A study of relationships between bone-related vitamins and minerals, related risk markers, and subsequent mortality in older British people: the National Diet and Nutrition Survey of People Aged 65 Years and Over.

SUMMARY: Follow-up of a British national survey of older people found that in men, all-cause mortality was predicted by baseline plasma concentrations of phosphorus, albumin, creatinine and α1-antichymotrypsin, and food energy intake and in women by plasma alkaline phosphatase, creatinine, α1-antichymotrypsin, 25-hydroxy-vitamin D (marginally), and phosphorus intake. INTRODUCTION: Predictive power, for all-cause mortality, of bone-related vitamin and mineral indices and intakes, measured at baseline (primary objective), was studied in the British National Diet and Nutrition Survey (community-living subset) of People Aged 65 Years and Over. A secondary objective was to identify cross-sectional relationships between indices at baseline to help explain mortality predictions. METHODS: Mortality status was recorded for 1,054 (mean age 76.6 ± 7.4 years, 49.0% female) participants from baseline survey in 1994/1995 until September 2008. Seventy-four per cent of male and 62% of female participants died. Cox proportional hazards models were used to relate baseline nutrient and risk marker estimates to subsequent survival. Results below 1.0 signified lower risk at greater nutrient (status or intake) values and vice versa. RESULTS: In both sexes, all-cause mortality was significantly predicted by body weight and mid-upper arm circumference. In men, it was predicted by baseline plasma concentrations (per SD) of: phosphorus (hazard ratio 1.18, 95% confidence interval (CI) = 1.06-1.30), albumin (hazard ratio 0.84, 95% CI = 0.74-0.94), creatinine (hazard ratio 1.20, 95% CI = 1.08-1.33) and α(1)-antichymotrypsin (hazard ratio 1.21, 95% CI = 1.11-1.33). In women, it was predicted by plasma albumin (hazard ratio 0.83, 95% CI = 0.72-0.96), alkaline phosphatase (hazard ratio 1.08, 95% CI = 1.01-1.16), creatinine (hazard ratio 1.37, 95% CI = 1.13-1.66), α(1)-antichymotrypsin (hazard ratio 1.27, 95% CI = 1.11-1.45) and marginally by 25-hydroxy-vitamin D (hazard ratio 0.87, 95% CI = 0.75-1.00). In men, it was predicted by dietary intake (per SD) of food energy; in women, by intake of phosphorus. Adjustment for plasma α(1)-antichymotrypsin or plasma creatinine reduced the significance of plasma phosphorus in men. CONCLUSION: Mortality prediction by higher plasma phosphorus in older British men may imply impaired renal function and/or acute phase status. Further studies are needed on which associations are causal and modifiable.

Blood indices of selenium and mercury, and their correlations with fish intake, in young people living in Britain.

Relationships between Se and Hg in erythrocytes, and between these indices and intakes of fish and other foods, were studied as an adjunct to the British National Diet and Nutrition Survey (NDNS) of young people aged 4-18 years. Hg was measured in 965 packed erythrocyte samples by inductively coupled plasma mass spectrometry. Fe measurements permitted the calculation of whole-blood Hg. Erythrocyte and plasma Se, and 7 d weighed dietary intake estimates, were available. Erythrocyte Hg was positively skewed, normalised by log-transformation. It was 20 % higher in girls than boys (3.17 v. 2.65 nmol/l, P=0.004), and increased with age in boys but not girls. It was directly and strongly correlated with erythrocyte or plasma Se. Hg and Se concentrations were directly correlated with fish intake. Certain other food groups were also directly correlated with Se and Hg concentrations, but less strongly than for fish. The strength and consistency of the relationship between erythrocyte Hg and Se suggests an important chemical link. Previous studies suggest that Se protects against the toxicity of Hg, and that fish is an important source of both. No toxic levels of Hg were found, which is reassuring because of the known health benefits of fish consumption, especially oily fish. Hg intakes need to be monitored, especially in women of child-bearing age, to ensure that Food Standards Agency guidelines are met.

Prevalences of hyperhomocysteinemia, unfavorable cholesterol profile and hypertension in European populations.

BACKGROUND: Hyperhomocysteinemia (HHCY) is a risk factor for cardiovascular diseases (CVD). HHCY may interact with hypertension (HTEN) and an unfavorable cholesterol profile (UNFAVCHOL) to alter the risk of CVD. OBJECTIVES: To estimate the prevalences of HHCY (1) isolated and (2) in combination with UNFAVCHOL and/or HTEN in different age categories. To provide information that may improve the screening and treatment of subjects at risk of CVD. DESIGN: Cross-sectional data on 12,541 men and 12,948 women aged 20 + y were used from nine European studies. RESULTS: The prevalence of isolated HHCY was 8.5% in subjects aged 20-40 y, 4.7% in subjects aged 40-60 y and 5.9% in subjects aged over 60 y. When combining all age groups, 5.3% had isolated HHCY and an additional 5.6% had HHCY in combination with HTEN and/or UNFAVCHOL. The combinations of risk factors increased with age and, except for HHCY&UNFAVCHOL, were more prevalent than predicted by chance. Of the young subjects (20-40 y), 24% suffered from one or more of the investigated CVD risk factors. This figure was 75.1% in the old subjects (60+ years). CONCLUSIONS: A substantial number of subjects in selected European populations have HHCY (10.9%). In half of these cases, subjects suffer also from other CVD risk factors like UNFAVCHOL and HTEN. Older people in particular tend to have more than one risk factor. Healthcare professionals should be aware of this when screening and treating older people not only for the conventional CVD risk factors like UNFAVCHOL and HTEN but also HHCY, as this can easily be reduced through increased intake of folic acid via supplement or foods fortified with folic acid.

Zinc and vitamin A intake and status in a national sample of British young people aged 4-18 y.

OBJECTIVE: To examine zinc and vitamin A intake and status and associated dietary, socio-demographic, lifestyle and physiological factors in British young people. DESIGN: National Diet and Nutrition Survey of young people aged 4-18 y. SETTING: Great Britain, 1997. SUBJECTS: Complete 7-day weighed dietary records were provided by 1520 participants, while 1193 provided blood samples. RESULTS: A total of 13 and 11% of participants respectively reported low dietary intakes of zinc and vitamin A (retinol equivalents), relative to the UK lower reference nutrient intake. These percentages were not altered significantly by including contributions to intake from supplements, mainly containing vitamin A (as retinol). Likelihood of low zinc and/or vitamin A intake was more often associated with age, sex and likely under-reporting of food consumption than with other socio-demographic and lifestyle factors. Low zinc and vitamin A intakes were generally less likely in those with higher consumption of dairy foods (mainly milk). Zinc and vitamin A status (assessed by plasma zinc and retinol concentrations) were adequate in almost all participants. Plasma zinc concentration was not significantly associated with zinc intake. Plasma retinol concentration was correlated with vitamin A intake (overall r=0.17, P<0.001; adjusted for age and plasma alpha(1)-antichymotrypsin concentration) and increased significantly with age (P<0.001) in both sexes. A significant association was found between plasma zinc and retinol concentrations in boys only (r=0.17, P=0.001). CONCLUSION: Zinc and vitamin A intakes and status were generally adequate in this national sample of British young people.

Selenium status and associated factors in a British National Diet and Nutrition Survey: young people aged 4-18 y.

OBJECTIVE: Assessment of selenium status to provide normative reference values, and investigation of associated socio-demographic factors, in a national sample of British young people aged 4-18 y. SETTING: National Diet and Nutrition Survey-a nationwide cross-sectional sample of young people aged 4-18 y living in mainland Britain in 1997. METHODS: Selenium status was measured, mainly in fasting blood samples, by plasma selenium concentration in 1127 participants, by red blood cell (RBC) selenium concentration in 1112, and by whole-blood glutathione peroxidase (GPx) activity in 658. RESULTS: No evidence of severe selenium deficiency or toxicity was observed. Plasma selenium concentration was directly correlated with RBC selenium concentration, and both were associated directly, although less strongly, with GPx activity. Plasma and RBC selenium concentrations increased significantly with age, with RBC concentrations significantly higher in older girls than boys. Region of domicile exhibited a significant relationship. Associations also occurred with parental occupational social class, selenium concentrations being higher in more socially advantaged children. Black and Indian children had considerably higher concentrations than Caucasian children. Concentrations, especially of plasma selenium, were significantly lower in children either (or both) of whose parents were smokers, although, unexpectedly, there was no evidence that children who themselves smoked had lower levels. CONCLUSIONS: The observed associations between selenium status indices and age, gender, social class, parental smoking and ethnic group indicate a complex network of biological factors which determine selenium concentrations in blood components, and which thus need to be controlled for when using these indices to assess selenium status in young people. SPONSORSHIP: The survey was commissioned jointly by the Department of Health and the Ministry of Agriculture, Fisheries and Food, whose responsibility has since been transferred to the Food Standards Agency. Support for the further analysis presented in this paper was provided by the Department of Health.

Intake and sources of phylloquinone (vitamin K1): variation with socio-demographic and lifestyle factors in a national sample of British elderly people.

Intake and sources of phylloquinone (vitamin K1) were examined according to socio-demographic and lifestyle factors in free-living British people aged 65 years and over, from the 1994-5 National Diet and Nutrition Survey. Complete 4-d weighed dietary records were obtained from 1152 participants living in private households. Using newly-available, mainly UK-specific food content data, the weighted geometric mean intake of phylloquinone was estimated at 65 (95 % CI 62, 67) microg/d for all participants, with higher intakes in men than in women (70 v. 61 microg/d respectively, P<0.01). The mean nutrient densities of phylloquinone intake were 9.3 and 10.5 microg/MJ for men and women respectively (P<0.01), after adjusting for age group, region and smoking status. Of all the participants, 59 % had phylloquinone intakes below the current guideline for adequacy of 1 microg/kg body weight per d. Participants aged 85 years and over, formerly in manual occupations, or living in Scotland or in northern England reported lower phylloquinone intakes than their comparative groups. Overall, vegetables contributed 60 % of total phylloquinone intake, with cooked green vegetables providing around 28 % of the total. Dietary supplements contributed less than 0.5 % of phylloquinone intake. Participants living in northern England or in Scotland, in particular, derived less phylloquinone from vegetables than those living in southern England.

Geographical variations in nutrition-related vascular risk factors in the UK: National Diet and Nutrition Survey of People Aged 65 Years and Over.

BACKGROUND: There is a strong north-south gradient of vascular disease in Britain, whose aetiology is not fully understood. OBJECTIVE: To test the hypothesis, in a cross-sectional survey of older people, that intakes and status indices for protective micronutrients, particularly those for which fruit and vegetables are rich sources, also vary on a north-south axis. DESIGN: The 1994-5 National Diet and Nutrition Survey of People Aged 65 Years and Over has provided a uniquely appropriate data-set for this purpose. The analysis, confined to free-living participants, compared nutrient intakes and status between people living in the north of Britain, from Scotland to Humberside, with those living south of the Wash, excluding the Midlands and Wales. RESULTS: Highly significant north-south differences, especially for vitamin C, but also to a significant extent for B-vitamins and carotenoids, indicated a more vitamin-rich diet, with more frequent use of vitamin supplements, in the south. Vitamin D status and fibre intakes were also higher in the south; sodium intake was greater in the north. Blood lipid indices did not, however, differ between north and south. North-south differences in the likelihood of receiving income support, of having manual socio-economic status and of smoking habit, appeared to be significant underlying socio-demographic factors. CONCLUSION: These findings are consistent with the hypothesis that for older British people, differences in nutrient intake and status indices between the north and south of Britain run parallel with, and may contribute to, the north-south axis of vascular disease risk.

Dietary supplement use at the population level: recent experience from the 1994-5 British National Diet and Nutrition Survey: people aged 65 years and over.

The purpose of this article is to alert readers of this issue to the ongoing National Diet and Nutrition Survey series in mainland Britain, and to draw attention to the existence of information on the use of dietary supplements by different age-groups in the UK, and to some specific issues which need to be addressed, in order to achieve reliable estimates of supplement use from surveys of this type.

Plasma total homocysteine response to oral doses of folic acid and pyridoxine hydrochloride (vitamin B6) in healthy individuals. Oral doses of vitamin B6 reduce concentrations of serum folate.

Plasma total homocysteine response was compared in four groups of healthy individuals given orally divided doses of vitamin supplementations for a duration of 5 weeks. The vitamin supplements; A, 0.3 mg folic acid; B, 120 mg vitamin B6; C, combination of 0.3 mg folic acid and 120 mg vitamin B6 or D, 0.6 mg folic acid reduced the concentrations of plasma total homocysteine 20, 17, 32 and 24%, respectively. However, the intergroup comparisons did not show a significant difference in the effects of vitamin supplements. Multivariate analysis with correction for differences in pre-supplement values indicated a significant effect of vitamin B6 supplementation on plasma total homocysteine and serum folate. Our data show that plasma total homocysteine concentrations are reduced with low to medium divided doses of folic acid alone or in combination with vitamin B6.

Vitamin D: seasonal and regional differences in preschool children in Great Britain.

OBJECTIVES: To examine seasonality of 25-hydroxyvitamin D (25OH-D) levels in British preschool children and the effect of vitamin D supplementation on this. DESIGN: The National Diet and Nutrition Survey of children aged 1.5 4.5 y in Britain during 1992-3 measured dietary intakes and blood status indices, including those for vitamin D, during all four seasons. The present study addresses the seasonal dependence of the relation between vitamin D intake and status. SETTING: 100 randomly selected postcode sectors throughout Britain, whose locations were classified as (a) Scotland; (b) Northern England; (c) Central, Wales, South+SW; (d) London+SE. SUBJECTS: Of 1859 whose parents or guardians were interviewed, 1675 provided a weighed diet estimate, and blood vitamin D status (25OH-D) was measured in 756, with approximately equal numbers in each season. RESULTS: Vitamin D status is highly dependent on season: moreover, the relation between vitamin D intake and status is also seasonally dependent, being strong in the winter and negligible in the summer. During the winter, those children who had relatively low 25OH-D concentrations generally were those not receiving vitamin D supplements. Vitamin D intakes and supplement use were lower in the north than in the south of Britain. CONCLUSIONS: For British preschool children, dietary vitamin D is of much greater importance in the winter than in the summer. There is evidence of regional inequality, with lesser use of supplements in the north. Supplements are needed in the winter, to achieve satisfactory vitamin D status and minimise the risk of rickets and of poor bone health, especially in high-risk groups.

North-south differences in some indices of Vitamin B6 nutritional status in older British people.

The National Diet and Nutrition Survey, nationally representative for the British population aged 65 years and over, has revealed a north-south geographical gradient, with a decline from south to north of vitamin B6 status indices. The present study further explores the possible explanatory factors (dietary intake of vitamin B6 and riboflavin, alcohol consumption, smoking habits and some other lifestyle determinants) on the difference of vitamin B6 indices--plasma concentrations of pyridoxal phosphate (pPLP) and pyridoxic acid (pPA), between older people living in the north (Scotland, North of England) and the south (Southern England, Wales and Midlands). The results showed that older people living in the northern half of Britain are at greater risk of poor vitamin B6 status, mainly as a result of low intakes of this vitamin, than the people living in the southern half of the country. Riboflavin intake, alcohol consumption, smoking and socio-economic status also correlated with the north-south gradient of pPLP and pPA. Other potential determinants such as use of vitamin B6 supplements, medicines probably affecting vitamin B6 metabolism, were not independent correlates of the north-south gradient in vitamin B6 status indices. This may have important implications for disease-risk geographical gradients in the UK.

Estimation of the use of dietary supplements in the National Diet and Nutrition Survey: people aged 65 years and Over. An observed paradox and a recommendation.

OBJECTIVE: To compare the evidence derived from blood biochemical status indices with the evidence from a questionnaire and from a 4-day weighed dietary record of micronutrient supplement use in the British National Diet and Nutrition Survey (NDNS) of People Aged 65 Years and Over; to resolve some apparent incompatibility between nutrient intake and status estimates, and to recommend an approach towards supplement recording that should improve accuracy. DESIGN: The survey procedures described in the National Diet and Nutrition Survey Report (1998) included a health-and-lifestyle questionnaire, a 4-day weighed diet record, and fasting blood and urine sample for biochemical indices, including a wide range of micronutrients. SETTING: Eighty randomly selected postcode sectors from mainland Britain during 1994-1995. SUBJECTS: Of 2060 people interviewed, 1467 provided a blood sample and 1217 provided both a blood sample, and a complete 4-day diet record. About 20% were living in institutions such as nursing homes, and the remainder were living in private households. RESULTS: After assigning the subjects to four categories by the use of dietary supplements (A, those not taking supplements (by questionnaire or by the 4-day record); B, those taking supplements (excluding prescribed ones) by questionnaire only; C, those taking supplements by 4-day record only; and D, those taking supplements by both questionnaire and 4-day record), these categories were then compared with respect to estimated total nutrient intakes and blood biochemical indices. Those in category B had estimated (4-day) nutrient intakes (from foods and supplements) that were indistinguishable from those in category A, but had biochemical indices that indicated significantly higher dietary intakes of several vitamins. CONCLUSIONS AND RECOMMENDATION: The 4-day weighed intake record may not have identified all of the subjects who were regularly taking micronutrient supplements in amounts sufficient to improve their biochemical status. Because survey respondents may use supplements irregularly or change their usual patterns of supplement use during a period of intensive diet-recording, it is important to design a dietary instrument that will minimise this potential source of inaccuracy. We therefore recommend that population surveys in which an accurate estimate of micronutrient intakes is required, from supplements as well as from food, should record supplement use for a period longer than 4-days. It is likely that a better estimate of long-term intakes can be achieved by combining a 4-day weighed diet record with a structured recall or several weeks of diary records, which focus specifically on the use of supplements.

Biochemical evidence of thiamine depletion during the Cuban neuropathy epidemic, 1992-1993.

During an epidemic outbreak of neuropathy in Cuba during 1992-1993, blood and urine samples were collected from 107 persons with confirmed neuropathy, from 106 control subjects without clinical abnormality who were broadly matched with the affected persons by age and domicile, and from 537 unmatched subjects, also free from clinical abnormality. The unmatched subjects lived in two locations in Cuba; at each location they were drawn from two age ranges: 11-15-y-old secondary school students and 16-64-y-old adults. Measurements of urinary thiamine and blood transketolase and its activation with thiamine pyrophosphate were made. For the neuropathy subjects, these measurements were repeated after 3 wk of rehabilitation. All groups showed biochemical evidence of thiamine depletion affecting 30-70% of their members, which is a high prevalence. Severity of biochemical depletion was, however, no greater in the neuropathy subjects than in the control subjects (P > 0.05). However, it was greater in Pinar del Rio, where the incidence of disease was higher, than in the city of Havana, where less disease was seen. Although the majority of the affected subjects responded biochemically to a daily oral multivitamin supplement containing thiamine (P < 0.001), in some cases normal biochemical status was not achieved even after 3 wk of intensive treatment. In the affected group, thiamine status was inversely correlated with the amount of alcohol consumed (P = 0.007). Thiamine status at the outset was correlated with clinical outcome after treatment. Although neither thiamine depletion nor alcohol abuse were likely to have been the sole cause of the neuropathy epidemic, they may have been contributory factors. Thiamine supplementation or food fortification may therefore be necessary in Cuba.

Quantitation of vitamin E and a carotenoid pigment in cataractous human lenses, and the effect of a dietary supplement.

The quantitation of tocopherols and carotenoids in lipid extracts of cataractous human lenses was performed in parallel with those of matched samples of plasma, which was also analysed at the same time. Alpha-tocopherol in cataractous lenses from elderly human subjects was present at 4.4 mumoles/kg wet weight, much less than the mean of 33 mumoles/l in plasma from these subjects. The mean ratio of alpha- and gamma-tocopherols was 3.5 in the lenses, and 11.3 in plasma. Lens extracts contained no detectable alpha- or beta-carotene, lycopene, or beta-cryptoxanthin. However, all the lens extracts contained a pigment with the retention time and spectrum of lutein and zeaxanthin. Using the molar extinction coefficient of lutein this was present at ca. 0.03 microM, compared with 0.2 microM in plasma. Seven patients with bilateral cataracts had one of their cataractous lenses removed and analysed, and were then given either an oral placebo, or an oral supplement of ascorbate, alpha-tocopherol and beta-carotene. Three months later, the second cataractous lens, and a blood sample, were analysed. Three of the seven had received the active supplement, as confirmed by substantially raised blood levels of alpha-tocopherol and beta-carotene, and raised aqueous humour levels of vitamin C. However, lens tocopherol levels remained unchanged, and no beta-carotene could be detected in the lenses after supplementation. This preliminary evidence needs to be confirmed in larger studies.

Biochemical indices and neuromuscular function tests in rural Gambian schoolchildren given a riboflavin, or multivitamin plus iron, supplement.

Ninety preselected children, aged between 8 and 14 years, living in two rural West African (Gambian) villages, were randomly divided into three groups, matched for age and sex. One group received a placebo (lactose) tablet, one received riboflavin (5 mg) on 5 d every week, which was sufficient to correct an endemic riboflavin deficiency, and one received a multivitamin supplement (Protovit; Hoffmann La Roche), on 5 d every week, together with FeSO4 (200 mg) once weekly, and the supplements were given for 1 year. Neuromuscular tests, including arm tremor and manipulative skills, were performed on three occasions: once just before the introduction of the supplements; again 6 weeks after commencing the supplements; and again 1 year later. Venous blood samples were collected at the same time as the first two sets of neuromuscular tests. These samples were used for haematology and nutrient status indices: plasma ferritin, ascorbic acid, cyanocobalamin and pyridoxal phosphate, and erythrocyte tests for folate status, for riboflavin status (erythrocyte glutathione reductase activation coefficient) and thiamine status (erythrocyte transketolase activation coefficient). The riboflavin in both supplements achieved a clear-cut response in biochemical status, which was dose-dependent. The pyridoxine, ascorbic acid and Fe components of the multivitamin also affected the associated biochemical indices. Although overall the arm tremor and related neuromuscular function tests did not respond significantly to the supplements, significant improvement was seen in the boys for the arm-tremor test in both the supplemented groups.

Breast milk as a source of vitamins, essential minerals and trace elements.

Human breast milk provides all of the vitamins and essential minerals and trace elements (micronutrients) that are required by the normal term infant, until weaning. With a few exceptions, excessive micronutrient supplies to the mother, or a moderate deficiency in her diet, do not greatly alter the supply to the infant. Thus, the infant is well-protected by maternal homeostatic processes, although the mechanisms of these are not yet well understood. Considerable progressive changes in concentration occur for some of the micronutrients during the course of lactation. Because the concentration of these nutrients, and of other substances that modify their absorption by the infant, such as binding proteins, differs considerably between human milk, animal milk and, hence, commercial milk formulae, there is great interest in the quantitative significance of micronutrient supplies, and their variability in breast milk, in the quest for improvement of commercial formulations. The aim of this review is to summarize the available information about the factors that determine breast milk contents of micronutrients.

Adequacy of dietary mineral supply for human bone growth and mineralisation.

The evidence on the relationship between dietary mineral supply and bone development in children has been extensively reviewed. Data from children and primates suggest that overt deficiencies of Ca, P and Zn are likely to produce rickets and growth retardation, while the effects of Mg deficiency on human bone are unknown. The manifestations of marginal deficiencies are little understood. The biological needs for Ca, P, Mg and Zn in childhood have been calculated based on mineral deposition rates, using published values for the mineral content of the human body, and on obligatory endogenous losses. As a rough guide, the estimated biological requirements for the Ca, P, Mg and Zn can be taken as 200, 100, 4 and 1 mg/d respectively. A comparison of measured daily intakes of children in developing countries with biological requirements was made. This revealed that P and Mg intakes were many times higher than estimated needs. Ca intakes at all ages were found to be close to the biological requirement for children in many Third World societies, before any allowance for possible poor absorption. Zn intakes approach estimated needs in breast-fed infants, particularly during weaning, but are 4-5 times higher in older children. Poor absorption from phytate-rich diets could affect Zn supply. Supplementation studies indicate that raising Zn intakes can increase height gains in certain vulnerable groups, such as infant and adolescent boys. In conclusion, the evidence suggests that inadequate dietary intakes of Ca and Zn may contribute to linear growth retardation in children of developing countries but more research is needed.

Nutritional efficacy of a fortified weaning rusk in a rural area near Beijing.

A micronutrient-fortified rusk for weanling children was tested in a rural area near Beijing. Two hundred twenty-six children aged 6-13 mo were randomly assigned by village to either a micronutrient-fortified or an unfortified rusk, daily for 3 mo. The fortified rusk contained extra zinc; iron; calcium; vitamins A, D, and B-12; thiamin, riboflavin, niacin, and folic acid. Infants receiving the fortified rusk exhibited no decline in hemoglobin concentrations during the study whereas those receiving the unfortified rusk exhibited a significant decline. Improvements were also seen in erythrocyte porphyrin, plasma vitamin A, and riboflavin status, but these improvements were seen in both of the groups. Micronutrient fortification was probably beneficial for iron status and the fortified rusk promises to be an effective vehicle for supplementation.

PIP: In February-June 1990, in China, researchers assigned, by village, 226 6-13 month old, full-term, healthy infants from 33 villages of the Mi-yun rural area near Beijing to receive daily either a micronutrient-fortified or an unfortified rusk for 3 months. 15% of all infants were initially anemic, but not severely so. Extra zinc; iron; calcium; vitamins A, D, and B-12; thiamin; riboflavin; niacin; and folic acid fortified the rusk. The study aimed to determine the efficacy of the micronutrient fortification. Mean hemoglobin levels decreased considerably in the infants in the unfortified rusk group (12.85 g/L vs. 12.95 g/L; p .01), but remained the same for the fortified rusk group. The change in the unfortified rusk group's hemoglobin levels was much greater than that of the fortified rusk group (p .01). The significance of the supplement-group effect fell when the researchers included initial ferritin and free erythrocyte porphyrin concentrations (p = .04-.08). There was a considerable reduction in free erythrocyte porphyrin in both groups of infants (p .001) and the response was basically the same for both groups. Even though the fortified rusk group experienced a significant increase in plasma vitamin A (.093 mcmol/L; p .01), the difference in response between the 2 groups was not significant. Infants in the fortified rusk group experienced a considerable fall in vitamin E levels (p .001) which was a significantly greater decline than that observed in the unfortified rusk group (2.6 mcmol/L vs. .79 mcmol/L; p = .012). The erythrocyte glutathione reductase index of riboflavin status improved significantly in the fortified rusk group (.07; p = .05), but it was not significantly different from that of the unfortified group. These results suggested that fortifying a commercial weaning risk with micronutrients benefited the iron status of these children.

A trial of zinc supplementation in young rural Gambian children.

The present study tested the hypothesis that inadequate Zn intake might be responsible for failure to thrive and impaired catch-up growth in young rural Gambian children, and that Zn supplements might be beneficial. Gambian children might be deprived of Zn because of its poor availability from their predominantly plant-based diet. Rural Gambian children (110; fifty boys, sixty girls) aged between 0.57 and 2.30 years were divided into two matched groups, one to receive 70 mg Zn twice weekly for 1.25 years, and the other a placebo. Growth and mid-upper-arm circumference were measured at weekly intervals throughout the study and illnesses were monitored. Capillary blood and urine samples were collected at 0, 2 and 8 weeks. Body weights and arm circumferences showed a linear increase, plus a seasonal effect (rainy season faltering). For body weight there was no significant overall effect of the supplement. For arm circumference, a very small (2%) but significant (P < 0.01) difference favoured the supplemented group. Plasma thymulin was much lower at the first clinic than at the second and third clinics, and in vitro Zn stimulation was greater at the first clinic. There was, however, no effect of Zn in vivo. Likewise, Zn did not significantly benefit T-cell numbers or ratios, secretory IgA in urine, circulating hormone levels or biochemical indices of Zn status. One index of intestinal permeability, i.e. lactulose: creatinine, was improved (P < 0.02) by the supplement, but the lactulose: mannitol value was not; this requires further investigation. Dietary Zn deficiency is, thus, unlikely to be of major overall importance for rural Gambian children's ability to thrive, and blanket Zn supplementation is not justified. There may, however, be vulnerable sub-groups who would benefit from Zn supplements.

Plasma folate levels in preterm infants, with and without a 1 mg daily folate supplement.

One hundred and four preterm infants were studied during the first few months of life in the Special Care Baby Unit of Addenbrooke's Hospital, Cambridge, United Kingdom. Previously, it had been the daily practice within the Unit to give a 1 mg oral supplement of folate (in the form of pteroylglutamic acid), once the infants had commenced full enteral feeding. At least one blood sample was obtained from 70 infants before oral folate supplementation was started. In these, the plasma folate levels fell progressively from a median value of 45 micrograms/l to a median of 12 micrograms/l, by the 2nd-3rd week of life. Once started on the oral supplement, 83 of the infants provided at least one blood sample. The plasma folate level of these infants rose immediately to a median value of 300 micrograms/l and a maximum of 1000 micrograms/l. Within individuals, these plasma folate levels decreased progressively following the introduction of the supplement, despite continuing daily supplementation. In a typical baby this decrease appeared to be explained by an increase in body-size, i.e. dilution of the folate into a larger pool. The implications of this level of supplementation are discussed, and in the light of our observations we suggest that daily supplementation in the range, 0.05-0.2 mg folate may be preferable for well preterm infants.