Retinol, β-carotene and oxidative stress in systemic inflammatory response syndrome / Retinol, β-caroteno e estresse oxidativo na síndrome da resposta inflamatória sistêmica.

Objective: patients suffering systemic inflammatory response syndrome (SIRS) constitute a group susceptible to elevated levels of oxidative stress. This study’s aim is to evaluate the state of oxidative stress and levels of serum retinol and β-carotene in these patients. Methods: forty-six patients were divided into 2 groups: those those without diet (G1; n=18) and those with enteral nutritional support (G2; n=28). Serum levels of retinol and total carotenoids were measured. C-reactive protein (CRP) levels and Apache scores were also calculated. Oxidative stress was estimated by measuring thiobarbituric acid reactive substance (TBARS) levels. Results: the patients’ median age was 66.9 (SD=19.3) years. Lower concentrations of retinol and carotenoids were found in 68.6 and 66.7% of G1, respectively. In G2, despite average vitamin A levels being 8078 + 4035, retinol and β-carotene were considered insufficient (31.2 and 33.4%, respectively). No difference was noted between the 2 groups, according to the variables studied, with the exception being PCR and β-carotene (p=0.002; p=0.01). Conclusion: the data presented in this study supports the need to establish/revise clinical practices in treating SIRS patients, in light of this micronutrient’s role in the immune system and antioxidant defense without it interfering with its toxicity. .

Objetivo: pacientes que apresentam a síndrome da resposta inflamatória sistêmica (SIRS) constituem um grupo suscetível a níveis elevados de estresse oxidativo. O objetivo do presente estudo é avaliar o estado de estresse oxidativo e os níveis séricos de retinol e β-caroteno nesses pacientes. Métodos: quarenta e seis pacientes foram divididos em dois grupos: aqueles sem dieta (G1; n = 18) e aqueles com suporte nutricional enteral (G2, n = 28). Foram investigadas as concentrações séricas de retinol e carotenoides totais, proteína C reativa, estresse oxidativo e escore Apache. O estresse oxidativo foi avaliado por dosagem da peroxidação lipídica e estimado por meio da dosagem de TBARS (substâncias reativas ao ácido tiobarbitúrico). Resultados: a média de idade dos pacientes foi de 66,9 (±19,3). Baixas concentrações de retinol e carotenoides foram encontradas em 68,6 e 66,7% do G1, respectivamente. No G2, a concentração sérica média de vitamina A foi de 8078 (± 4035), e o retinol e o β-caroteno apresentaram percentual de inadequação de 31,2 e 33,4%, respectivamente. Não foi observada nenhuma diferença entre os dois grupos, de acordo com as variáveis estudadas, com exceção do PCR e do β-caroteno (p=0,002; p=0,01). Conclusão: os dados apresentados neste estudo indicam a necessidade de estabelecer/rever práticas clínicas no tratamento de pacientes com SIRS, tendo em conta o papel desse micronutriente no sistema imunológico e na defesa antioxidante, sem que isso interfira na sua toxicidade. .

Normal values and seasonal differences in the serum concentration of vitamin A and beta-carotene in the Iranian camel [Camelus dromedarius]

Vitamin A which is found in different tissues and organs plays a particular role in detecting clinical signs in various deficiency conditions. However, sometimes the marginal deficiency is present in a way that clinical signs are not visible but performance defects, such as infertility is seen. In this study, the normal baseline levels of vitamin A and beta-carotene in clinically healthy camels [Camelus dromedarius] in the Yazd province were investigated. A total of 168 Iranian camels of both sexes were sampled from February 2009 to July 2010. Spectrophoto-metry was used for measuring the serum values. The mean +/- SE concentration of vitamin A and beta- carotene were 63.9 +/- 4.7 and 9 +/- 1.1 micro g/dL, respectively. Although, the beta-carotene concentration was significantly higher in summer, vitamin A was not influenced by season. No significant difference in the serum levels of the measured parameters was observed in different ages and sexes. The results of this study, for the first time, indicate the concentration of vitamin A and beta-carotene in the camels in Iran. This finding can be used as a reference guide for evaluation of the deficiency or excess of vitamin A and beta-carotene in camels in Iran. Furthermore, due to the lower levels of vitamin A and beta-carotene in Iranian dromedaries during winter, supplementary feeding of vitamin A is recommended during this season

Beta-carotene, vitamin E, MDA, glutathione reductase and arylesterase activity levels in patients with active rheumatoid arthritis

Many studies have investigated the possible role of reactive oxygen species in the etiology and pathogenesis of Rheumatoid Arthritis [RA]. The aim of this study was to investigate the activities of some antioxidants in RA patients. In this case-control study, 59 RA patients and 60 healthy sex and age-matched controls were selected. Vitamin E and Beta-carotene were determined using HPLC. Erythrocytes glutathione reductase [GR] activity was measured spectrophotometrically, and malondialdehyde [MDA] was determined by colorimetric method. Arylesterase activity [AEA] was measured by Phenylacetate. The clinical data were determined by a rheumatologist, medical history and filling the questionnaire by interview. Statistical analyses were carried out using the SPSS software. In patients with RA, serum MDA level was significantly higher and plasma concentration of vitamin E, Beta-carotene and GR activity, were significantly lower than healthy control [P<0.001]. AEA activity differences between two groups were non-significant. Oxidative stress may play an important role in the inflammation and pathogenesis of RA

Validation of a food frequency questionnaire to assess the consumption of carotenoids, fruits and vegetables among adolescents: the method of triads / Validação de um questionário de frequência alimentar para avaliar o consumo de carotenóides, frutas e hortaliças: o método das tríades

The aim of this study was to validate the intake of carotenoids, fruits and vegetables estimated by the Food Frequency Questionnaire for Adolescents (FFQA) using the method of triads. Blood samples were collected from 80 elementary school adolescents to assess serum levels of β-carotene. Partial correlation coefficients (r) were calculated between an estimated intake of carotenoids, fruits and vegetables and the serum levels of β-carotene. Validity coefficients were calculated using the method of triads. With the exception of carotenoids, partial r from the food frequency questionnaire (FFQ) were greater than those of the 24-hour recall (24hR). The fruit/vegetable group showed the highest partial r for the FFQ (r = 0.235) and the 24hR (r = 0.137). The highest validity coefficient was obtained for the vegetable group, as assessed by the FFQ (r = 0.873). On average, the validity coefficient values for the FFQ were greater than those obtained for the 24hR or the β-carotene serum levels. The FFQA is an accurate tool for estimating the intake of carotenoids, fruits and vegetables in this population group.

O objetivo do estudo foi validar a ingestão de carotenóides, frutas e hortaliças estimada pelo Questionário de Frequência Alimentar para Adolescentes (QFAA) utilizando o método das tríades. Foram coletadas amostras sanguíneas de 80 adolescentes de uma escola de Ensino Fundamental para análise do b-caroteno plasmático. Coeficientes de correlação (r) parciais foram obtidos entre a ingestão de carotenóides, frutas e hortaliças e o b-caroteno plasmático. Os coeficientes de validade foram estimados a partir do método das tríades. O QFA apresentou valores de r parcial superiores ao recordatório alimentar de 24 horas (R24h), exceto para carotenóides. O grupo das frutas/hortaliças apresentou os maiores valores de r parciais tanto para o questionário de frequência alimentar (QFA) (r = 0,235) quanto para R24h (r = 0,137). O maior coeficiente de validade foi o do grupo de hortaliças avaliado pelo QFA (r = 0,873). Os valores de coeficiente de validade observados para o QFA foram em média superiores aos obtidos para R24h e b-caroteno plasmático. O QFAA é um instrumento com boa acurácia para estimar o consumo de carotenóides, frutas e hortaliças nesse grupo populacional.

Concentração de micronutrientes em mães e seus recém-nascidos por ocasião do parto / Mothers' and newborns' plasmatic concentration of micronutrients at the moment of childbirth

Trata-se de estudo transversal com uma amostra sequencial de conveniência de 73 gestantes, não fumantes, sem intercorrências durante a gravidez e seus recém-nascidos normais, objetivando comparar concentrações plasmáticas de retinol, β caroteno, licopeno, α tocoferol e cobre entre mães e recém-nascidos. Colheu-se sangue da parturiente e do cordão umbilical (após dequitação) para dosagem dos micronutrientes. Retinol, β caroteno, licopeno e α tocoferol foram dosados por HPLC e o cobre por espectrofotometria de absorção atômica. Para análise foram separados 2 grupos:- grupo 1, 38 gestantes com suplementação vitaminico-mineral pelo menos no último trimestre da gravidez e grupo 2, 35 gestantes que não haviam recebido suplementação. As comparações estatísticas foram pelo teste t de Student ou pelo teste de Wilcoxon, com um α crítico de 0,05. Os dois grupos de mães eram símiles quanto a idade, paridade, IMC e a baixa ingestão de calorias e de micronutrientes. Os grupos de recém-nascidos não evidenciaram diferença quanto a sexo, peso, comprimento e perímetro cefálico. As concentrações plasmáticas maternas do grupo 1 foram maiores para o retinol(p = 0,0034) e a tocoferol(p = 0,0279). β caroteno, licopeno e cobre não evidenciaram diferenças entre os dois grupos de mães. Nos dois grupos de recém-nascidos as concentrações de retinol, tocoferol e cobre foram semelhantes e praticamente não houve concentrações detectáveis de licopeno e α caroteno. Em ambos os grupos retinol, a tocoferol e cobre apresentaram maiores concentrações nas mães do que nos recém-nascidos, p = 0,0003, p = 0,0001, p = 0,0001, respectivamente. Conclui-se que as concentrações nos recém-nascidos foram sempre menores do que as maternas, independentemente da ingestão e da suplementação durante a gravidez

Concentrações séricas das vitaminas A e E, e beta-caroteno em adultos com HIV/Aids em terapia antirretroviral de alta potência / Serum concentrations of vitamins A and E, and beta-carotene in adults with HIV/AIDS on highly active antiretroviral therapy

As deficiências de vitaminas, verificadas em indivíduos com HIV/Aids em terapia antirretroviral de alta potência (HAART) têm sido associadas à piora do curso clínico da doença e maior risco de mortalidade. Objetivo Mostrar a distribuição das concentrações séricas de vitaminas A e E, e beta-caroteno em adultos com infecção pelo HIV/Aids e estudar a associação de suas concentrações, segundo diferentes esquemas de HAART. Métodos Foram selecionados 182 adultos de 20 a 59 anos de idade, de ambos os sexos, com HIV/Aids em HAART estável por no mínimo 6 meses, e com níveis de linfócitos T-CD4+ 200 células/mm3. Os indivíduos foram divididos em três grupos por esquema de HAART utilizado: inibidores de transcriptase reversa análogos de nucleosídeo (ITRN) associados a inibidores de transcriptase reversa não análogos de nucleosídeo (ITRNN); ITRN associada a inibidores de protease (IP); ITRN associadas a outras classes (inibidores de fusão, inibidores de integrasse, inibidores de entrada e IP associada a essas medicações). A determinação dos micronutrientes foi realizada por cromatografia líquida de alta eficiência. Foram verificadas variáveis sócio-demográficas e econômicas, estilo de vida, história da doença, uso de medicações e variáveis antropométricas e laboratoriais. Para medir os efeitos das variáveis explanatórias (esquemas de tratamento, tempo de uso e adesão ao último esquema) sobre cada variável resposta (retinol, alfa-tocoferol e beta-caroteno), foram realizadas análises de regressão linear múltipla. Sexo, idade, escolaridade, tabagismo, prática de atividade física, tempo de infecção por HIV, presença de comorbidades, relação cintura-quadril e níveis de linfócitos T-CD4+ e colesterol foram usadas como variáveis de controle. Resultados Foram encontradas concentrações deficientes e baixas de vitaminas A...

Deficiency of vitamins found in individuals with HIV/AIDS on highly active antiretroviral therapy (HAART) has been associated with an increased risk of disease progression and mortality. Objective To show the distribution of serum concentrations of vitamins A and E and beta-carotene in adults with HIV/AIDS, and to study the association of their concentrations, according to different regimens of HAART. Methods We selected 182 men and women aged 20-59 years with HIV/AIDS on stable HAART for at least six months and with levels of CD4+ T-lymphocytes 200 cells/mm3. Individuals were divided into three groups according to the HAART regimen used: nucleoside reverse transcriptase inhibitors (NRTI) combined with nonnucleoside reverse transcriptase inhibitors (NNRTI); NRTI combined with protease inhibitors (PI); NRTI combined with other classes (fusion inhibitors, integrase inhibitors, entry inhibitors, and PI associated with these medications). Determinations of vitamins A and E and beta-carotene were performed by high-performance liquid chromatography. Socio-demographic and economic variables, lifestyle, disease history, medication use, and anthropometric and laboratory variables were assessed. Multiple regression analyses were used to measure the effects of the explanatory variables (treatment regimens, duration and adherence to the last treatment regimen) on each response variable (retinol, alpha-tocopherol and beta-carotene). Sex, age, education, smoking, physical activity, duration of HIV infection, comorbidity, waist-to-hip ratio and levels of CD4+ T-lymphocytes and cholesterol were used as control variables. Results Deficient and low concentrations of vitamin A...

Lycopene and ß-carotene protect in vivo iron-induced oxidative stress damage in rat prostate

It has been suggested that iron overload may be carcinogenic. In the present study, we evaluated the effect of plasma and prostate carotenoid concentration on oxidative DNA damage in 12-week-old Wistar rats treated with intraperitoneal (ip) ferric nitrilotriacetate (Fe-NTA) (10 mg Fe/kg). Plasma ß-carotene and lycopene concentrations were measured as a function of time after ip injection of carotenoids (10 mg kg-1 day-1 ß-carotene or lycopene) in rats. The highest total plasma concentration was reached 3 and 6 h after ip injection of lycopene or ß-carotene, respectively. After 5 days of carotenoid treatment, lycopene and ß-carotene were present in the 0.10-0.51 nmol/g wet tissue range in the prostate. Using a sensitive method to detected 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) by HPLC/EC, the level of 8-oxodGuo in rat prostate DNA was significantly higher (6.3 ± 0.6 residues/10(6) dGuo) 3 h after Fe-NTA injection compared with control rats (1.7 ± 0.3 residues/10(6) dGuo). Rats supplemented with lycopene or ß-carotene for 5 days prior to Fe-NTA treatment showed a reduction of about 70 percent in 8-oxodGuo levels to almost control levels. Compared with control rats, the prostate of Fe-NTA-treated animals showed a 78 percent increase in malondialdehyde accumulation. Lycopene or ß-carotene pre-treatment almost completely prevented lipid damage. Epidemiological studies have suggested a lower risk of prostate cancer in men reporting a higher consumption of tomato products. However, before associating this effect with tomato sauce constituents, more information is required. The results described here may contribute to the understanding of the protective effects of carotenoids against iron-induced oxidative stress.

Brain tumor and role of beta-carotene, a-tocopherol, superoxide dismutase and glutathione peroxidase.

The erythrocyte levels of the antioxidant enzymes SOD and GPx, and serum levels of antioxidants vitamins beta-carotene and beta-tocopherol were estimated in various types of brain tumors, and were compared with the levels in controls. Statistically significant (P<.001) diminished levels of beta-carotene, beta-tocopherol, SOD and GPx, were observed in all the brain tumor patients as compared to controls. Malignant tumor also showed a relative decrease in antioxidant levels as compared to benign tumors. Comparison of histopathological sections of brain tumors also suggested a inverse relationship between antioxidant level and grades of malignancy. Marked decrease in antioxidant levels may have a role in genesis of considerable oxidative stress in brain tumors. Furthermore, the degree of decline in antioxidant levels may indicate severity of malignancy in brain tumors.

Some markers of oxidative stress and antioxidant status in patients with psoriasis

Psoriasis is a common, chronic inflammatory skin disease with unknown etiology. It has been suggested that increased reactive oxygen species [ROS] production and deficient function of antioxidant systems activities may be involved in the pathogenesis of the disease. The goal of this study was to determine the role of lipid peroxidation, assess the antioxidant activity in psoriasis patients and to correlate it with severity of the disease. In this study malondialdehyde [MDA], super oxide dismutase [SOD] enzyme activity, and total antioxidant oxidative capacity [AOC%], Vit E and beta carotene levels in 24 patients with psoriasis were investigated and compared with those of 12 control subjects. Clinical severity of the disease was determined according to the Psoriasis Area Severity Index [PASI] scores in patients. Our results showed that MDA as a marker of oxidative stress was significantly higher in psoriatic patients, while AOC%, SOD, Vit E and beta carotene as markers of antioxidant status were significantly lower in psoriatic patients compared to control. However, there was no correlation between PASI score and plasma AOC% and erythrocyte SOD levels. In conclusion our results may provide some evidence for the role of ROS production associated with decrease antioxidant potential in psoriasis

Serum antioxidant vitamin levels of people in Khon Kaen, northeastern Thailand.

Three antioxidant vitamins, the alpha- and beta-carotenes as well as vitamin E, were measured in sera of a normal population in Northeastern Thailand using HPLC. The mean serum beta-carotene level of females was significantly higher than the value for males, i.e, 37.55 (95%CI=34.59-40.51) versus 32.97 (95% CI=30.01-35.93) micro/dl. The beta-carotene level tended to decrease as age increased, particularly in the male population. The mean serum beta-carotene level was also higher in females than in males, i.e., 7.08 (95%CI=6.57-7.59) and 6.26 (95% CI=5.77-6.75) micro/dl, respectively. The average serum alpha-tocopherol (Vitamin E) level of the whole population was 1.08 (95% CI=1.04-1.12) micro/dl and did not show age or sex differences. In general, the serum antioxidant vitamins of smokers were lower than those of the non-smokers but a significant difference was observed only for alpha-tocopherol. Alcohol drinking resulted in slightly lower serum beta-carotene values, whereas coffee or tea drinking and betel nut chewing did not cause any differences with these three antioxidant vitamins. However, we report higher in serum beta-carotene levels of people in Ban Fang district than in Chonnabot district. The results from our study give the base line data of serum antioxidant vitamins in a Thai population and also suggest future intensive study on the relationship of dietary intake and cancer prevention.

Análise das concentraçöes de alfa-tocoferol e beta-caroteno nos sangues materno e do cordäo umbilical de fumantes e näo fumantes / Analysis of the concentrations of alpha-tocopherol and beta-carotene in maternal blood and umbilical cord, in smokers and non-smokers

Objetivos. Sendo os nutrientes contidos no sangue materno a única fonte de nutriçäo do feto fornecida pela via placentária, realizou-se este estudo para determinar as concentraçöes de alfa-tocoferol e beta-caroteno, nos sangues materno e do cordäo umbilical, de um grupo e parturientes e recém-nascidos, em um hospital maternidade do município de Joinville, SC. Amostras de sangue venoso das parturientes e do cordäo umbilical foram utilizadas para determinaçäo das concentraçöes do antioxidantes alfa-tocoferol e beta-caroteno, além das fraçöes lipídicas. A diferença estatística entre as médias de concentraçöes de alfa-tocoferol e beta-caroteno nos sangues materno e do cordäo umbilical, entre o grupo de fumantes e näo fumantes foi verificada através da Análise de Variância (ANOVA); e a relaçäo entre o alfa-tocoferol e beta-caroteno nos sangues materno e do cordäo umbilical, foi de 33,5 por cento. As concentraçöes plasmáticas de beta-caroteno apresentaram diferença estatística entre o grupo de fumantes, tanto no sangue materno como no cordäo umbilical. Verificou-se forte correlaçäo para a razäo beta-caroteno/total lipídico entre os sangues materno e do cordäo umbilical. O consumo de alimentos ricos em vitamina E beta-caroteno, foi maior entre as parturientes näo fumantes. Conclusöes. As concentraçöes plasmáticas de beta-caroteno nos sangues materno e do cordäo umbilical foram influenciadas pelo uso do tabaco, no entanto, o mesmo comportamento näo foi observado para o alfa-tocoferol

Correlation of vitamin A, beta carotene and fibrinogen with other parameters in ischemic heart disease

Planned to find the He of biochemical parameters in the early diagnosis of IHD, 34 males and 36 females were taken with ischeamic heart disease. Results show that the level of total lipid, cholesterol and ration of chol/HDL-chol was increased, but the level of LDL, HDL-chol and triglyceride were decreased as compared to control subjects. No change in electrolytes level was observed. Level of enzymes like AST, CK-MB etc, were increased in patients. Renal function parameters were also increased. Levels of total proteine, albumin and carotene were decreased whereas the levels of globulin and vitamin A were increased in patients as compared to their controls. It is therefore concluded that in IHD not only enzyme and lipid metabolism is effected but it also shows that the constituent of lipoprotein like vitamin A and carotene level is changed. It was also observed that the severity of disease may effect on urea, creatinine and uric acid level resulting in the involvement of kidney

Plasma and low density lipoproteins levels of fat- soluble vitamins in obese Egyptian girls

Obesity is an important health problem which is deeply rooted in human biologic system resulting in many complications namely atherosclerosis and coronary heart disease. This work was designed to investigate the antioxidant status of obese Egyptian girls. Lycopene, beta- carotene and alpha-tocopherol levels were analyzed in plasma and low density lipoprotein [LDL] fraction of plasma lipids as well as the fatty acids composition of LDL as a substrate for oxidative stress. Twenty two obese girls and ten age and sex matched healthy controls were included in this work. The plasma lycopene/total lipids, beta- carotene/total lipids and alpha-tocopherol/total lipids were significantly lower in the obese girls compared to controls Moreover, the three vitamins contents in LDL fraction were significantly lower than controls, although the plasma levels of the three studied vitamins showed no statistically significant differences in obese girls compared to control In obese girls group, LDL contained more polyunsaturated fatty acids [PUFA] compared to normal controls. When the peroxidizability index [PI] was calculated to estimate susceptibility of fatty acids to oxidative stress, obese girls had significantly higher PI values than normal controls. The LDL lycopene/PI, beta-carotene/PI and alpha-tocopherol/PI ratios were significantly lower in obese girls than controls. Significant negative correlations were found between the studied vitamins levels, their calculated ratios and their contents in LDL fraction when correlated to body mass index [BMI] of obese girls. The best parameters which can predict high BMI were found to be the P1 and lycopene/total lipids. These results indicate the increased susceptibility of LDL to oxidative stress in obese girls along with decreased levels of antioxidant fat-soluble vitamins. These findings may promote atherosclerosis or coronary heart disease later in their life

Vitamin A and beta-carotene status in childhood diarrhea

Assessment of vitamin A status and beta-carotenes and an association between acute diarrhea and plasma levels of vitamin A were done. Plasma vitamin A and beta-carotenes were measured by colorimetric method of Neeld and Pearson. Eighty-four children in the age group of 6-60 months with a current history of diarrhea were studied. They were divided into two groups, one group included 22 children with recurrent diarrhea and the other one included 62 children with non- recurrent diarrhea, in addition to 56 healthy age matched children served as a control group. Children with a history of diarrhea showed significant low levels as compared with controls. Studying the odds ratio [OR] revealed that the risk for developing recurrence of diarrhea is increased if the child has a low vitamin A level or bad nutritional status

Lipid peroxide, beta-carotene and alpha-tocopherol in ischaemic stroke and effect of exogenous vitamin E supplementation on outcome.

30 patients with CT proven infarct presenting within 24 hours of the acute event were included in the study with 20 age and sex matched controls. On day 1 and day 15 of stroke, levels of plasma lipid peroxide (oxidant) and plasma alpha-tocopherol and beta carotene (antioxidant) were estimated. The patients were randomly assigned to two groups, one group receiving 300 mg/day of vitamin E for 15 days. Neurological examination was conducted according to Mathew scale on day 1 and day 15 and rehabilitation assessment was done at day 15 and at 6 weeks according to Barthel Index. On day 1, the mean value of plasma lipid peroxidation in controls was 4.97 +/- 1.44 nmol/ml and in stroke patients 5.89 +/- 1.56 nmol/ml (p < 0.05). The plasma beta-carotene in controls was 2.35 +/- 1.09 mg/L while in stroke patients was 1.07 +/- 0.55 mg/L (p < 0.001) and plasma alpha-tocopherol in control 9.74 +/- 2.76 micrograms/ml as compared to 7.57 +/- 2.92 micrograms/ml in stroke patients (p < 0.02). Initially the plasma lipid peroxide levels are high and antioxidant levels are low in patients of ischemic stroke. Exogenous vitamin E supplementation does not have any significant effect on early neurological outcome but it does bring about significant changes in subsequent recovery and rehabilitation of patients of stroke.

Plasma cholesterol, B-carotene and ascorbic acid changes in human malaria.

Serum cholesterol (Total and free) as well as B-carotene and vitamin C level concentrations during and after severe infection by Plasmodium falciparum were determined. The decrease in the concentrations of cholesterol and B-carotene during and after infection was not statistically significant (P > 0.01), while the decrease in vitamin C was statistically significant (P < 0.01) during and after infection.