Short-term effects of large-dose vitamin A supplementation on viral load and immune response in HIV-infected women

What Are the Effects of Vitamin A Oral Supplementation in the Prevention and Management of Viral Infections? A Systematic Review of Randomized Clinical Trials

Vitamin A (VA) deficiency is associated with increased host susceptibility to infections, but evidence on its role in the prevention and management of viral infections is still lacking. This review aimed at summarizing the effects of VA supplementation against viral infections to support clinicians in evaluating supplemental treatments. PubMed, Scopus, and Web of Science were searched. Randomized clinical trials comparing the direct effects of VA oral supplementation in any form vs. placebo or standard of care in the prevention and/or management of confirmed viral infections in people of any age were included. A narrative synthesis of the results was performed. The revised Cochrane Risk-Of-Bias tool was used to assess quality. Overall, 40 articles of heterogeneous quality were included. We found data on infections sustained by Retroviridae (n = 17), Caliciviradae (n = 2), Flaviviridae (n = 1), Papillomaviridae (n = 3), Pneumoviridae (n = 4), and Paramyxoviridae (n = 13). Studies were published between 1987 and 2017 and mostly conducted in Africa. The findings were heterogeneous across and within viral families regarding virological, immunological, and biological response, and no meaningful results were found in the prevention of viral infections. For a few diseases, VA-supplemented individuals had a better prognosis and improved outcomes, including clearance of HPV lesions or reduction in some measles-related complications. The effects of VA oral supplementation seem encouraging in relation to the management of a few viral infections. Difference in populations considered, variety in recruitment and treatment protocols might explain the heterogeneity of the results. Further investigations are needed to better identify the benefits of VA administration.

Lean Mass Improvement from Nutrition Education and Protein Supplementation among Rural Indian Women Living with HIV/AIDS: Results from Cluster Randomized Factorial Trial at 18-Month Follow-Up

Loss of lean muscle mass impairs immunity and increases mortality risk among individuals with HIV/AIDS. We evaluated the relative contributions of protein supplementation and nutrition education on body composition among 600 women living with HIV/AIDS in rural Andhra Pradesh, India. We conducted a cluster randomized controlled 2 × 2 factorial trial lasting six months with follow up at twelve and eighteen months. Interventions occurred in the Nellore and Prakasam regions of Andhra Pradesh by trained village women, ASHA (Accredited Social Health Activists), and included: (1) the usual supportive care from ASHA (UC); (2) UC plus nutrition education (NE); (3) UC plus nutritional protein supplementation (NS); (4) combined UC plus NE plus NS. A Bioimpedance Analyzer Model 310e measured body composition. SAS 9.4 analyzed all data. Mixed models using repeated measures evaluated lean mass change from baseline as primary and fat weight and total weight as secondary outcomes. Lean mass change was significantly associated with NS (p = 0.0001), NE (p = 0.0001), and combined NS plus NE (p = 0.0001), with similar associations for secondary outcomes. Stronger associations for total weight were observed with greater ART adherence. Nutritional interventions may improve physiologic response to HIV. Significant increases in lean mass resulted from independent and combined protein supplementation and nutrition education.

Micronutrient supplementation in adults with HIV infection

BACKGROUND

Micronutrient deficiencies are common among adults living with HIV disease, particularly in low-income settings where the diet may be low in essential vitamins and minerals. Some micronutrients play critical roles in maintenance of the immune system, and routine supplementation could therefore be beneficial. This is an update of a Cochrane Review previously published in 2010.

OBJECTIVES

To assess whether micronutrient supplements are effective and safe in reducing mortality and HIV-related morbidity of HIV-positive adults (excluding pregnant women).

SEARCH METHODS

We performed literature searches from January 2010 to 18 November 2016 for new randomized controlled trials (RCTs) of micronutrient supplements since the previous review included all trials identified from searches prior to 2010. We searched the CENTRAL (the Cochrane Library), Embase, and PubMed databases. Also we checked the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and the ClinicalTrials.gov trials registers. We also checked the reference lists of all new included trials.

SELECTION CRITERIA

We included RCTs that compared supplements that contained either single, dual, or multiple micronutrients with placebo, no treatment, or other supplements. We excluded studies that were primarily designed to investigate the role of micronutrients for the treatment of HIV-positive participants with metabolic morbidity related to highly active antiretroviral therapy (HAART). Primary outcomes included all-cause mortality, morbidity, and disease progression.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, and appraised trial quality for risk of bias. Where possible, we presented results as risk ratios (RR) for dichotomous variables, as hazard ratios (HRs) for time-to-event data, and as mean differences (MD) for continuous variables, each with 95% confidence intervals (CIs). Since we were often unable to pool the outcome data, we tabulated it for each comparison. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 33 trials with 10,325 participants, of which 17 trials were new trials. Ten trials compared a daily multiple micronutrient supplement to placebo in doses up to 20 times the dietary reference intake, and one trial compared a daily standard dose with a high daily dose of multivitamins. Nineteen trials compared supplementation with single or dual micronutrients (such as vitamins A and D, zinc, and selenium) to placebo, and three trials compared different dosages or combinations of micronutrients. Multiple micronutrientsWe conducted analyses across antiretroviral therapy (ART)-naive adults (3 trials, 1448 participants), adults on antiretroviral therapy (ART) (1 trial, 400 participants), and ART-naive adults with concurrent active tuberculosis (3 trials, 1429 participants). Routine multiple micronutrient supplementation may have little or no effect on mortality in adults living with HIV (RR 0.91, 95% CI 0.72 to 1.15; 7 trials, 2897 participants, low certainty evidence).Routine supplementation for up to two years may have little or no effect on the average of mean CD4+ cell count (MD 26.40 cells/mm³, 95% CI -22.91 to 75.70; 6 trials, 1581 participants, low certainty evidence), or the average of mean viral load (MD -0.1 log₁₀viral copies, 95% CI -0.26 to 0.06; 4 trials, 840 participants, moderate certainty evidence). One additional trial in ART-naïve adults did report an increase in the time to reach a CD4+ cell count < 250 cells/mm³ after two years of high dose supplementation in Botswana (HR 0.48, 95% CI 0.26 to 0.88; 1 trial, 439 participants). However, the trial authors reported this effect only in the trial arm that received multiple micronutrients plus selenium (not either supplementation alone), which is inconsistent with the findings of other trials that used similar combinations of micronutrients and selenium.In one additional trial that compared high-dose multiple micronutrient supplementation with standard doses in people on ART, peripheral neuropathy was lower with high dose supplements compared to standard dose (incidence rate ratio (IRR) 0.81, 95% CI 0.7 to 0.94; 1 trial, 3418 participants), but the trial was stopped early due to increased adverse events (elevated alanine transaminase (ALT) levels) in the high dose group. Single or dual micronutrientsNone of the trials of single or dual micronutrient supplements were adequately powered to assess for effects on mortality or morbidity outcomes. No clinically significant changes in CD4 cell count (data not pooled, 14 trials, 2370 participants, very low or low certainty evidence) or viral load (data not pooled, seven studies, 1334 participants, very low or low certainty evidence), were reported. Supplementation probably does increase blood concentrations of vitamin D and zinc (data not pooled, vitamin D: 4 trials, 299 participants, zinc: 4 trials, 484 participants, moderate certainty evidence) and may also increase blood concentrations of vitamin A (data not pooled, 3 trials, 495 participants, low certainty evidence), especially in those who are deficient.

AUTHORS' CONCLUSIONS

The analyses of the available trials have not revealed consistent clinically important benefits with routine multiple micronutrient supplementation in people living with HIV. Larger trials might reveal small but important effects.These findings should not be interpreted as a reason to deny micronutrient supplements for people living with HIV where specific deficiencies are found or where the person's diet is insufficient to meet the recommended daily allowance of vitamins and minerals.

The Relationship between Vitamin A Deficiency and Hiv Infection: Review of Scientific Studies

Review of the literature shows that in adults there are variations in the association of hyporetinemia with disease progression as well as variations in the response to supplementation. Populations that are likely to be deficient in vitamin A show the biggest responses. Additional vitamin A supplementation may not be necessary, and may even be harmful, in adults who already have a good dietary intake of vitamin A and who take many other vitamin supplements. Vitamin A supplementation does not appear to have any impact on mother-to-child transmission of HIV; nevertheless, vitamin A supplementation of pregnant women in the third trimester may be useful to reduce the incidence of low-birthweight and premature infants. the impact of vitamin A on mother-to-child transmission of HIV in preterm infants is awaiting further investigation. Vitamin A supplementation of HIV-infected children appears to be beneficial to reduce the incidence and severity of diarrhea in particular. Randomized, placebo-controlled trials in pregnant women and adults have shown that the association between vitamin A and HIV is probably an association of reverse causality.

An evidence-based systematic review of vitamin A by the natural standard research collaboration

An evidence-based systematic review of vitamin A by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated and reproducible grading rationale. This paper includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

Nutrition and disease progression pre-highly active antiretroviral therapy (HAART) and post-HAART: can good nutrition delay time to HAART and affect response to HAART?

Several studies have investigated a variety of nutritional supplementation interventions in adults with HIV. In this narrative review, we summarize the evidence from 31 clinical trials that explore clinical benefits of macronutrient and micronutrient supplementation in this population while attempting to answer the question of whether good nutrition can delay the time to highly active antiretroviral therapy (HAART) initiation and response. We focused on trials published in English between 1990 and 2010 that reported on CD4 count, viral load, and disease progression or survival. Among 9 macronutrient and 22 micronutrient trials, we found that evidence for improved CD4 count and HIV viral load with nutritional supplementation was limited; only 11.1% and 36.8% of macronutrient and micronutrient supplementation trials, respectively, reported improved CD4 count; and 33.3% and 12.5% of macronutrient and micronutrient trials, respectively, reported decreased viral load. Given their utility as surrogate markers of HIV disease progression, this suggests limited evidence for nutritional interventions having an impact on delaying HAART initiation or on improving HAART response. However, there are challenges in evaluating the effects of nutritional supplementation on clinical disease in that comparisons are difficult due to heterogeneity in study design, patient population, nutrient doses and combinations, baseline levels of deficiency, and study endpoints, including lack of clarity in defining and reporting HAART status. Future studies need to adopt a more rigorous standard design with adequate power and follow-up and require a consensus on composition and dose of nutrient interventions to be tested to more specifically answer the question on the impact of nutritional interventions on HIV disease progression and HAART response.

Micronutrient supplementation in children and adults with HIV infection

BACKGROUND

Micronutrient deficiencies are widespread and compound the effects of HIV disease; micronutrient supplements may be effective and safe in reducing this burden.

OBJECTIVES

To assess whether micronutrient supplements are effective and safe in reducing mortality and morbidity in adults and children with HIV infection.

SEARCH STRATEGY

The CENTRAL, EMBASE, PubMed, and GATEWAY databases were searched for randomised controlled trials of micronutrient supplements using the search methods of the Cochrane HIV/AIDS Group.

SELECTION CRITERIA

Randomised controlled trials were selected that compared the effects of micronutrient supplements (vitamins, trace elements, and combinations of these) with other supplements, placebo or no treatment on mortality, morbidity, pregnancy outcomes, immunologic indicators, and anthropometric measures in HIV-infected adults and children. Any adverse effects of supplementation were recorded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials, appraised trial quality for risk of bias using standardised criteria, and extracted data using standardised forms.

MAIN RESULTS

Sixteen additional trials are included in this update to the original Cochrane review (Irlam 2005). Overall, 30 trials involving 22 120 participants are reviewed: 20 trials of single supplements (vitamin A, vitamin D, zinc, selenium) and 10 of multiple micronutrients. Eight trials were undertaken in child populations.None of the six trials of vitamin A or beta-carotene supplementation in adults demonstrated any significant reduction in HIV disease progression. Vitamin A halved all-cause mortality in a meta-analysis of three trials in African children, had inconsistent impacts on diarrhoeal and respiratory morbidity, and improved short-term growth in one trial. No significant adverse effects of vitamin A in adults or children have been reported.Zinc supplements reduced diarrhoeal morbidity and had no adverse effects on disease progression in a single safety trial in South African children. No significant clinical benefits were found from zinc supplementation of pregnant Tanzanian women or Peruvian adults with persistent diarrhoea.Selenium reduced diarrhoeal morbidity in pregnant women in Tanzania, and reduced viral load in two separate small trials in American adults.Single trials of vitamin D supplements in adults, and in adolescents and children, demonstrated safety but no clinical benefits.Multiple micronutrient supplements conferred multiple clinical benefits to pregnant women and their offspring in a large Tanzanian trial. Supplementation in another Tanzanian trial reduced the recurrence of pulmonary TB and increased weight gain in co-infected patients. No significant adverse effects were reported.

AUTHORS' CONCLUSIONS

Multiple micronutrient supplements reduced morbidity and mortality in HIV-infected pregnant women and their offspring and also improved early child growth in one large randomised controlled trial in Africa. Additional research is needed to determine if these are generalisable findings. Vitamin A supplementation is beneficial and safe in HIV-infected children, but further evidence is needed to establish if supplementation confers similar benefits in HIV-infected adults. Zinc is safe in HIV-infected adults and children. It may have similar benefits in HIV-infected children and adults, and uninfected children with diarrhoea, as it does in HIV-uninfected children.Further trials of single supplements (vitamin D, zinc, and selenium) are required to build the evidence base. The long-term clinical benefits, adverse effects, and optimal formulation of multiple micronutrient supplements require further investigation in individuals with diverse disease status. 

Vitamin A status is associated with T-cell responses in Bangladeshi men

Recommendations for vitamin A intake are based on maintaining liver stores of > or = 0.070 micromol/g, which is sufficient to maintain normal vision. We propose that higher levels may be required to maintain normal immune function. To test this hypothesis, we conducted an 8-week residential study among thirty-six healthy Bangladeshi men with low vitamin A stores. Subjects were randomised to receive vitamin A (240 mg in four doses) or placebo during study weeks 2 and 3. Vitamin A stores were estimated by isotopic dilution at week 8. Total T-cells, the naive T-cells:memory T-cells ratio and mitogen-induced lymphocyte proliferation were positively and significantly correlated with vitamin A stores (P < 0.05). Mitogen-stimulated IL-2, IL-4 and TNFalpha increased significantly (P < 0.05) in the vitamin A but not placebo group after supplementation, while IL-10 production was significantly and negatively correlated with vitamin A stores (P < 0.05). Segmented linear regression analysis revealed that naive T-cell counts and T-cell blastogenesis were positively associated with vitamin A stores above but not below 0.070 mumol/g liver. These data show that increasing vitamin A stores above the level that maintains normal vision enhances some measures of T-cell-mediated immunity, suggesting a difference in requirements for maintaining vision and immune function.

Micronutrient interventions and HIV infection: a review of current evidence

OBJECTIVE

To review the current evidence on the role of micronutrient supplementation in HIV transmission and progression.

METHOD

Literature review.

RESULTS

The importance of micronutrients in the prevention and treatment of childhood infections is well known, and evidence is emerging that micronutrient interventions may also affect HIV transmission and progression.

CONCLUSION

Interventions to improve micronutrient intake and status could contribute to a reduction in the magnitude and impact of the global HIV epidemic. However, more research is needed before specific recommendations can be made.

Micronutrient levels and HIV disease status in HIV-infected patients on highly active antiretroviral therapy in the Nutrition for Healthy Living cohort

BACKGROUND

Low serum micronutrient levels were common before widespread use of highly active antiretroviral therapy (HAART) and were associated with adverse outcomes. Few data are available on micronutrient levels in subjects taking HAART.

OBJECTIVE

To determine the prevalence of low serum retinol, alpha-tocopherol, zinc, and selenium in HIV-infected subjects taking HAART and to assess the association of micronutrient levels with HIV disease status.

DESIGN

Cross-sectional.

SETTING

Nutrition for Healthy Living (NFHL) study.

PARTICIPANTS

HIV-infected subjects on HAART.

METHODS

Retinol, alpha-tocopherol, zinc, and selenium were determined in frozen serum samples from 171 men and 117 women. Low serum levels were defined as retinol <30 microg/dL, selenium <85 microg/L, alpha-tocopherol <500 microg/dL, and zinc <670 microg/L. Association of micronutrient quartiles with CD4 cell count, CD4 count <200 cells/mm, HIV viral load (VL), and undetectable VL was assessed using adjusted multivariate regression.

RESULTS

Five percent of men and 14% of women had low retinol, 8% of men and 3% of women had low selenium, and 7% of men and no women had low alpha-tocopherol. Forty percent of men and 36% of women had low zinc, however. Subjects in the upper quartiles of zinc had lower log VL levels than those in the lowest quartile (significant for women). Subjects in the upper quartiles of selenium also tended to have lower VL levels compared with those in the lowest quartile. Surprisingly, women in the upper quartiles of retinol had higher log VLs than those in the lowest quartile. There was no significant association of any micronutrient with CD4 cell count or likelihood of CD4 count <200 cells/mm. The level of CD4 cell count influenced the association of retinol with log VL in men, however. In men with CD4 counts >350 cells/mm, those with higher retinol had higher log VLs compared with the lowest quartile, whereas in men with CD4 counts <350, those with higher retinol levels had lower log VLs compared with the lowest quartile.

CONCLUSIONS

Low retinol, alpha-tocopherol, and selenium are uncommon in HIV-infected subjects on HAART. Zinc deficiency remains common, however. Decreased retinol levels in women and in men with CD4 counts >350 cells/mm and increased zinc and selenium levels in both genders may be associated with improved virologic control.

Effects of vitamins, including vitamin A, on HIV/AIDS patients

An estimated 25 million lives have been lost to acquired immune-deficiency syndrome (AIDS) since the immunodeficiency syndrome was first described in 1981. The progress made in the field of treatment in the form of antiretroviral therapy (ART) for HIV disease/AIDS has prolonged as well as improved the quality of life of HIV-infected individuals. However, access to such treatment remains a major concern in most parts of the world, especially in the developing countries. Hence, there is a constant need to find low-cost interventions to complement the role of ART in prevention of HIV infection and slowing clinical disease progression. Nutritional interventions, particularly vitamin supplementation, have the potential to be a low-cost method for being such an intervention by virtue of their modulation of the immune system. Among all the vitamins, the role of vitamin A has been studied most extensively; most observational studies have found that low vitamin A levels are associated with increased risk of transmission of HIV from mother to child. This finding has not been supported by large randomized trials of vitamin A supplementation; on the contrary, these trials have found that vitamin A supplementation increases the risk of mother-to-child transmission (MTCT). There are a number of potential mechanisms that might explain these contradictory findings. One is the issue of reverse causality in observational studies-for instance, advanced HIV disease may suppress release of vitamin A from the liver. This would lead to low levels of vitamin A in the plasma despite the body having enough vitamin A liver stores. Further, advanced HIV disease is likely to increase the risk of MTCT, and hence it would appear that low serum vitamin A levels are associated with increased MTCT. The HIV genome also has a retinoic acid receptor element-hence, vitamin A may increase HIV replication via interacting with this element, thus increasing risk of MTCT. Finally, vitamin A is known to increase lymphoid cell differentiation, which leads to an increase in CCR5 receptors. These receptors are essential for attachment of HIV to the lymphocytes and therefore, an increase in their number is likely to increase HIV replication. Vitamin A supplementation in HIV-infected children, on the other hand, has been associated with protective effects against mortality and morbidity, similar to that seen in HIV-negative children. The risk for lower respiratory tract infection and severe watery diarrhea has been shown to be lower in HIV-infected children supplemented with vitamin A. All-cause mortality and AIDS-related deaths have also been found to be lower in vitamin A-supplemented HIV-infected children. The benefits of multivitamin supplementation, particularly vitamins B, C, and E, have been more consistent across studies. Multivitamin supplementation in HIV-infected pregnant mothers has been shown to reduce the incidence of adverse pregnancy outcomes such as fetal loss and low birth weight. It also has been shown to decrease rates of MTCT among women who have poor nutritional or immunologic status. Further, multivitamin supplementation reduces the rate of HIV disease progression among patients in early stage of disease, thus delaying the need for ART by prolonging the pre-ART stage. In brief, there is no evidence to recommend vitamin A supplementation of HIV-infected pregnant women; however, periodic vitamin A supplementation of HIV-infected infants and children is beneficial in reducing all-cause mortality and morbidity and is recommended. Similarly, multivitamin supplementation of people infected with HIV, particularly pregnant women, is strongly suggested.

Synergy between mannose-binding lectin gene polymorphisms and supplementation with vitamin A influences susceptibility to HIV infection in infants born to HIV-positive mothers

BACKGROUND

Mannose-binding lectin (MBL-2) allele variants are associated with deficiencies in innate immunity and have been found to be correlated with HIV infection in adults and children.

OBJECTIVE

We tested whether MBL-2 variants among infants born to HIV-positive mothers have an increased susceptibility to HIV.

DESIGN

MBL-2 allele variants were measured among 225 infants born to HIV-positive mothers enrolled in a trial in Durban, South Africa. Mothers of 108 infants were randomly assigned to receive vitamin A and beta-carotene supplementation and 117 to receive placebo. Infants were followed with regular HIV tests to determine rates of mother-to-child HIV transmission.

RESULTS

A high proportion of infants were either homozygous (10.7%) or heterozygous (32.4%) for MBL-2 variants. MBL-2 variants within the placebo arm were associated with an increased risk of HIV transmission (odds ratio: 3.09; 95% CI: 1.21, 7.86); however, MBL-2 variants within the supplementation arm were not associated with an increased risk of transmission (P = 0.04; test of interaction). Among infants with MBL-2 variants, supplementation was associated with a decreased risk of HIV transmission (odds ratio: 0.37; 95% CI: 0.15, 0.91).

CONCLUSION

We observed what appears to be a gene-environment interaction between MBL-2 variants and an intervention with vitamin A plus beta-carotene that is relevant to mother-to-child HIV transmission.

Recommended dose for repair of serum vitamin A levels in patients with HIV infection/AIDS may be insufficient because of high urinary losses

OBJECTIVE

Retinol deficiency is quite frequent in the population of human immunodeficiency virus (HIV)-infected individuals. Serum retinol levels of less than 1.05 micromol/L determine a 3.5 to five times higher death risk. However, studies evaluating the efficacy of retinol supplementation in HIV-seropositive individuals have reported conflicting results. The World Health Organization recommends the treatment of vitamin A deficiency in seropositive individuals in the same manner as for seronegative individuals, but clinical studies proving the efficacy of this scheme are lacking. The proposal of the present study was to assess the efficacy of supplementation with high retinol doses in HIV-infected patients with vitamin A deficiency.

METHODS

Twenty-five adult HIV-seropositive individuals were monitored over a period of 9 months, with determination of serum and urinary retinol every 3 months. The subjects received retinol palmitate doses ranging from 300,000 IU to 600,000 IU. Patients whose retinol levels were higher than 1.60 micromol/L were only observed.

RESULTS

Eighteen patients received supplementation during clinical monitoring. The dose of 600,000 IU induced a significant mean increase in serum levels of 0.47 micromol/L (P = 0.049) within a period of three months. Those who received 300,000 IU presented a mean increase of 0.29 micromol/L. In contrast, the patients who did not receive replacement therapy presented a significant decrease (P = 0.017) in serum retinol levels, with initial and final values of 1.77 micromol/L and 1.55 micromol/L. The individuals with the worst response to supplementation presented a higher urinary loss of retinol at the beginning of the study. Even with a mean retinol supplementation of 771,428 IU during the study period, six patients had marginal serum retinol levels at the end of the study.

CONCLUSION

We conclude that, in view of the high urinary loss of this nutrient, there is the need to redefine the ideal dose for the treatment of HIV-infected individuals.

The acute and chronic toxic effects of vitamin A

The acute and chronic effects of vitamin A toxicity are well documented in the literature. Emerging evidence suggests that subtoxicity without clinical signs of toxicity may be a growing concern, because intake from preformed sources of vitamin A often exceeds the recommended dietary allowances (RDA) for adults, especially in developed countries. Osteoporosis and hip fracture are associated with preformed vitamin A intakes that are only twice the current RDA. Assessing vitamin A status in persons with subtoxicity or toxicity is complicated because serum retinol concentrations are nonsensitive indicators in this range of liver vitamin A reserves. The metabolism in well-nourished persons of preformed vitamin A, provided by either liver or supplements, has been studied by several research groups. To control vitamin A deficiency, large therapeutic doses are administered in developing countries to women and children, who often are undernourished. Nevertheless, little attention has been given to the short-term kinetics (ie, after absorption but before storage) of a large dose of vitamin A or to the short- and long-term effects of such a dose given to lactating women on serum and breast-milk concentrations of retinol and its metabolites. Moreover, appropriate dosing regimens have not been systematically evaluated to ascertain the quantitative improvement in vitamin A status of the women and children who receive these supplements. The known acute and chronic effects of vitamin A toxicity have been reported previously. However, further research is needed to ascertain the areas of the world in which subclinical toxicity exists and to evaluate its effects on overall health and well-being.

Micronutrient supplementation in children and adults with HIV infection

BACKGROUND

The scale and impact of the HIV/AIDS pandemic has made the search for simple, affordable, safe, and effective public health interventions all the more urgent. Micronutrient supplements hold the promise of meeting these criteria, but their widespread use needs to be based on sound scientific evidence of effectiveness and safety.

OBJECTIVES

To assess whether micronutrient supplements are effective in reducing morbidity and mortality in adults and children with HIV infection.

SEARCH STRATEGY

The Cochrane Library (CENTRAL), EMBASE, MEDLINE, AIDSearch, CINAHL, and conference proceedings were searched, and pharmaceutical manufacturers and researchers in the field were contacted to locate any ongoing or unpublished trials.

SELECTION CRITERIA

Randomised controlled trials comparing the effects of micronutrient supplements (vitamins, trace elements, and combinations of these) with placebo or no treatment on mortality and morbidity in HIV-infected individuals.

DATA COLLECTION AND ANALYSIS

Two reviewers independently appraised trial quality and extracted data. Study authors were contacted for additional data where necessary. A meta-analysis was not deemed appropriate due to significant heterogeneity between trials.

MAIN RESULTS

Fifteen trials were included. Six trials comparing vitamin A/beta-carotene with placebo in adults failed to show any effects on mortality, morbidity, CD4 and CD8 counts, or on viral load. Four trials of other micronutrients in adults did not affect overall mortality, although there was a reduction in mortality in a low CD4 subgroup. In a large Tanzanian trial in pregnant and lactating women, daily multivitamin supplementation was associated with a number of benefits to both mothers and children: a reduction in maternal mortality from AIDS-related causes; a reduced risk of progression to stage four disease; fewer adverse pregnancy outcomes; less diarrhoeal morbidity; and a reduction in early-child mortality among immunologically- and nutritionally-compromised women. Vitamin A alone reduced all-cause mortality and improved growth in a small sub-group of HIV-infected children in one hospital-based trial, and reduced diarrhoea-associated morbidity in a small HIV-infected sub-group of infants in another trial.

AUTHORS' CONCLUSIONS

There is no conclusive evidence at present to show that micronutrient supplementation effectively reduces morbidity and mortality among HIV-infected adults. It is reasonable to support the current WHO recommendations to promote and support adequate dietary intake of micronutrients at RDA levels wherever possible. There is evidence of benefit of vitamin A supplementation in children. The long-term clinical benefits, adverse effects, and optimal formulation of micronutrient supplements require further investigation.

Effects of vitamin a supplementation on immune responses and correlation with clinical outcomes

Vitamin A supplementation to preschool children is known to decrease the risks of mortality and morbidity from some forms of diarrhea, measles, human immunodeficiency virus (HIV) infection, and malaria. These effects are likely to be the result of the actions of vitamin A on immunity. Some of the immunomodulatory mechanisms of vitamin A have been described in clinical trials and can be correlated with clinical outcomes of supplementation. The effects on morbidity from measles are related to enhanced antibody production and lymphocyte proliferation. Benefits for severe diarrhea could be attributable to the functions of vitamin A in sustaining the integrity of mucosal epithelia in the gut, whereas positive effects among HIV-infected children could also be related to increased T-cell lymphopoiesis. There is no conclusive evidence for a direct effect of vitamin A supplementation on cytokine production or lymphocyte activation. Under certain circumstances, vitamin A supplementation to infants has the potential to improve the antibody response to some vaccines, including tetanus and diphtheria toxoids and measles. There is limited research on the effects of vitamin A supplementation to adults and the elderly on their immune function; currently available data provide no consistent evidence for beneficial effects. Additional studies with these age groups are needed.

Elevated serum concentrations of beta-glucuronide metabolites and 4-oxoretinol in lactating sows after treatment with vitamin A: a model for evaluating supplementation in lactating women

BACKGROUND

The effects of large doses of preformed vitamin A, such as those provided in supplementation programs for the prevention of deficiency, on total serum vitamin A have been inadequately investigated.

OBJECTIVE

This study characterized the time course of serum vitamin A metabolites in lactating sows after single high doses of retinyl ester.

DESIGN

Lactating sows were fitted with jugular catheters and subsequently fed either 1.05 or 2.1 mmol retinyl ester (n = 6/group) or a corn oil vehicle (n = 3). Blood was collected at baseline and at intervals to 48 h and analyzed by gradient HPLC for retinol, retinyl esters, and metabolites.

RESULTS

The mean (+/-SD) total serum vitamin A concentration peaked at 1 h (3.69 +/- 4.0 mumol/L) and 2 h (7.70 +/- 6.8 mumol/L) in the low- and high-dose groups, respectively (P < 0.05). Retinyl esters accounted for most of the serum vitamin A in both groups at peak time points. Mean serum retinol concentrations changed little and accounted for most of the serum vitamin A at baseline (94% and 97% for the low- and high-dose groups, respectively) but for only 22% and 14% at peak times for the low- and high-dose groups, respectively. Postdosage increases were observed for total vitamin A and retinyl esters, 4-oxoretinol, retinoyl beta-glucuronide, and retinyl beta-glucuronide but not for retinoic acid.

CONCLUSIONS

Serum retinol concentration remains relatively static after a large dose of preformed vitamin A and therefore is not an appropriate measure of intervention efficacy. The increases in beta-glucuronide metabolites and 4-oxoretinol suggest a preventive role against a rise in retinoic acid and retinol.

One-time vitamin A supplementation of lactating sows enhances hepatic retinol in their offspring independent of dose size

BACKGROUND

Single megadoses of vitamin A between 200,000 and 400,000 IU have been administered to lactating mothers to improve the vitamin A status of both mothers and breastfeeding infants. However, the most beneficial dosing regimen is not known.

OBJECTIVE

The effect of megadoses of vitamin A supplements given to lactating sows on hepatic vitamin A concentrations in their nursing offspring was examined.

DESIGN

Lactating sows were given a high (2.1 mmol), low (1.05 mmol), or control (0 mmol) dose of retinyl acetate in oil (n=3 sows per treatment). Piglets nursed for 3 or 14 d, consumed a vitamin A-free diet for the next 4 d, and were then killed. Liver and serum samples were analyzed for vitamin A.

RESULTS

After 3 d, piglets of the control, low-dose, and high-dose sows had different (P=0.034) hepatic vitamin A concentrations, ie, 0.078+/-0.004, 0.14+/-0.053, and 0.13+/-0.026 micromol/g, respectively. Liver vitamin A concentrations on day 18 were 0.069+/-0.004, 0.14+/-0.044, and 0.11+/-0.026 micromol/g in the control, low-dose, and high-dose piglets, respectively (P=0.017). Liver vitamin A concentrations in piglets of the low- and high-dose sows were not significantly different (day 3: P=0.97; day 18: P=0.59). Serum retinol concentrations were higher (P=0.02) at early kill (0.95+/-0.22 micromol/L) than at late kill (0.76+/-0.24 micromol/L) but were not significantly different between groups.

CONCLUSIONS

Maternal vitamin A supplementation enhances liver vitamin A concentrations in offspring. Larger one-time doses are not more effective than are smaller doses. Additional research is needed to determine the most effective maternal dosing regimens for improving infant vitamin A status.

A theoretical increase in infants' hepatic vitamin a is realized using a supplemented lactating sow model

Vitamin A deficiency (VAD) is a public health problem affecting millions in developing nations. Supplementation for lactating women, whose needs are high, involves large oral doses of the preformed vitamin. The safety and efficacy of these doses has been inadequately studied. Lactating women typically receive 210 micro mol of retinyl ester during early lactation, but 420 micro mol has also been administered. If larger doses of vitamin A are not significantly more effective in preventing VAD in mothers and infants, then smaller doses would be recommended. We therefore examined the vitamin A concentration of milk from lactating sows (n = 15) that were provided two different doses of vitamin A (i.e., 1050 or 2100 micro mol, n = 6/group) or corn oil (n = 3), corresponding to doses given women on the basis of body weight. Compared with controls, an overall significant treatment effect was found (P = 0.0019), but there was no difference in milk concentration between treatment groups. Theoretically, applying the mean milk vitamin A concentrations of the groups through 12 h and values to 48 h from 4 sows, we estimate that an infant of a supplemented mother could realize an increase of +0.08 or 0.16 micro mol/g liver from the low or high dose, respectively.

Plasma vitamin A and zinc levels in HIV-infected adults in Cape Town, South Africa

A cross-sectional study of 132 adults attending an HIV clinic in Cape Town, South Africa, was conducted to determine predictors of low plasma vitamin A and Zn levels. No patients were on antiretroviral therapy. The possible confounding effect of the acute-phase response was controlled by including C-reactive protein levels in multivariate analysis and by excluding active opportunistic infections. Retinol levels were low (<1.05 micromol/l) in 39 % of patients with early disease (WHO clinical stages I and II) compared with 48 and 79 % of patients with WHO stage III and IV respectively (P<0.01). Plasma Zn levels were low (<10.7 micromol/l) in 20 % of patients with early disease v. 36 and 45 % with stage III and IV disease respectively (P<0.05). C-reactive protein levels were normal in 63 % of subjects. Weak, positive associations were found between CD4+ lymphocyte count and plasma levels of retinol (r 0.27; 95 % CI 0.1, 0.43) and Zn (r 0.31; 95 % CI 0.25, 0.46). Multivariate analysis showed the following independent predictors of low retinol levels: WHO stage IV (odds ratio 3.4; 95 % CI 2.1, 5.7) and body weight (odds ratio per 5 kg decrease 1.15; 95 % CI, 1.08, 1.25), while only body weight was significantly associated with low Zn levels (OR per 5 kg decrease 1.19; 95 % CI 1.09, 1.30). CD4+ lymphocyte count <200/microl was not significantly associated with either low retinol or Zn levels. In resource-poor settings, simple clinical features (advanced disease and/or weight loss) are associated with lowered blood concentrations of vitamin A and/or Zn. The clinical significance of low plasma retinol and/or Zn levels is unclear and more research is required to establish the role of multiple micronutrient intervention strategies in HIV disease.

Vitamin A deficiency and the acute phase response among HIV-1-infected and -uninfected women in Kenya

Among HIV-1-infected individuals, vitamin A deficiency has been associated with faster disease progression and greater infectivity in observational studies, but randomized clinical trials have shown no effect of vitamin A supplementation. We conducted a cross-sectional study of 400 HIV-1-infected and 200 HIV-1-uninfected women in Mombasa, Kenya to examine the relations between vitamin A deficiency (serum retinol <30 microg/dL) and HIV-1 status, HIV-1 disease stage, and the acute phase response (serum C-reactive protein >or=10 mg/L and/or alpha1-acid glycoprotein >or=1.2 g/L). Among the HIV-1-infected women, the effect of vitamin A supplementation was examined in a randomized trial. Vitamin A deficiency was independently associated with HIV-1 infection (OR = 2.7, 95% CI: 1.9-4.0) and the acute phase response (OR = 2.8, 95% CI: 1.9-4.1). Among HIV-1-infected women, vitamin A deficiency and the acute phase response were associated with each other and were both independently associated with higher HIV-1 plasma viral load and lower CD4 count. HIV-1-infected women having an acute phase response had no increase in serum vitamin A levels after supplementation. Serum levels increased significantly among women without an acute phase response, although not to normal levels among women who were deficient at baseline. Among HIV-1-infected individuals, it is likely that low serum vitamin A concentrations reflect more active infection and the acute phase response. These results provide possible explanations for the disparity between observational studies and randomized trials of vitamin A for HIV-1 infection.

Randomized trial of vitamin supplements in relation to transmission of HIV-1 through breastfeeding and early child mortality

BACKGROUND

HIV-1 transmission through breastfeeding is a global problem and has been associated with poor maternal micronutrient status.

METHODS

A total of 1078 HIV-infected pregnant women from Tanzania were randomly assigned to vitamin A or multivitamins excluding A from approximately 20 weeks' gestation and throughout lactation.

RESULTS

Multivitamins excluding A had no effect on the total risk of HIV-1 transmission (RR 1.04, 95% CI 0.82-1.32, P= 0.76). Vitamin A increased the risk of transmission (RR 1.38, 95% CI 1.09-1.76, P = 0.009). Multivitamins were associated with non-statistically significant reductions in transmission through breastfeeding, and mortality by 24 months among those alive and not infected at 6 weeks. Multivitamins significantly reduced breastfeeding transmission in infants of mothers with low baseline lymphocyte counts (RR 0.37; 95% CI 0.16-0.85, P = 0.02) compared with infants of mothers with higher counts (RR 0.99, 95% CI 0.68-1.45, P = 0.97; -for-interaction 0.03). Multivitamins also protected against transmission among mothers with a high erythrocyte sedimentation rate (P-for-interaction 0.06), low hemoglobin (P-for-interaction 0.06), and low birthweight babies (P-for-interaction 0.04). Multivitamins reduced death and prolonged HIV-free survival significantly among children born to women with low maternal immunological or nutritional status. Vitamin A alone increased breastfeeding transmission but had no effect on mortality by 24 months.

CONCLUSION

Vitamin A increased the risk of HIV-1 transmission. Multivitamin (B, C, and E) supplementation of breastfeeding mothers reduced child mortality and HIV-1 transmission through breastfeeding among immunologically and nutritionally compromised women. The provision of these supplements to HIV-infected lactating women should be considered.

Micronutrients and vertical transmission of HIV-1

ABSTRACT Vertical transmission of HIV from mother to infant can occur during pregnancy, at the time of delivery, or post-natally through breast-feeding and is a major factor in the continuing spread of HIV infection. Inadequate nutritional status may increase the risk of vertical HIV transmission by influencing mater-nal and child factors for transmission. The potential effects on these factors include impaired systemic immune function in pregnant women, fetuses, and children; an increased rate of clinical, immunologic, and virologic disease progression; impaired epithelial integrity of the placenta and genital tract; increased viral shedding in breast milk from inflammation of breast tissue; increased risk of low birth weight and preterm birth; and impaired gastrointestinal immune function and integrity in fetuses and children. Micronutrient deficiencies are prevalent in many HIV-infected populations, and numerous studies have reported that these deficiencies impair immune responses, weaken epithelial integrity, and are associated with accelerated HIV disease progression. Although low serum vitamin A concentrations were shown to be associated with an increased risk of vertical HIV transmission in prospective cohort studies, randomized, placebo-controlled trials have reported that vitamin A and other vitamin supplements do not appear to have an effect on HIV transmission during pregnancy or the intrapartum period. However, the ability of prenatal and postpartum micronutrient supplements to reduce transmission during the breast-feeding period is still unknown.

Vitamin A and HIV infection: disease progression, mortality, and transmission

Among HIV-infected individuals, many nutritional factors that influence disease progress, mortality, and transmission are not well understood. Of particular interest is the role of vitamin A. The benefits of vitamin A have been recognized since ancient times by Egyptian physicians who successfully treated night blindness with vitamin A. Contemporary scientists have since recognized the importance of vitamin A and have provided evidence that it may help in repairing damaged mucosal surfaces; what remains unclear, however, is its role during HIV infection. In this review, we examine the evidence provided in both observational studies and randomized controlled trials that assessed the effect of vitamin A during HIV infection.