Stretch-shortening cycle muscle power in women and men aged 18-81 years: Influence of age and gender.

This study explored the age-related deterioration in stretch-shortening cycle (SSC) muscle power and concurrent force-velocity properties in women and men across the adult life span. A total of 315 participants (women: n = 188; men: n = 127) aged 18-81 years performed maximal countermovement jumps on an instrumented force plate. Maximal SSC leg extension power expressed per kg body mass (Ppeak) was greater in men than in women across the adult age span (P < 0.001); however, this gender difference was progressively reduced with increasing age, because men showed an ∼50% faster rate of decline in SSC power than women (P < 0.001). Velocity at peak power (VPpeak) was greater in men than in women (P < 0.001) but declined at a greater rate in men than in women (P = 0.002). Vertical ground reaction force at peak power (FPpeak) was higher in men than in women in younger adults only (P < 0.001) and the age-related decline was steeper in men than in women (P < 0.001). Men demonstrated a steeper rate of decline in Ppeak than women with progressive aging. This novel finding emerged as a result of greater age-related losses in men for both force and velocity. Consequently, maximal SSC power production was observed to converge between genders when approaching old age.

Subjects heterozygous for genetic loss of function of the thiazide-sensitive cotransporter have reduced blood pressure.

Gitelmans syndrome (GS) is an inherited recessive disorder caused by homozygous or compound heterozygous loss of function mutations of the NaCl cotransporter (NCCT) gene encoding the kidney-expressed NCCT, the pharmacological target of thiazide diuretics. An observational study estimated the prevalence of GS to 19/1,000,000, in Sweden, suggesting that approximately 1% of the population carries one mutant NCCT allele. As the phenotype of GS patients, who always carry two mutant alleles, is indistinguishable from that seen in patients treated with high-dose thiazide diuretics, we aimed at investigating whether subjects carrying one mutated NCCT allele have a phenotype resembling that of treatment with low-dose thiazide diuretics. We screened first-degree relatives of 18 of our patients with an established clinical end genetic diagnosis of GS for NCCT loss of function mutations and identified 35 healthy subjects carrying one mutant allele (GS-heterozygotes). Each GS-heterozygote was assigned a healthy control subject matched for age, BMI and sex. GS-heterozygotes had markedly lower blood pressure (systolic 103.3 +/- 16.4 versus 123.2 +/- 19.4 mmHg; diastolic 62.5 +/- 10.5 versus 73.1 +/- 9.4 mmHg; P < 0.001) than controls. There was no significant difference between the groups either in plasma concentration or urinary excretion rate of electrolytes, however, GS-heterozygotes had higher fasting plasma glucose concentration. Similar to patients being treated with low-dose thiazide diuretics, GS-heterozygotes have markedly lower blood pressure and slightly higher fasting plasma glucose compared with control subjects. Our findings suggest that GS-heterozygotes, the prevalence of which can be estimated to 1%, are partially protected from hypertension through partial genetic loss of function of the NCCT. However, as our study had a case-control design, it is important to underline that any potential effects on population blood pressure and risk of future cardiovascular disease need to be examined in prospective and population-based studies.

Salt intake in young Swedish men.

OBJECTIVE: To measure dietary salt intake in a Swedish population. DESIGN: A cross-sectional study with measured 24 h urinary excretion of Na and K. Completeness of urine collection was assessed using p-aminobenzoic acid. The subjects were interviewed on their habitual food intake. SETTING: Sahlgrenska University Hospital, Gothenburg, Sweden. SUBJECTS: Eighty-six young men (age 18-20 years), randomly selected from the population of Gothenburg. Seven men were excluded due to incomplete urine collection. RESULTS: The mean excretion of Na and K over 24 h was 198 and 84 mmol, respectively (corresponding to 11.5 g NaCl and 3.3 g K). The mean 24 h excretion in the highest quartile of Na excretion was 297 mmol Na and 105 mmol K, and in the lowest quartile, 100 mmol Na and 68 mmol K. The mean Na:K ratio was 2.3, and respectively 3.2 and 1.8 in the highest and lowest Na excretion quartiles. Calculated energy intake did not differ between the highest and lowest quartiles of Na excretion, but body weight, BMI and the intake of certain foods known to be Na-rich did. CONCLUSIONS: Salt intake in young men was alarming high and even subjects in the lowest quartile of Na excretion did not meet present recommendations to limit salt intake to 5-6 g/d. At this point we can only speculate what the consequences of the high salt intake may be for CVD and stroke later in life. Regulation of the salt content in processed and fast food and in snacks is advocated, to curtail the salt burden on society imposed by the food industry.

Physical activity, sports participation and aerobic fitness in children who have undergone surgery for congenital heart defects.

AIM: To investigate physical activity, sports participation and aerobic fitness in children who have undergone surgery for congenital heart defects. SUBJECTS AND METHODS: Children who had undergone surgery for congenital heart defects and healthy controls in the Gothenburg area were invited to participate in the study. All participants were aged 9-11 or 14-16 years. The activity monitor ActiReg was used to assess physical activity. Participants were interviewed about their participation in sports and performed a maximal exercise test on a bicycle with measured oxygen uptake. RESULTS: A total of 32 and 25 patients, and 61 and 45 controls, in the two age-groups were included, respectively. The patients had a wide range of severity of congenital heart defects. The physical activity level was similar in the patients and the controls. The rate of sports participation was high for both patients and controls; 80-94% of all participants took part in sports at least once a week. The majority of the patients were considered to have at least a moderate level of aerobic fitness. CONCLUSIONS: Although children who have undergone surgery for congenital heart defects have a similar level of physical activity compared with that of healthy children, some of them may require support to participate in exercise and vigorous physical activity.

The importance of bioavailability of dietary iron in relation to the expected effect from iron fortification.

BACKGROUND: The most common method of combating iron deficiency is iron fortification, especially in developing countries. However, few studies have shown a significant effect on iron status following iron fortification of low bioavailability diets. OBJECTIVE: To investigate how iron fortification and dietary modifications affect iron absorption and rates of changes in iron stores. METHODS: Research has made it possible to predict both iron absorption and the effects of iron fortification and diet modifications on iron stores using recently developed algorithms. Iron absorption and rate of change in iron stores were calculated from nine diets representing a broad range of iron bioavailability and iron contents. The calculations were related to the main target group for iron fortification, that is, women of reproductive age having empty stores but normal haemoglobin concentrations. RESULTS: As the only measure, iron fortification has practically no effect on iron status if the original diet has low bioavailability. However, after dietary modifications such a diet shows a positive effect on iron stores. The combined action of fortification (6 mg/day) and modest bioavailability changes in a low bioavailability diet results approximately in 40 and 70% greater increases in iron stores than through iron fortification or dietary modification alone. CONCLUSIONS: It is difficult to achieve good effects on iron status from iron fortification as the only measure if the diet has low bioavailability. Both dietary modifications as well as iron fortification are required to improve effectively the iron status of a population.

A Paleolithic-type diet results in iodine deficiency: a 2-year randomized trial in postmenopausal obese women.

BACKGROUND/OBJECTIVES: Different diets are used for weight loss. A Paleolithic-type diet (PD) has beneficial metabolic effects, but two of the largest iodine sources, table salt and dairy products, are excluded. The objectives of this study were to compare 24-h urinary iodine concentration (24-UIC) in subjects on PD with 24-UIC in subjects on a diet according to the Nordic Nutrition Recommendations (NNR) and to study if PD results in a higher risk of developing iodine deficiency (ID), than NNR diet. SUBJECTS/METHODS: A 2-year prospective randomized trial in a tertiary referral center where healthy postmenopausal overweight or obese women were randomized to either PD (n=35) or NNR diet (n=35). Dietary iodine intake, 24-UIC, 24-h urinary iodine excretion (24-UIE), free thyroxin (FT4), free triiodothyronine (FT3) and thyrotropin (TSH) were measured at baseline, 6 and 24 months. Completeness of urine sampling was monitored by para-aminobenzoic acid and salt intake by urinary sodium. RESULTS: At baseline, median 24-UIC (71.0 µg/l) and 24-UIE (134.0 µg/d) were similar in the PD and NNR groups. After 6 months, 24-UIC had decreased to 36.0 µg/l (P=0.001) and 24-UIE to 77.0 µg/d (P=0.001) in the PD group; in the NNR group, levels were unaltered. FT4, TSH and FT3 were similar in both groups, except for FT3 at 6 months being lower in PD than in NNR group. CONCLUSIONS: A PD results in a higher risk of developing ID, than a diet according to the NNR. Therefore, we suggest iodine supplementation should be considered when on a PD.

Capturing the onset of the common cold and its effects on iron absorption.

Hypoferremia is a well-known response to infections and inflammatory disorders. It seems to be managed by the key mediator of iron kinetics, hepcidin. There are several studies on induced-acute phase reactions. However, to our best knowledge there are no previous published reports on the outbreak of a common cold and its initial effect on iron kinetics. The objective of this case report is to describe such an observation. From an apparently healthy state in the morning we observed, in a 28-year-old male, every hour for 6 h the outbreak of a common cold and the modulations in the levels of serum iron (S-Fe) and interleukin-6 (IL-6). Despite a 100 mg oral iron loading there was a substantial reduction in S-Fe, which seemed to precede the IL-6 peak. Interestingly, this observed succession is in conflict with the proposed infection chain of order in which IL-6 stimulates hepcidin induction.

Energy expenditure in underweight chronic obstructive pulmonary disease patients before and during a physiotherapy programme.

OBJECTIVE: To investigate how total daily energy expenditure (TEE) changes when underweight patients with chronic obstructive pulmonary disease (COPD) enters a physiotherapy programme. DESIGN: Prospective intervention study. SETTING: Sahlgrenska University Hospital, Göteborg, Sweden. SUBJECTS: Fifteen patients with severe COPD and BMI<21 kg/m(2) were recruited consecutively at the outpatient COPD unit at the Department of Respiratory Medicine. Fourteen patients completed the whole study. INTERVENTION: TEE was assessed by the doubly labelled water method in a 2-week control period and during 2 weeks of physiotherapy. Energy intake was assessed using 7-day dietary record during control and physiotherapy period. RESULTS: Mean TEE during physiotherapy period was 500 kJ (6%) lower than during control period but the difference was not statistically significant. Ten of the 14 patients had lower and four had higher TEE. Mean energy intake during the physiotherapy period did not change from the control period (7700 vs 7600 kJ/day). CONCLUSIONS: Since underweight patients with COPD may show variable TEE during physiotherapy compared to a control period, an assessment of individual energy requirements is recommended.

Physical activity questionnaire for adolescents validated against doubly labelled water.

OBJECTIVE: To validate a physical activity questionnaire for adolescents (PAQA) adapted from the International Physical Activity Questionnaire (IPAQ). DESIGN: Energy expenditure was measured during a 14-day period with doubly labelled water (DLW). PAQA was administered as an interview at the end of the period, asking for physical activity in school, during transportation and leisure-time, during a habitual week. Energy expenditure (EE(PAQA)) was calculated as the product of total physical activity + sleep and predicted resting metabolic rate, and was compared to energy expenditure from DLW (EE(DLW)), thermic effect of feeding excluded. SETTING: Participants were recruited from grade 9 in a compulsory school in Göteborg, Sweden. All data were collected at school, and distribution of DLW and measuring of resting metabolic rate were performed at Sahlgrenska University Hospital. SUBJECTS: A total of 33 adolescents (16 girls, 17 boys) 15.7 (0.4) y performed all measurements. RESULTS: : For the whole group, PAQA underestimated energy expenditure by 3.8 (1.7) MJ (P<0.001). There was a strong correlation (r = 0.62, P<0.001) between EE(PAQA) and EE(DLW), but not for boys (r = 0.42, P = 0.090) and girls (r = 0.33, P = 0.22) separately. CONCLUSIONS: PAQA is not able to predict energy expenditure in Swedish adolescents, largely explained by the amount of unreported time. The ability to rank adolescents energy expenditure is questioned because of the gender effect, although we found a strong correlation for the whole group.

Comparison of food habits, iron intake and iron status in adolescents before and after the withdrawal of the general iron fortification in Sweden.

BACKGROUND/OBJECTIVES: Sifted flour was fortified with carbonyl iron for 50 years in Sweden. This study evaluates changes in food habits, intake of iron, factors affecting iron absorption and iron status after the discontinuation of the general iron fortification in adolescents with the highest requirements. SUBJECTS/METHODS: A total of 2285 15- to 16-year-old students in 1994 (634 girls and 611 boys) and in 2000 (534 girls and 486 boys) in 13 schools in Gothenburg, Sweden, were included in two cross-sectional surveys assessing food habits with diet history interviews and iron deficiency defined with serum ferritin stores ⩽ 15 µg/l and no preceding infection. RESULTS: In girls, iron deficiency increased from 37 to 45%, while in boys, it was stable at 23%. Total iron intake decreased from 15.7 to 9.5 mg/day and 22.5 to 13.9 mg/day in girls and boys, respectively. Cereals were the main iron source. Among girls, the increase of fish and decrease of calcium intake may not counteract the effect of decreased intake of fortification iron. Among boys, more meat, less calcium and more vitamin C may have favoured the bioavailability of iron. CONCLUSIONS: The discontinuation of the general iron fortification resulted in a 39% decrease in total iron intake and iron deficiency increased substantially in girls. However, in boys no change in iron deficiency was observed. Whether this was a result of changed bioavailability of dietary iron or simultaneous changes of non-dietary factors remains to be explored.

Nutrition impact symptoms and body composition in patients with COPD.

BACKGROUND/OBJECTIVES: Anorexia or lack of appetite is common in chronic obstructive pulmonary disease (COPD) and may be caused or augmented by several symptoms affecting appetite and eating. We aimed to investigate and quantify the extent of nutrition impact symptoms (NIS) in patients with COPD and to explore relationships between NIS and fat-free mass depletion. SUBJECTS/METHODS: The results in this cross-sectional study are based on 169 COPD patients (62% female subjects). Body composition was assessed using bioelectrical impedance spectroscopy and the patients reported NIS by two newly developed questionnaires: the Eating Symptoms Questionnaire (ESQ) and the Disease-Related Appetite Questionnaire (DRAQ). RESULTS: Symptoms with the highest prevalence were dry mouth (71%), stomach ache (39%), pain or aches affecting appetite (36%) and constipation (35%). Problems with diarrhoea and feeling affected by smells were more severe among women compared with men (P<0.05). Thirty-six percent of the patients were depleted (fat-free mass index (FFMI) <15 kg/m2 for women and FFMI<16 kg/m2 for men). Depleted patients had more NIS (P<0.05) and also rated appetite and taste of food as worse compared with non-depleted patients (P<0.05). CONCLUSIONS: NIS are common in patients with COPD, and depleted patients have more severe symptoms. To investigate how these symptoms are best prevented and/or managed and whether NIS prevention/treatment can affect development of malnutrition in patients with COPD is a challenge for the future.

GH is needed for the maturation of muscle mass and strength in adolescents.

The postpubertal period and the early years of adulthood may be of importance for continuing tissue maturation of importance in adulthood and aging. An example of this is the peak bone mass. This study has evaluated the importance of GH for lean mass and muscle strength in adolescents and young adults. GH treatment was discontinued in 40 adolescents aged 16-21 yr with GH deficiency of childhood onset. Measurements of isometric and isokinetic knee-extensor and flexor strength, handgrip strength, lean body mass, fat-free mass, and total body nitrogen were performed annually for 2 yr. Two hundred fifty healthy adolescents were randomly selected for prospective measurements of lean mass and handgrip strength between the ages of 17 and 21 yr. In the adolescents with continuing GH deficiency, lean body mass decreased, compared with the patients defined as having sufficient endogenous GH. The isometric strength in knee flexors increased in the sufficient endogenous GH group and was unchanged in the GH deficiency group during the 2 yr off GH treatment (between group, P < 0.05). The mean and peak handgrip strength increased on average by 9-15% in the group with sufficient endogenous GH and was unchanged in those with GH deficiency (P < 0.05). Lean body mass and handgrip strength (both, P < 0.001) increased in both the healthy boys and girls who were followed for 4 yr with a more marked increase in the boys. The mean increase in handgrip between the age of 17 and 21 yr was 7-9%. The increased lean mass and improved muscle performance seen in healthy adolescents did not occur in adolescents with GH deficiency. These findings suggest that GH is of importance for the maturation of lean mass and muscle strength in adolescents and young adults.

Antihypertensive and renal effects of captopril in relation to renin activity and bradykinin-induced vasodilation.

The effect of captopril on blood pressure and renal hemodynamics in relation to plasma renin activity (PRA) was assessed together with the vasodilator responses to brachial artery infusions of bradykinin (BK) and sodium nitroprusside (NP) before and after 4 wk of therapy with doses of up to 450 mg/day in patients with essential hypertension. The average blood pressure reduction of captopril was from 174.4/110.6 to 155.3/96.6 mm Hg (n = 12, P less than 0.001) without increases in heart rate or body weight. It was effective in the eight patients with normal renin, but showed little effect in the four with a low renin. There was a correlation between the changes in blood pressure after captopril and the pretreatment PRA (r = -0.82, P less than 0.01 for mean pressure). Brachial artery infusions of BK and NP induced dose-dependent rises in forearm blood flow (FBF), but this was not related to the captopril blood pressure-lowering effect. Repeat measurements during captopril therapy showed a shift to the left of the BK/FBF, but not of the NP/FBF, dose-response curve, indicating effective vascular kininase II inhibition. Captopril decreased renal vascular resistance. Our data are compatible with the view that captopril's antihypertensive action mainly involves blockade of the renin-angiotensin-aldosterone system and not cumulation of BK. The favorable effects on renal hemodynamics and the lack of tachycardia and volume retention after captopril make it a valuable drug for the treatment of hypertension.

Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability of dietary iron.

BACKGROUND: Dietary iron absorption from a meal is determined by iron status, heme- and nonheme-iron contents, and amounts of various dietary factors that influence iron absorption. Limited information is available about the net effect of these factors. OBJECTIVE: The objective was to develop an algorithm for predicting the effects of factors known to influence heme- and nonheme-iron absorption from meals and diets. DESIGN: The basis for the algorithm was the absorption of iron from a wheat roll (22.1 +/- 0.18%) containing no known inhibitors or enhancers of iron absorption and adjusted to a reference dose absorption of 40%. This basal absorption was multiplied by the expected effect of different amounts of dietary factors known to influence iron absorption: phytate, polyphenols, ascorbic acid, meat, fish and seafood, calcium, egg, soy protein, and alcohol. For each factor, an equation describing the dose-effect relation was developed. Special considerations were made for interactions between individual factors. RESULTS: Good agreement was seen when measurements of iron absorption from 24 complete meals were compared with results from use of the algorithm (r(2) = 0.987) and when mean iron absorption in 31 subjects served a varied whole diet labeled with heme- and nonheme-iron tracers over a period of 5 d was compared with the mean total iron absorption calculated by using the algorithm (P = 0.958). CONCLUSIONS: This algorithm has several applications. It can be used to predict iron absorption from various diets, to estimate the effects expected by dietary modification, and to translate physiologic into dietary iron requirements from different types of diets.

Bioelectrical impedance: effect of 3 identical meals on diurnal impedance variation and calculation of body composition.

BACKGROUND: Bioelectrical impedance analysis (BIA) can be used for estimating body composition. Earlier studies showed that the ingestion of meals lowers bioelectrical impedance, but none studied the effect of repeated ingestion of an identical meal in narrow intervals on impedance measurements during 24 h. OBJECTIVES: The objectives were to study the effect on bioelectrical impedance of 3 identical meals and to compare the results from single-frequency BIA measurements with those from multiple-frequency BIA measurements. DESIGN: Bioelectrical impedance was measured 18 times during 24 h in 18 healthy subjects [10 women and 8 men; x +/- SD age: 31.5 +/- 11.7 y; body mass index (in kg/m(2)): 22.2 +/- 2.7]. An identical meal was given at breakfast, lunch, and dinner. RESULTS: Bioelectrical impedance decreased after ingestion of a standard meal (P < 0.05). The decrease in impedance lasted 2-4 h after each meal. The decrease was additive during the day, although it was more pronounced after the first meal because of the combined effect of rising from the supine position and meal ingestion. This is an important consideration when calculating body composition: percentage of body fat varied by 8.8% from the highest to the lowest measurement in women and by 9.9% from the highest to the lowest measurement in men. The bioelectrical impedance at 50 kHz was identical when measured with multiple frequencies or a single frequency. CONCLUSION: The ingestion of meals leads to an additive decrease in bioelectrical impedance and thus to a decrease in the calculated percentage of body fat.

Iron fortification of flour with a complex ferric orthophosphate.

The unexpectedly low bioavailability in humans of elemental iron powder prompted us to search for other Fe compounds suitable for Fe fortification of flour that fulfill the two requirements of insolubility in water (due to high water content of flour) and good bioavailability in humans. Systematic studies of compatibility, solubility, and bioavailability led to this study of a microcrystalline complex ferric orthophosphate (CFOP), Fe3H8(NH4)-(PO4)6.6H2O, a well-defined compound. This compound was labeled with 59Fe, and the native Fe in meals was labeled with 55FeCl3. The ratio of absorbed 59Fe to absorbed 55Fe is a direct measure of the fraction of CFOP that joins the nonheme Fe pool and that is made potentially available for absorption. The relative bioavailability of CFOP varied from 30% to 60% when labeled wheat rolls were served with different meals. The CFOP meets practical requirements of an Fe fortificant for flour well, with regard to both compatibility and bioavailability in humans.

Iron absorption from the whole diet: comparison of the effect of two different distributions of daily calcium intake.

The possibility of reducing calcium inhibition of iron absorption by decreasing calcium intake in lunch and dinner meals, which provided the most dietary iron, was examined in 21 healthy female volunteers. During a 10-d period, nonheme iron in all meals was extrinsically labeled with radioisotopic iron to a uniform specific activity. Iron absorption from two identical 10-d periods was compared when meals were labeled with two different iron radioisotopes and when the same amount of calcium (937 mg) was distributed in two ways, in either mainly breakfast and late evening meals or more evenly in all meals. About 30-50% more iron was absorbed when no milk or cheese was served with lunch or dinner. The difference was statistically significant. Median iron requirements (1.61 mg/d) calculated from body weight and menstrual iron losses agreed with the mean value of median iron absorption in the two 10-d periods (1.54 mg/d), which supports the validity of the present method. A reasonable separation of calcium and iron intakes would improve iron nutrition.

Inositol phosphates with different numbers of phosphate groups influence iron absorption in humans.

BACKGROUND: Inositol hexaphosphate (IP(6)) is a well-known inhibitor of iron absorption, whereas the effects of the less-phosphorylated derivatives of IP(6) are less known. OBJECTIVES: The objective was to investigate the effects of inositol tri-, tetra-, and pentaphosphates (IP(3), IP(4), and IP(5), respectively) on iron absorption in humans. DESIGN: Iron absorption was measured in 5 experiments from single meals by extrinsic labeling with (55)Fe and (59)Fe and determination of whole-body retention and the erythrocyte uptake of isotopes. In experiments 1-3 the meals contained white-wheat rolls to which 10 mg P as IP(5), IP(4), or IP(3), respectively, was added. Inositol 1,2,6-triphosphate [Ins(1,2, 6)P(3)] and a mixture of isomers of IP(4) and IP(5) were studied. White-wheat rolls contained 10 mg P as IP(3) + IP(4) and 2 mg P as IP(5) + IP(6) in experiment 4 and 20 mg P as IP(3) + IP(4) and 3 mg P as IP(5) + IP(6) in experiment 5; inositol phosphates were obtained via fermentation of sodium phytate. Each experiment had 8-11 subjects. RESULTS: In experiment 1, iron absorption was reduced by 39%, whereas there was no significant effect on iron absorption in experiments 2 and 3. In experiments 4 and 5, iron absorption was reduced by 54% and 64%, respectively, suggesting that IP(3) and IP(4) contributed to the inhibitory effect. CONCLUSIONS: IP(5) has an inhibitory effect on iron absorption, whereas IP(3) and IP(4) in isolated form have no such effect. IP(3) and IP(4) in processed food contribute to the negative effect on iron absorption, presumably by binding iron between different inositol phosphates. To improve iron absorption from cereals and legumes, degradation of inositol phosphates needs to be to less-phosphorylated inositol phosphates than IP(3).

Blood pressure and hypertension in middle-aged women in relation to weight and length at birth: a follow-up study.

OBJECTIVES: To examine the relationship between indicators at birth and adult blood pressure and risk for developing hypertension at two age levels. DESIGN: Original midwife records of 438 women born at term participating in a prospective population study in Göteborg, Sweden with blood pressure and hypertension assessment at both 50 and 60 years of age. RESULTS: Systolic blood pressure at both age levels showed a U-shaped relationship to weight and length at birth. Hypertension prevalence at 60 years was significantly and inversely related to both weight and length at birth, but not at 50 years. Significantly higher risk for hypertension was found in the lowest birth weight quintile [odds ratio (OR) = 2.0, 95% confidence interval (CI) 1.1-3.8] and lowest birth length tertile (OR = 1.8, 95% CI 1.1-3.0), in relation to the middle quintile/tertile, with or without adjustment for adult body size (as body mass index), at 60 years but not at 50 years. At 50 years, hypertension risk decreased by 3% (95% CI 0.92-1.01) for every 100 g increase in birth weight and 6% (95% CI 0.83-1.05) per cm birth length. At age 60 years, hypertension risk decreased by 4% (95% CI 0.92-0.99) per 100 g birth weight and 10% (95% CI 0.81-0.99) per cm length. CONCLUSIONS: Size at birth was a predictor of hypertension risk in women at 60 years but not 50 years. This study supports the hypothesis that poor fetal growth, as measured by low weight or length at birth, may contribute to the development of hypertension in later life and that this relationship became stronger with age.

Is there a physiological role of vitamin C in iron absorption?

Nonheme iron usually constitutes more than 90% of the dietary iron. Its absorbability is a resultant of the balance between factors enhancing and inhibiting the absorption. Ascorbic acid is the most potent enhancer, and is the same for native and synthetic AA. The enhancing effect is strongly dose related (log dose/effect), and is different for different meals probably mainly due to varying content of inhibitors in the meals. AA also increases the iron absorption from simple meals with no known inhibitor, probably because AA impairs the formation of unavailable iron complexes with ligands normally present in the gastrointestinal lumen. The effect of AA is so unequivocal and marked that it must be considered as a physiological factor essential for the absorption of dietary iron.