Margo E. Barker

Milk intake and bone mineral acquisition in adolescent girls: randomised, controlled intervention trial.

Abstract Objectives: To investigate the effect of milk supplementation on total body bone mineral acquisition in adolescent girls. Design: 18 month, open randomised intervention trial. Subjects: 82 white girls aged 12.2 (SD 0.3) years, recruited from four secondary schools in Sheffield. Intervention: 568 ml (one pint) of whole or reduced fat milk per day for 18 months. Main outcome measures: Total body bone mineral content and bone mineral density measured by dual energy x ray absorptiometry. Outcome measures to evaluate mechanism included biochemical markers of bone turnover (osteocalcin, bone alkaline phosphatase, deoxypyridinoline, N-telopeptide of type I collagen), and hormones important to skeletal growth (parathyroid hormone, oestradiol, insulin-like growth factor I). Results: 80 subjects completed the trial. Daily milk intake at baseline averaged 150 ml in both groups. The intervention group consumed, on average, an additional 300 ml a day throughout the trial. Compared with the control group, the intervention group had greater increases of bone mineral density (9.6% v 8.5 %, P=0.017; repeated measures analysis of variance) and bone mineral content (27.0% v 24.1 %, P=0.009). No significant differences in increments in height, weight, lean body mass, and fat mass were observed between the groups. Bone turnover was not affected by milk supplementation. Serum concentrations of insulin-like growth factor I increased in the milk group compared with the control group (35% v 25 %, P=0.02). Conclusion: Increased milk consumption significantly enhances bone mineral acquisition in adolescent girls and could favourably modify attainment of peak bone mass. Key messages Osteoporosis is a major public health problem; 40% of women will sustain an osteoporotic fracture Maximising peak bone mass at skeletal maturity may be one of the most important protective measures against fracture in later life Adolescence is a critical time for bone mineral acquisition An increase in milk consumption among adolescent girls resulted in significant gains in bone mineral over an 18 month period This simple intervention indicates that increased milk consumption may be associated with higher peak bone mass

Accuracy of weighed dietary records in studies of diet and health.

OBJECTIVE--To provide an independent evaluation of seven day weighed dietary records, which are currently accepted as the most accurate technique for assessing habitual dietary intake in studies investigating the links between diet and health. DESIGN--Subjects who had previously participated in the Northern Ireland diet and health study were reselected by stratified random sampling to represent the range of energy intakes in the study as assessed by the seven day weighed dietary record. SETTING--Northern Ireland. SUBJECTS--31 Free living adults (16 men and 15 women). MAIN OUTCOME MEASURES--Energy intake as measured by the seven day weighed dietary record and total energy expenditure estimated concurrently by the doubly labelled water technique. RESULTS--Average recorded energy intakes were significantly lower than measured expenditure in the group overall (9.66 MJ/day v 12.15 MJ/day, 95% confidence interval 1.45 to 3.53 MJ/day). Among those in the upper third of energy intakes the mean (SE) ratio of intake to expenditure was close to 1.0, indicating accurate records (men 1.01 (0.11), women 0.96 (0.08]. In the middle and lower thirds the ratios for men were only 0.74 (0.05) and 0.70 (0.07) respectively and for women 0.89 (0.07) and 0.61 (0.07). CONCLUSIONS--These results show a serious bias in reporting habitual energy intake. If substantiated they may have wide implications for the interpretation of many nutritional studies.

Do ‘food deserts’ influence fruit and vegetable consumption?—a cross-sectional study

Lack of access to affordable healthy foods has been suggested to be a contributory factor to poor diet. This study investigated associations between diet and access to supermarkets, transport, fruit and vegetable price and deprivation, in a region divergent in geography and socio-economic indices. A postal survey of 1000 addresses (response rate 42%) gathered information on family demographics, supermarket and shop use, car ownership, mobility and previous days fruit and vegetable intake. Postcode information was used to derive road travel distance to nearest supermarket and deprivation index. Fruit and vegetable prices were assessed using a shopping basket survey. Generalised linear regression models were used to ascertain predictors of fruit and vegetable intake. Male grocery shoppers ate less fruit than female grocery shoppers. Consumption of vegetables increased slightly with age. Deprivation, supermarket fruit and vegetable price, distance to nearest supermarket and potential difficulties with grocery shopping were not significantly associated with either fruit or vegetable consumption. These data suggest that the three key elements of a food desert, fruit and vegetable price, socio-economic deprivation and a lack of locally available supermarkets, were not factors influencing fruit or vegetable intake. We suggest that food policies aimed at improving diet should be orientated towards changing socio-cultural attitudes towards food.

A Longitudinal Study of Bone Gain in Pubertal Girls: Anthropometric and Biochemical Correlates

The aim of this longitudinal study was to investigate the factors associated with bone mineral acquisition in pubertal girls. Subjects were 37 healthy, Caucasian girls aged 12.1 years (SD 0.3). Measurements were made at 6‐month intervals over a period of 18 months and included total body bone mineral content (TBBMC), total body bone mineral density (TBBMD), lean mass, and fat mass by dual‐energy X‐ray absorptiometry, anthropometry, lifestyle factors, four biochemical markers of bone turnover, hormonal status, and fractional calcium absorption. In multiple regression analysis, correlates of relative gain in TBBMC were gain in lean mass (p < 0.001) and estradiol (p = 0.008). For TBBMD, correlates were gain in lean (p < 0.001) and fat mass (p = 0.003), estradiol (p < 0.001), dietary energy intake (p = 0.003), and parathyroid hormone (p = 0.023). Statural growth and gain in bone mass were unrelated; both height velocity and bone turnover peaked ∼20 months prior to menarche, whereas gain in bone mass peaked at menarche. Bone turnover markers correlated with height velocity (0.40 < r < 0.62), but not with bone gain. Estradiol was independently and negatively associated with all markers of bone turnover (−0.67 < r < −0.80). We conclude that estradiol is an important determinant of bone mineral gain in pubertal girls and is probably responsible for the reduction in bone turnover in late puberty; lean mass was the body composition parameter most closely associated with bone gain; height gain and bone gain are dissociated during the period of rapid growth at puberty; and bone turnover markers are modestly related to height gain, but are not predictive of bone gain.

Clinical trial: a multistrain probiotic preparation significantly reduces symptoms of irritable bowel syndrome in a double-blind placebo-controlled study

Background  The efficacy of probiotics in alleviating the symptoms of irritable bowel syndrome (IBS) appears to be both strain‐ and dose‐related.

Phosphate supplementation in young men: lack of effect on calcium homeostasis and bone turnover

Objective: To examine the effect of phosphate supplements on calcium homeostasis and bone turnover in young men.Design: Study 1 was a randomised, controlled, cross-over trial of 1000 mg elemental phosphate given for one week, with a standard diet of 800 mg/d each of calcium and phosphorus. Study 2 was an escalating dose study of 0, 1000, 1500 and 2000 mg/d elemental phosphate, each given for one week, with a standard diet of 1000 mg/d each of calcium and phosphate.Setting: Northern General Hospital, Sheffield.Subjects: Study 1, 10 healthy men ages 19–32 y. Study 2, 12 healthy men ages 19–38 y.Interventions: Sodium acid phosphate tablets each containing 500 mg elemental phosphorus (16.1 mmol/d), given with meals.Results: Study 1, administration of 32.2 mmol/d phosphorus resulted in a mean increase of 13.2 mmol/d urinary phosphorus, a mean decrease of 1.1 mmol/d urinary calcium, and a mean increase of 7 ng/mL in serum intact PTH. There were no changes in serum phosphate, osteocalcin or urinary N-telopeptide excretion. Study 2, administration of 64.4 mmol/d phosphorus resulted in a mean increase of 27.2 mmol/d urinary phosphorus, a mean decrease of 2.4 mmol/d urinary calcium, with no change in serum phosphate, PTH or urinary deoxypyridinoline.Conclusions: Phosphate supplementation of the diet does not affect bone turnover in young men.Sponsorship: Arthritis and Rheumatism Council Programme Grant.

Attitudinal dimensions of food choice and nutrient intake

A diet low in fat and rich in fibre has been recommended to optimize general health and in particular cardiovascular health. Health attitudes to fat and fibre were studied in relation to food and nutrient intake and sociocultural and lifestyle factors amongst the general population of Northern Ireland. The study population comprised 592 adults aged 16-64 years; health attitudes to fat and fibre were assessed by questionnaire (based on a social psychological model, which adjusted for taste and convenience factors). Dietary intake was estimated using the weighed inventory technique. Fat-phobic and fibre-philic attitudes were more prevalent in women than men. Fat-phobic attitudes in women were inversely related to intake of fat through a reduced intake of chips, butter and sausages. In contrast, mens fat-phobic attitudes were not strongly correlated with fat intake; consumption of chips and sausages was negatively associated with fat-phobic attitudes, but cake/biscuit, buns/pastries and milk consumption was positively associated with fat-phobic attitudes. Fibre-philic attitudes were positively associated with dietary fibre intake; intakes of potatoes, vegetables, wholemeal bread and breakfast cereal were positively associated with fibre-philic attitudes. There were clear sociocultural and lifestyle differences in relation to dietary attitude. These findings have implications for campaigns designed to effect population dietary change.

Serum Retinoids and β-Carotene as Predictors of Hip and Other Fractures in Elderly Women†

There is debate about the possible deleterious effect of excessive vitamin A exposure on fracture risk. In this nested case control study in older women (312 cases and 934 controls), serum retinol, retinyl palmitate, and β‐carotene were not associated with fracture risk, and there was no evidence of excess risk with multivitamin or cod liver oil supplementation.

Potential contribution of leisure activity to the energy expenditure patterns of sedentary populations

Total daily energy expenditure (TEE) by the doubly-labelled (2H218O) water method and basal metabolic rate (BMR) by indirect calorimetry were measured in thirty-two healty free-living adults in Northern Ireland. Habitual physical activity patterns in occupational and discretionary activities were assessed by interview questionnaire. Expressed as a multiple of BMR the TEE values for the sixteen males (1.88 (SD 0.28), range 1.44-2.57) and sixteen females (1.77 (SD 0.16), range 1.50-2.06) were compatible with current Department of Health and Social Security (DHSS; 1979) and Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU; 1985) estimates of energy requirements. The results suggest that discretionary physical activity is now emerging as an equally important determinant of energy expenditure in the UK as the occupational classifications currently used as the basis of DHSS (1979) and FAO/WHO/UNU (1985) recommendations for energy requirements. Therefore, realistically achievable inputs of recreational exercise can have a significant impact in counteracting low levels of energy expenditure which are associated with modern lifestyles and are implicated as a risk factor for coronary heart disease and obesity.

Combining self-affirmation with implementation intentions to promote fruit and vegetable consumption

OBJECTIVE The current study tested whether self-affirmation in the context of a threatening health message helps promote a health behavior (fruit and vegetable consumption) over a 3-month period, and whether adding a manipulation to support the translation of intentions into behavior (an implementation intentions induction) enhances the impact of self-affirmation. METHODS Participants (N = 332, 71% women) reported their baseline consumption and were randomly assigned to condition in a 2 (self-affirmation: yes, no) × 2 (implementation intentions: formed, not formed) between-subjects factorial design. They completed a self-affirmation/control task and then read a health communication advising eating at least 5 portions of fruit and vegetables daily. Next participants reported intentions for behavior change, after which they formed/did not form relevant implementation intentions. Consumption was measured again 7 days and 3 months postintervention. RESULTS Self-affirmed (vs. nonaffirmed) participants reported eating more fruit and vegetables at both follow-ups. Forming (vs. not forming) implementation intentions was also beneficial for consumption. At 7 days, there was also a significant self-affirmation × implementation intentions interaction: consumption was highest when self-affirmed participants also formed implementation intentions. CONCLUSIONS The present study offers new evidence concerning the impact and durability of self-affirmation on health behaviors and the role of implementation intentions in enhancing the impact of self-affirmation.