Trends in food consumption over 30 years: evidence from a British birth cohort

BACKGROUND/OBJECTIVES

As populations are ageing, more emphasis is placed on healthy ageing. Over the past decades, food consumption patterns and food availability have also changed drastically, and therefore this study aimed to describe these changes in an ageing population.

SUBJECTS/METHODS

Food consumption of participants from the Medical Research Council National Survey on Health and Development, a British birth cohort study, was assessed using a 5-day estimated food records at 60-64 years (2006-11), 53 years (1999), 43 years (1989) and 36 years (1982). Only those who recorded ⩾3 days at all four time points were included in the analyses, n=989 (n=438 men and n=551 women); trends were tested using the Friedman test.

RESULTS

Consumption of white bread, whole milk, fats and oils, meat and meat products, alcoholic drinks, coffee, sugar, preserves and confectionery decreased (P<0.001), whereas consumption of wholemeal and granary bread, semi-skimmed milk, fish and fruit and vegetables increased (P<0.001) over time. These observed changes in food consumption reflect a healthier diet, for example, replacement of white bread by granary and wholemeal bread, lower consumption of red and processed meats, somewhat higher consumption of fish, higher consumption of vegetables and lower consumption of coffee. This could partly be because of ageing of the cohort or compliance with dietary recommendations, facilitated by greater availability of healthier foods, such as semi-skimmed milk and wholegrain bread, in the UK.

CONCLUSIONS

The changes in food consumption in this British birth cohort over the past three decades are encouraging and reflect a healthier diet in the later years.

Diurnal eating rhythms: association with long-term development of diabetes in the 1946 British birth cohort

BACKGROUND AND AIMS

Few studies have described the association between time-of-day of macronutrient intake and diabetes. This study examined the prospective association between time-of-day and nutrient composition of eating occasions in relation to diabetes incidence in the 1946 British birth cohort.

METHODS AND RESULTS

The study included 1618 survey members who completed dietary assessment at age 43 (1989) and for whom data on glycosylated haemoglobin at age 53 years (1999) were available. Diet was assessed using 5d estimated diaries, divided into seven meal slots: breakfast, mid-morning, lunch, mid-afternoon, dinner, late evening and extras. Diabetes was defined by glycosylated haemoglobin (HbA1c) ≥ 6.5% or diabetes medication use. The association between time-of-day of macronutrient intake at age 43 years and diabetes at age 53 years was assessed using logistic multivariate nutrient density models after adjustment for potential confounders. There were 66 cases of diabetes at age 53 years. Survey members with diabetes obtained 50.4% of their energy from carbohydrate at breakfast compared to 55.9% in survey members without diabetes (P = 0.001). Increasing carbohydrate intake at breakfast at the expense of fat was related to lower odds ratio (OR) of diabetes (OR = 0.86; 95%CI = 0.79-0.93; P < 0.001). This relationship was attenuated after adjustment for body mass index and waist circumference.

CONCLUSION

Increasing energy intake from carbohydrate at the expense of fat at breakfast is inversely associated with 10-year diabetes incidence. However, further studies are required to elucidate whether the type or source of carbohydrates or fat influences the above association.

Time-of-day and nutrient composition of eating occasions: prospective association with the metabolic syndrome in the 1946 British birth cohort

Background:

Diet is a key modifiable factor in the prevention and treatment of the metabolic syndrome. However, few studies have examined the prospective association between time-of-day of nutrient intake and the metabolic syndrome.

Objective:

To examine the association between time-of-day and nutrient composition of eating occasions and the long-term development of metabolic syndrome in the Medical Research Council (MRC) National Survey of Health and Development (NSHD; 1946 British birth cohort).

Methods:

The analysis comprised 1488 survey members who completed at least 3 days of estimated diet records at age 43 years (1989) and for whom data on metabolic syndrome at age 53 years (1999) were available. Dietary records were divided into seven meal slots: breakfast, mid-morning, lunch, mid-afternoon, dinner, late evening and extras. Metabolic syndrome was defined by the criteria of the adult treatment panel (ATPIII8), and was modified to include glycosylated haemoglobin instead of fasting glucose. Associations between time-of-day of nutrient intake at age 43 years and prevalence of metabolic syndrome at age 53 years were assessed using multivariate nutrient density logistic models after adjustment for sex, social class, smoking status, region, alcohol intake and recreational physical activity.

Results:

There were 390 cases of metabolic syndrome at age 53 years. Substituting 5% of energy from carbohydrate for a similar amount of energy from fat at breakfast (odds ratio=0.93; 95% confidence interval=0.89–0.98; P=0.002) and mid-morning at age 43 years (odds ratio=0.96; 95% confidence interval=0.93–0.99; P=0.011) was associated with lower odds of the metabolic syndrome at age 53 years. Carbohydrate intake at breakfast or mid-morning was particularly protective against abdominal obesity (P⩽0.001). Increasing carbohydrate intake at breakfast while simultaneously decreasing fat intake was also negatively related to triacylglycerols (P⩽0.001).

Conclusions:

Increasing carbohydrate intake in the morning while simultaneously reducing fat intake could be protective against long-term development of the metabolic syndrome and its components.

Daily profiles of energy and nutrient intakes: are eating profiles changing over time?

BACKGROUND/OBJECTIVES:

Associations between timing of eating occasions and their nutrient composition and health have been described in interventional and cross-sectional studies. However, data from longitudinal data are limited. This study examined 17-year changes in energy and macronutrient intake across eating occasions in the 1946 British birth cohort.

SUBJECTS/METHODS:

Data were obtained from the 1946 British birth cohort. Cohort members completed 5d-estimated diaries at ages 36 (1982), 43 (1989) and 53 years (1999). Data from subjects who provided dietary data at all three time points were analysed (n=1253). Repeated-measures analysis of variance with post hoc Bonferroni's adjustment was used to examine changes in energy and macronutrient at breakfast, mid-morning, lunch, mid-afternoon, evening and extra meal slots between 1982 and 1999. Analyses were stratified by sex and social class.

RESULTS:

The proportion of energy and macronutrients consumed at lunch declined between 1982 and 1999, which was compensated by a greater intake in the mid-afternoon and evening. This trend was seen across sex and social class, although women and adults with a non-manual occupation reported greater energy, carbohydrate and non-starch polysaccharide intake at breakfast in 1982 and had a higher protein intake in the evening compared with men and adults with a manual occupation.

CONCLUSIONS:

The timing of energy and nutrient intake has shifted slightly over time, with a greater proportion of intake later in the day. The association between the observed sex and occupational social class differences in eating profiles and chronic disease warrants investigation.

Meat consumption after disaggregation of meat dishes in a cohort of British adults in 1989 and 1999 in relation to diet quality

BACKGROUND/OBJECTIVES

The aim of the study was to quantify more precisely the meat intake of a cohort of adults in the UK by disaggregating composite meat dishes.

SUBJECTS/METHODS

Subjects were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort. Five-day diaries were collected from 2256 men and women in 1989 and 1772 men and women in 1999. From the details provided, composite meat dishes were broken down into their constituent parts and the meat fraction was added to meat portions only. Meat intake was classified as red meat, processed meat and poultry.

RESULTS

Meat consumption without disaggregation of meat dishes resulted in a mean overestimation of 50% in men and 33% in women. Red meat consumption fell between 1989 and 1999 from 51.7 to 41.5 g per day in men and 35.7 to 30.1 g per day in women. Poultry consumption rose from 21.6 to 32.2 g per day in men and 18.2 to 29.4 g per day in women. Re-calculating red meat intakes resulted in the percentage of subjects in 1999 consuming more than the recommendation of the World Cancer Research Fund falling from 30 to 12%. Increasing consumption of red and processed meat was associated with increased intakes of energy, fat, haem iron, zinc and vitamin B(12), and lower intake of fibre. Increased sodium intake was associated with increased consumption of processed meat.

CONCLUSIONS

Disaggregation of meat dishes provided a more precise estimate of meat consumption. The quantity of red or processed meat in the diet was reflected in the nutrient content of the entire diet.

Consumption of red or processed meat does not predict risk factors for coronary heart disease; results from a cohort of British adults in 1989 and 1999

OBJECTIVES

To investigate whether a high consumption of red or processed meat is associated with increased risk of coronary heart disease (CHD).

SUBJECTS/METHODS

The subjects were 517 men and 635 women, who were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort. Assessment of diet was carried out at two time points 1989 and 1999 with outcome measures collected in 1999. Food intake data were recorded in 5-day diaries. Meat consumption was estimated by adding individual meat portions to the meat fractions of composite dishes.

RESULTS

There was no significant association between red or processed meat consumption in 1989 and 1999 and serum cholesterol concentrations and blood pressure measured in 1999. The combined intake of red and processed meat in 1999 had a significant positive association with blood pressure in men only. Red and processed meat intakes in 1989, separately and combined, had a significant positive association with waist circumference in 1999: a 10 g increase in red meat consumption accounted for a 0.3 cm increase in waist circumference; P=0.04 (men), 0.05 (women).

CONCLUSIONS

Consumption of red or processed meat assessed separately was not related to the major risk factors for CHD but contributed to increased waist circumference that has also been identified as a risk factor.

Haem and non-haem iron intake through 17 years of adult life of a British Birth Cohort

An investigation was carried out to determine whether there were significant changes in the intake of haem and non-haem Fe of adult men and women in the UK from 1982 (aged 36 years) to 1999 (aged 53 years). The 1253 subjects studied were members of the Medical Research Council National Survey of Health and Development; a longitudinal study of a nationally representative cohort of births in 1946. Food intake was recorded in a 5-d diary at age 36 years in 1982, 43 years in 1989 and 53 years in 1999. Outcome measures were mean intakes of total Fe, haem and non-haem Fe, by year, gender and food source. There were significant changes in total Fe, haem Fe and non-haem Fe intake over the three time points. Total Fe intake was significantly higher in 1989 than in 1982 or 1999 for both men and women but haem Fe was significantly lower in 1999 mainly due to a 40% fall in haem Fe from beef during this period. Haem Fe from processed meats fell by more than 50% between 1989 and 1999 but that from poultry rose by more than 50%. Cereal foods remained the most important source of non-haem Fe and the contribution from breakfast cereals rose relative to that of bread over the 17 years. Several factors could be responsible for these changes, particularly the importance of the epidemic of BSE from 1990. The possible advantages of a lower haem Fe intake in older subjects are discussed.

The impact of inter-generational social and regional circumstances on dietary intake patterns of British adults: results from the 1946 British Birth Cohort

Objectives:

(1) To determine the extent to which an individual's childhood social circumstances and region of residence influence their dietary pattern at age 43 years and (2) to establish the extent to which an individual adopts the dietary pattern of their social and regional circumstances at age 43 years.

Design:

Longitudinal study of a social class stratified, random sample of all legitimate, singleton births in the week of 3–9 March 1946.

Settings:

England, Scotland and Wales.

Subjects:

The 3187 survey members who provided sociodemographic information at age 4 years in 1950 and sociodemographic and dietary data (48-hour dietary recall) at 43 years in 1989.

Results:

People who remained in the non-manual social class consumed significantly higher amounts of food items correlated with the factor health aware (items include high-fibre breakfast cereals, wholemeal breads, apples and bananas) than those who remained in the manual social class. Those who made the transition from manual social class in childhood to non-manual social class at age 43 years partly adopted the distinctive dietary patterns of the non-manual social classes. Consumption of items in the factors refined (items include whole-fat milk, white bread, sugar and butter) and sandwich (items include tomatoes, lettuce, onions, bacon and ham) did not differ by social class or regional mobility.

Conclusions:

This work suggests that although adult dietary patterns are developed as a result of childhood influences, these patterns can be modified as a result of social and regional transitions. Such changes in dietary patterns may influence susceptibility to disease.

Changes in intake of key nutrients over 17 years during adult life of a British birth cohort

An investigation was carried out to determine whether there were significant changes in nutrient intake over 17 years of adult life. The Medical Research Council National Survey of Health and Development is a longitudinal study of a nationally representative cohort of singleton births in the UK in 1946. Of this cohort, 1253 survey members provided information on diet recorded in a 5 d diary at age 36 years in 1982, 43 years in 1989 and 53 years in 1999. The outcome measures were mean intakes of energy, macronutrients, minerals and vitamins. There were significant changes in the intake of most nutrients in 1999 compared with previous years. Intakes of fat, Na, Fe and Cu have fallen, but there was a rising trend in the intakes of Ca, P, carotene, thiamin, pyridoxine, folic acid and vitamins C, D and E in both men and women. Additionally, intakes of K, Mg and vitamin K1 have risen in women. There were significant gender differences, women showing a higher percentage rise in the intakes of carotene, riboflavin, folic acid, vitamin C and vitamin E. These changes were related to changes in the consumption of certain key foods, such as the increased consumption of fruit and vegetables and a shift away from whole milk, butter and red meat. Most of these trends are in line with accepted nutritional guidelines. How far these changes are due to consumer choice and real changes in food composition or are due to artefacts inherent in the methodology is discussed.

Intake and sources of phylloquinone (vitamin K(1)) in 4-year-old British children: comparison between 1950 and the 1990s

OBJECTIVES

To compare dietary intake and sources of phylloquinone (vitamin K1) in 4-year-old British children between 1950 and the 1990s, and report their variation by sociodemographic factors.

DESIGN

Nationally representative samples of 4-year-olds from the longitudinal Medical Research Council National Survey of Health and Development (NSHD) (1950) and the cross-sectional National Diet and Nutrition Surveys (NDNS, 1992/93 and 1997).

SETTING

Great Britain.

SUBJECTS

Subjects were 4599 children born on 3-9 March 1946 (NSHD) and 307 children in the 1990s (NDNS).

RESULTS

Geometric mean dietary phylloquinone intake was significantly higher in 1950 (39 mug day(-1), 95% confidence interval (CI) 37, 40) compared with the 1990s (24 mug day(-1), 95% CI 22, 25) (P<0.001). This difference remained when intake was expressed per MJ energy intake and per kilogram body weight, and after accounting for sex, region and occupational social class of the family. In 1950, phylloquinone intake in Scotland was significantly lower than in the rest of Britain. By the 1990s these regional differences had disappeared. Food sources of phylloquinone intake changed significantly between 1950 and the 1990s, with fats and oils contributing more and vegetables less, although vegetables contributed most (60% and 48%, respectively) to phylloquinone intake in both surveys.

CONCLUSIONS

Phylloquinone intakes of children have decreased significantly since 1950. With the suggested need for adequate phylloquinone intake for optimal development and maintenance of bone and the cardiovascular system, the substantially lower phylloquinone intakes reported in children of the 1990s, compared with 1950, may have implications for the health of these two systems in later adulthood.

Dietary acid-base balance and intake of bone-related nutrients in Cambridge teenagers

OBJECTIVES

To evaluate the diet of 16-18-y-old boys and girls with particular reference to intakes of nutrients believed to affect bone health and dietary acid-base balance.

DESIGN

A 7-day food diary was completed between the months of October and December.

SETTING

Cambridge, UK.

SUBJECTS

A total of 111 boys and 101 girls aged 16-18 y who were recruited into the Cambridge Bone Studies.

MAIN OUTCOME MEASURES

Mean daily intakes of foods and selected nutrients (protein, calcium, phosphorus, magnesium, potassium, vitamins C and K) were calculated. Two estimates of acid-base balance were calculated from the diet using the formulae of Remer (net acid excretion, estimated indirectly; NAE(ind)) and Frassetto (protein/potassium ratio).

RESULTS

Mean calcium and phosphorus intakes were above the UK Reference Nutrient intake (RNI). In all, 39% of the boys and 36% of the girls had vitamin K intakes lower than 1 microg/kg body weight/day. Calcium intake was positively correlated with all other nutrients except vitamins C and K. Boys had a significantly higher estimated net acid excretion (NAE(ind)) than girls (P<0.001). Although a strong correlation (r=0.76, P<0.001) was found between the two methods, at higher acid levels a divergence was observed. A significant positive correlation was found between NAE(ind) and the weight consumed per day of milk, cheese, meat and cereal foods and a negative correlation was found with the weight of potatoes and fruit. Diet composition is such that a lower NAE(ind) is accompanied by a lower calcium intake.

CONCLUSIONS

The interpretation of the effects of calcium and other nutrients on bone cannot be considered in isolation from the other components of the diet. These results challenge some of the accepted perceptions about what constitutes an optimal diet for the promotion of bone health in adolescents.

Sociodemographic inequalities in the diet of young children in the 1946 British birth cohort

OBJECTIVE

To evaluate whether there was food and nutrient equality across occupational social classes and geographical region for members of the 1946 British birth cohort at age 4 years.

DESIGN

Cross-sectional analysis of selected food groups, energy and nutrients from one-day recall diet records.

SETTING

England, Scotland and Wales in 1950.

SUBJECTS

Nationally representative sample of 4419 children aged 4 years in 1950 from the MRC National Survey of Health and Development (NSHD) (1946 Birth Cohort).

RESULTS

Significant food and nutrient inequalities occurred by region and occupational social class of the father. Disparity in fruit and vegetable consumption primarily led to the nutrient differences, especially with respect to lower vitamin C and carotene intakes in children from Scotland and from a manual social class background. Lower energy intake in Scottish children was attributable to inequality in the consumption of foods providing fat, and also to the retention of the traditional Scottish diet that included porridge and soups. Consumption of some rationed foods -- bacon, orange juice and tea -- was inequitably distributed by father's social class, but others, in particular meat and spreading fats, were consumed more uniformly. In contrast to fruits and vegetables, which showed marked sociodemographic disparities, other non-rationed foods such as bread and potatoes were consumed universally.

CONCLUSION

Local cultural norms may have played as strong a part in sociodemographic differences in the diet of children in the early 1950s as did the strict, post-war food rationing that prevailed. In consequence, nutritional equality was not achieved, and the relatively low intake of antioxidant vitamins during early childhood in certain population groups may have compromised health in the long term.

Food and nutrient intake of a national sample of 4-year-old children in 1950: comparison with the 1990s

OBJECTIVE

To evaluate the food and nutrient intake of members of a birth cohort study when young children in 1950 and investigate differences from present-day children's diets.

DESIGN

One-day recall diet records from the MRC National Survey of Health and Development (NSHD) (1946 Birth Cohort) at age 4 years were analysed for energy and selected nutrients and compared to the published results for 4-year-olds in the 1992/93 National Diet and Nutrition Survey (NDNS).

SETTING

England, Scotland and Wales in 1950 and 1992/93.

SUBJECTS

4,599 children in 1950 and 493 children in 1992/93.

RESULTS

Mean (SD) daily intakes in 1950 were energy 1,445 (343) kcal, or 6.1 (1.4) MJ, protein 46 (11)g, fat 64 (20)g, starch 117 (33)g, sugar 62 (24)g, unavailable carbohydrate 13 (4)g, calcium 736 (230) mg, iron 7.7 (2.1) mg, retinol 738 (1,273) microg, carotene 1,049 (1,130) microg and vitamin C 40 (26) mg. Compared to 1992/93, the 1950 diet contained substantially more bread and vegetables and less sugar and soft drinks, giving it a higher starch and fibre content and making it more in line with current recommendations on healthy eating. However, fat provided 40% of energy in 1950, compared to 35% in 1992/93. In 1950, red meat was an important source of iron, but by 1992 most iron came from fortified breakfast cereals. Vitamin C came mainly from vegetables in 1950, but from soft drinks in 1992.

CONCLUSIONS

The relative austerity of post-war food supplies resulted in food and nutrient intakes in 1950 which in many respects may well have been beneficial to the health of young children, despite fat intake being higher than present-day recommendations.

The effects of a supplement of dietary fibre on faecal excretion by human subjects

1. Four human subjects on strictly controlled diets were given a fibre supplement, 25 g Ispaghula husk (Isogel)/d, for 3 weeks. 2. Replicate diets and faeces were collected during two 5 d balance periods. The first period served as control for the second which occurred after the supplement had been fed for 2 weeks. 3. Diets and faeces were analysed for total solids, gross energy, total nitrogen, fat, available and unavailable carbohydrates. 4. Three of the four subjects showed a considerable increase in faecal bulk; total faecal weight was more than doubled in two subjects. In two subjects the increase was brought about mainly by extra fibre in the faeces accompanied by a higher proportion of faecal water whereas in one subject it was also an increased excretion of nutrients. One subject showed very little change in faecal bulk. 5. High values for the apparent digestibility of fibre were found during the control period; from 0.70 to 0.80. There was more variation during the experimental period when apparent digestibility of total fibre ranged from 0.47 to 0.82. Values arrived at for the minimum apparent digestibility of the fibre supplement were generally high; one subject appeared to digest Isogel completely. Isogel was degraded preferentially to the food-derived fibre; in particular, cellulose in the faeces was increased during the experimental period. 6. Only one subject showed distinct decreases in the apparent digestibility of energy, N and fat in the diet. The results do not therefore agree with the generally held view that increased fibre in the diet decreases the apparent digestibility of the other nutrients.