Adaptation and evaluation of the National Cancer Institute's Diet History Questionnaire and nutrient database for Canadian populations

BACKGROUND AND OBJECTIVE: Despite assumed similarities in Canadian and US dietary habits, some differences in food availability and nutrient fortification exist. Food-frequency questionnaires designed for the USA may therefore not provide the most accurate estimates of dietary intake in Canadian populations. Hence, we undertook to evaluate and modify the National Cancer Institute's Diet History Questionnaire (DHQ) and nutrient database. METHODS: Of the foods queried on the DHQ, those most likely to differ in nutrient composition were identified. Where possible these foods were matched to comparable foods in the Canadian Nutrient File. Nutrient values were examined and modified to reflect the Canadian content of minerals (calcium, iron, zinc) and vitamins (A, C, D, thiamin, riboflavin, niacin, B6, folate and B12). DHQs completed by 13 181 Alberta Cohort Study participants aged 35-69 years were analysed to estimate nutrient intakes using the original US and modified versions of the DHQ databases. Misclassification of intake for meeting the Dietary Reference Intake (DRI) was determined following analysis with the US nutrient database. RESULTS: Twenty-five per cent of 2411 foods deemed most likely to differ in nutrient profile were subsequently modified for folate, 11% for vitamin D, 10% for calcium and riboflavin, and between 7 and 10% for the remaining nutrients of interest. Misclassification with respect to meeting the DRI varied but was highest for folate (7%) and vitamin A (7%) among men, and for vitamin D (7%) among women over 50 years of age. CONCLUSIOn: Errors in nutrient intake estimates owing to differences in food fortification between the USA and Canada can be reduced in Canadian populations by using nutrient databases that reflect Canadian fortification practices.     

Complementary foods consumed by 6-12-month-old rural infants in South Africa are inadequate in micronutrients

OBJECTIVE: To determine the nutrient composition of complementary foods consumed by 6-12-month-old South African infants. DESIGN: Nutrient intake was determined for infants who were recruited to participate in a randomised controlled trial using a single 24-hour dietary recall. SETTING/SUBJECTS: Infants aged 6-12 months (n=475) residing in The Valley of a Thousand Hills, a rural area in KwaZulu-Natal, South Africa. RESULTS: Energy and protein intakes from complementary foods were adequate. Infants who consumed infant products (commercially available fortified infant cereals/ready-to-eat canned baby foods/formula milk powder) had significantly higher intakes of calcium, iron, zinc, vitamin A, thiamine, riboflavin, niacin, vitamin B6, vitamin B12 and vitamin C than infants who did not consume any infant products. For infants who consumed infant cereals (n=142), these cereals provided 51% of total iron intake. Infant cereals provided more than 25% of total intake for magnesium, thiamine, niacin and vitamin B12. For infants consuming ready-to-eat canned baby foods (n=77), these products contributed less than 15% of total intake for all the micronutrients. The nutrient density of the complementary diet was less than half the desired density for calcium, iron and zinc. Animal products were consumed by 17% of infants, 26% consumed dairy products and 18% consumed vitamin-A-rich fruit and vegetables during the 24-hour recall period. CONCLUSION: The nutrient composition of complementary foods among rural South African infants was inadequate, especially for iron, zinc and calcium. Strategies should be developed to improve the nutritional quality of their diets.     

The impact of high non-starch polysaccharide intake on serum micronutrient concentrations in a cohort of women

OBJECTIVE: Many public health campaigns encourage increased fibre consumption, but short-term studies suggest that various components of dietary fibre inhibit the absorption of certain micronutrients including carotenoids. These do not take into account long-term adaptation to nutrient intake levels. We aimed to investigate the effect of non-starch polysaccharide (NSP) fibre on plasma micronutrient concentrations in a large free-living population consuming their usual diet. DESIGN: Prospective cohort study. Semi-weighed 4-day food diaries were analysed for micronutrient and NSP fibre intakes. Blood samples were taken and analysed for carotenoids, vitamin A, vitamin E, thiamine, riboflavin, vitamin B6, vitamin B12, folic acid, vitamin C and trace metals. SETTING: Participants in a large national cohort study who lived within 30 miles of Leeds. SUBJECTS: Two hundred and eighty-three middle-aged women. RESULTS: The association between NSP intake and plasma nutrient concentrations was assessed taking into account nutrient intakes and other dietary and lifestyle factors. Higher levels of NSP were not associated with lower plasma concentrations of the micronutrients measured, even allowing for the higher nutrient levels generally found in high-fibre foods. CONCLUSIONS: Amongst middle-aged women we have shown that current guidelines for increasing the population's NSP consumption can be safely applied. Such guidelines are unlikely to reduce serum micronutrient concentrations, although other, more vulnerable population groups may benefit from further investigation.     

Unique patterns of dietary adequacy in three cultures of Canadian Arctic indigenous peoples

BACKGROUND: Information is needed on dietary adequacy of Arctic indigenous populations in Canada. Extensive work has been completed on composition of Arctic food and food use, and dietary reference intakes are available. OBJECTIVE: To complete the first comprehensive dietary adequacy assessment of three populations of adult Arctic indigenous people. SETTING AND SUBJECTS: Dietary assessment interviews were conducted with randomly selected indigenous adults during two seasons in 44 representative communities of Yukon First Nations (n = 797), Dene/Métis, (n = 1007) and Inuit (n = 1525). METHODS: Twenty-four-hour recalls were used to derive adjusted distributions of usual nutrient intakes in four age/gender groups for assessment of dietary adequacy for carbohydrate, dietary fibre, protein, n-3 fatty acids, n-6 fatty acids, calcium, copper, iron, magnesium, manganese, phosphorus, selenium, zinc, vitamin A, riboflavin, folate, vitamin B6, vitamin C, vitamin D and vitamin E. RESULTS: Nutrients with high prevalence of adequacy for most age/gender groups in all three cultures were protein, carbohydrate, n-3 fatty acids, iron, copper, zinc, manganese, selenium, riboflavin and vitamin B6; some individuals exceeded the upper intake level for iron, zinc, selenium, vitamin A and vitamin D. Estimated average requirement nutrients of concern for adequacy were magnesium, folate, vitamin A, vitamin C and vitamin E; however, a few age/gender groups were exceptions. Prevalence of inadequacy for AI nutrients which may be undesirably high were fibre, n-6 fatty acids and calcium. Vitamin D was more adequate in Inuit women and men than for Yukon First Nations or Dene/Métis. CONCLUSIONS: Unique patterns of dietary adequacy exist among Arctic indigenous peoples. Local wildlife food sources and market food sources should be maximised for their nutrient contributions to Arctic diets.     

Effect of Micronutrient Fortification on Nutritional and Other Properties of Nixtamal Tortillas

Nixtamalization is the process of steeping dried corn in hot water with calcium hydroxide (lime) with subsequent removal of all or most of the pericarp through washing. The resulting product is called nixtamal. Approximately 60% of corn tortillas in Mexico are produced from nixtamal, with the remainder prepared from nixtamalized corn flour. Nixtamal was fortified with micronutrient premix containing iron, zinc, folic acid, niacin, riboflavin, and thiamin. Premix composition followed a proposed Mexican regulation for corn flour fortification, adjusted for moisture. Effects of premix on masa adhesiveness, hardness, and pH, as well as tortilla sensory properties, stretchability, rollability, and color were measured. Micronutrient levels were tested in the dry corn, nixtamal, masa, and tortillas. There were no significant differences in masa texture or pH, tortilla rollability, or consumer acceptance of tortillas when comparing unfortified control and fortified treatments. Added thiamin was almost entirely degraded during processing. Folic acid and riboflavin decreased 26 and 45%, respectively, through the masa‐tortilla manufacturing process. Niacin showed no significant loss. Despite processing losses, fortification resulted in significant nutrient increases compared with control tortillas. Folic acid increased 974%, riboflavin increased 300%, niacin increased 141%, iron increased 156%, and zinc increased 153% in fortified tortillas.     

Impact of disaggregation of composite foods on estimates of intakes of meat and meat products in Irish adults

OBJECTIVE: To evaluate the impact of the disaggregation of composite foods on intake estimates of meat and individual meat categories and on the contribution of meat to nutrient intakes in Irish adults. DESIGN: Data were analysed from the North/South Ireland Food Consumption Survey, which used a 7-day food diary to estimate food intake. Of 742 food codes that contained meat, 320 were codes for meat consumed as an individual portion and 422 were composite foods and were disaggregated to estimate the meat content. SUBJECTS: A nationally representative sample of 475 men and 483 women (not pregnant or lactating) from the Republic of Ireland aged 18-64 years. RESULTS: The mean intake of meat was 134 g day(-1) in consumers (98.5%) and men (168 g day(-1)) consumed significantly more (P<0.001) than women (102 g day(-1)). Mean intakes of meat were higher in subjects with manual skilled occupations (P<0.01) and lower in those with third-level educational qualifications (P<0.05). Without disaggregating meat from composite foods, meat intake was overestimated by 43% (57 g day(-1)) and varied widely by meat category. Meat disaggregated from composite foods contributed 25% of meat intake. The contribution meat made to nutrient intakes ranged from 29% for protein, vitamin B12, zinc and niacin to 20% for vitamin D, 16% for vitamin B6, 15% for thiamine and 14% for iron. CONCLUSIONS: Failure to disaggregate meat from composite foods substantially overestimates meat intake, with a large variation between meat categories. This has important implications for estimates of meat intakes in nutritional epidemiological studies and for food safety purposes.     

Effects of revision of Japanese food composition tables on estimation of nutrient intakes, with reference to age-dependent differences

OBJECTIVE: To identify effects of revision of the Japanese food composition tables from the fourth version to the fifth version on nutrient intake estimation. DESIGN: A database on 783 samples of 24-hour food duplicate portions was re-visited. Nutrients in the duplicate portions were estimated by use of the fourth and fifth versions of the Japanese food composition tables in parallel, together with supplemental use of other databases. The two sets of estimates were subjected to comparison. SETTING: The sample collection was conducted at 31 sites all over Japan. SUBJECTS: The sample donors were 783 women aged 20-78 years. RESULTS: Compared with the estimates by use of the fourth version of the tables, the estimates by the fifth version were substantially higher for intakes of energy, carbohydrate, dietary fibre, vitamin A and niacin, and lower for iron intake. The increase in carbohydrate intake estimates was more evident in older women than in young women, whereas the decrease in the intake estimation of iron and the increase in that of dietary fibre were more marked in young women than in older women. CONCLUSION: The recent revision of food composition tables in Japan induced substantial changes in the estimation of nutrient intakes, i.e. an increase in energy, carbohydrate, dietary fibre, vitamin A and niacin, and a decrease in iron. The extent of the changes varied depending on age.     

Tracking of energy and nutrient intakes from adolescence to young adulthood: the experiences of the Young Hearts Project, Northern Ireland

OBJECTIVE: To assess tracking of energy and nutrient intakes between adolescence and young adulthood. DESIGN: Longitudinal study of a random sample of adolescents (aged 15 years at baseline). The extent of tracking of dietary intakes (assessed by diet history) was investigated using weighted kappa statistics (kappa). SETTING: Northern Ireland population survey. SUBJECTS: Adolescents who participated in the Young Hearts Project, Northern Ireland at age 15 years, and subsequently at young adulthood aged between 20 and 25 years (n=245 males, n=231 females). RESULTS: Despite overall increases in height and weight (both P<0.001), increases in body mass index in males (P<0.001) and body fatness in females (P<0.001), median reported intakes of energy (kJ kg(-1) day(-1)), carbohydrate (g day(-1)) and fat (g day(-1)) decreased (all P<0.001) over time. Expressed as nutrient densities (per MJ), diets at young adulthood were overall richer in thiamin, vitamin B6, total folate (all P<0.001), vitamin C (P<0.01) and vitamin D (P<0.05). Whereas the nutrient density of the males' diets decreased over time for calcium (P<0.05) and vitamin A (P<0.001), iron and riboflavin densities increased in the females' diet (P<0.001). Tracking of energy (MJ day(-1)) and nutrient intakes (expressed per MJ day(-1)) at the individual level was only poor to fair (all kappa<0.25), indicating substantial drift of subjects between the low, medium and high classes of intake with increasing age. CONCLUSIONS: These data suggest that individual dietary patterns exhibited at 15 years of age are unlikely to be predictive of dietary intakes at young adulthood.     

Fortification of maize meal improved the nutritional status of 1-3-year-old African children

OBJECTIVE: To evaluate the effectiveness of a vitamin-fortified maize meal to improve the nutritional status of 1-3-year-old malnourished African children. DESIGN: A randomised parallel intervention study was used in which 21 experimental children and their families received maize meal fortified with vitamin A, thiamine, riboflavin and pyridoxine, while 23 control children and their families received unfortified maize meal. The maize meal was provided for 12 months to replace the maize meal habitually consumed by these households. METHODS: Sixty undernourished African children with height-for-age or weight-for-age below the 5th percentile of the National Center for Health Statistics' criteria and aged 1-3 years were randomly assigned to an experimental or control group. Baseline measurements included demographic, socio-economic and dietary data, as well as height, weight, haemoglobin, haematocrit, serum retinol and retinol-binding protein (RBP). Anthropometric, blood and serum variables were measured again after 12 months of intervention. Complete baseline measurements were available for 44 children and end data for only 36. Changes in these variables from baseline to end within and between groups were assessed for significance with paired t-tests, t-tests and analysis of variances using the SPSS program, controlling for expected weight gain in this age group over 12 months. Relationships between changes in variables were examined by calculating correlation coefficients. RESULTS: The children in the experimental group had a significantly (P < or = 0.05) higher increase in body weight than control children (4.6 kg vs. 2.0 kg) and both groups had significant (P < or = 0.05) but similar increases in height. The children in the experimental group showed non-significant increases in haemoglobin and serum retinol, while the control children had a significant (P = 0.007) decrease in RBP. The change in serum retinol showed a significant correlation with baseline retinol (P = 0.014), RBP (P = 0.007) and weight (P = 0.029), as well as with changes in haemoglobin (P = 0.029). CONCLUSION: Despite a small sample size, this study showed positive effects of a vitamin-fortified maize meal on weight gain and some variables of vitamin A status in 1-3-year-old African children. The study confirmed the relationship between vitamin A and iron status. The results suggest that fortification of maize meal would be an effective strategy to address micronutrient deficiencies in small children in South Africa.     

The influence of cereal and dairy consumption on the Irish diet: implications for developing food-based dietary guidelines

OBJECTIVES: To estimate the intakes of cereal and dairy products and their contribution to nutrient intakes in men and women from the Republic of Ireland with a view to formulating food-based dietary guidelines. DESIGN: The North/South Ireland Food Consumption Survey established a database of habitual food and drink consumption using a 7-day food diary. From this database all cereal and dairy products from recipes and identifiable sources were identified and a new database was generated from which analysis of the role of cereal and dairy products in the diet was carried out. RESULTS: Almost 100% of the population consumed cereal and dairy products over the course of the survey week. In general, men consumed significantly more cereal and dairy products than did women (P<0.05). Cereal products made an important contribution to the mean daily intakes of energy (26%), protein (21%), fat (13%), carbohydrate (41%), fibre (45%), iron (43%) and folate (27%). Dairy products also contributed largely to the mean daily intakes of energy (11%), protein (14%), fat (17%), calcium (48%), phosphorus (24%) and vitamin A (27%). Analysis of nutrient intakes across tertiles of cereal and dairy consumption showed that high consumers of wholemeal bread, breakfast cereals, reduced-fat milk and yoghurt had lower fat and higher carbohydrate, fibre and micronutrient intakes than low consumers of these foods. CONCLUSIONS: Findings from the present study could be used to develop effective health strategies to implement changes in cereal and dairy consumption that could alter fat, fibre and micronutrient intakes in the diet.     

Dietary intake and different types of physical activity: full-day energy expenditure, occupational and leisure-time

OBJECTIVE: To describe the relationship between dietary intake and different levels and types of physical activity (PA). DESIGN: Cross-sectional evaluation of the EPIPorto study. Energy expenditure (metabolic energy equivalent tasks) and dietary intake during the past year were assessed using a PA questionnaire and a semi-quantitative food-frequency questionnaire, respectively. SETTING: Representative sample of adults in Porto, Portugal. SUBJECTS: Data were analysed for 2404 Portuguese Caucasian adults, aged between 18 and 92 years. RESULTS: For total PA, males who were active had significantly higher mean intake of energy (10.76 (2570.7) vs. 9.78 (2336.9) MJ/d (kcal/d), P < 0.001) and lower level of protein consumption (16.9 vs. 17.6 % of energy, P < 0.001) compared with sedentary males. In males, the association between total PA and energy intake remained after adjustment for age, education and body mass index. Similar results were observed when occupational activity was analysed. Concerning the energy expended in leisure time, in both genders, after adjustment for the previously described variables, a significant positive association was found between PA and intake of vitamin C (g/d): beta = 0.12, 99 % confidence interval (CI) 0.02, 0.21 for females and beta = 0.13, 99 % CI 0.03, 0.22 for males. Leisure-time activity in females was also positively associated with intakes of fibre, vitamin E, folate, calcium and magnesium, and negatively associated with saturated fat. CONCLUSIONS: Higher levels of PA in leisure time were associated with higher intakes of micronutrients and lower intakes of saturated fat, particularly in females. For total and occupational PA, similar nutrient intake was observed between active and sedentary individuals.     

The National Food Consumption Survey (NFCS): South Africa, 1999

OBJECTIVE: The aim of the National Food Consumption Survey (NFCS) in South Africa was to determine the nutrient intakes and anthropometric status of children (1-9 years old), as well as factors that influence their dietary intake. DESIGN: This was a cross-sectional survey of a nationally representative sample of all children aged 1-9 years in South Africa. A nationally representative sample with provincial representation was selected using 1996 Census information. SUBJECTS: Of the 3120 children who were originally sampled data were obtained from 2894, a response rate of 93%. METHODS: The sociodemographic status of each household was assessed by a questionnaire. Dietary intake was assessed by means of a 24-hour recall and a food-frequency questionnaire from the caregivers of the children. Food purchasing practices were determined by means of a food procurement questionnaire. Hunger was assessed by a modified hunger scale questionnaire. Nutritional status was determined by means of anthropometric measurements: height, weight, head circumference and arm circumference. RESULTS: At the national level, stunting (height-for-age below minus two standard deviations (< -2SD) from the reference median) was by far the most common nutritional disorder, affecting nearly one in five children. The children least affected (17%) were those living in urban areas. Even with regard to the latter, however, children living in informal urban areas were more severely affected (20%) compared with those living in formal urban areas (16%). A similar pattern emerged for the prevalence of underweight (weight-for-age < -2SD), with one in 10 children being affected at the national level. Furthermore, one in 10 (13%) and one in four (26%) children aged 1-3 years had an energy intake less than half and less than two-thirds of their daily energy needs, respectively. For South African children as a whole, the intakes of energy, calcium, iron, zinc, selenium, vitamins A, D, C and E, riboflavin, niacin, vitamin B6 and folic acid were below two-thirds of the Recommended Dietary Allowances. At the national level, data from the 24-hour recalls indicated that the most commonly consumed food items were maize, sugar, tea, whole milk and brown bread. For South African children overall, one in two households (52%) experienced hunger, one in four (23%) were at risk of hunger and only one in four households (25%) appeared food-secure. CONCLUSION: The NFCS indicated that a large majority of households were food-insecure and that energy deficit and micronutrient deficiencies were common, resulting in a high prevalence of stunting. These results were used as motivation for the introduction of mandatory fortification in South Africa.     

Issues in assessing the validity of nutrient data obtained from a food-frequency questionnaire: folate and vitamin B12 examples

OBJECTIVE: To compare methods used to assess the validity of nutrient intake data obtained from a food-frequency questionnaire (FFQ), using folate and vitamin B12 as nutrient examples. DESIGN: Cross-sectional sample from a population cohort. SETTING: Two postcode areas west of Sydney, Australia. SUBJECTS: In total, 2895 people aged 49 years and older provided dietary data using a semi-quantitative FFQ (79% of 3654 subjects examined). The validity of the FFQ was assessed against three 4-day weighed food records (WFRs) completed by 78 people (mean age 70 years). RESULTS: Folate and vitamin B12 validity data were assessed using different methods. The Spearman ranked correlations (energy-adjusted) were 0.66 for folate and 0.38 for vitamin B12. Using the Bland-Altman method, following loge transformation, no linear trend existed between the differences and means for folate and vitamin B12. Large differences existed between the FFQ and WFR in individual cases, particularly for vitamin B12. Finally, data were divided into quintile categories for the test and reference method: 79% classified folate within one quintile, 65% classified vitamin B12 within one quintile; there was no gross misclassification for folate and only 3% misclassification for vitamin B12. CONCLUSIONS: Different methods of analysis provided different information about the validity of the FFQ. Correlation coefficients should not be used alone to assess the validity of nutrient data, but should be used in conjunction with Bland-Altman analyses. Depending on the use of the data, additional assessment of classification categories is recommended. This worked example demonstrates that absolute intakes of folate and vitamin B12 should be used with caution.     

Folate deficiency is associated with nutritional anaemia in Lebanese women of childbearing age

OBJECTIVE: The objective of this study was to identify the determinants of anaemia in Lebanese women of childbearing age attending health centres in Lebanon. DESIGN: Cross-sectional study carried out between May and December 2003. Anthropometric measurements as well as sociodemographic, health and dietary intake data were collected using a questionnaire. Haemoglobin (Hb), plasma ferritin, plasma folate and vitamin B12 were assessed using standard laboratory methods. SETTING: Governmental health centres in Lebanon. SUBJECTS: Four hundred and seventy non-pregnant Lebanese women aged 15-45 years. RESULTS: Anaemia (Hb <12 g dl(-1)) and iron deficiency (ferritin <15 microg l(-1)) were prevalent in 16.0 and 27.2% of the study sample, respectively. Of the total sample, 7.7% had iron-deficiency anaemia. The percentage of women with either Hb or ferritin deficiency or both was 35.6%. Plasma folate and vitamin B12 deficiency was reported in 25.1 and 39.4%, respectively, and 12.6% of the women had both folate and vitamin B12 deficiencies. Of the anaemic group, 48.0% of the women had iron deficiency. The intake of iron was lower in iron-deficient than in non-deficient women and a positive relationship was shown between folate intake and its corresponding serum levels. Regression analysis showed that ferritin, plasma folate and family history of anaemia were significant determinants of the anaemia in the sample of women. CONCLUSIONS: Anaemia not related to iron deficiency was partly explained by plasma folate deficiency. Measures to control folate and iron deficiency should be considered.     

The nutritional status of asymptomatic HIV-infected Africans: directions for dietary intervention?

OBJECTIVE: To compare the relationships between food (nutrient) intakes and biochemical markers of nutritional status of asymptomatic HIV-infected with HIV-uninfected subjects, to gain more information on the appropriate diet for HIV-infected persons at an early stage of infection. DESIGN: Cross-sectional population-based survey. SETTING: North West Province, South Africa. SUBJECTS: Two hundred and sixteen asymptomatic HIV-infected and 1550 HIV-uninfected men and women volunteers aged 15 years and older, recruited as 'apparently healthy' subjects from 37 randomly selected sites. OUTCOME MEASURES: Food and nutrient intakes, measured with a validated food-frequency questionnaire, and nutritional status indicated by anthropometric and biochemical variables, measured by a standardised methodology. RESULTS: The prevalence of HIV infection in the study population was 11.9%. The anthropometric indices and nutrient intakes of HIV-infected and uninfected subjects did not differ significantly, indicating that these 216 HIV-infected subjects were at an early stage of infection. Of the biochemical nutritional status variables, high-density lipoprotein cholesterol and total cholesterol, haemoglobin, albumin and triglycerides were significantly lower in infected subjects. They also had higher globulin and liver enzyme levels than uninfected subjects. In infected subjects, serum albumin correlated significantly with serum lipids, serum vitamin A, serum vitamin E, serum iron, total iron-binding capacity and haemoglobin. The significant positive correlations of the liver enzymes with serum lipids, albumin, vitamin A and iron, observed in HIV-uninfected subjects, disappeared in the infected subjects. Polyunsaturated fat intake showed significant positive correlations with the increased liver enzymes in infected subjects. A principal components analysis indicated that, in infected subjects, increased liver enzymes correlated with higher consumption of maize meal and lower consumption of meat and vegetables. CONCLUSIONS AND RECOMMENDATIONS: This survey indicated that asymptomatic HIV-infected subjects who followed a diet rich in animal foods had smaller decreases in serum albumin, haemoglobin and lipid variables, and smaller increases in liver enzymes, than those who consumed a diet based on staple foods. This suggests that animal foods are associated with improved nutritional status in HIV-infected persons. These results should be confirmed with intervention studies before dietary recommendations for asymptomatic HIV-infected individuals can be made.     

The effect of personal characteristics on the validity of nutrient intake estimates using a food-frequency questionnaire

OBJECTIVE: To assess validity of the Nambour food-frequency questionnaire (FFQ) relative to weighed food records (WFRs), and the extent to which selected demographic, anthropometric and social characteristics explain differences between the two dietary methods.DESIGN: Inter-method validity study; 129-item FFQ vs. 12 days of WFR over 12 months.SETTING: Community-based Nambour Skin Cancer Prevention Trial.SUBJECTS: One hundred and fifteen of 168 randomly selected participants in the trial (68% acceptance rate) aged 25-75 years.RESULTS: Spearman correlations between intakes from the two methods ranged from 0.18 to 0.71 for energy-adjusted values. Differences between FFQ and WFR regressed on personal characteristics were significantly associated with at least one characteristic for 16 of the 21 nutrients. Sex was significantly associated with differences for nine nutrients; body mass index (BMI), presence of any medical condition and age were each significantly associated with differences for three to six nutrients; use of dietary supplements and occupation were associated with differences for one nutrient each. There was no consistency in the direction of the significant associations. Regression models explained from 7% (riboflavin) to 27% (saturated fat) of variation in differences in intakes.CONCLUSIONS: The relative validity of FFQ estimates for many nutrients is quite different for males than for females. Age, BMI, medical condition and level of intake were also associated with relative validity for some nutrients, resulting in the need to adjust intakes estimates for these in modelling diet-disease relationships. Estimates for cholesterol, beta-carotene equivalents, retinol equivalents, thiamine, riboflavin and calcium would not benefit from this.     

The influence of fruit and vegetable intake on the nutritional status and plasma homocysteine levels of institutionalised elderly people

OBJECTIVE: To determine the difference in the nutritional status of elderly people depending on their consumption of fruits and vegetables, and to study the possible association between the consumption of these foods and different cardiovascular risk factors, especially total plasma homocysteine (t-Hcys) levels. DESIGN, SETTING AND SUBJECTS: A cross-sectional study in 152 institutionalised older people from Madrid aged > or = 65 years. Food and nutrient intakes were recorded over 7 days using the 'precise individual weighing' method. The weight, height, and waist and hip circumferences of all subjects were recorded, as were their alpha-erythrocyte glutathione reductase, serum B6, B12 and folate levels, erythrocyte folate levels, t-Hcys levels, serum lipids and blood pressure. The experimental population was then divided into tertiles depending on the serving intake of fruit and vegetables (T1, < 2.29 servings day(-1); T2, 2.29-2.79 servings day(-1); and T3, >2.79 servings day(-1)). RESULTS: Compared with T1 subjects, T3 subjects showed consumptions of cereals, pulses, meat, fish and eggs closer to those recommended (P < 0.05). In addition, the contribution of their diet towards covering the recommended daily intake of vitamin B1, niacin, vitamin B6, folic acid, vitamin C, B12, vitamin A, and P, Mg, Zn and Fe was higher. The intake of fibre increased with consumption of fruit and vegetables (r = 0.6839, P < 0.001). T3 subjects also had better serum and erythrocyte folate levels than T1 and T2 subjects (P < 0.05). A positive correlation was found between the consumption of fruit and vegetables and serum folate (r = 0.2665, P < 0.01) and with erythrocyte folate levels (r = 0.2034, P < 0.05), and a negative correlation with t-Hcys (r = -0.2493, P < 0.01). CONCLUSIONS: Greater consumption of fruit and vegetables is associated with better food habits, increased vitamin and mineral intakes and lower t-Hcys levels. Considering that the fruit and vegetable intake in Spanish elderly people is very low, it is recommended that the consumption of fruits and vegetables by elderly people be increased.     

Biofortification of common bean as a complementary approach to addressing zinc deficiency in South Africans

Deficiencies of vitamin A, iodine, iron and zinc (Zn) in humans are caused partly by the consumption of food that has insufficient quantities of these. Their deficiency has a negative impact on the health, wellbeing, social and economic status of human beings. A national survey conducted in 2012 identified deficiencies of vitamin A, Fe, and Zn among other nutrients in South Africans and regarded the deficiencies of vitamin A and Fe as a moderate but not Zn. This review discusses causes of Zn prevalence in low-income South Africans and that it is largely caused by the low content of Zn in their diets. Initiatives to reduce Zn deficiency include fortification of wheat products and maize meal which has failed to address it successfully. Weaknesses of fortification include high cost of fortified food products to low-income populations, poor regulation in ensuring compliance in fortification, non-fortification of sorghum meal, and leaching of fortified nutrients during processing. This review suggests Zn-biofortification of locally-preferred common bean cultivars as an alternative strategy to compliment fortification. The review also discusses advantages of adopting biofortified Nutritional Andean common beans. Furthermore, the review suggests initiatives including evaluation of the common bean genotypes’ adaptation to different agro-ecologies.     

24-hour national dietary survey data: how do we interpret them most effectively?

OBJECTIVE: To illustrate the effect of common mistakes when using 24-hour national dietary survey data to estimate the prevalence of inadequate nutrient intakes. DESIGN: Raw data on nutrient intake from the Australian 1995 National Nutrition Survey were adjusted for within-person variance using standard techniques and corrected for underreporting using the criteria of Goldberg et al. The distributions for six nutrients were compared with current dietary reference values from the UK, USA and Australia. SETTING: A national sample of the Australian population with a 61.4% response rate. RESULTS: Adjusting for within-person variance reduced the range of nutrient intakes to 66-80% of the raw data range and the proportion with intakes below the estimated average requirement (EAR) by up to 20%. Excluding underreporters further reduced the proportion below the EAR by up to 10%. Using the dietary reference values from different countries also resulted in some markedly different estimates. For example, the prevalence of low folate intakes ranged from < 1 to 92% for adult women depending on the reference used. Except for vitamin A and protein, the prevalence of low intakes was invariably higher for women than for men. CONCLUSIONS: Estimates of the prevalence of low nutrient intakes based on raw 24-hour survey data are invariably misleading. However, even after adjustment for within-person variance and underreporting, estimates of the prevalence of low nutrient intakes may still be misleading unless interpreted in the light of the reference criteria used and supported by relevant biochemical and physiological measures of nutritional status.     

The UK Women's Cohort Study: comparison of vegetarians, fish-eaters and meat-eaters

BACKGROUND: This paper describes the development of the UK Women's Cohort Study and presents cohort baseline characteristics. METHODS: In total, 35,372 women, aged 35-69 years at recruitment, were selected to ensure a wide range of dietary intakes. Diet was assessed by a 217-item food-frequency questionnaire (FFQ). Detailed lifestyle information was collected by postal questionnaire. Vegetarians, fish-eaters and meat-eaters were compared. RESULTS: The cohort women are mainly white, well-educated, middle-class and married with children. They are health-conscious with only 11% current smokers and 58% taking dietary supplements. Twenty-eight per cent of subjects self-report as being vegetarian and 1% as vegan. However, only 18% are defined as 'vegetarian' from the FFQ. Fat provides 32% of energy; vitamin and mineral intakes are high, with a broad range of intakes. Meat-eaters are older, with a higher body mass index (BMI) and the lowest intakes of carbohydrate, fibre, vitamin C, folate, iron and calcium. Other fish-eaters are similar to vegetarians. Vegetarians have the lowest intakes of protein, fat and saturated fat. Oily fish-eaters have the lowest BMI; are the least likely to smoke or use full-fat milk; and are the most likely to use dietary supplements and consume the most fruit and vegetables. Oily fish-eaters have the highest total energy intake and vegetarians the lowest. Semi-skimmed milk, bread, potatoes, wine, bananas and muesli are important contributors to energy for all groups. CONCLUSION: A large cohort of middle-aged women has been created encompassing a wide range of different eating patterns, including diets currently of interest to research into protection against cancer and coronary heart disease. Participants will be followed up to study the effects of different food and nutrient intakes on long-term health outcomes.