Diets of healthy Swedish children 4-24 months old. III. Nutrient intake

Variability and uncertainty in Swedish exposure factors for use in quantitative exposure assessments

Information of exposure factors used in quantitative risk assessments has previously been compiled and reported for U.S. and European populations. However, due to the advancement of science and knowledge, these reports are in continuous need of updating with new data. Equally important is the change over time of many exposure factors related to both physiological characteristics and human behavior. Body weight, skin surface, time use, and dietary habits are some of the most obvious examples covered here. A wealth of data is available from literature not primarily gathered for the purpose of risk assessment. Here we review a number of key exposure factors and compare these factors between northern Europe--here represented by Sweden--and the United States. Many previous compilations of exposure factor data focus on interindividual variability and variability between sexes and age groups, while uncertainty is mainly dealt with in a qualitative way. In this article variability is assessed along with uncertainty. As estimates of central tendency and interindividual variability, mean, standard deviation, skewness, kurtosis, and multiple percentiles were calculated, while uncertainty was characterized using 95% confidence intervals for these parameters. The presented statistics are appropriate for use in deterministic analyses using point estimates for each input parameter as well as in probabilistic assessments.

Effect of dietary phytate on zinc homeostasis in young and elderly Korean women

BACKGROUND

Previous studies suggest that consumption of predominantly plant-based diets with high phytate content contribute to zinc deficiency by inhibiting zinc absorption. Age of the individual may also affect the ability to maintain zinc homeostasis.

OBJECTIVE

This study was designed to determine the effect of dietary phytate on zinc homeostasis and to evaluate the effect of age on the capacity to maintain the zinc homeostasis with changes in dietary phytate in young and elderly Korean women.

DESIGN AND METHODS

Seven healthy young women (22-24 yr) and 10 healthy elderly women (66-75 yr) were studied consecutively for 3 months in 2 metabolic periods (MP) in two different metabolic units. During MP1 the women consumed a high phytate (HP) diet (P:Zn molar ratio = 23) for 9 days. After a 10 d wash-out period at home eating their usual diets, a lower phytate diet (LP) (P:Zn molar ratio = 10) was fed in MP2 for 9 d. Phytase was added to selected foods in the high phytate diet to reduce the phytate content of the meals in the LP period. The zinc content of both diets was about 6.5 mg/d. Stable isotopes of Zn ((70)Zn) were administered intravenously on d 5 of MP 1 and 2 for measuring endogenous fecal zinc excretion. Plasma samples were also collected on d 5 for measuring plasma zinc concentrations by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). 24 hr urine samples were collected for 5 d and complete fecal samples were collected for 9 d after isotope administration. Fractional zinc absorption (FZA) was calculated from mass balance corrected for endogenous fecal zinc (EFZ) excretion and EFZ was determined by using an isotopic dilution technique. Isotopic ratios for FZA and EFZ were measured by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Statistical analyses were done using ANOVA.

RESULTS

Both the young and elderly women were in negative zinc balance during the HP period. This was due to a significant decrease in FZA and total absorbed zinc (TAZ) with a HP diet (43 vs 22% in young women, 34 vs 20% in elderly women, p < 0.001). EFZ excretion did not differ in the young and elderly women during the LP and HP periods. Dietary phytate did not alter plasma zinc concentrations or and urinary zinc excretion in either group.

CONCLUSIONS

Adjustments in zinc homeostasis with an increase in dietary phytate did not differ between young and elderly women in this study.

Intake of vitamin D by Finnish children aged 3 months to 3 years in relation to sociodemographic factors

OBJECTIVE

To study the total daily intake of vitamin D from food and supplements among Finnish children aged 3 months to 3 years, the dietary sources of vitamin D and the association between vitamin D intake and sociodemographic factors.

SUBJECTS AND METHODS

The subjects are participants in the Finnish Type I Diabetes Prediction and Prevention Nutrition Study born between October 1997 and October 1998. At the age of 3 and 6 months, 1, 2 and 3 years, 342 (72% of the invited families), 298 (63%), 267 (56%), 233 (49%) and 209 (44%) families, respectively, participated in the present study. Food consumption was assessed by a 3-day food record. A structured questionnaire was used to record the parents' socioeconomic status.

RESULTS

The mean dietary vitamin D intake exceeded the recommendation (10 microg/day) at the age of 3 (11.0 microg) and 6 months (12.0 microg), but decreased thereafter being 9.8, 5.0 and 4.1 microg at 1, 2 and 3 years of age, respectively. Among the children 91, 91, 81, 42 and 26% used vitamin D supplements at the age of 3 and 6 months, and 1, 2 and 3 years, respectively. In children not using vitamin D supplements, vitamin D intake was less than 10 microg/day at all ages. Vitamin D intake from food did not differ in children who used and did not use vitamin D supplements. Vitamin D supplements were the main source of vitamin D intake in all age groups studied, followed by vitamin D-fortified infant formula in 3-month-olds and infant formula and baby foods in 6-month-olds. After the age of 1 year, the most important food sources of vitamin D were margarine, fish, baby foods, low-fat milk and eggs. Sociodemographic factors, especially the number of children in the family and maternal age, were associated with the total vitamin D intake and vitamin D supplement use.

CONCLUSION

Vitamin D supplements are not used according to the dietary recommendations in a substantial proportion of Finnish children.

Effects of weaning cereals with different phytate contents on hemoglobin, iron stores, and serum zinc: a randomized intervention in infants from 6 to 12 mo of age

BACKGROUND

Weaning foods frequently contain phytate, an inhibitor of iron and zinc absorption, which may contribute to the high prevalence of iron and zinc deficiency seen in infancy.

OBJECTIVE

The objective was to investigate whether either an extensive reduction in the phytate content of infant cereals or the use of milk-based, iron-fortified infant formula would improve iron and zinc status in infants.

DESIGN

In a double-blind design, infants (n = 300) were randomly assigned to 3 cereal groups from 6 to 12 mo of age: commercial milk-based cereal drink (MCD) and porridge (CC group), phytate-reduced MCD and phytate-reduced porridge (PR group), or milk-based infant formula and porridge with the usual phytate content (IF group). Venous blood samples were collected at 6 and 12 mo. Dietary intake was recorded monthly. After the intervention, 267 infants remained in the analysis.

RESULTS

Hemoglobin concentrations of < 110 g/L, serum ferritin concentrations of < 12 microg/L, and serum zinc concentrations of < 10.7 micromol/L had overall prevalences at baseline and 12 mo of 28% and 15%, 9% and 18%, and 22% and 27%, respectively. After the intervention, there were no significant differences in any measure of iron or zinc status between the CC and the PR groups. However, hemoglobin was significantly higher (120 g/L compared with 117 g/L; P = 0.012) and the prevalence of anemia was lower (13% compared with 23%; P = 0.06) in the PR group than in the IF group, which could be explained by differences in daily iron intake between the 2 groups.

CONCLUSION

Extensive reduction in the phytate content of weaning cereals had little long-term effect on the iron and zinc status of Swedish infants.

Copper in drinking water: not a strong risk factor for diarrhoea among young children. A population-based study from Sweden

AIM

To assess whether mean daily intake of copper or maximal concentration of copper in drinking water is related to the incidence of diarrhoea and vomiting among young children.

METHODS

Mean daily intake of copper from drinking water was estimated prior to episodes of diarrhoea among 430 children aged 9 to 21 mo. A total of 4703 samples of tap water were collected in the homes of the children. The mean daily intake of copper and the maximal concentration of copper in samples of consumed water were used as measures of exposure. The cumulative incidence of acute diarrhoea and vomiting was studied during 12 wk of follow-up. Cases of diarrhoea caused by viral and bacterial infections were identified.

RESULTS

The median copper level of the mean value for each child was 0.61 mg/L with 10th and 90th percentiles of 0.04 and 1.57 mg/L. Among the 430 children, 43 had episodes of acute diarrhoea, of which 23 had no identified viral or bacterial origin, and vomiting was reported in 95 children. No significant associations were found between daily intake of copper or maximal concentration of copper in drinking water and the risk of diarrhoea or vomiting.

CONCLUSION

There is unlikely to be a strong association between daily intake of copper or maximal concentration of copper in drinking water and the risk of diarrhoea or vomiting within the range of copper intakes/concentrations studied.

Dietary intakes of 6-24-month-old urban South Island New Zealand children in relation to biochemical iron status

OBJECTIVE

To investigate food sources and intakes of iron, and dietary factors associated with serum ferritin levels in 6-24-month-old children.

DESIGN

A cross-sectional survey employing proportionate cluster sampling was conducted in 1998/1999. Dietary intakes were assessed using a non-consecutive 3-day weighed food record. Serum ferritin and C-reactive protein were analysed from non-fasting venepuncture blood samples and general sociodemographic data were collected.

SETTING

Cities of Christchurch, Dunedin and Invercargill, New Zealand.

SUBJECTS

Randomly selected healthy 6-24-month-old non-breast-feeding children (n = 226).

RESULTS

Total iron intakes (+/- standard deviation (SD)) among non-breast-feeding infants (< 12 months old; n = 42) and toddlers (> or = 12 months old; n = 184) were 8.4 +/- 2.9 mg day(-1) and 5.0 +/- 2.5 mg day(-1), respectively. Fifteen per cent of infants and 66% of toddlers were at risk of inadequate iron intakes. Main sources of dietary iron were infant formula (60%) for infants and cereals (31%) for toddlers. Meat contributed on average 2% and 10% of dietary iron in the infant and toddler diets, respectively. Dietary factors positively associated with serum ferritin were intakes of iron and vitamin C, whereas intakes of calcium and dietary fibre were negatively associated. For each 1% increase in percentage of energy from iron-fortified formula concomitant with a 1% decrease from dairy products, there was a 4.2% increased odds of replete iron stores (ferritin > or = 20 microg l(-1)).

CONCLUSIONS

Toddlers were at higher risk of sub-optimal iron intakes than infants. Results suggest that a diet high in bioavailable iron is important for optimising the iron stores of young children in New Zealand.

Food and nutrient intake in a cohort of 8-month-old infants in the south-west of England in 1993

OBJECTIVE

To investigate food and nutrient intakes in 8-month-old infants.

DESIGN

Prospective study.

SETTING

Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC), south-west England.

SUBJECTS

A total of 1131 singleton Caucasian infants (82% of those invited) from a 10% random sample of ALSPAC, known as Children in Focus (CIF).

METHODS

Diet was assessed using a structured 3-day unweighed dietary record. Food and nutrient intakes were compared with intakes from the 6--9 month age group of a British infant feeding survey, which formed part of the National Diet and Nutrition Survey (NDNS). Nutrient intakes were compared with dietary reference values (DRV).

RESULTS

Intakes of energy and most nutrients were very similar between CIF and NDNS. The main difference was in the type of fat eaten resulting in a higher polyunsaturated to saturated fatty acid ratio in CIF (0.34) compared with NDNS (0.21). Other differences included the much lower calcium and iodine intakes in CIF compared with the NDNS. Differences in the proportion of consumers of formula and cow's milk accounted for most of the nutrient differences. Energy intakes were similar to the estimated average requirements (EAR), however, breastfed infants were slightly below and non-breastfed were slightly above the EAR. Mean intakes of zinc and vitamin D were below the Reference Nutrient Intakes.

CONCLUSIONS

The diets of 8-month-old infants in this study were adequate in most nutrients. Breastfed infants had slightly lower energy intakes than non-breastfed infants.

Growth and nutrient intake in three- to twelve-month-old infants fed human milk or formulas with varying protein concentrations

BACKGROUND

Results on growth and nutrient intake in infants in the second half of infancy fed human milk or formulas with varying protein concentrations in combination with supplementary foods have not previously been reported.

METHODS

Seventy-one healthy infants were studied from 3 to 12 months of age. They were exclusively breast-fed until 3 months and were then randomly assigned to one of three feeding groups, F13, F15, or F18, indicating formulas with 13, 15 or 18 g/l of protein, respectively. Formula was gradually introduced when breast-feeding was terminated. Infants fed breast milk only were included in the breast-fed group, and those with breast milk and formula were included in the mixed-fed group. The same supplementary foods were provided to all infants.

RESULTS

There were no differences in growth between the feeding groups. Total protein intake exceeded minimum recommendations in all groups at all ages and was higher at 6 months in F18 than in F13 (2.3 vs. 1.9 g/kg per day; p < 0.01), whereas formula protein intake was higher at all ages in F18 compared with F13. Intake of protein from supplementary foods increased, but that from formula decreased between 6 and 12 months in all groups.

CONCLUSIONS

Intake of breast milk or infant formula with 13 g/l of protein along with high-protein supplementary foods provided enough protein with no adverse effect on growth. Infants fed formulas with higher protein concentrations had similar growth, despite higher intakes of formula protein.

Energy and macronutrient intake of one-year-old South African urban children: the Birth to Ten (BTT) Study

With the changing situation in South Africa, new, reliable, longitudinal nutritional information on young children is needed. Part of the objective of the Birth to Ten (BTT) Study (1990-2000) in the Soweto-Johannesburg area, is to assess the nutrient intake of children. For each of the 2059 one-year-old children mean nutrient intake was determined using food frequency intakes, determined through interviewing parents or guardians. Urban 'coloured' children had the highest daily intake of all the macronutrients, energy being significantly higher than the other groups. Urban black children had the lowest macronutrient intake and energy was significantly lower than that of white children. All groups consumed a typical westernised diet, low in unrefined carbohydrate (47-49% of energy), but high in protein (200% of Recommended Dietary Allowances (RDA)) and fat (38-40% of energy). Among the 'black', 'coloured' and 'white' clinics a difference of approximately 300 kcal/day was noted between the highest and the lowest energy intakes, Pimville and Mofolo showing significantly higher differences among the 'black' clinics. Among the 'coloured' clinics Westbury had a significantly higher energy intake than Eldorado Park. Results have indicated that one-year-old 'coloured' and white children had adequate nutrient intakes, but black and Indian had inadequate energy intakes based on RDA and excluding the contribution of breast milk.

Protein nutrition during infancy. An update

Good nutrition is essential during the critical period of infancy to promote the child's optimal growth and development. Proteins in human milk are discussed. Protein requirement and recommended dietary intake of healthy term infants during the first 6 months are reviewed. Recommendations for protein content in infant starting formulas and weaning are also discussed.

Fat needs of term infants and fat content of milk formulae

Term infants have precise dietary fat requirements for their metabolic, energy and structural needs. The fat content of commercial milk formulae differs from maternal milk in that it contains no long-chain polyunsaturated derivatives or cholesterol. Artificially fed children thus have less of these molecules available for their biological needs, and hence lower levels of long-chain polyunsaturated derivatives in circulating and membrane lipids than breast-fed children. The functional effects of this difference have not been investigated thoroughly in term infants. Dietary lack of essential fatty acids and their derivatives is evident also in weaned children during the second half of their first year of life. Qualitative changes in the fat content of commercial milk formulae could help to correct some widely encountered dietary imbalances, using the pattern of fats provided in breast milk as the ideal.

Follow-on formulae

Follow-on formulae are recommended as part of the liquid intake of the weaning diet for infants from 6 months on and children aged 12-36 months. The amount of energy and nutrients absorbed by infants from Beikost and milk differs enormously depending on a number of factors and therefore the recommended composition of follow-on formulae varies accordingly. In the future a greater understanding of the nutritional needs of infants and the possibility of choosing between high- or low-protein content formulae may provide infants with a better balanced diet.