Alison A. Paul

Characteristics of the low-energy reporters in a longitudinal national dietary survey

The aim of the present study was to establish whether the characteristics of members of a large national birth cohort study who submitted diet diaries with implausibly low-energy intake differed from those whose recorded energy intake was more plausible. Survey members (n 1898) recorded their diets in a 7 d diary in household measures. Those whose reported energy intake (EI) as a fraction of their estimated BMR was less than 1.10, here termed low-energy reporters (LER) but often called under-reporters, constituted 20.6% of the study population. None of the variables describing dietary, smoking or exercise behaviour bore a significant relationship with low EI/BMR (< 1.10), neither did those describing region of residence, subjective adequacy of income, current social class, social relations or the social environment of the subjects. Results of logistic regression analysis showed that the only independently significant characteristic for men was higher BMI. In women, in addition to higher BMI, having been overweight or obese as an adult independently, but less significantly, predicted low EI/BMR, while membership as a child of social class III (non-manual), having more children in the household and having a paid job marginally but independently decreased the probability of reporting low EI/BMR. Submission of a diary with EI/BMR < 1.10 7 years earlier in the same survey was an even more powerful predictor of current low EI/BMR than higher BMI in both sexes. The average reported diet-composition of LER was more micronutrient- and protein-rich than that of the others, indicating different dietary, or diet-recording, behaviour in this group of subjects. LER are not a random sample of the survey population, and their characteristics, definable to some extent, put them at risk for lower health status. Although EI/BMR cut-off points can be used to identify LER, the problem of how to use their data is still unresolved.

Relative contributions of diet and sunlight to vitamin D state in the elderly.

In winter the vitamin D state of elderly people may reach levels associated with osteomalacia, although the disease may not be clinically apparent. A statistical correlation was observed in a group of elderly subjects during the winter between dietary vitamin D intake and vitamin D state, but the intake was generally too low to make a biologically important contribution to maintaining vitamin D concentrations. Ultraviolet light (UVL) is the primary determinant of vitamin D state in summer and winter, in winter owing to the pools of vitamin D built up during the previous summer. Plasma concentrations of 25-hydroxy vitamin D (25-OHD) in winter of 15.0-22.5 nmol/l (6-9 ng/ml) require that the concentration in the previous summer was over 40 nmol/l (16 ng/ml). To maintain plasma concentrations in the elderly above those associated with osteomalacia a mean dietary vitamin D intake of over 5 microgram/day is required. A more physiological approach, however, would be to increase exposure to UVL.

Seasonal changes in activity, birth weight and lactational performance in rural Gambian women

The activity of 81 pregnant, lactating and non-pregnant, non-lactating women in the rural subsistence farming village of Keneba, The Gambia, was measured for 12 months using a combination of 24-hour activity recall and activity diaries. During the course of pregnancy women became gradually less active and in the month before giving birth were 25% less active than non-pregnant, non-lactating women and lactating women when women in the month after birth were excluded. There were striking seasonal changes in activity. During the dry season, from January to April, lactating women were active 55% of the 15-hour working day. At the start of the farming season in June and July this figure increased to 92%. Similar changes were observed in the pregnant women whose activity increased from a mean 50% in April to 83% in June. The period of intense activity coincided with a general shortage of food and increased incidence of disease. The intense activity of pregnant women in the farming season coupled with the low food intakes are most probably the main factors responsible for the striking fall in birth weights observed at this time of the year. Reduced lactational performance was apparent in relation to high activity when it necessitated the mother regularly spending much of the day away from her child. FAO/WHO-recommended energy intakes during pregnancy and lactation are inappropriate for this community.

FACTORS INFLUENCING LACTATION PERFORMANCE IN RURAL GAMBIAN MOTHERS

Breast-milk consumption has been measured in a rural African community in which breast-feeding on demand is universally practised until the baby is 18 mos old. The mothers long-term capacity for breast-milk production is determined by the end of the second month of lactation, yield being closely correlated with the infants birth-weight. Other factors significantly influencing output were parity, month of lactation, babys weight-for-age, season, and maternal diet. Daily milk consumption was limited primarily by the amount delivered per feed, not the frequency of feeding.

The calcium and phosphorus intakes of rural Gambian women during pregnancy and lactation

The Ca and P intakes of 148 pregnant and lactating women in a rural village in The Gambia, West Africa, have been estimated by direct weighing of food on a total of 4188 d. The Ca and P contents of local foods were determined by analysis of raw ingredients, snack foods and prepared dishes. Information about the contribution of mineral-rich seasonings was obtained. Efforts were made to discover unusual sources of Ca that might not be perceived as food by subject or observer. The main contributors to daily Ca intake were shown to be leaves, fish, cereals, groundnuts and local salt. Cows milk accounted for only 5% of Ca intake. Unusual sources of Ca were discovered, namely baobab (Adansonia digitata) fruit and selected earths, but these were consumed infrequently and their contributions to Ca intakes were small. Cereals and groundnuts were the main sources of P. Ca and P intakes (mg/d) were shown to average 404 (SD 110) and 887 (SD 219) respectively. Seasonal changes in the availability of leaves, cereals and groundnuts resulted in variations in Ca and P intakes. The rainy season was associated with increased Ca intakes (by 16%) but decreased P consumption (by 15%). No difference was observed in Ca intake between pregnant and lactating women but P intake in lactation was 11% higher than that in pregnancy during the post-harvest season. The implications of these low Ca intakes require investigation.

The quantitative effects of maternal dietary energy intake on pregnancy and lactation in rural Gambian women

The quantitative relationships between dietary energy intake and weight gain in pregnancy, birthweight and lactation performance during the first three months of infancy have been studied in such a way as to take account of major differences in the patterns of heavy manual labour at different times of the year in a subsistence farming community. Maternal weight gain and the accumulation of subcutaneous fat were significantly lower when the last trimester of pregnancy fell during the time of heaviest farm work and lowest energy intakes. The birth-weight of babies was also significantly correlated with differences in energy intake throughout the year. During early lactation breast milk yields were significantly related to concomitant alterations in the subcutaneous fat stores. Evidence has been produced which suggests that in undernourished nursing women there could be a competition for dietary energy between the repleting maternal subcutaneous fat organs and the mammary glands at the expense of milk production.

Long-term vitamin status and dietary intake of healthy elderly subjects

1. Long-term clinical and biochemical vitamin C (ascorbic acid and dehydroascorbic acid) status and dietary intake of vitamin C were monitored for 18 months in twenty-three relatively-healthy elderly subjects living at home in the north of England. 2. Plasma vitamin C showed a strong positive correlation with buffy-coat vitamin C both cross-sectionally between subjects and longitudinally within subjects; plasma levels, therefore, were almost as good an index of long-term status as buffy-coat levels. 3. Vitamin C intake was strongly correlated with plasma and with buffy-coat levels both between subjects and within subjects. This contrasts with the poor correlation observed between riboflavin intake and biochemical riboflavin status in the same subjects. 4. Subjects with relatively high average intakes showed considerable seasonal variation, and several widely-spaced measurements would be needed to characterize their long-term status accurately. Those with low average intakes and blood levels showed little variation during the study. 5. The strongest within-subject correlation was obtained by relating the biochemical values to the 7 d dietary intake directly preceding the biochemical analysis. Blood and tissue levels therefore appear to be strongly related to the current dietary intake. 6. Although some subjects had blood vitamin C levels consistently within the region associated with biochemical deficiency, none showed clinical evidence of specific deficiency symptoms. 7. After the main study, fifteen of the subjects received supplementary vitamin C for 2 months. Plasma and buffy-coat levels rose sharphy, but fell to presupplementation levels within 1 month of withdrawal, emphasizing the transitory nature of increased tissue levels. No significant changes were detected in the following collagen-related urinary ratios: hydroxyproline: creatinine, proline: creatinine, proline: total amino-nitrogen and proline: hydroxyproline in hydrolysates either of whole urine or of various fractions. These variables thus appear to be insensitive to short-term changes in vitamin C status over the ranges encountered in this study.

Riboflavin status in infants born in rural Gambia, and the effect of a weaning food supplement.

Riboflavin status was measured in infants between birth and two years of age, by the erythrocyte glutathione reductase (NAD(P)H2: glutathione oxidoreductase, EC 1.6.4.2) test on finger-prick blood samples. The infants were living in three rural Gambian villages: Keneba, Manduar and Kanton Kundar; those in Keneba were receiving a weaning food supplement between three and 12 months, which provided 0.15 to 0.20 mg riboflavin per day, in addition to their normal intake from breast milk and locally available weaning foods, which provided 0.13 to 0.21 mg/day over the same age range. On the basis of currently accepted criteria of biochemical normality, the unsupplemented infants were born deficient and, in the absence of a supplement, remained so throughout their first two years of life, with only a minor, short-lived improvement during the first few months. In the supplemented group, however, riboflavin status fell within normal limits for the duration of the supplement, but rapidly deteriorated again once the supplement was withdrawn. It is concluded that infants born to deficient mothers are usually deficient at birth, and remain so throughout suckling and weaning on to locally available foods. The daily requirement, to achieve satisfactory biochemical status, is thus greater than 0.13 to 0.21 mg/day, and probably approaches 0.4 mg/day, for most individuals up to the age of one year.

Breast‐milk Antimicrobial Factors of Rural Gambian Mothers: Influence of Stage of Lactation and Maternal Plane of Nutrition

ABSTRACT. The concentrations of IgA, IgG, IgM, C3, C4, lactoferrin, lysozyme and secretory component in the mature breast milk of 152 rural Gambian mothers were measured up to 26 months lactation. The concentrations and daily secretion of all the immunoproteins, except lysozyme, decreased during the first year of lactation, but were well maintained thereafter. The production of lysozyme increased progressively throughout lactation. Compared with 10 mothers in Cambridge, U.K., the daily secretion of IgG, IgM, C3 and C4 was higher in The Gambia, that of IgA and lactoferrin was similar in the two communities, and that of lysozyme and secretory component was lower in The Gambia. A dietary supplement given to 90 Gambian mothers, raised the mean daily energy intake from a maximum of 1650 kcal/day and a hungry‐season minimum of 1200 kcal/day to 2300 kcal/day throughout the study. The supplement did not enhance the production of breast milk immunoproteins.

Weaning Practices in the United Kingdom and Variations in Anthropometric Development

ABSTRACT. The influence of different weaning practices on the dietary energy intake and growth of Cambridge infants has been investigated. Bottle fed children were in general given solid foods sooner, 10.6 weeks for boys and 13.9 weeks with girls: among breast‐fed babies the average age was 14.9 weeks in the case of boys and 17.4 weeks for girls. All four groups of children exhibited different growth patterns from those of the NCHS and Tanner reference curves. Over the first three months both boys and girls exhibited a faster velocity of growth in weight, length and weight‐for‐length. After this time, however, growth velocity was slower than that of the reference children particularly among breast‐fed boys who were not given solids until after 16 weeks. For most of infancy triceps and subscapular skinfold thicknesses remained around the 10th centile of the corresponding Tanner reference children, although again the babies weaned later had the lower values. Bottle‐fed infants had growth patterns similar to those of the earlier weaned breast‐fed babies for all parameters. It is concluded that babies grow differently now that infant feeding patterns have changed.