Black men are known to have a higher risk for prostate cancer (PC). Carotenoids and retinol, linked to PC, have not been compared in different black populations at risk. We examined serum carotenoid and retinol levels between PC-free African-Caribbean (AC) Tobagonian men with a high PC risk (high-grade prostatic intraepithelial neoplasia, atypical foci or repeated abnormal PC screenings) and African-American (AA) men with elevated serum prostate-specific antigen (PSA) levels (≥4 ng/ml). AC men who participated in the 2003 lycopene clinical trial and AA men who participated in the 2001–2006 National Health and Nutrition Examination Survey were compared. Serum specimens were analysed for carotenoid (β-carotene, α-carotene, β-cryptoxanthin, lutein/zeaxanthin and lycopene) and retinol levels by isocratic HPLC. Quantile regression was used to examine the association between serum carotenoid and retinol levels and black ethnicity, overall and among men with elevated serum PSA. There were sixty-nine AC men and sixty-five AA men, aged 41–79 years, included. AC men were associated with lower serum lycopene and retinol levels, and higher serum α- and β-carotenes and lutein/zeaxanthin levels compared with AA men, after adjusting for age, BMI, ever smoked cigarettes, education and hypertension (P≤0·03). Among men with elevated PSA, serum retinol was no longer statistically significant with ethnicity (P=0·06). Possible differences may be attributed to dietary intake, genetics and/or factors that influence bioavailability of these micronutrients. Prospective studies are warranted that investigate whether these differences in micronutrients between AC Tobagonian and AA men influence PC risk.

This research evaluates the prevalence of inadequate folate status in early pregnancy, the pattern of prenatal folic acid (FA) supplementation and associated factors in Spanish pregnant women from the ECLIPSES study, which included 791 participants prior gestational week 12. A cross-sectional evaluation of erythrocyte folate levels was performed at recruitment and used to calculate the prevalence of folate deficiency (erythrocyte folate < 340 nmol/l) and insufficiency (erythrocyte folate < 906 nmol/l). Sociodemographic and lifestyle data as well as information on prenatal FA supplementation were recorded. Descriptive and multivariate statistical analyses were performed. The prevalence of folate deficiency and insufficiency were 9·6 % and 86·5 %, respectively. Most of women used prenatal FA supplements, but only 6·3 % did so as recommended. Supplementation with FA during the periconceptional period abolished folate deficiency and reduced folate insufficiency. Prenatal FA supplementation with ≥1000 µg/d in periconceptional time and pregnancy planning increased erythrocyte folate levels. The main risk factor for folate insufficiency in early pregnancy was getting prenatal FA supplementation out of the periconceptional time (OR 3·32, 95 % CI 1·02, 15·36), while for folate deficiency they were young age (OR 2·02, 95 % CI 1·05, 3·99), and smoking (OR 2·39, 95 % CI 1·30, 4·37). In addition, social and ethnic differences according to folate status were also identified. As conclusion, periconceptional FA use is crucial for achieving optimal folate levels in early pregnancy. Pregnancy planning should focus on young women, smokers, those with low consumption of folate-rich foods, low socio-economic status or from ethnic minorities.

Air displacement plethysmography (ADP) has been considered as the ‘standard’ method to determine body fat in children due to superior validity and reliability compared with bioelectrical impedance analysis (BIA). However, ADP and BIA are often used interchangeably despite few studies comparing measures of percentage body fat by ADP (%FMADP) with BIA (%FMBIA) in children with and without obesity. The objective of this study was to measure concurrent validity and reliability of %FMADP and %FMBIA in 6-to-12-year-old boys with and without obesity. Seventy-one boys (twenty-five with obesity) underwent body composition assessment. Ten boys participated in intra-day reliability analysis. %FMADP was estimated by Bodpod using sex- and age-specific equations of body density. %FMBIA was estimated by a multi-frequency, hand-to-foot device using child-specific equations based on impedance. Validity was assessed by t tests, correlation coefficients and limits of agreement (LoA); and reliability by technical error of measurement (TEM) and intraclass correlation coefficients (ICC). Compared with %FMADP, %FMBIA was significantly underestimated in the cohort (–3·4 ± 5·6 %; effect size = 0·42) and in both boys with obesity (–5·2 ± 5·5 %; ES = 0·90) and without obesity (–2·4 ± 5·5 %; ES = 0·52). A strong, significant positive correlation was found between %FMADP and %FMBIA (r = 0·80). Across the cohort, LoA were 22·3 %, and no proportional bias was detected. For reliability, TEM were 0·65 % and 0·55 %, and ICC were 0·93 and 0·95 for %FMBIA and %FMADP, respectively. Whilst both %FMADP and %FMBIA are highly reliable methods, considerable differences indicated that the devices cannot be used interchangeably in boys age 6-to-12 years.

1. Twelve young men were given for periods of 20 d, each of three mixed diets, namely a low-protein (LP) diet (9% total energy as protein, 67% of animal origin), a high-animal-protein (HA) diet (16% total energy as protein, 67% of animal origin) and a high-vegetable-protein (HV) diet (16% total energy as protein, 67% of vegetable origin). Retention of calcium, magnesium, iron, zinc and copper as well as various bowel function indices were investigated during each dietary period.

2. Neither the HA diet nor the HV diet changed the retention of the minerals considerably. Only Fe balance decreased significantly on the HV diet.

3. Substituting the HV diet for the HA diet resulted in significant increases in faecal wet weight (17 g/d), defaecation frequency (0.12 stools/d), faecal volatile fatty acids (2.6 mmol/d) and a decrease in faecal bile acids (128 μmol/d).

4. It is concluded that a HV diet, rather than a HA diet is to be recommended with respect to bowel function, whereas the HV diet does not necessarily have a significant influence on mineral retention.

The ongoing Coronavirus disease 19 (Covid-19) pandemic and associated mortality in children led to an effort to address risk factors and develop protective measures. Observational studies in adults showed that vitamin D deficiency is associated with Covid-19 severity. The aim of this review was to summarise data regarding the role of serum vitamin 25(OH)D concentration in the severity of Covid-19 and the associated multisystem inflammatory syndrome in children (MIS-C). Many studies noted lower concentrations of vitamin 25(OH)D in children with Covid-19 compared with healthy controls; however, studies that assessed vitamin 25(OH)D suboptimal concentrations as a risk factor for Covid-19 severity were scarce. There was no high-quality evidence that vitamin 25(OH)D concentrations are associated with Covid-19 severity. Similarly, for MIS-C, a few studies with a small number of patients found that vitamin D deficiency was associated with more severe MIS-C. Vitamin D has many immunomodulatory actions and is consumed in the immunomodulatory cells, especially in infections such as the Covid-19 which is associated with increased inflammation and cytokine storm. Therefore, decreased concentrations of plasma vitamin 25(OH)D have been proposed to be the result of vitamin use by immunomodulatory cells in severe Covid-19, rather than a predisposing factor. In conclusion, the available data cannot prove that vitamin D deficiency is a risk factor for severe Covid-19 disease. More studies, of prospective design, are needed to investigate the role of this marker independently of other risk factors.

Previous studies have reported inconsistent associations between low-carbohydrate diets (LCD) and plasma lipid profile. Also, there is little evidence on the role of the quality and food sources of macronutrients in LCD in cardiometabolic health. We investigated the cross-sectional associations between LCD and plasma cardiometabolic risk markers in a nationwide representative sample of the US population. Diet was measured through two 24-h recalls. Overall, healthy (emphasising unsaturated fat, plant protein and less low-quality carbohydrates) and unhealthy (emphasising saturated fat, animal protein and less high-quality carbohydrate) LCD scores were developed according to the percentage of energy as total and subtypes of carbohydrate, protein and fat. Linear regression was used to estimate the percentage difference of plasma marker concentrations by LCD scores. A total of 34 785 participants aged 18–85 years were included. After adjusting for covariates including BMI, healthy LCD was associated with lower levels of insulin, homoeostatic model assessment for insulin resistance (HOMA-IR), C-reactive protein (CRP) and TAG, and higher levels of HDL-cholesterol, with the percentage differences (comparing extreme quartile of LCD score) of −5·91, −6·16, −9·13, −9·71 and 7·60 (all P trend < 0·001), respectively. Conversely, unhealthy LCD was associated with higher levels of insulin, HOMA-IR, CRP and LDL-cholesterol (all P trend < 0·001). Our results suggest that healthy LCD may have positive, whereas unhealthy LCD may have negative impacts on CRP and metabolic and lipid profiles. These findings underscore the need to carefully consider the quality and subtypes of macronutrients in future LCD studies.

In the early 1930s, after obtaining her PhD on the carbohydrates in apples, Dr Elsie Widdowson embarked on a postgraduate course in dietetics at King’s College of Household and Social Science, London. During the hospital training element of this course at St Bartholomew’s Hospital, she was appalled at the inaccuracy of the food compositional data being used to formulate medically-prescribed diets. She resolved to change matters, and after she had joined Dr McCance’s team she realized that they had already obtained sufficient new analytical data on the majority of the food groups to form the basis of completely new tables.

We assessed the effectiveness of lyophilised banked human milk (HM) as a fortifier to feed very-low-birth-weight infants (VLBWI). This study aimed to evaluate the safety and tolerability of HM with HM lyophilisate as an additive compared with the standard additive (cows’ milk protein). In this phase I double-blind randomised controlled clinical trial, set in the intensive and intermediate care units of a tertiary hospital, forty VLBWI were enrolled and allocated into two groups: HM plus HM lyophilisate (LioNeo) or HM plus commercial additive (HMCA). The inclusion criteria were preterm infants, birth weight 750–1500 g, small or adequate for gestational age, exclusively receiving donor HM, volume ≥ 100 ml/kg per d and haemodynamically stable. Participants were followed up for 21 consecutive days. The primary outcome measures were necrotising enterocolitis (NEC), late-onset sepsis (LOS), death, gastrointestinal (GI) bleeding or perforation, diarrhoea, regurgitation, vomiting and abdominal distension. The LioNeo and HMCA groups had similar weights at baseline. The regression models showed no differences between the groups in terms of the primary outcomes. Diarrhoea, GI perforation, NEC and LOS were absent in the LioNeo group (one LOS and one NEC in the HMCA group). Multiple regression analysis with the total volume of milk as a covariate did not show significant differences. The lyophilisation of donor HM was considered safe and tolerable for use in stable haemodynamically VLBWI.

The peptide hormone hepcidin functions as a negative regulator of intestinal Fe absorption and Fe recycling. Since its discovery as a systemic negative regulator of Fe metabolism, hepcidin has attracted enormous interest as a potential drug for the treatment and/or prevention of several forms of Fe overload. We therefore tested whether multiple doses of intraperitoneally administered synthetic renatured hepcidin can prevent hepatic Fe loading in mice concurrently fed an Fe-rich diet, and whether the same treatment affects hepatic Fe stores in mice fed a normal diet. Cohorts of male mice were fed either a normal defined diet (180 parts per million Fe) or an Fe-rich diet (the same diet supplemented with 2 % carbonyl iron for 2 weeks). Concurrently, half of the animals in each diet group received 100 μg of renatured hepcidin intraperitoneally every 12 h, for the same 2-week period. The second half of the animals received PBS only. The renatured synthetic hepcidin demonstrated biological activity by significantly decreasing transferrin saturation, which lasted for up to 24 h after a single hepcidin dose. However, the 14 d intraperitoneal hepcidin therapy did not prevent hepatic Fe overload in mice fed the Fe-rich diet, nor did it affect hepatic Fe stores in mice fed the normal diet. Both hepcidin agonists and antagonists are expected to have broad therapeutic potential. The absence of an effect of biologically active hepcidin on hepatic Fe loading shows the need for thorough future studies on the hepcidin regulation of Fe absorption and tissue distribution.

1. The metabolism of dehydroretinyl ester has been studied in vitamin-A-deficient white leghorn chicks. Dehydroretinyl ester was metabolized to 3-hydroxyretinol diester, 3-hydroxyanhydroretinol and rehydrovitamin A2 which were isolated from the intestines and livers of chicks.

2. The metabolism of 3-hydroxyretinol diester and 3-hydroxyanhydroretinol, which were immediate metabolites of dehydroretinol, was studied in chicks.

3. Retinol was not detected in these experiments.

1. The kidneys of normal rats were analysed for water, fat, protein, RNA and DNA, at 10, 21 and 36 d after birth. The effects on growth caused by two types of malnutrition were investigated.

2. An increase in the RNA:DNA ratio was demonstrated between 10 and 36 d, contrary to previous evidence that this ratio is fixed at birth.

3. Energy deficiency during the first 21 d of life resulted mainly in fewer kidney cells, whereas protein-energy deficiency between 21 and 36 d resulted mainly in a smaller cellular content of RNA and protein.

4. In response to metabolic acidosis, both groups of malnourished rats increased urinary excretion of ammonia and there was enhanced gluconeogenesis in vitro; the basal rate of gluconeogenesis was lower in the protein-energy-deficient rats than in the controls.

5. Protein-energy-deficient rats did not exhibit the renal hypertrophy shown by the control rats in response to acidosis.

No risk assessment tools for the efficacy of folic acid treatment for hyperhomocysteinaemia (HHcy) have been developed. We aimed to use two common genetic risk score (GRS) methods to construct prediction models for the efficacy of folic acid therapy on HHcy, and the best gene–environment prediction model was screened out. A prospective cohort study enrolling 638 HHcy patients was performed. We used a logistic regression model to estimate the associations of two GRS methods with the efficacy. Performances were compared using area under the receiver operating characteristic curve (AUC). The simple count genetic risk score (SC-GRS) and weighted genetic risk score (wGRS) were found to be independently associated with the efficacy of folic acid treatment for HHcy. Using the SC-GRS, per risk allele increased with a 1·46-fold increased failure risk (P < 0·001) after adjustment for traditional risk factors, including age, sex, BMI, smoking, alcohol consumption, history of diabetes, history of hypertension, history of hyperlipidaemia, history of stroke and history of CHD. When used the wGRS, the association was strengthened (OR = 2·08, P < 0·001). Addition of the SC-GRS and wGRS to the traditional risk model significantly improved the predictive ability by AUC (0·859). A precise gene–environment predictive model with good performance was developed for predicting the treatment failure rate of folic acid therapy for HHcy.

1. Nutritional factors affecting the urinary excretion of acid-soluble peptides (ASP) were studied in rats. The ratio, total urinary nitrogen: ASP-form leucine + valine was lowest in the rats fed on a protein-free diet and increased as retained N: absorbed N decreased. The ratio was not affected by dietary protein level when the level was below the National Research Council (1978) recommended requirement, but increased greatly when it exceeded the recommended requirement.

2. The excretion of ASP-form leucine + valine per kg body-weight was significantly lower in the protein- deficient rats than in those fed on protein-adequate diets. This variable decreased during the stage of rapid growth, but did not change as markedly after the onset of adolescence. It increased again when the rats became older. The patterns of change in the rate of excretion of ASP-form amino acids during growth and that of Nr-methylhistidine were different.

3. When labelled amino acids were injected into rats, the largest amount of the ASP-form label was excreted on the 1st day of injection. From the 2nd day the excretion of ASP-form label decreased exponentially.

4. The findings suggest that the rate of urinary excretion of ASP-form amino acids can be employed as an index of protein metabolism, particularly as a simple index of the assessment of the status of protein nutrition.