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Background: Although alcohol intake has been positively associated with breast cancer risk in epidemiologic studies, a causal relationship has not been established, and the mechanisms mediating this association are speculative. Alcohol may act through altered status of folate and vitamin B(12), two vitamins required for DNA methylation and nucleotide synthesis, and thus cell integrity. Although the effects of heavy alcohol intake on folate and vitamin B(12) status have been well-documented, few studies have addressed the effects of moderate alcohol intake in a controlled setting., Objective: The objective of this study was to determine the effects of moderate alcohol intake on folate and vitamin B(12) status in healthy, well-nourished, postmenopausal women., Design: The study design was a randomized, diet-controlled crossover intervention. Postmenopausal women (n=53) received three 8-week alcohol treatments in random order: 0, 15, and 30 g/day. Treatment periods were preceded by 2-5-week washout periods. Blood collected at baseline and week 8 of each treatment period was analyzed for serum folate, vitamin B(12), homocysteine (HCY), and methylmalonic acid (MMA) concentrations., Results: After adjusting for body mass index (BMI), a significant 5% decrease was observed in mean serum vitamin B(12) concentrations from 0 to 30 g of alcohol/day (461.45+/-30.26 vs 440.25+/-30.24 pg/ml; P=0.03). Mean serum HCY concentrations tended to increase by 3% from 0 to 30 g of alcohol/day (9.44+/-0.37 vs 9.73+/-0.37 micromol/l; P=0.05). Alcohol intake had no significant effects on serum folate or MMA concentrations., Conclusions: Among healthy, well-nourished, postmenopausal women, moderate alcohol intake may diminish vitamin B(12) status.

Background: The concentration of circulating total homocysteine is a sensitive marker of inadequate folate and vitamin B12 status. Elevated homocysteine concentrations are associated with an increased risk for vascular disease., Objective: To identify reference ranges for serum total homocysteine concentration in U.S. residents and quantify the contribution of circulating vitamin concentrations to high homocysteine concentrations., Design: Cross-sectional prevalence study., Setting: United States., Patients: A nationally representative sample of 3563 male participants and 4523 female participants 12 years of age or older who participated in the third National Health and Nutrition Examination Survey., Measurements: Reference ranges (5th and 95th percentiles) for the total homocysteine concentration were defined among participants who were folate- and vitamin B12-replete and had normal creatinine concentrations. A high total homocysteine concentration was defined as one that exceeded the sex-specific 95th percentile for the reference sample (participants 20 to 39 years of age). The population attributable risk percentage was calculated to determine the contribution of low folate (<11 nmol/L) and vitamin B12 (<185 pmol/L) concentrations to a high homocysteine concentration., Results: Reference ranges for serum total homocysteine concentration increased with age; these ranges were 4.3 to 9.9 micromol/L for male participants and 3.3 to 7.2 micromol/L for female participants 12 to 19 years of age and from 5.9 to 15.3 micromol/L for men and 4.9 to 11.6 micromol/L for women 60 years of age or older. A high homocysteine concentration was defined as at least 11.4 micromol/L for male participants and at least 10.4 micromol/L for female participants. Approximately two thirds of the cases of high homocysteine concentrations were associated with low vitamin concentrations., Conclusions: Upper reference limits for the serum total homocysteine concentration increased with age and were higher for male participants than for female participants at all ages. In most cases, high homocysteine concentrations were associated with low serum vitamin concentrations.

Background: Dried blood spots (DBS) on filter paper have been a successful and economical matrix for neonatal screening., Objective: Our objective was to develop and evaluate an optimized method for DBS folate analysis and to assess DBS folate stability., Design: DBS were eluted from paper by sonication in 5 g ascorbic acid/L containing 0.1% (by vol) Triton X-100 and hemoglobin folate values (HF; as pmol/g) were calculated from DBS eluate folate and hemoglobin concentrations., Results: Over 95% of DBS folate was eluted during a standardized sonication cycle and DBS folate assay reproducibility was acceptable both within (CV: <8%) and between (CV: <9%) runs. HF means (+/-1 SD) from finger-stick DBS and conventional venous methods were 2513 +/- 1144 and 2607 +/- 1195 pmol/g, respectively, in blood samples taken concurrently from 80 donors, and they correlated well (r = 0.97, P < 0.001). HF values and erythrocyte folate measures may be interconverted by using the mean cell hemoglobin concentration., Conclusion: The DBS matrix has potential as an inexpensive and practical option for folate screening studies.

Objective: A study of children (2-8 years; n = 613) in Belize, Central America, was conducted to determine what proportion of the children might be at risk of vitamin A (vit A) deficiency. The data provide an opportunity to compare results of three methods of assessing vit A status in a population which was not severely malnourished. Serum retinyl ester concentrations were also determined; their relevance to one of the tests, the relative dose response (RDR) test, is discussed., Methods: The three methods of assessing vit A status were: RDR test, fasting serum retinol concentration, and conjunctival impression cytology (CIC). Retinol-binding protein (RBP), serum retinyl esters and serum zinc concentrations were also determined., Results: Inadequate vit A status was indicated for 17% of subjects by the RDR test (14% cutoff), for 24% by fasting serum retinol concentration (< 0.87 mumol/L), and for 49% by "abnormal" CIC score. Retinyl esters constituted 24% of serum retinoids at the time (5 hours after a retinyl palmitate dose) at which the second blood sample is taken for the RDR test. Regression tree analyses (CART) indicated ethnicity was a predictor of RDR score; ethnicity, stunting and age were predictors of fasting serum retinol concentration; ethnicity and stunting were predictors of 0-hour retinyl ester concentration., Conclusion: The three indices of vit A status did not identify the same individuals nor indicate the same percentage of the population to be at risk for vit A deficiency. Increased concentrations of retinyl esters at 5 hours compared to those at 0 hours suggest that insufficient retinol may have been taken up by the liver at 5 hours to release all accumulated retinol-binding protein (RBP) in deficient individuals; prevalence of vit A deficiency might therefore be underestimated by the RDR test. The selection of ethnicity as a predictor of RDR score and of 0-hour retinol and retinyl ester concentrations suggests that factors other than vit A status affect vit A metabolism and may affect the RDR test.

This paper summarizes iron status measurements included in the three cross-sectional National Health and Nutrition Examination Surveys (NHANES) completed to date, as well as a special study of Hispanics, known as the Hispanic Health and Nutrition Examination Survey (HHANES). Approaches for defining iron status in the population based on these measurements are also described as well as issues in comparing iron status data between surveys, using NHANES II and III data as an example.

The purpose of this review is to examine current research on the iron status of the elderly and factors that influence the body burden of iron. Studies of noninstitutionalized elderly individuals report mean iron intakes that meet current Recommended Dietary Allowances for iron. Dietary practices that may decrease iron bioavailability, and hence iron stores in the body, include low intakes of ascorbic acid or high intakes of calcium, and decreased consumption of highly available iron from meat, fish, and poultry. Although not well documented, the effect of age on iron absorption and iron excretion appears to be small, and body stores of iron increase with age. It is difficult to estimate the prevalence of iron deficiency in elderly persons, because impaired iron status can be the result of iron deficiency or chronic disease. Further study is necessary to determine whether red blood cell ferritin and serum transferrin receptors may be useful biochemical markers to differentiate the anemia of chronic disease from iron deficiency anemia. Hereditary hemochromatosis is a genetic disease that greatly increases the body burden of iron and the risk of hepatic disease among homozygotes. Because iron deficiency or iron excess may impair health, the role of iron in diseases associated with aging such as depressed immune response, neurological dysfunction, cancer, and heart disease is discussed.