Oxidative stress may be involved in the progression of hypothyroidism in patients with Hashimoto thyroiditis (HT). Vitamin C is a well-known powerful antioxidant. To our knowledge, whether vitamin C intake relates to hypothyroidism in patients with HT remains unclear. In this cross-sectional study based on the National Health and Nutrition Examination Survey, 2007–2012, we aimed to explore the relationship between total vitamin C intake and hypothyroidism in patients with HT, using multivariate logistic regression models and restricted cubic spline analyses. Our results showed a significant negative linear association between total vitamin C intake (log10-transformed data) and hypothyroidism in HT. Compared with those with the lowest quartile of total vitamin C intake (log10-transformed), participants with the highest quartile were at lower odds of having hypothyroidism (adjusted OR 0·40, 95 % CI: 0·18, 0·88, Ptrend = 0·027). This association was consistent in subgroups stratified by sex (Pfor interaction = 0·084) and age (≥ 60 years and < 60 years, Pfor interaction = 0·330). This study revealed that total vitamin C intake was inversely associated with hypothyroidism among individuals with HT, indicating that higher vitamin C intakes (4·57–1258·9 mg/d) may be associated with a lower likelihood of hypothyroidism among HT participants.

Fruit juice (FJ) is typically low in energy, contains natural sugars, important amounts of micronutrients and is not permitted to have added sugars/sweeteners. However, its role in a healthy diet is under scrutiny partly due to the wider adoption of the definition for free sugars in nutrition policy. This review aimed to identify data on FJ consumption from national food consumption surveys across Europe, to examine current intakes, percent consumers and its contribution to intakes of energy, total sugars, free sugars, vitamin C, folate and potassium. Data were extracted on the population mean intake of FJ and its contribution to nutrient intakes across the lifecycle and crude estimates of population mean intakes across countries were reported for the total population and for consumers only. This review highlighted significant gaps/challenges regarding the availability of country-specific national food consumption surveys across Europe and specifically data on FJ consumption (including complexities surrounding categorisations). Nonetheless, using a comparable/homogenous definition, the mean intake of FJ among consumers was approximately 1 × 150 ml glass/day for adults/older adults, with lower intakes among infants (86 g/d), children (108 g/d) and teenagers (112 g/d). FJ made important contributions to intakes of vitamin C while making little contribution to energy intakes but also contributed 2–14 % of free sugars intake (which may be considered modest compared to other sources). The complexity of collating and interpreting data on FJ intake as elucidated in this review raises questions surrounding the categorisation of FJ in research and presents significant challenges for policymakers with respect to dietary guidance for FJ.

In recent years, the rapidly increasing incidence of obesity is becoming a worldwide public health problem. Obesity is a chronic disease which may have a major negative effect on the people’s quality of life. Previous studies on the comprehensive effects of multivitamins on central obesity and general obesity are relatively few. The aim of this study was to evaluate association of vitamins exposure with obesity risk and obesity-related indicators. We fitted three statistical models (linear regression model, logistic regression model, and Bayesian kernel machine regression model) to evaluate the correlation between vitamin levels and obesity in the study population. The vitamin score represents the overall level of vitamin in serum, which was mutually verified with the results obtained from statistical model. The vitamin (A, C, and D) levels were significantly higher among non-obesity group compared to the obesity group. Using the lowest quartile of vitamin level as a referent, vitamin A, C, and D levels showed significantly negative correlation with the obesity risk in both adjusted and unadjusted models. When considering all vitamin as a mixed exposure, we found a generally negative relationship between vitamin mixtures with binary outcome (obesity) and continuous outcome (BMI, waist circumference, and hsCRP). Reduced levels of vitamins (A, C and D) increased the risk of obesity. Increased levels of vitamin mixtures can significantly reduce obesity risk and obesity-related indicators. Vitamins may reduce the risk of obesity by suppressing inflammatory responses.

Strawberry contains many bioactive compounds such as vitamin C and polyphenols as well as folate, a vitamin that is especially important for women of childbearing age. We investigated the effects of the acute consumption of strawberry on the serum levels of vitamin C and folate, and on the antioxidant potential of low-density lipoprotein (LDL). In a randomised, placebo-controlled, double-blind, crossover study, twenty-three healthy female volunteers (age 22⋅5 ± 1⋅4 years) ingested 500 g of a strawberry purée beverage or a sugar content-matched placebo beverage. Blood samples were collected at fasting and at 0⋅5, 1, 2 and 4 h post-ingestion. The serum concentrations of vitamin C and folate were significantly elevated from 0⋅5 to 4 h after the strawberry beverage ingestion (P < 0⋅001); the levels peaked at 2 h, with peak levels of 15⋅0 ± 2⋅5 μg/ml for vitamin C and 14⋅4 ± 7⋅0 ng/ml for folate. Notably, at 1 h after the strawberry beverage ingestion, the LDL oxidation lag time was significantly prolonged (P < 0⋅05), suggesting that the antioxidant potential of LDL was increased. After the ingestion of either beverage, the serum levels of glucose and insulin reached a peak at 0⋅5 h and then quickly returned to baseline levels. These results suggest that strawberries are a useful source of vitamin C and folate and may help enhance the antioxidant potential of LDL in healthy young women.

Greenlandic traditional nutrition was unique in the arctic environment. The aim of the present study was to reanalyse the Høygaard et al. data, focusing on two micronutrients object of discussion, i.e. Ca and vitamin C. Høygaard et al. left Copenhagen in August 1936 and stayed in East-Greenland until August 1937. The members of the expedition recorded nutritional intake whilst residing in families. However, the nutritional intake was analysed on a household level. In total, thirty-five adults and fourty-one children participated. Median total energy expenditure in kcal per d was estimated at 2978 and 2627 for male and female adults, respectively, and 1997 for children and adolescents. Median (IQR) energy consumption in kcal per d was 3881 (1568) for male and 2910 (882) for female adults. This was 2442 (857) and 2023 (1122) for male and female children and adolescents. Median (IQR) Ca intake in mg.d–1 was 555 (1110) for male and 484 (883) for female adults. This was 458 (747) and 358 (838) for male and female children and adolescents. Median (IQR) vitamin C intake in mg.d–1 was 79 (77) for male and 59 (56) for female adults. This was 44 (47) and 60 (52) for male and female children and adolescents. In this study, the importance of traditional foods in reaching an acceptable energy balance was emphasised, together with the confirmation of a low Ca intake in East-Greenland traditional dietary pattern, and the important role of algae consumption in Inuit traditional dietary pattern to avoid scurvy.

Vitamin E (α-tocopherol; VE) is known to be regenerated from VE radicals by vitamin C (L-ascorbic acid; VC) in vitro. However, their in vivo interaction in various tissues is still unclear. Therefore, we alternatively examined the in vivo interaction of VC and VE by measurement of their concentrations in various tissues of senescence marker protein-30 (SMP30) knockout (KO) mice as a VC synthesis deficiency model. Male SMP30-KO mice were divided into four groups (VC+/VE+, VC+/VE–, VC–/VE+ and VC–/VE–), fed diets with or without 500 mg/kg VE and given water with or without 1·5 g/l VC ad libitum. Then, VC and VE concentrations in the plasma and various tissues were determined. Further, gene expression levels of transporters associated with VC and VE, such as α-tocopherol transfer protein (α-TTP) and sodium-dependent vitamin C transporters (SVCTs), were examined. These results showed that the VE levels in the VC-depleted (VC–/VE+) group were significantly lower than those in the VC+/VE+ group in the liver and heart; the VC levels in the VE-depleted (VC+/VE–) group were significantly lower than those in the VC+/VE+ group in the kidneys. The α-TTP gene expression in the liver and kidneys was decreased by VC and/or VE depletion. Moreover, SVCT1 gene expression in the liver was decreased by both VC and VE depletion. In conclusion, these results indicate that VC spares VE mainly in the liver and heart and that VE spares VC in the kidneys of SMP30-KO mice. Thus, interaction between VC and VE is likely to be tissue specific.

Nutrition in early life has a long-term influence on later health. In order to the explore effects of in ovo feeding (IOF) of vitamin C on splenic development, splenic metabolism and apoptosis were detected in embryo, adult chickens and in vitro. A total of 360 fertile eggs were selected and randomly assigned to control (CON) and vitamin C (VC) groups which were injected with saline and vitamin C on embryonic day 11, respectively. Functional enrichment of differentially expressed genes by transcriptome on embryonic day 19 suggested that purine nucleotide metabolism might be a potential pathway for the IOF of vitamin C to regulate spleen development. Additionally, the IOF of vitamin C significantly increased splenic vitamin C content on post-hatch day 21. Meanwhile, the splenic expression of adenosine deaminase, serine/threonine kinase 1 and proliferating cell nuclear antigen was down-regulated, whereas the expression of cysteinyl aspartate specific proteinase 9 was up-regulated in the VC group. On post-hatch day 42, the IOF of vitamin C significantly down-regulated the splenic expression of B-cell lymphoma 2 and increased the mRNA level of cysteinyl aspartate specific proteinase 9. The IOF of vitamin C could regulate the expression of genes related to adenylate metabolism and increased the apoptosis rate in vitro, which is consistent with the result in vivo. In conclusion, the IOF of vitamin C regulated splenic development and maturation by affecting purine nucleotide metabolism pathway and promoting apoptosis.

Vitamin C (ascorbic acid) is a water-soluble vitamin with an array of biological functions. A number of proposed factors contribute to the vitamin’s plasma bioavailability and ability to exert optimal functionality. The aim of this review was to systematically assess plasma vitamin C levels post-surgery compared with pre-surgery/the magnitude and time frame of potential changes in concentration. We searched the PUBMED, SCOPUS, SciSearch and the Cochrane Library databases between 1970 and April 2020 for relevant research papers. Prospective studies, control groups and true placebo groups derived from controlled trials that reported means and standard deviations of plasma vitamin C concentrations pre- and postoperatively were included into the meta-analysis. Data were grouped into short-term (≤7 d) and long-term (>7 d) postoperative follow-up. Twenty-three of thirty-one studies involving 642 patients included in the systematic review were suitable for meta-analysis. Pooled data from the meta-analysis revealed a mean depletion of plasma vitamin C concentration of −17·99 µmol/l (39 % depletion) (CI −22·81, −13·17) (trial arms = 25, n 565, P < 0·001) during the first postoperative week and −18·80 µmol/l (21 % depletion) (CI −25·04, −12·56) (trial arms = 6, n 166, P < 0·001) 2–3 months postoperatively. Subgroup analyses revealed that these depletions occurred following different types of surgery; however, high heterogeneity was observed amongst trials assessing concentration change during the first postoperative week. Overall, our results warrant larger, long-term investigations of changes in postoperative plasma vitamin C concentrations and their potential effects on clinical symptomology.

Chronic foot ulcers are associated with a high risk of osteomyelitis, poor quality of life, amputations and disability. Few strategies improve their healing, and amputation rates in high-risk foot services are usually over 30 %. We conducted a randomised, inactive-placebo controlled, double-blind trial of 500 mg of slow-release vitamin C in sixteen people with foot ulcers in the Foot Wound Clinic at Westmead Hospital. Nine were randomised to control and seven to vitamin C. When serum vitamin C results become available at 4 weeks, all people with deficiency were offered both vitamin C and glucosamine tablets for the next 4 weeks. Patients without baseline deficiency continued their original assigned treatment. The primary outcome was percentage ulcer healing (reduction in ulcer size) at 8 weeks. Fifty percentage of subjects had baseline vitamin C deficiency, half having undetectable levels. Healing at 8 weeks was significantly better in the vitamin C group (median 100 v. –14 %, P = 0·041). Healing without amputation occurred in all patients in the vitamin C group. In contrast, 44 % of controls had not healed their ulcer at the end of the study period. Vitamin C improved healing of foot ulcers. Further studies are needed to determine whether there is a threshold effect for serum vitamin C above which therapy is ineffective and whether there are better or lesser responding subgroups. Because of its low cost and ease of access and administration, we recommend offering vitamin C therapy to all people who have chronic foot ulcers and potentially suboptimal vitamin C intake. Trial registration number: ACTRN12617001142325.

This study aimed to evaluate the effect of in ovo feeding (IOF) of vitamin C at embryonic age 11 (E11) on post-hatch performance, immune status and DNA methylation-related gene expression in broiler chickens. A total of 240 Arbor Acres breeder eggs (63 (sem 0·5) g) were randomly divided into two groups: normal saline and vitamin C (VC) groups. After incubation, newly hatched chicks from each group were randomly divided into six replicates with ten chicks per replicate. Hatchability, average daily feed intake (D21–42 and D1–42), and average daily gain and feed conversion ratio (D1–21) were improved by vitamin C treatment (P < 0·05). IOF of vitamin C increased vitamin C content (D1), total antioxidant capacity (D42), IgA (D1), IgM (D1 and D21), stimulation index for T lymphocyte (D35) and lysozyme activity (D21) in plasma (P < 0·05). On D21, vitamin C increased the splenic expression of IL-4 and DNMT1 and decreased IL-1β, Tet2, Tet3 and Gadd45β expression (P < 0·05). On D42, vitamin C increased the splenic expression of IL-4 and DNMT3A and decreased IFN-γ, Tet3, MBD4 and TDG expression (P < 0·05). In conclusion, the vitamin C via in ovo injection can be absorbed by broiler’s embryo and IOF of vitamin C at E11 improves the post-hatch performance and immune status and, to some extent, the antioxidant capacity of broiler chickens. The expression of enzyme-related DNA methylation and demethylation indicates that the level of DNA methylation may increase in spleen in the VC group and whether the fluctuating expression of pro- and anti-inflammatory cytokines is related to DNA methylation change remained to be further investigated.

The vitamin status of a child depends on many factors and most of the clinical studies do not take into account the different access to adequate nutrition of children coming from different countries and the consequent major differences in micronutrients or vitamin deficits between low-income and high-income countries. Vitamin supplements are included in the general field of dietary supplements. There is a large amount of not always factual material concerning vitamin supplements, and this may sometimes create confusion in clinicians and patients. Inadequate information may lead to the risk of attributing beneficial properties leading to their over-use or misuse in the paediatric field. Vitamin supplementation is indicated in all those conditions in which a vitamin deficiency is found, either because of a reduced intake due to reduced availability of certain foods, restrictive diets or inadequate absorption. The lack of guidelines in these fields may lead paediatricians to an improper use of vitamins, both in terms of excessive use or inadequate use. This is due to the fact that vitamin supplementation is often intended as a therapy of support rather than an essential therapeutic tool able to modify disease prognosis. In fact, various vitamins and their derivatives have therapeutic potential in the prevention and treatment of many diseases, especially in emerging conditions of paediatric age such as type 2 diabetes and the metabolic syndrome. The aim of the present article is to analyse the state of the art and consider new perspectives on the role of vitamin supplements in children.

Vitamin C (VC) is a vital micronutrient for humans and some other mammals and also has antioxidant activity. Stress-induced elevation of glucocorticoid production is well known to cause immunosuppression. The present study evaluated the effect of high VC intake on glucocorticoid-induced immune changes in mice. Senescence marker protein 30 knockout mice with genetic VC deficiency were fed a diet containing the recommended VC content (20 mg/kg per d; 0·02 %VC group) or a high VC content (200 mg/kg per d; 0·2 %VC group) for 2 months, then dexamethasone was given by intraperitoneal injection. After administration of dexamethasone, the plasma ascorbic acid concentration decreased significantly in the 0·02 %VC group and was unchanged in wild-type C57BL/6 mice on a VC-deficient diet (wild-type group), while it was significantly higher in the 0·2 %VC group compared with the other two groups. In the 0·02 %VC and wild-type groups, dexamethasone caused a significant decrease in the cluster of differentiation (CD)4+ and CD8+ T cells among splenocytes as well as a significant decrease in IL-2, IL-12p40 and interferon-γ protein production by splenocytes and a significant decrease in T-cell proliferation among splenocytes. In the 0·2 %VC group, these dexamethasone-induced immunosuppression improved when compared with the other two groups. In addition, reduction in the intracellular levels of ascorbic acid, superoxide dismutase and glutathione in splenocytes by dexamethasone as well as elevation in thiobarbituric acid-reactive substances were significantly suppressed in the 0·2 %VC group. These findings suggest that high dietary VC intake reduces glucocorticoid-induced T-cell dysfunction by maintaining intracellular antioxidant activity.

Recent studies have shown that micronutrients are involved in the pathology of type 2 diabetes. Antioxidant effects of vitamins C and B2 and homocysteine-lowering effects of vitamins B6, folate and B12 may have protective roles. However, a few reports have investigated the association between dietary water-soluble vitamin intakes and risk of diabetes. In a prospective study encompassing 19 168 healthy Japanese men and women aged 40–79 years, we examined the associations between dietary intakes of water-soluble vitamins, determined by a validated self-administered FFQ, with the risk of 5-year cumulative incidence of type 2 diabetes by using the logistic regression model. Within the 5-year period, there were 494 self-reported new cases of diabetes. Higher dietary intakes of vitamins C, B2 and folate were associated with lower risk of incident diabetes only in women, whereas no associations of dietary intakes of vitamins B1, B3, B5, B6 and B12 were observed in either sex. The multivariable OR in the highest v. the lowest quartile of intakes among women were 0·61 (95 % CI 0·44, 0·94; P-trend = 0·04) for vitamin C, 0·56 (95 % CI 0·34, 0·93; P-trend = 0·03) for vitamin B2 and 0·70 (95 % CI 0·46, 0·98; P-trend = 0·03) for folate. Other than that for sex (P < 0·05), the P-interactions with age, BMI, smoking status or having a family history of diabetes were >0·10. In conclusion, higher dietary intakes of vitamins C, B2 and folate, but not other water-soluble vitamins, were associated with reduced risk of type 2 diabetes in Japanese women.

Direct swim-up procedure is widely used to separate the motile competent spermatozoa from the antioxidant-rich semen. Subsequently, spermatozoa become more vulnerable to reactive oxygen species (ROS) due to their cytological characteristics. The effect of vitamin C, a highly concentrated antioxidant in the semen, on direct swim-up-enriched sperm population is not fully investigated. Therefore, the aim of the present study was to assess the effect of vitamin C on sperm functional properties during direct swim-up procedure. Semen samples were collected from 22 participants. Each semen sample was divided into several aliquots. The first portion was overlaid with sperm medium without ascorbic acid (0 µM AA). The second and third fractions were overlaid with sperm medium supplemented with 300 µM and 600 µM AA; respectively. After 1 h of incubation, basic sperm parameters, intracellular ROS levels, acrosome reaction, chromatin integrity, and glucose uptake were assessed. Swim-up without AA significantly increased the percentage of ROS(+) spermatozoa compared with the raw semen (P<0.01). Interestingly, swim-up with 300 µM AA did not increase the percentage of ROS(+) sperm compared with the raw semen. In parallel, the percentage of sperm with altered chromatin integrity was significantly lower in the 300 µM AA group compared with that in the raw semen (P<0.05). These findings suggest that supplementation of vitamin C to sperm medium could be beneficial for direct swim-up-derived spermatozoa.

Sepsis is defined as the dysregulated host response to an infection resulting in life-threatening organ dysfunction. The metabolic demand from inefficiencies in anaerobic metabolism, mitochondrial and cellular dysfunction, increased cellular turnover, and free-radical damage result in the increased focus of micronutrients in sepsis as they play a pivotal role in these processes. In the present review, we will evaluate the potential role of micronutrients in sepsis, specifically, thiamine, l-carnitine, vitamin C, Se and vitamin D. Each micronutrient will be reviewed in a similar fashion, discussing its major role in normal physiology, suspected role in sepsis, use as a biomarker, discussion of the major basic science and human studies, and conclusion statement. Based on the current available data, we conclude that thiamine may be considered in all septic patients at risk for thiamine deficiency and l-carnitine and vitamin C to those in septic shock. Clinical trials are currently underway which may provide greater insight into the role of micronutrients in sepsis and validate standard utilisation.

We aimed to systematically review available data on the association between vitamin C intake and bone mineral density (BMD), as well as risk of fractures and osteoporosis, and to summarise this information through a meta-analysis. Previous studies on vitamin C intake in relation to BMD and risk of fracture and osteoporosis were selected through searching PubMed, Scopus, ISI Web of Science and Google Scholar databases before February 2017, using MeSH and text words. To pool data, either a fixed-effects model or a random-effects model was used, and for assessing heterogeneity, Cochran’s Q and I2 tests were used. Subgroup analysis was applied to define possible sources of heterogeneity. Greater dietary vitamin C intake was positively associated with BMD at femoral neck (pooled r 0·18; 0·06, 0·30) and lumbar spine (pooled r 0·14; 95 % CI 0·06, 0·22); however, significant between-study heterogeneity was found at femoral neck: I2=87·6 %, Pheterogeneity<0·001. In addition, we found a non-significant association between dietary vitamin C intake and the risk of hip fracture (overall relative risk=0·74; 95 % CI 0·51, 1·08). Significant between-study heterogeneity was found (I2=79·1 %, Pheterogeneity<0·001), and subgroup analysis indicated that study design, sex and age were the main sources of heterogeneity. Greater dietary vitamin C intake was associated with a 33 % lower risk of osteoporosis (overall relative risk=0·67; 95 % CI 0·47, 0·94). Greater dietary vitamin C intake was associated with a lower risk of hip fracture and osteoporosis, as well as higher BMD, at femoral neck and lumbar spine.

Circulating vitamin C and carotenoids are used as biomarkers of fruit and vegetable intake in research, but their comparative validity has never been meta-analysed. PubMed, EMBASE, CENTRAL, CINAHL and Web of Science were systematically searched up to December 2013 for randomised trials of different amounts of fruit and vegetable provision on changes in blood concentrations of carotenoids or vitamin C. Reporting followed PRISMA guidelines. Evidence quality was assessed using the GRADE system. Random effects meta-analysis combined estimates and meta-regression tested for sub-group differences. In all, nineteen fruit and vegetable trials (n 1382) measured at least one biomarker, of which nine (n 667) included five common carotenoids and vitamin C. Evidence quality was low and between-trial heterogeneity (I2) ranged from 74 % for vitamin C to 94 % for α-carotene. Groups provided with more fruit and vegetables had increased blood concentrations of vitamin C, α-carotene, β-carotene, β-cryptoxanthin and lutein but not lycopene. However, no clear dose–response effect was observed. Vitamin C showed the largest between-group difference in standardised mean change from the pre-intervention to the post-intervention period (smd 0·94; 95 % CI 0·66, 1·22), followed by lutein (smd 0·70; 95 % CI 0·37, 1·03) and α-carotene (smd 0·63; 95 % CI 0·25, 1·01), but all CI were overlapping, suggesting that none of the biomarkers responded more than the others. Therefore, until further evidence identifies a particular biomarker to be superior, group-level compliance to fruit and vegetable interventions can be indicated equally well by vitamin C or a range of carotenoids. High heterogeneity and a lack of dose–response suggest that individual-level biomarker responses to fruit and vegetables are highly variable.