Median urinary iodine concentration reflected sufficient iodine supply in neonates from Northeast Germany in 2005-2006.

PURPOSE: Data from recent adult studies suggest a decline of median urinary iodine concentrations (UIC) in Germany, but since 1996 no German study investigated UIC in neonates. The aim of our study was to investigate UIC and serum thyroid-stimulating hormone (TSH) levels in neonates from Germany. METHODS: We used data from 399 neonates, which were born between April 2005 and November 2006 in the Northeast of Germany. UIC were evaluated by a photometric procedure with Sandell and Kolthoff reaction and afterwards corrected to be comparable with an ICP-MS method. TSH was determined from capillary blood, which was taken within 5 days after birth, by DELFIA. RESULTS: Median UIC were 150 µg/L (25th percentile: 104 µg/L; 75th percentile: 196 µg/L) and differed between boys (153.3 µg/L) and girls (131.5 µg/L; p = 0.012). The prevalence of serum TSH levels > 5 mIU/L was 14%. Neonates from mothers with intake of iodine supplementation (150 µg/L) had significantly higher median UIC than neonates from mothers without iodine supplementation (132 µg/L; p = 0.011). Multivariable linear regression adjusted for sex and iodine supplementation of the mother revealed a significant association between UIC and log-transformed serum TSH levels (ß = 0.003: 95% confidence interval (CI) = 0.0001-0.005; p = 0.028). CONCLUSIONS: Neonates in Northeast Germany did show a sufficient supply of iodine. This points towards the possibility of a sufficient iodine supply of neonates also in other regions of Germany, even though recent studies in adults may indicate mild iodine deficiency.

Glucocorticoid activity and metabolism with NaCl-induced low-grade metabolic acidosis and oral alkalization: results of two randomized controlled trials.

Low-grade metabolic acidosis (LGMA), as induced by high dietary acid load or sodium chloride (NaCl) intake, has been shown to increase bone and protein catabolism. Underlying mechanisms are not fully understood, but from clinical metabolic acidosis interactions of acid-base balance with glucocorticoid (GC) metabolism are known. We aimed to investigate GC activity/metabolism under alkaline supplementation and NaCl-induced LGMA. Eight young, healthy, normal-weight men participated in two crossover designed interventional studies. In Study A, two 10-day high NaCl diet (32 g/d) periods were conducted, one supplemented with 90 mmol KHCO3/day. In Study B, participants received a high and a low NaCl diet (31 vs. 3 g/day), each for 14 days. During low NaCl, the diet was moderately acidified by replacement of a bicarbonate-rich mineral water (consumed during high NaCl) with a non-alkalizing drinking water. In repeatedly collected 24-h urine samples, potentially bioactive-free GCs (urinary-free cortisol + free cortisone) were analyzed, as well as tetrahydrocortisol (THF), 5α-THF, and tetrahydrocortisone (THE). With supplementation of 90 mmol KHCO3, the marker of total adrenal GC secretion (THF + 5α-THF + THE) dropped (p = 0.047) and potentially bioactive-free GCs were reduced (p = 0.003). In Study B, however, GC secretion and potentially bioactive-free GCs did not exhibit the expected fall with NaCl-reduction as net acid excretion was raised by 30 mEq/d. Diet-induced acidification/alkalization affects GC activity and metabolism, which in case of long-term ingestion of habitually acidifying western diets may constitute an independent risk factor for bone degradation and cardiometabolic diseases.

Dietary protein's and dietary acid load's influence on bone health.

A variety of genetic, mechano-response-related, endocrine-metabolic, and nutritional determinants impact bone health. Among the nutritional influences, protein intake and dietary acid load are two of the factors most controversially discussed. Although in the past high protein intake was often assumed to exert a primarily detrimental impact on bone mass and skeletal health, the majority of recent studies indicates the opposite and suggests a bone-anabolic influence. Studies examining the influence of alkalizing diets or alkalizing supplement provision on skeletal outcomes are less consistent, which raises doubts about the role of acid-base status in bone health. The present review critically evaluates relevant key issues such as acid-base terminology, influencing factors of intestinal calcium absorption, calcium balance, the endocrine-metabolic milieu related to metabolic acidosis, and some methodological aspects of dietary exposure and bone outcome examinations. It becomes apparent that for an adequate identification and characterization of either dietary acid load's or protein's impact on bone, the combined assessment of both nutritional influences is necessary.

Alkaline salts to counteract bone resorption and protein wasting induced by high salt intake: results of a randomized controlled trial.

High sodium chloride (NaCl) intake can induce low-grade metabolic acidosis (LGMA) and may thus influence bone and protein metabolism. We hypothesized that oral potassium bicarbonate (KHCO(3)) supplementation may compensate for NaCl-induced, LGMA-associated bone resorption and protein losses. Eight healthy male subjects participated in a randomized trial with a crossover design. Each of two study campaigns consisted of 5 d of dietary and environmental adaptation followed by 10 d of intervention and 1.5 d of recovery. In one study campaign, 90 mmol KHCO(3)/d were supplemented to counteract NaCl-induced LGMA, whereas the other campaign served as a control with only high NaCl intake. When KHCO(3) was ingested during high NaCl intake, postprandial buffer capacity ([HCO(3)(-)]) increased (P = 0.002). Concomitantly, urinary excretion of free potentially bioactive glucocorticoids [urinary free cortisol (UFF) and urinary free cortisone (UFE)] was reduced by 14% [∑(UFF,UFE); P = 0.024]. Urinary excretion of calcium and bone resorption marker N-terminal telopeptide of type I collagen was reduced by 12 and 8%, respectively (calcium, P = 0.047; N-terminal bone collagen telopeptide, P = 0.044). There was a trend of declining net protein catabolism when high NaCl was combined with KHCO(3) (P = 0.052). We conclude that during high salt intake, the KHCO(3)-induced postprandial shift to a more alkaline state reduces metabolic stress. This leads to decreased bone resorption and protein degradation, which in turn might initiate an anticatabolic state for the musculoskeletal system in the long run.

[Time trends and seasonal variation of iodine content in German cow's milk--investigations from Northrhine-Westfalia]. / Aktuelle Untersuchungen zeitlicher Trends und saisonaler Effekte des Jodgehaltes in Kuhmilch--Untersuchungen aus Nordrhein Westfalen.

Cow's milk is one of the most important iodine providers in the human diet. The milk iodine content (MIC) is significantly determined by cattle feeding. The aim of the study was to investigate the longitudinal development of the MIC of German cow's milk during the last years and to assess the current contribution of milk consumption to the population's iodine supply. MIC was analysed by a Cer-Arsenit method after alkaline wet washing in 112 milk samples from nationwide available trademarks (eight samples each were purchased in June and December from 2004 onward to 2010 in the same food markets in the greater Dortmund area). We found an increasing trend of MIC until 2010 (p < 0.005).The mean MIC in 2004/05 was 97 +/- 32 microg/I, in 2009/10 it was 110 +/- 36 microg/l. This increase was only observable for conventionally (p = 0.0003), and not for organically produced milk (p = 0.6). The MIC of summer milk was about 22 microg/l lower than that of winter milk (p < 0.0001), however, seasonal variation was especially pronounced in organically produced milk. MIC of organically produced milk was in average about 54 microg/l lower than that of conventionally produced milk (p < 0.0001). Thus, the moderate increase of MIC to 110 microg/l on average contributes to the maintainence of the population's iodine supply, whereas the analysed maximum iodine contents of around 160 microg/l do not give reason to expect an excessive iodine intake, even in case of a high milk consumption. An appropriate iodine supplementation in foodstuff can be assumed.

Urinary isoflavone phytoestrogens in German children and adolescents--a longitudinal examination in the DONALD cohort.

SCOPE: In light of concerns about hormonally active agents, it is important to assess human exposure to such compounds, especially in children as a susceptible subgroup. Estrogenic plant constituents are present in the human diet in varying levels, in particular the isoflavones daidzein (DAI) and genistein (GEN). We aimed to examine age-dependent and secular trends in phytoestrogen exposures and to investigate equol (EQ) excretion of German children using biomarker analysis in 24-h urine samples from a longitudinally designed study. METHODS AND RESULTS: The concentrations of DAI, its metabolite EQ and GEN were determined by GC-MS analysis in 24-h urines (510 samples) collected between 1985 and 2000 in 90 (47 boys) German children (6-18 years old), who are participants in the Dortmund Nutritional and Anthropometric Longitudinally Designed study. The results from the urinary biomarker analysis indicate isoflavone exposures at quite variable levels in German children: Analyte concentrations in over 500 urine samples cover the range reported previously in adults on typical German diet and with soy intake. EQ, the DAI metabolite produced by the gastrointestinal microflora, was detected in a high fraction of all samples, with 28/90 children (31%) excreting EQ in all their urines, and 62/90 children (68%) in at least one sample. Interestingly, when multiple urines obtained from individuals at different ages (6-18 years) were analyzed, EQ formation did not appear to be a constant trait over time. When stratified by sex, DAI, EQ and GEN concentrations (ng/mL) in urines and excretion rates (µg/day) were similar in boys and girls. Total isoflavone excretion rates (µg/day) increased during childhood (6-12 years) (p=0.02) and were constant during adolescence (13-18 years) (p=0.6). No clear trend for changes in dietary isoflavone exposure over the total study period was seen (p=0.7). CONCLUSIONS: In conclusion, biomarkers in urine of German children and adolescents indicate a frequent, but widely variable dietary isoflavone intake and suggest no secular increase (1985-2000) in the exposure to isoflavone phytoestrogens among German children and adolescents.

Relation of isoflavones and fiber intake in childhood to the timing of puberty.

BACKGROUND: It has been suggested that phytoestrogens and dietary fiber can affect puberty timing. OBJECTIVE: We examined whether intake of isoflavone and fiber in healthy white children before their pubertal growth spurt [age at take-off (ATO)] was associated with puberty timing. DESIGN: Multivariate regression analyses were performed in 227 DONALD (DOrtmund Nutritional and Anthropometric Longitudinally Designed) Study participants with 3-d weighed dietary records and information on potential confounders at baseline (1 and 2 y before ATO). In a subsample (n = 111), urinary isoflavones were determined in 24-h urine samples by gas chromatography-mass spectrometry analysis. Puberty timing was examined by using ATO and chronologic ages at pubertal stage 2 for breast development (B2) or gonadal development, peak height velocity (PHV), and menarche or voice break. RESULTS: Girls whose diet was in the highest dietary isoflavone tertile experienced Tanner stage 2 for breast development ap 0.7 y later and reached PHV ap 0.6 y later than did girls whose diet was in the lowest isoflavone tertile [age (95% CI) at B2: 10.7 y (10.4, 10.9 y) compared with 10.0 y ( 9.7, 10.3 y), respectively; P for trend = 0.04; age at PHV: 11.9 y (11.6, 12.2 y) compared with 11.3 y (11.0, 11.6 y), respectively; P for trend = 0.04; adjusted for body mass index z score and fiber intake]. In boys, dietary isoflavones were not associated with pubertal markers. Urinary isoflavone and dietary fiber intakes were not associated with pubertal markers. CONCLUSIONS: Girls, but not boys, with higher prepubertal isoflavone intakes appear to enter puberty at a later age. Fiber intake in this sample of healthy white girls and boys was not relevant for puberty timing.

Renal net acid excretion capacity is comparable in prepubescence, adolescence, and young adulthood but falls with aging.

OBJECTIVES: To evaluate whether renal net acid excretion capacity (NAEC) varies across different age groups and, specifically, whether it falls in elderly people. DESIGN: Cross-sectional observational study. SETTING: Community-based. PARTICIPANTS: Young participants were from the DOrtmund Nutritional and Anthropometric Longitudinally Designed Study, Dortmund, Germany; elderly participants were from Gothenburg, Sweden. MEASUREMENTS: Twenty-four-hour urine pH, net acid excretion (NAE), urinary phosphorus, total nitrogen excretion, and anthropometric data were measured in healthy elderly people (aged 55-75; n=85), young adults (aged 18-22; n=117), adolescents (aged 13-14; n=112), and prepubescent children (aged 6-7; n=217). NAEC was determined as 24-hour NAE adjusted for urine pH using the residual method. RESULTS: In elderly participants 24-hour urinary pH (5.9+/-0.53) was lower (P<.05) and NAE (60+/-27 mEq/d) higher (P<.05) than in the three other groups. In a regression model adjusted for age, sex, and body surface area, NAEC showed a clear decrease with age, with highest values in prepubescents and lowest in elderly participants. However, NAEC remained significantly lower only in elderly participants (P<.001) after the inclusion of total nitrogen excretion, a protein intake index, which was included because protein intake is known to modulate renal function. NAEC was approximately 8 mEq/d lower in healthy elderly participants than in young adults. CONCLUSION: The capacity to excrete net endogenous acid does not vary markedly from childhood to young adulthood but falls significantly with age, implying that elderly people may require higher daily alkalizing mineral intake to compensate for renal function losses.

Longitudinal examination of 24-h urinary iodine excretion in schoolchildren as a sensitive, hydration status-independent research tool for studying iodine status.

BACKGROUND: Because worldwide iodine status (IS) depends on continuous fortification, the adequacy of IS needs to be regularly monitored. OBJECTIVE: Our study aimed to evaluate IS in a longitudinal sample of healthy schoolchildren who regularly used table salt iodized with 20 microg I/g. DESIGN: Urine osmolality (Uosm) and 24-h urinary excretion rates of iodine (24-h UI), sodium, creatinine, and total urine volume (24-h Uvol) were measured in 1046 specimens that were collected at repeated intervals from 1996 to 2003 in a sample of 358 German children aged 6-12 y. Energy intake and food consumption were calculated from 3-d weighed dietary records that were collected in parallel to the urine samples. RESULTS: During the 4-y period from 1996 to 1999, the median 24-h UI increased from 87 to 93 microg I/d (P = 0.017), whereas urinary iodine concentration (UIC), Uosm, and 24-h Uvol did not change significantly. Thereafter (from 2000 to 2003), UIC stagnated and Uosm decreased (P = 0.004), whereas 24-h Uvol (P = 0.008) and 24-h UI (P = 0.002) increased. The final median 24-h UI reached 120 microg I/d. Milk, fish, egg, and meat intakes and 24-h sodium excretion were all significant predictors of IS, with an almost doubled contribution from milk intake during the second 4-y period. CONCLUSIONS: Our study shows a continuous improvement of IS in a longitudinal sample of German schoolchildren. This improvement was masked when UIC was used as an IS index, especially from 2000 to 2003 because of changes in hydration status. Thus, in research-oriented studies that focus on UIC measurements, hydration status can be a relevant confounder. Longitudinal analyses of 24-h UI in cohort studies may represent an alternative hydration status-independent tool to examine trends in IS and the contribution of relevant foods to IS.