A re-analysis of the iron content of plant-based foods in the United Kingdom.

In the UK contemporary estimates of dietary Fe intakes rely upon food Fe content data from the 1980s or before. Moreover, there has been speculation that the natural Fe content of foods has fallen over time, predominantly due to changes in agricultural practices. Therefore, we re-analysed common plant-based foods of the UK diet for their Fe content (the '2000s analyses') and compared the values with the most recent published values (the '1980s analyses') and the much older published values (the '1930s analyses'), the latter two being from different editions of the McCance and Widdowson food tables. Overall, there was remarkable consistency between analytical data for foods spanning the 70 years. There was a marginal, but significant, apparent decrease in natural food Fe content from the 1930s to 1980s/2000s. Whether this represents a true difference or is analytical error between the eras is unclear and how it could translate into differences in intake requires clarification. However, fortificant Fe levels (and fortificant Fe intake based upon linked national data) did appear to have increased between the 1980s and 2000s, and deserve further attention in light of recent potential concerns over the long-term safety and effectiveness of fortificant Fe. In conclusion, the overall Fe content of plant-based foods is largely consistent between the 1930s and 2000s, with a fall in natural dietary Fe content negated or even surpassed by a rise in fortificant Fe but for which the long-term effects are uncertain.

Comparative whole-grain intake of British adults in 1986-7 and 2000-1.

Epidemiological evidence suggests that higher consumption of whole-grain foods can significantly reduce the risk of chronic diseases such as CVD, type 2 diabetes and some cancers. The present study compares whole-grain intake of 2086 adults aged 16-64 years from the 1986-7 Dietary and Nutritional Survey of British Adults with that of 1692 adults aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. For each survey, whole-grain intake was estimated from consumption of all foods containing > or = 10% whole-grain content (as DM/fresh weight of food) from 7d weighed dietary records. In 1986-7, median whole-grain intake was 16 (interquartile range 0-45) g/d v. 14 (interquartile range 0-36) g/d in 2000-1 (P< 0.001). In 1986-7, 77% of adults had less than three 16 g amounts of whole-grain intake/d; 25 % reported no whole-grain intake. In 2000-1, corresponding percentages were 84 and 29%, respectively. Foods with <51% whole-grain content provided 18% of whole-grain intake in 1986-7 v. 27% in 2000-1 (P<0.001). In both surveys, whole-grain intake was significantly lower among adults with a manual v. non-manual occupation (indicative of lower socio-economic status) and among smokers v. non-smokers, independent of occupational social class. In 1986-7, whole-grain breakfast cereals and wholemeal bread contributed 28 and 48% of whole-grain intake, respectively, v. 45 and 31% in 2000-1. At each time, one-third of adults consumed neither of these two largest contributors to whole-grain intake. Findings from the present study suggest that whole-grain intake of British adults was low in 1986-7 and became even lower over the subsequent decade.

Comparative dietary intake and sources of phylloquinone (vitamin K1) among British adults in 1986-7 and 2000-1.

Using data from 7 d weighed dietary records, dietary intake and sources of phylloquinone (vitamin K1) were examined by socio-demographic and lifestyle factors in 1916 participants aged 16-64 years from the 1986-7 Dietary and Nutritional Survey of British Adults, and 1423 participants aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. Using UK-specific food content data, geometric mean phylloquinone intakes were estimated as 72 (95% CI 70, 74) and 67 (95% CI 65, 69) microg/d in 1986-7 and 2000-1 respectively (P<0.001). In 1986-7, 47% of participants had phylloquinone intakes below the UK guideline for adequacy (> or =1 microg/kg body weight per d), compared with 59% in 2000-1 (P<0.001). In both surveys, daily phylloquinone intake was higher among men than women and increased significantly with age. Participants of manual occupational social class, or who were smokers, had lower phylloquinone intake than their counterparts. Participants living in Scotland and northern England had lower phylloquinone intake than those living elsewhere in mainland Britain, particularly in 1986-7 when the contribution from vegetables was also lower than elsewhere. However, by 2000-1 this regional difference was no longer significant. Overall, vegetables contributed 63% of phylloquinone intake in 1986-7 and 60% in 2000-1, with cooked leafy green vegetables (LGV) providing 23 and 19% respectively. In both surveys, the contribution of vegetables (cooked LGV in particular) was directly associated with age. These data show a decrease in phylloquinone intake from 1986-7 to 2000-1, mainly owing to lower consumption of cooked LGV.

Plasma phylloquinone (vitamin K1) concentration and its relationship to intake in British adults aged 19-64 years.

Plasma phylloquinone (vitamin K1) concentration from non-fasted blood samples was examined by season, smoking status, socio-demographic factors and phylloquinone intake in a nationally representative sample of 1154 British individuals aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. Geometric mean plasma phylloquinone concentration was 0.94 (95% CI 0.88, 1.00) nmol/l, with 95% of values in the range 0.10-8.72 nmol/l. Plasma phylloquinone concentrations of 530 men were significantly higher than those of 624 women (1.13 (95% CI 1.04, 1.22) v. 0.81 (95% CI 0.74, 0.88) nmol/l; P<0.001), independent of other factors. Women aged 19-34 years had significantly lower plasma phylloquinone concentration than their older counterparts. Women were also found to have lower plasma phylloquinone concentrations during summer compared with winter and spring (each P<0.01). In contrast, plasma phylloquinone concentration in men did not vary significantly by season or any of the socio-demographic or lifestyle factors. Plasma phylloquinone concentrations were positively correlated with phylloquinone intake in men and women (r 0.26 and 0.32 respectively; each P<0.001). Overall, forward stepwise multiple regression analysis revealed that 8% of the variation in plasma phylloquinone concentration was explained by phylloquinone intake, with a further 10% of its variation explained by plasma concentrations of gamma-tocopherol (6%) and retinyl palmitate (4%). After adjustment for age and corresponding nutrient intakes, plasma phylloquinone concentration was significantly associated (each P<0.01) with plasma concentrations of total and LDL-cholesterol, alpha- and gamma-tocopherols, retinyl palmitate, beta-carotene, lycopene and lutein plus zeaxanthin in men and women.

How well do Australian women comply with dietary guidelines?

OBJECTIVE: To investigate the proportion of middle-aged Australian women meeting national dietary recommendations and its variation according to selected sociodemographic and behavioural characteristics. DESIGN: This cross-sectional population-based study used a food-frequency questionnaire to investigate dietary patterns and compliance with 13 commonly promoted dietary guidelines among a cohort of middle-aged women participating in the Australian Longitudinal Study on Women's Health. SETTING: Nation-wide community-based survey. SUBJECTS: A total of 10,561 women aged 50-55 years at the time of the survey in 2001. RESULTS: Only about one-third of women complied with more than half of the guidelines, and only two women in the entire sample met all 13 guidelines examined. While guidelines for meat/fish/poultry/eggs/nuts/legumes and 'extra' foods (e.g. ice cream, chocolate, cakes, potatoes, pizza, hamburgers and wine) were met well, large percentages of women (68-88%) did not meet guidelines relating to the consumption of breads, cereal-based foods and dairy products, and intakes of total and saturated fat and iron. Women working in lower socio-economic status occupations, and women living alone or with people other than a partner and/or children, were at significantly increased risk of not meeting guidelines. CONCLUSIONS: The present results indicate that a large proportion of middle-aged Australian women are not meeting dietary guidelines. Without substantial changes in their diets, and help in making these changes, current national guidelines appear unachievable for many women.

Consumption of whole-grain foods by British adults: findings from further analysis of two national dietary surveys.

OBJECTIVE: To assess the consumption of whole-grain foods in different age and sociodemographic groups in Great Britain, using data from two national surveys. DESIGN: Cross-sectional analysis of the consumption of whole-grain foods. SETTING: The 1986-87 Dietary and Nutritional Survey of British Adults and the 1994-95 National Diet and Nutrition Survey of people aged 65 years and over. SUBJECTS: In 1986-87, 2086 British adults aged 16-64 years; 1189 British adults aged 65 years and over in 1994-95. RESULTS: In the 1986-87 survey population, consumption of whole-grain foods increased with age. Median consumption of whole-grain foods was 1 serving per week in 16-24-year-olds and 3 servings per week in the 35-64-year-olds In 1994-95, median consumption was 5 servings per week in adults aged 65 years and over. Overall, one-third of British adults ate no whole-grain foods on a daily basis, and less than 5% ate 3 or more servings per day. Manual occupation and smoking were consistently associated with a higher proportion of non-consumers and fewer servings per week of whole-grain foods, independent of age, sex, region and season (each ). The main sources of whole-grain foods were wholemeal bread and breakfast cereals, which accounted for more than three-quarters of all servings. CONCLUSIONS: Consumption of whole-grain foods in the adult UK populations is more prevalent in the non-smoking, higher socio-economic groups. Amongst consumers of whole-grain foods, the frequency is similar to that reported in the USA and Norway.

Selenium status and its correlates in a British national diet and nutrition survey: people aged 65 years and over.

Plasma selenium (Se) concentrations were measured in 1134 British people aged 65 years and over, living in mainland Britain during 1994-1995. Eight hundred and eighty-three lived in the community ("free-living"), while the remainder lived in institutions (residential and nursing homes). The overall mean plasma Se concentrations was 0.90 micromol/l (inner 95% range 0.50-1.36 micromol/l). Free-living people had significantly higher values than counterparts living in institutions, and there was an overall inverse correlation with age. Plasma Se varied with season (lower from October to December than at other times of the year), while values were higher in southern Britain than in the North. Socio-economic associations also existed (lower plasma Se in people receiving state benefits or with poorer educational attainment), while smokers had lower values than non-smokers. Several indices of poor health status or of medicine use were correlated with lower plasma Se, which was also predicted by several biochemical or haematological indices of infection or inflammation. Plasma Se was strongly and directly correlated with plasma albumin, zinc, cholesterol, vitamin C, several carotenoids, alpha-tocopherol, pyridoxal phosphate, and with blood haemoglobin and several anthropometric indices. All relationships were independent of age and gender, and are consistent with the view that plasma Se levels are higher in fit and well-nourished elderly people and lower in those who are frail, poorly-nourished and unwell. Whole-blood glutathione peroxidase generally did not share these relationships, was only very weakly correlated with plasma Se, and appeared to be less useful as a status indicator in this population group.