Vitamin D deficiency has previously been linked to higher rates of exacerbation and reduced lung function in asthmatics. Previous randomised controlled trials investigating the effect of vitamin D supplementation have mainly focused on children with asthma. Trials involving adults have typically used bolus dosing regimens, and the main outcomes have been patient-focused without investigating underlying inflammation. The present study aimed to conduct a 12-week placebo-controlled randomised controlled trials administering a daily 125 µg vitamin D3 supplement to adults with mild to moderate asthma. A total of 32 participants were randomised to receive either the 125 μg vitamin D3 supplement or an identical matching placebo. The primary outcome of the study was lung function measured by the ratio of FEV1:FVC (effect size 2·5) with secondary outcomes including asthma symptoms and inflammatory biomarkers. There was a small but statistically significant higher increase in the mean (±sd) ratio of FEV1:FVC from baseline to post-intervention in the vitamin D group (+0·05 ± 0·06) compared with the placebo group (+0·006 ± 0·04, P = 0·04). There was no effect of the intervention on asthma control test scores, or the inflammatory biomarkers measured. There was a moderate, significant association between baseline plasma 25(OH)D concentration and baseline plasma IL-10 (r = 0·527, P = 0·005) and TNF-α (r = −0·498. P = 0·008) concentrations. A daily vitamin D3 supplement led to slightly improved lung function in adult asthmatics and may be a useful adjunct to existing asthma control strategies, particularly for individuals with suboptimal vitamin D status.

The aim of this review paper is to explore the strategies employed to tackle micronutrient deficiencies with illustrations from field-based experience. Hidden hunger is the presence of multiple micronutrient deficiencies (particularly iron, zinc, iodine and vitamin A), which can occur without a deficit in energy intake as a result of consuming an energy-dense, but nutrient-poor diet. It is estimated that it affects more than two billion people worldwide, particularly in low- and middle-income countries where there is a reliance on low-cost food staples and where the diversity of the diet is limited. Finding a way to improve the nutritional quality of diets for the poorest people is central to meeting the UN sustainable development goals particularly sustainable development goal 2: end hunger, achieve food security and improved nutrition and promote sustainable agriculture. As we pass the midpoint of the UN's Decade for Action on Nutrition, it is timely to reflect on progress towards achieving sustainable development goal 2 and the strategies to reduce hidden hunger. Many low- and middle-income countries are falling behind national nutrition targets, and this has been exacerbated by the COVID-19 pandemic as well as other recent shocks to the global food system which have disproportionately impacted the world's most vulnerable communities. Addressing inequalities within the food system must be central to developing a sustainable, cost-effective strategy for improving food quality that delivers benefit to the seldom heard and marginalised communities.

EPA and DHA are required for normal cell function and can also induce health benefits. Oily fish are the main source of EPA and DHA for human consumption. However, food choices and concerns about the sustainability of marine fish stocks limit the effectiveness of dietary recommendations for EPA + DHA intakes. Seed oils from transgenic plants that contain EPA + DHA are a potential alternative source of EPA and DHA. The present study investigated whether dietary supplementation with transgenic Camelina sativa seed oil (CSO) that contained EPA and DHA was as effective as fish oil (FO) in increasing EPA and DHA concentrations when consumed as a dietary supplement in a blinded crossover study. Healthy men and women (n 31; age 53 (range 20–74) years) were randomised to consume 450 mg/d EPA + DHA provided either as either CSO or FO for 8 weeks, followed by 6 weeks washout and then switched to consuming the other test oil. Fasting venous blood samples were collected at the start and end of each supplementation period. Consuming the test oils significantly (P < 0·05) increased EPA and DHA concentrations in plasma TAG, phosphatidylcholine and cholesteryl esters. There were no significant differences between test oils in the increments of EPA and DHA. There was no significant difference between test oils in the increase in the proportion of erythrocyte EPA + DHA (CSO, 12 %; P < 0·0001 and FO, 8 %; P = 0·02). Together, these findings show that consuming CSO is as effective as FO for increasing EPA and DHA concentrations in humans.

Chronic heat stress (CHS) exposure negatively impairs avian’ immunoneuroendocrine interplay. Thymol has shown several bioactive properties including antioxidant, bactericidal, antifungal and gamma-aminobutyric acid modulator activities. Indeed, supplementation with thymol has been used with positive effects on poultry production and immune-related variables. This study evaluates whether a thymol dietary supplementation can be used as a new functional feed strategy to mitigate CHS deleterious effects on endocrine, biochemical and immune-related variables. Starting at 100 days of age, 24 fully adult Japanese quail were fed with a diet supplemented with thymol (≈80 mg/quail per day) and other 24 quail remained non-supplemented (control diet). Between 119 and 127 days of age, half of the quail within those groups were submitted to a CHS by increasing environmental temperature from 24°C to 34°C during the light phase and the other half remained at 24°C (non-stressed controls). A period of 3 days after CHS ended (during the recovery period), corticosterone, albumin, total proteins and globulins and glucose concentrations, inflammatory response, antibody production and heterophil to lymphocyte (H/L) ratio were assessed. No differences between groups were found in basal corticosterone concentrations. Total proteins, total globulins and glucose concentrations were found elevated in the previously CHS group compared with their control counterparts. Regardless of the previous CHS exposure, thymol supplementation increased albumin concentrations and inflammatory responses and decreased antibody titers. An interaction between thymol supplementation and prior CHS exposure was found on the H/L ratio. Quail previously exposed to CHS and supplemented with thymol showed similar H/L values than their control non-stressed counterparts, suggesting that thymol has a stress preventive effect on this variable. The present findings together with the already reported thymol bioactive properties, suggest that feed supplementation with this compound could be a useful strategy to help overcoming some of the CHS induced alterations.

We evaluated the effect of maternal vitamin E supplementation on the α-tocopherol concentrations of colostrum, transitional milk and mature milk of women who had given birth prematurely. This longitudinal randomised-controlled trial divided eighty-nine women into two groups: a control group and a supplemented group. Blood and breast milk were collected from all the participants after delivery. Next, each woman in the supplemented group received 400 IU of RRR-α-tocopheryl acetate. Further breast milk samples were collected 24 h after the first collection, as well as 7 and 30 d after delivery. α-Tocopherol concentrations were determined by HPLC. The baseline α-tocopherol concentrations in the maternal serum of the two groups were similar: 1159·8 (sd 292·4) μg/dl (27·0 (SD 6·8) μmol/l) for the control group and 1128·3 (sd 407·2) μg/dl (26·2 (SD 9·5) μmol/l) for the supplemented group. None of the women was vitamin E deficient. Breast milk α-tocopherol concentrations increased by 60 % 24 h after supplementation in the intervention group and did not increase at all in the control group. α-Tocopherol concentration of the transitional milk in the supplemented group was 35 % higher compared with the control group. α-Tocopherol concentrations of the mature milk in both groups were similar. Maternal supplementation with 400 IU of RRR-α-tocopherol increased the vitamin E concentrations of the colostrum and transitional milk, but not of the mature milk. This study presents relevant information for the design of strategies to prevent and combat vitamin E deficiency in the risk group of preterm infants.

Weaning is associated with a major shift in the microbial community of the intestine, and this instability may make it more acquiescent than the adult microbiota to long-term changes. Modulation achieved through dietary interventions may have potentially beneficial effects on the developing immune system, which is driven primarily by the microbiota. The specific aim of the present study was to determine whether immune development could be modified by dietary supplementation with the human probiotic Bifidobacterium lactis NCC2818 in a tractable model of weaning in infants. Piglets were reared by their mothers before being weaned onto a solid diet supplemented with B. lactis NCC2818, while sibling controls did not receive supplementation. Probiotic supplementation resulted in a reduction in IgA (P< 0·0005) and IgM (P< 0·009) production by mucosal tissues but had no effect on IgG production (P>0·05). Probiotic-supplemented pigs had more mast cells than unsupplemented littermates (P< 0·0001), although numbers in both groups were low. In addition, the supplemented piglets made stronger serum IgG responses to fed and injected antigens (P< 0·05). The present findings are consistent with B. lactis NCC2818 reducing intestinal permeability induced by weaning, and suggest that the piglet is a valuable intermediate between rodent models and human infants. The results also strongly suggest that measures of the effect of probiotic supplementation on the immune system need to be interpreted carefully as proxy measures of health benefit. However, they are useful in developing an understanding of the mechanism of action of probiotic strains, an important factor in predicting favourable health outcomes of nutritional intervention.

Blood pressure (BP) shows a continuous relationship with the risk of CVD. There is substantial evidence that dietary potassium exerts an anti-pressor effect. Most clinical trials have used KCl. However, the chloride ion may have a pressor effect and in foods potassium is associated with organic anions. In a double-blind randomized placebo-controlled trial we explored the effect on BP of two salts of potassium, KCl and potassium citrate (K-cit), in predominantly young healthy normotensive volunteers. The primary outcome was the change in mean arterial pressure as measured in a clinic setting. After 6 weeks of supplementation, compared with the placebo group (n 31), 30 mmol K-cit/d (n 28) changed mean arterial pressure by − 5·22 mmHg (95 % CI − 8·85, − 4·53) which did not differ significantly from that induced by KCl (n 26), − 4·70 mmHg ( − 6·56, − 2·84). The changes in systolic and diastolic BP were − 6·69 (95 % CI − 8·85, − 4·43) and − 4·26 (95 % CI − 6·31, − 2·21) mmHg with K-cit and − 5·24 (95 % CI − 7·43, − 3·06) and − 4·30 (95 % CI − 6·39, − 2·20) mmHg with KCl, and did not differ significantly between the two treatments. Changes in BP were not related to baseline urinary electrolytes. A greater treatment-related effect was observed in those with higher systolic BP. Increasing dietary potassium could therefore have a significant impact on the progressive rise in BP in the entire population.

Dietary long-chain n-3 PUFA (n-3 LCPUFA) are thought to have immune-modulating effects, but the specific effects and mechanisms are not fully elucidated. The aim of this study was to determine whether dietary n-3 LCPUFA could affect ex vivo oxidative burst in healthy young men. The study had a randomised 2 × 2-factorial design in which subjects were randomly assigned to 8-week supplementation with capsules containing fish oil (about 2·9 g n-3 LCPUFA/d) or olive oil (control). Subjects were also randomly assigned to household use of oils and fat spreads with a high or a low 18 : 2n-6 content. At baseline and at the end of the intervention, the fatty acid composition of peripheral blood mononuclear cells (PBMC) was analysed by GLC and oxidative burst was studied in whole blood stimulated with zymosan using luminol-enhanced chemiluminescence. The PBMC content of n-3 LCPUFA was markedly increased by the fish oil-supplementation (P < 0·001, compared to the olive oil groups). No effect of the intervention was observed on neutrophil count, but one measure of the zymosan-induced oxidative burst was higher in the fish oil groups (P = 0·03) compared to the olive oil groups. The fat intervention did not in itself affect oxidative burst neither did it change the effect of the fish-oil intervention. The measures of oxidative burst at the end of the intervention period were found to be associated with the DHA content of PBMC (r 0·44, P = 0·016), suggesting a dose–response relationship. These results indicate that n-3 LCPUFA may have immuno-stimulating effects.

The present study is the first to examine the hypothesis that dietary supplementation with β-casein A1 promotes an increased risk relative to supplementation with β-casein A2 in patients traditionally at high risk of developing CVD. The study was conducted in fifteen asymptomatic participants (six male; nine female) at high risk of developing CVD. A double-blind cross-over study design was used with a total duration of 24 weeks. Dietary intervention was a daily supplementation (25g) of either casein A1 or A2 (for 12 weeks each). Surrogate measures of cardioprotection studied included the examination of vascular (endothelium and arterial) function, resting blood pressure, plasma lipids and biochemical markers of inflammation. Total plasma cholesterol levels were significantly lower following 12 weeks of both casein A1 and A2 interventions but the decrease was not different between intervention. Plasma insulin, homocysteine, C-reactive protein, fibrinogen, protein C and S and von Willebrand factor levels were not different between the two casein supplements. Endothelium function, measured as a vascular response using venous occlusion plethysmography to intra-aterial infusions of the endothelium-dependent agonist acetylcholine, were not different between the two casein interventions. Similarly, neither blood pressure nor measures of large artery stiffness were affected by differing the casein variant. We therefore conclude that there is no evidence from the present study that supplementation with casein A1 has any cardiovascular health disadvantage over consumption of casein A2.

Diarrhoea is a major cause of short-term growth faltering in children of the developing world. If catch-up weight gain is delayed by inadequate dietary intake, or by further bouts of diarrhoea, progressive growth failure occurs. To test the hypothesis that early refeeding is as effective as later feeding after acute diarrhoea with weight loss, we measured the effects of a timed dietary intervention on weight gain after acute diarrhoea in underweight Gambian children. Thirty-four children aged 4–22 months with weight loss following acute diarrhoea were given a high-energy-protein supplement for 14 d beginning either immediately after rehydration or a fortnight later. With a 50% increase in energy intake and a 100% increase in protein intake there was a rapid and highly significant (P < 0.001) gain in weight within a fortnight whether the supplement was given immediately or 2 weeks after presentation. Rates of weight increase were similar whether supplementation was provided early or late, but over the full 28 d (of intervention and non-intervention) children who received late supplementation had greater overall weight gain (P < 0.02) than those supplemented early. Vigorous and early feeding with a high-energy-protein supplement should be central to the management of malnourished children with acute diarrhoea in developing countries, and may be as important as control of diarrhoea in preventing malnutrition and growth failure. This may be achieved in the community using IocaUy available foods, in the face of continuing diarrhoea

Five apparently healthy, chronically undernourished (UN) male volunteers aged between 18 and 30 years were studied before and after 12 weeks of dietary supplementation. The thermic effect of a meal (TEM) was measured over a period of 6 h using a ventilated-hood system. Results indicated a significant increase in body-weight after supplementation due to increases in body fat and fat-free mass (FFM) in the proportion of 69% and 31% respectively. The basal metabolic rates (BMR) measured post supplementation were significantly higher in absolute terms, with a trend towards higher values when adjusted for the changes in FFM. TEM responses measured after 12 weeks of supplementation were significantly lower when expressed either in absolute terms (presupplementation 227.0 kJ v. post supplementation 193.5 kJ), or as a percentage of the energy density of the meal (9.1% v. 7.7%). This lower TEM was reciprocal to the changes in the BMR (r −0.86). The post-meal total energy output (PMTEO) was, however, not significantly different after 12 weeks of dietary supplementation. The unchanged PMTEO would indicate an unaltered ‘thermogenic capacity’, following supplementation, in these chronically undernourished subjects. These results confirm our earlier conclusion that, in chronic undernutrition, the thermic response to a meal may not contribute to any energy saving.

Chronic undernutrition: Dietary supplementation: Basal metabolic rates: Thermic effect: Substrate oxidation rates

In the present study the effect of combined iron, calcium and folic acid supplementation of the diet on 65Zn retention and zinc status was studied in the pregnant rat. Female Wistar rats were fed on a low-(8 μg/g) or high- (60 μg/g) Zn diet for 14 d and then mated overnight. After mating, half the rats were fed on the low- or high-Zn diet as before, whilst the other half were fed on similar diets supplemented with Fe, Ca and folic acid. The level of supplementation was chosen to reflect proportionately the possible increase in daily intakes of these nutrients by pregnant women. Rats which did not mate successfully were used as non-pregnant controls. On day 18 of pregnancy, each animal was given a meal of the appropriate diet labelled extrinsically with 65Zn, and on day 20 rats were killed. Carcass 65zn retention was lower in pregnant and non-pregnant rats fed on the supplemented diets compared with those fed on the unsupplemented diets. Rats which consumed the supplemented diets throughout pregnancy had reduced plasma Zn concentrations but femur and fetal Zn concentrations were unaffected. Maternal femur Ca and fetal Fe concentrations were lower in the high-Zn groups compared with rats fed on low-Zn diets. It was concluded that the risk of inducing fetal Zn depletion as a consequence of Fe, Ca and folic acid supplementation during pregnancy appeared to be slight. However, significant differences in 65Zn retention and maternal plasma Zn concentration in the supplemented groups, and reduced maternal bone Ca deposition and fetal Fe accretion in the high-Zn groups, indicated that it would seem wise to adopt a cautious approach to routine supplementation with individual minerals during pregnancy.