin resistance was estimated on the basis of fasting glucose and insulin, using the glucose homeostasis model (HOMA scores). Insulin resistance was defined as the upper quartile of the HOMA scores. Three dietary patterns were identified by cluster analysis (traditional Irish diet, a prudent diet and an alcohol and convenience foods diet). Participants in clusters 1 (traditional Irish diet) and 3 (high alcohol and convenience foods) had a lower intake of more 'healthy' food groups (such as fruit, vegetables, low fat dairy products, poultry, fish and whole grain products) and higher intake of foods richer in total and SFA content (such as high fat dairy products, butter, meat and meat products). Cluster 2 (prudent dietary pattern) was characterized by a higher intake of food groups that are typically recommended in health promotion programs and a lower intake of meat (read meat), meat products, sweets, high fat dairy and white bread (white bread and unrefined cereal). The prudent diet had the lowest HOMA scores in analysis of covariance. The prevalence of insulin resistance in the prudent diet was lower than that in the traditional diet (OR=0.53; 95%CI, 0.33-0.85 in fully adjusted analysis).

CONCLUSION

A prudent diet may be associated with enhanced insulin sensitivity and a lower risk of type 2 diabetes.

A Probabilistic Estimation of Fluoride Intake by Infants up to the Age of 4 Months from Infant Formula Reconstituted with Tap Water in the Fluoridated Regions of Ireland

Two probabilistic models were developed to estimate the acute and chronic exposure to fluoride of exclusively formula-fed infants aged 0-4 months as a result of the consumption of infant formula reconstituted with fluoridated tap water in Ireland. The estimates were based on calculated infant formula consumption and accepted body weight standards, together with reported concentrations of fluoride in infant formula powder and measured values for the fluoride content of water in Ireland. The mean acute exposure of infants to fluoride on any single day in areas served by 387 fluoridated water supplies was estimated to be between 0.11 and 0.14 mg/kg body weight depending on age group (95th percentiles 0.2 and 0.26 mg/kg b.w., respectively). These predicted intakes were well below the intake of fluoride associated with acute toxic effects, which is considered to be 5 mg fluoride (F(-))/kg body weight. The mean chronic exposure of infants to fluoride was estimated to be between 0.106 and 0.170 mg/kg b.w./day depending on body weight (95th percentiles 0.108 and 0.172 mg/kg b.w./day, respectively). This estimate described the average daily fluoride intake of infants during the first 4 months of life residing in the areas served by 226 water supplies that achieved an average yearly fluoride concentration below 1.03 mg/l. Dental fluorosis may be considered to be the only risk at these low doses and from our work it is estimated that there is a very low risk of moderate dental fluorosis of the permanent dentition in infants exposed to fluoride at these levels.

Vitamin D intakes in 18–64-y-old Irish adults

OBJECTIVE

To estimate vitamin D intakes in a representative sample of Irish adults and to assess the contribution of foods to these intake estimates.

DESIGN

Vitamin D intakes in 1379, 18-64-y-old adults from the North/South Ireland Food Consumption Survey were estimated using a combination of new analytical data for vitamin D in foods, determined by HPLC, and used to revise recipe calculations, together with existing data from McCance and Widdowson's The Composition of Foods, 5th Edition plus supplements.

RESULTS

The total mean daily intake (MDI) of vitamin D (1 microg=40 IU) from all sources was 4.2 microg. The MDI was significantly higher (P<0.001) when the contribution from nutritional supplements was included (4.2 microg) compared with food sources only (3.2 microg). Men had significantly higher intakes (4.4 microg) than women (4.0 microg; P<0.001), which increased significantly (P<0.001) with age in both sexes. Meat/meat products (30.1%), fish/fish products (14.3%) and eggs/egg dishes (9.1%) were the main contributors to vitamin D intake. Supplements contributed 6.8 and 12% to MDI in men and women, respectively. In all, 74% of adults had an MDI of vitamin D that was less than the median (5 microg) of the recommended daily range of 0-10 microg.

CONCLUSION

The findings of this study suggest that a large number of Irish adults have low vitamin D intakes. This, along with emerging evidence of low vitamin D status in at least some population subgroups, suggests that strategies to increase vitamin D intakes, including fortification of food, should be investigated.

Effect of a high-protein, high-salt diet on calcium and bone metabolism in postmenopausal women stratified by hormone replacement therapy use

The objective of this study was to investigate the influence of a high-sodium, high-protein diet on bone metabolism in postmenopausal women (aged 49-60 y) stratified by hormone replacement therapy (HRT) use. In a crossover trial, 18 women (n = 8 HRT users (+HRT) and n = 10 nonusers (-HRT)) were randomly assigned to a diet high in protein (90 g/day) and sodium (180 mmol/day) (calciuric diet) or a diet moderate in protein (70 g/day) and low in sodium (65 mmol/day) for 4 weeks followed by crossover to alternative dietary regimen for a further 4 weeks. The calciuric diet significantly (P < 0.05) increased urinary sodium, calcium and nitrogen in both groups. While the calciuric diet increased urinary N-telopeptide crosslinks of collagen (by approximately 25%, P = 0.003) in the -HRT group, it had no effect in the +HRT group. It appears that postmenopausal HRT use attenuates the increase in a marker of bone resorption associated with a calciuric diet.

A mutant receptor with enhanced dominant-negative activity for the blockade of human prolactin signalling

An effective mechanism for interfering with prolactin signalling would provide a powerful tool for clarifying the importance of prolactin in breast cancer, as well as for investigating functions of prolactin in other tissues. Based on our previous identification of a dominant-negative mutation in the growth hormone receptor that causes familial short stature, we investigated the potential for using a similar truncated mutant of the prolactin receptor (PRLR1-242). Like the mutant growth hormone receptor, PRLR1-242 exerts an exceptionally powerful dominant-negative effect. A probable explanation for the strong dominant-negative activity of this class of mutation is that, lacking internalisation motifs, the truncated mutants accumulate at the cell surface and form non-functional heterodimers with wild-type receptors. In accordance with evidence for heterodimer formation between the two receptors, PRLR1-242 also blocks signalling by the growth hormone receptor. When expressed from an adenoviral vector, PRLR1-242 inhibits activation of STAT5 (signal transducer and activator of transcription 5) by prolactin in T47-D breast cancer cells, and blocks the ability of prolactin to induce proliferation in these cells. Thus PRLR1-242 provides an effective means of blocking the responsiveness of target tissues to human prolactin.

Impact of ready-to-eat breakfast cereal (RTEBC) consumption on adequacy of micronutrient intakes and compliance with dietary recommendations in Irish adults

OBJECTIVE

To describe the consumption of ready-to-eat-breakfast cereals (RTEBCs) in Irish adults and its impact on adequacy and safety of micronutrient intakes and compliance with dietary recommendations.

DESIGN

Analysis for this paper used data from the North/South Ireland Food Consumption Survey that estimated habitual food intake using a 7-day food diary in a representative sample of adults aged 18-64 years ( 662 men, 717 women).

RESULTS

Despite the small quantity consumed (mean 28.6 g day-1 or 4.7% of total energy intake), RTEBCs made an important contribution to the mean daily intake of carbohydrate (8.1%), starch (10.8%), dietary fibre (9.8%) and non-starch polysaccharides (NSP) (10.8%) in consumers. Increased consumption was associated with a more fibre-dense diet and with greater compliance with dietary recommendations for fat, carbohydrate and NSP. Fortified RTEBCs contributed significantly to mean daily intakes of iron (18%), thiamin (14%), riboflavin (17%), niacin (15%), vitamin B6 (13%), total folate (18%) and vitamin D (10%) and most of the contribution was from micronutrients added to RTEBCs. Increased consumption of fortified RTEBCs was associated with an increased nutrient density for a number of micronutrients and with a lower prevalence of dietary inadequacy of calcium, iron, riboflavin and folate, particularly in women. However, it was not associated with intakes in excess of the Tolerable Upper Intake Level for any micronutrient.

CONCLUSIONS

The consumption of RTEBCs is associated with improved compliance with dietary recommendations for fat, carbohydrate and fibre, with a more micronutrient-dense diet and a reduced risk of dietary inadequacy for calcium, iron, riboflavin and folate, without increasing the risk of excessive intakes of micronutrients.

Signalling and anti-proliferative effects mediated by gonadotrophin-releasing hormone receptors after expression in prostate cancer cells using recombinant adenovirus

Gonadotrophin-releasing hormone receptors (GnRH-Rs) are found in cancers of reproductive tissues, including those of the prostate, and gonadotrophin-releasing hormone (GnRH) can inhibit growth of cell lines derived from such cancers. Although pituitary and extra-pituitary GnRH-R transcripts appear identical, their functional characteristics may differ. Most extra-pituitary GnRH-Rs have low affinity for GnRH analogues and may not activate phospholipase C or discriminate between agonists and antagonists in the same way as do pituitary GnRH-Rs. Here we have assessed whether GnRH-Rs expressed exogenously in prostate cancer cells differ functionally from those of gonadotrophs. We found no evidence for endogenous GnRH-Rs in PC3 cells, but after infection with adenovirus expressing the GnRH-R (Ad GnRH-R) at 10 plaque forming units (p.f.u.)/cell or greater, at least 80% of the cells expressed GnRH-Rs. These sites had high affinity (K(d )for [(125)I]Buserelin 1.1+/-0.4 nM) and specificity (rank order of potency: Buserelin> GnRH>>chicken (c) GnRH-II), and mediated stimulation of [(3)H]inositol phosphate (IP) accumulation. Increasing viral titre from 3 to 300 p.f.u./cell increased receptor number (2000 to 275 000 sites/cell respectively) and [(3)H]IP responses. GnRH also caused a biphasic increase in the cytoplasmic Ca(2+) concentration in Ad GnRH-R-infected cells but not in control cells. Mobilization of Ca(2+) from intracellular stores contributed to the spike phase of this response whereas the plateau phase was dependent upon Ca(2+) entry across the plasma membrane. This effect on Ca(2+) and stimulation of [(3)H]IP accumulation were both blocked by the GnRH-R antagonist, Cetrorelix. In addition, GnRH reduced cell number (as measured in MTT activity assays) and DNA synthesis (as measured by [(3)H]thymidine incorporation) in Ad GnRH-R-infected cells (but not in control cells). This effect was mimicked by agonist analogues and inhibited by two antagonists. Thus, when exogenous GnRH-Rs are expressed at a density comparable to that in gonadotrophs, they are functionally indistinguishable from the endogenous GnRH-Rs in gonadotrophs. Moreover, expression of high affinity GnRH-Rs can facilitate a direct anti-proliferative effect of GnRH agonists on prostate cancer cells.

Selenium intakes in 18-64-y-old Irish adults

OBJECTIVE

To measure the intake of selenium (Se) and the contribution of different food groups to Se intake in adults aged 18-64 y in Ireland. The adequacy of Se intake in the population is also assessed.

DESIGN

Food consumption was estimated using a 7 day food diary for a representative sample (n=1379; men=662, women=717) of 18-64-y-old Irish adults selected randomly from the electoral register. Se intake was estimated using updated tables of food composition.

RESULTS

Mean daily Se intakes (+/-s.d.) from all sources (ie food plus supplements), and from food sources alone, for the group of Irish adults aged 18-64 y were 52 (+/-23) and 50 (+/-21) microg, respectively. Mean daily Se intake (from all sources) was significantly higher in men of all ages than women of all ages at levels of 60 and 44 microg, respectively (P<0.001). Meat/meat products (30%), bread and rolls (24%), fish/fish products (approximately 11%), and milk and yoghurt (9%) were the main contributors to mean daily Se intake. Adequacy of Se intake in population groups was estimated as the percentage of the population with mean daily Se intakes that were lower than the average requirement of 40 microg. Using this measure, 45.6% of women and 17.1% of men had inadequate Se intakes.

CONCLUSION

A significant prevalence of inadequate Se intakes was observed in Irish adults. Therefore, it would seem prudent that the Se status of the Irish population be investigated at this time.

Overweight, obesity and physical activity levels in Irish adults: evidence from the North/South Ireland food consumption survey

In the present paper the prevalence of obesity (BMI > or = 30 kg/m2) and current physical activity levels in Irish adults have been evaluated. The prevalence of obesity in Irish adults is currently 18%, with men at 20% and women at 16%. A further 47% of men and 33% of women are overweight (BMI 25.0-29.9 kg/m2). Since 1990, obesity has more than doubled in men from 8% to 20%, and increased from 13% to 16% in women. The highest prevalence of obesity (30%) was found in women aged 51-64years. Defined waist circumference action levels identified 48% of the population who are in need of weight management and who also are at a 1.5-4.5 times increased risk of having at least one cardiovascular disease risk factor. Physical activity levels were low overall. Men were more active in work and recreational pursuits than women, but women were more active in household activities. Walking was the most popular recreational pursuit. However, TV viewing occupied most of the leisure time of men and women. Higher levels of activity were associated with a lower BMI and waist circumference. The results indicate the need for sensitive and individualised strategies to promote physical activity and to achieve a healthy weight status.

Signaling and antiproliferative effects mediated by GnRH receptors after expression in breast cancer cells using recombinant adenovirus

GnRH receptors (GnRH-Rs) are found in human cancers, including those of the breast, and GnRH can inhibit the growth of cell lines derived from such cancers. Although pituitary and extrapituitary GnRH-R transcripts appear identical, their functional characteristics may differ. Most extrapituitary GnRH-Rs have low affinity for GnRH analogs and may not activate PLC or discriminate between agonists and antagonists in the same way as pituitary GnRH-Rs. Here we have assessed whether GnRH-Rs expressed exogenously in breast cancer cells differ from those in gonadotropes. We found no evidence for endogenous GnRH-Rs in MCF7 cells, but after infection with adenovirus expressing the GnRH-R (Ad GnRH-R) at a multiplicity of infection of 10 or greater, at least 80% expressed GnRH-Rs. These had high affinity (K(d) for [(125)I]buserelin, 1.4 nM) and specificity (rank order of potency, buserelin>GnRH>>chicken GnRH-II) and mediated stimulation of [(3)H]IP accumulation. Increasing viral titer [from multiplicity of infection, 3-300] increased receptor number (10,000-225,000 sites/cell) and [(3)H]IP responses. GnRH stimulated ERK2 phosphorylation in Ad GnRH-R-infected cells, and this effect, like stimulation of [(3)H]IP accumulation, was blocked by GnRH-R antagonists. GnRH also inhibited [(3)H]thymidine incorporation into Ad GnRH-R-infected cells (but not control cells). This effect was mimicked by agonist analogs and inhibited by two antagonists. Thus, when exogenous GnRH-Rs are expressed at density comparable to that in gonadotropes, they are functionally indistinguishable from the endogenous GnRH-Rs in gonadotropes, and increasing expression of high affinity GnRH-Rs can dramatically enhance the direct antiproliferative effect of GnRH agonists on breast cancer cells.

Differential internalization of mammalian and non-mammalian gonadotropin-releasing hormone receptors. Uncoupling of dynamin-dependent internalization from mitogen-activated protein kinase signaling

Desensitization and internalization of G-protein-coupled receptors can reflect receptor phosphorylation-dependent binding of beta-arrestin, which prevents G-protein activation and targets receptors for internalization via clathrin-coated vesicles. These can be pinched off by a dynamin collar, and proteins controlling receptor internalization can also mediate mitogen-activated protein kinase signaling. Gonadotropin-releasing hormone (GnRH) stimulates internalization of its receptors via clathrin-coated vesicles. Mammalian GnRH receptors (GnRH-Rs) are unique in that they lack C-terminal tails and do not rapidly desensitize, whereas non-mammalian GnRH-R have C-terminal tails and, where investigated, do rapidly desensitize and internalize. Using recombinant adenovirus expressing human and Xenopus GnRH-Rs we have explored the relationship between receptor internalization and mitogen-activated protein kinase signaling in HeLa cells with regulated tetracycline-controlled expression of wild-type or a dominant negative mutant (K44A) of dynamin. These receptors were phospholipase C-coupled and had appropriate ligand affinity and specificity. K44A dynamin expression did not alter human GnRH-R internalization but dramatically reduced internalization of Xenopus GnRH-R (and epidermal growth factor (EGF) receptor). Blockade of clathrin-mediated internalization (sucrose) abolished internalization of all three receptors. Both GnRH-Rs also mediated phosphorylation of ERK 2 and for both receptors, this was inhibited by K44A dynamin. The same was true for EGF- and protein kinase C-mediated ERK 2 phosphorylation. ERK 2 phosphorylation was also inhibited by a protein kinase C inhibitor but not affected by an EGF receptor tyrosine kinase inhibitor. We conclude that a) desensitizing and non-desensitizing GnRH-Rs are targeted for clathrin-coated vesicle-mediated internalization by functionally distinct mechanisms, b) GnRH-R signaling to ERK 2 is dynamin-dependent and c) this does not reflect a dependence on dynamin-dependent GnRH-R internalization.

The efficacy and safety of nutritional supplement use in a representative sample of adults in the North/South Ireland Food Consumption Survey

OBJECTIVE

To describe the current use of nutritional supplements and their contribution to micronutrient intakes in a representative sample of Irish adults, to evaluate the impact of supplement use on the adequacy of micronutrient intakes and to assess the risk to supplement users of exceeding tolerable upper intake levels (UL).

STUDY DESIGN AND SUBJECTS

Food intake data were collected in 1379 (662 male and 717 female) randomly selected Irish adults aged 18 to 64 years using a 7-day food diary. The current use of nutritional supplements was assessed using a self-administered questionnaire and respondents entered each supplement as it was consumed into the food diary.

RESULTS

Twenty-three per cent of respondents regularly used nutritional supplements. Twice as many women used supplements as men. The intakes of micronutrients were significantly higher (P<0.001) in supplement users than in non-users. Micronutrient intakes from food sources were similar in male users and non-users of supplements, but were significantly higher (P<0.01) in female users, by 3 to 13%, for Fe, Mg, Mn, vitamins C and E and niacin than in non-users. The percentage of female users between 18 and 50 years who had mean Fe intakes below the average requirement (AR) (10 mg) decreased from 50 to 25 when the contribution from supplements was included. The use of supplements reduced the percentage of men who had mean intakes below the AR for Zn from 19 to 13, for riboflavin from 14 to 6 and for vitamin A from 20 to 5, and reduced the percentage of women with intakes below the AR for Ca from 23 to 16 and for riboflavin from 23 to 14. Twenty-one women out of 80 aged between 18 and 50 years, who consumed supplemental folate, achieved the intake of 600 microg recommended to prevent neural tube defects. Twenty-two per cent of the women who took iron and 15% of the women who took vitamin B6 in supplemental form had mean daily intakes that exceeded that UL for these nutrients. Supplement users did not exceed the UL for the other micronutrients.

CONCLUSIONS

Supplementation appears to be beneficial in promoting adequate intakes of some micronutrients, particularly Fe and folate in women aged 18-50 years and vitamin A in men. There appears to be little risk to supplement users of experiencing adverse side effects due to excessive intakes of micronutrients.

The North/South Ireland Food Consumption Survey: mineral intakes in 18-64-year-old adults

OBJECTIVE

To measure mineral intakes and the contribution of different food groups to mineral intakes in adults aged 18-64 years in Ireland. Intakes are reported for Ca, Mg, P, Fe, Cu and Zn. The adequacy of mineral intakes in the population and the risk of occurrence of excessive intakes are also assessed.

DESIGN

Food consumption was estimated using a 7-day food diary for a representative sample (n=1379; 662 men, 717 women) of 18-64-year-old adults in the Republic of Ireland and Northern Ireland selected randomly from the electoral register. Mineral intakes (Ca, Mg, P, Fe, Cu and Zn) were estimated using tables of food composition.

RESULTS

Mean nutrient density of intakes was higher for women than men for Ca and Fe and increased with age for all minerals, except Ca for men and Fe for women. Meat and meat products were the major contributor to mean daily intakes of Zn (38%), P (23%), Fe (18%), Cu (15%) and Mg (13%); dairy products (milk, yoghurt and cheese) to Ca (44%), P (22%), Zn (14%) and Mg (11%); bread and rolls to Fe (21%), Cu (18%), Ca and Mg (17%), Zn (13%) and P (12%); potatoes and potato products to Cu (16%), Mg (14%) and Fe (10%); and breakfast cereals to Fe (13%). In women of all ages nutritional supplements contributed 7.6%, 4.4%, 3.6% and 2.2% of mean daily intake of Fe, Zn, Cu and Ca, respectively, while in men of all ages, nutritional supplements contributed 2.7%, 2.3%, 1.7% and 0.6%, respectively, to mean daily intakes of Fe, Zn, Cu and Ca. Adequacy of minerals intakes in population groups was assessed using the average requirement (AR) as a cut-off value. A significant prevalence of intakes below the AR was observed for Ca, Fe, Cu and Zn but not P. A higher proportion of women than men had intakes below the AR for all minerals. Almost 50% of 18-50-year-old females had intakes below the AR for Fe, while 23%, 23% and 15% of women of all ages had intakes below the AR for Ca, Cu and Zn, respectively. For men of all ages, 11%, 8% and 13% had intakes below the AR for Ca, Cu and Zn, respectively. There appears to be little risk of excessive intake of Ca, Mg, P, Cu or Zn in any age/sex category. However, 2.9% of women of all ages had intakes above the tolerable upper intake level for Fe (45 mg) due to supplement use.

CONCLUSION

Almost 50% of women aged 18-50 years had Fe intakes below the AR and relatively high proportions of women of all ages had intakes below the AR for Ca, Cu and Zn. With the possible exception of iron intake from supplements in women, there appears to be little risk of excessive intake of minerals in the adult population. Meat and meat products, dairy products (milk, cheese and yoghurt), bread and rolls, potatoes and potato products and breakfast cereals are important sources of minerals; nutritional supplements make only a small contribution to mineral intakes in the population as a whole but may contribute significantly to intakes among supplement users.

Analyses of the anthropometric data from the North/South Ireland Food Consumption Survey

OBJECTIVE

To obtain measured anthropometric data for weight, height and other parameters not previously measured in the Irish population such as waist and hip circumferences and body composition.

DESIGN

A cross-sectional survey. Weight, height, waist circumference, hip circumference and body composition were measured according to standard procedures.

SETTING

Northern Ireland and the Republic of Ireland, 1997-1999.

SUBJECTS

Random representative sample of 1379 adults aged 18-64 years.

RESULTS

With the exception of body fat, all anthropometric values were significantly higher for men than women (P<0.001). All measurements were significantly higher in the 36-50-year-old age group compared with 18-35 year olds. Height was the exception, which decreased significantly with age (P<0.05). Weight, height and body mass index (BMI) have increased in Ireland since last measured in 1988 and in 1990. Over the last decade, obesity has increased in men 2.5 fold from 8% to 20% and in women by 1.25 fold from 13% to 16%. Significantly more women have a normal BMI than men (50.4% vs. 33.3%; P<0.05). Cut-off points for a high waist circumference and high waist-to-hip ratio identified 47% and 33% of the population, respectively, to be at an increased risk for cardiovascular disease. Social class did not have any significant effect on mean BMI. Location of residence influenced BMI but not in any consistent manner. Ex-smokers had a significantly higher BMI than non-smokers and smokers (P<0.05).

CONCLUSIONS

A revision of current recommendations for combating obesity is warranted to improve the health of the Irish population. Further research is needed to identify the factors that have contributed to the dramatic increase in the prevalence of obesity in men over the last decade and have resulted in a higher prevalence of obesity in men than in women.

Sampling description and procedures used to conduct the North/South Ireland Food Consumption Survey

OBJECTIVE

The purpose of this survey was to establish a database of habitual food and drink consumption in a representative sample of Irish adults, aged 18-64 years. The present paper describes the sampling protocol, response rate and characteristics of the survey population in terms of sex and age groups, seasonality, geographical location, marital status, social class, socio-economic status and education level.

DESIGN

A cross-sectional food consumption survey was carried out. In the Republic of Ireland, a nationally representative sample of adults was randomly selected with a validated two-stage clustered design, using the electoral register as the sampling frame. This method produced a self-weighting or 'epsem' sample of individuals, where each adult who was registered to vote had an equal opportunity of being selected. Similarly, in Northern Ireland, a two-stage random sampling procedure was used. The sampling frame was the electoral register, and the sample was stratified by urban/rural and by an index of material deprivation, to ensure representation of each sector of the community. The recruitment procedure was the same in the North and South. An introductory letter with an information leaflet was posted to each selected individual and these were followed up by a visit from a fieldworker, who invited participation in the survey.

SETTING

Northern Ireland and Republic of Ireland between 1997 and 1999.

RESULTS

The response rate, which is the percentage of the total number of people who completed a 7-day food diary (n=1379) out of the total eligible sample (n=2177), was 63%. Non-respondents and dropouts constituted 34% and 3%, respectively, of the total eligible sample. Compared with the most recent census figures available, the sample was generally found to be representative in terms of sex and age group profiles, geographical location, marital status, seasonality, social class, socio-economic group and education level. Data on sex and age group and geographical location were collected from non-respondents for comparison with the survey sample. There were no apparent differences between them.

CONCLUSION

The North/South Ireland Food Consumption Survey has established a relational database of habitual food and drink consumption, in addition to data on habitual physical activity, anthropometric measurements, socio-demographic factors, lifestyle, health status indicators and attitudes, in a nationally representative sample of the population of the island of Ireland.

The North/South Ireland Food Consumption Survey: the dietary fibre intake of Irish adults

OBJECTIVE

Mean daily intakes of dietary fibre (DF, Southgate) and non-starch polysaccharide (NSP, Englyst) are estimated in a representative sample of adults aged 18-64 years in Ireland. The contribution of food groups to DF and NSP intake is reported and fibre intakes are compared with dietary recommendations and with intakes in some European countries.

DESIGN

Food consumption was estimated using 7-day food diaries for a representative sample (n=1379); 662 men, 717 women) of 18-64 year old adults in the Republic of Ireland and Northern Ireland selected from the electoral register. DF and NSP intakes were estimated from tables of food composition.

RESULTS

The mean daily intake of DF in the total sample was 20.2 g (standard deviation (SD) 7.8) [23.2 g (SD 8.5) in men, 17.4 g (SD 5.9) in women] or 2.24 g MJ(-1) (SD 0.7) [2.16 g MJ(-1) (SD 0.7) in men, 2.33 g MJ(-1) (SD 0.7) in women]. Mean daily intake of NSP was 14.8 g (SD 6.2) [16.7 g (SD 6.8) in men, 13.0 g (SD 5.0) in women] or 1.65 g MJ(-1) (SD 0.6) [1.56 g MJ(-1) (SD 0.6) in men, 1.74 g MJ(-1) (SD 0.6) in women]. The main food groups that contributed to mean daily intake of DF (NSP) in the sample were breads 31% (23%), potatoes 19% (23%), and vegetables 17% (19%). Absolute intakes of DF and NSP were higher (P<0.001) in men than women; however, women overall consumed more (P<0.001) fibre-dense diets than men. Women aged 18-35 years consumed less (P<0.01) DF and NSP (g) than women aged 36-64 years. Both men and women aged 18-35 years consumed less (P<0.01) fibre-dense diets than men and women aged 36-64 years. The NSP intake was below the nutritional goal of 18 g day(-1) in 77% of adults and below the minimum of the recommended range (12 g day(-1) in 37% of the total sample. Compliance (i.e. the maximum number of individuals whose collective mean daily intake corresponded to the population goal) with the (UK) population goal for an average intake of 18 g day(-1) NSP was achieved by a greater proportion of the population (63%) than compliance with the (German) dietary fibre recommendation of 30 g day(-1) (27%) or the (Nordic) recommendation of 3 g MJ(-1) day(-1) (33%).

CONCLUSION

DF (NSP) intakes were lower than dietary recommendations in a substantial proportion of the population. This is likely to contribute to impaired bowel function and constipation, which in turn may contribute to increased risk of chronic gastrointestinal disease.

The North/South Ireland Food Consumption Survey: vitamin intakes in 18-64-year-old adults

OBJECTIVE

To estimate vitamin intakes and assess the contribution of different food groups to vitamin intakes in adults aged 18-64 years in Ireland as estimated in the North/South Ireland Food Consumption Survey. Intakes are reported for retinol, carotene, total vitamin A, vitamin D, vitamin E, thiamin, riboflavin, pre-formed niacin, total niacin equivalents, vitamin B6, vitamin B12, folate, biotin, pantothenate and vitamin C. The adequacy of vitamin intakes in the population and the risk of occurrence of excessive vitamin intakes are also assessed.

DESIGN

Food consumption was estimated using a 7-day food diary for a representative sample (n=1379; 662 men and 717 women) of 18-64-year-old adults in the Republic of Ireland and Northern Ireland selected randomly from the electoral register. Vitamin intakes were estimated using tables of food composition.

RESULTS

In general, the percentage of the population with vitamin intakes below the average requirement (AR) was low. Mean daily intake of total vitamin A was below the AR in 20.2% and 16.6% of men and women, respectively, and mean daily intake of riboflavin was below the AR in 12.5% and 20.6% of men and women, respectively. Mean daily folate intakes were below the AR for folate in 11.2% and 6.6% of women aged 18-35 years and 36-50 years, respectively. Only 2.2% of women aged 18-35 years and 5.2% of women aged 36-50 years achieved the recommended folate intake of 600 microg day(-1) for women of reproductive age for the prevention of neural tube defects. A high proportion of the population has a low dietary vitamin D intake and is largely dependent on sunlight exposure to maintain adequate vitamin D status. Except for pre-formed niacin, the 95th percentile intake of vitamins did not exceed the tolerable upper intake level (UL) for any group and was much less than the UL for most vitamins. Although 20.8% of men and 6.3% of women exceeded the UL for pre-formed niacin (which is 35 mg, based on nicotinic-acid-induced flushing), the large contribution of meat and fish to the intake of niacin (as nicotinamide) suggests that the risk of overexposure to nicotinic acid is much lower than this and is probably solely related to supplement use. A small proportion of men (4.0%) and women (1.2%) aged 51-64 years had retinol intakes that exceeded the UL (3000 microg) and while the 95th percentile intake of women in the 18-50 year age group was well below the UL, 1.5% of 18-35-year-old and 2.4% of 36-50-year-old women had mean daily retinol intakes above the UL. About 2.0% of women had intakes of vitamin B6 that exceeded the UL (25 mg). There were significant differences by age and sex in nutrient densities of vitamin intakes between men and women and between age groups, which may be explained by differences in consumption of particular food groups as well as different patterns of supplement use.

CONCLUSION

Nutritional adequacy of the population for most vitamins was good. Folate intake in women of childbearing age is not meeting current recommendations for the prevention of neural tube defects. The public health significance of the relatively high proportion of men and women with inadequate intakes of vitamin A and riboflavin and with low dietary intakes of vitamin D is unclear and should be investigated further. With the possible exception of niacin (flushing) and vitamin B6 (neuropathy), there appears to be little risk of the occurrence of adverse effects due to excessive consumption of vitamins in this population, based on current dietary practices.

Foods for tomorrow: the challenge for nutrition

Diet related diseases, including cardiovascular disease, cancer, osteoporosis, and degenerative changes of ageing are a major cause of morbidity and mortality throughout Europe. There is considerable potential to improve public health by means of diet. This includes changing eating behaviour at the population level, through the development and implementation of nutrition policy and promulgation of dietary guidelines for healthy eating. This must be complemented by measures which modify the nature of the food supply. Europe's food industry has a central role in facilitating dietary change by providing health promoting foods, including novel and functional foods, which are safe, convenient, palatable and acceptable to consumers. The development of policies, programmes and products for improving public health will need to be informed by innovative research which strengthens our fundamental understanding of the relationships between food and physiological functions related to health, as well as of factors which influence food choice and eating behaviour. This is a considerable challenge for nutrition and will require the organisation of research to provide for the integration of appropriate disciplines and expertise, including recent advances achieved in molecular and cell biology and in the analysis of the human genome.

No effect of copper supplementation on biochemical markers of bone metabolism in healthy young adult females despite apparently improved copper status

OBJECTIVE

To investigate the effects of increasing Cu intakes, above the usual dietary intake, on biomarkers of bone metabolism in healthy young adult females (aged 21-28 y) over a 4 week period.

DESIGN

A double-blind, placebo-controlled randomised repeat crossover Cu supplementation trial.

SETTING

The study was conducted at the Royal Veterinary and Agricultural University (RVAU), Copenhagen, Denmark.

SUBJECTS

Sixteen healthy young adult females aged 20-28 y were recruited from among students at the RVAU.

INTERVENTION

During the 4 week intervention periods in this randomised, crossover trial (3x4 weeks with a minimum 3 week wash-out period), each subject received, in addition to their usual diet, either 3 or 6 mg elemental Cu/day as CuSO4 or a matching placebo. On the last 3 days of each dietary period 24 h urines were collected. In addition, blood was collected on the last day of each dietary period.

RESULTS

Serum Cu and erythrocyte superoxide dismutase (but not caeruloplasmin protein concentration or activity (putative indices of Cu status)) were significantly increased (P<0.05) after daily Cu supplementation with 3 and 6 mg/day for 4 weeks. Serum osteocalcin (biomarker of bone formation), urinary creatinine (Cr) concentration, urinary pyridinoline (Pyr)/Cr or deoxypyridinoline (Dpyr)/Cr excretion, or daily urinary Pyr or Dpyr excretion (biomarkers of bone resorption) were unaffected by Cu supplementation.

CONCLUSION

Copper supplementation of the usual diet in healthy young adult females, while apparently improving Cu status, had no effect on biochemical markers of bone formation or bone resorption over 4 week periods.

SPONSORSHIP

Funding from the European Commission.