Celeste E. Naude

Low Carbohydrate versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A Systematic Review and Meta-Analysis

Background Some popular weight loss diets restricting carbohydrates (CHO) claim to be more effective, and have additional health benefits in preventing cardiovascular disease compared to balanced weight loss diets. Methods and Findings We compared the effects of low CHO and isoenergetic balanced weight loss diets in overweight and obese adults assessed in randomised controlled trials (minimum follow-up of 12 weeks), and summarised the effects on weight, as well as cardiovascular and diabetes risk. Dietary criteria were derived from existing macronutrient recommendations. We searched Medline, EMBASE and CENTRAL (19 March 2014). Analysis was stratified by outcomes at 3–6 months and 1–2 years, and participants with diabetes were analysed separately. We evaluated dietary adherence and used GRADE to assess the quality of evidence. We calculated mean differences (MD) and performed random-effects meta-analysis. Nineteen trials were included (n = 3209); 3 had adequate allocation concealment. In non-diabetic participants, our analysis showed little or no difference in mean weight loss in the two groups at 3–6 months (MD 0.74 kg, 95%CI −1.49 to 0.01 kg; I2 = 53%; n = 1745, 14 trials; moderate quality evidence) and 1–2 years (MD 0.48 kg, 95%CI −1.44 kg to 0.49 kg; I2 = 12%; n = 1025; 7 trials, moderate quality evidence). Furthermore, little or no difference was detected at 3–6 months and 1–2 years for blood pressure, LDL, HDL and total cholesterol, triglycerides and fasting blood glucose (>914 participants). In diabetic participants, findings showed a similar pattern. Conclusions Trials show weight loss in the short-term irrespective of whether the diet is low CHO or balanced. There is probably little or no difference in weight loss and changes in cardiovascular risk factors up to two years of follow-up when overweight and obese adults, with or without type 2 diabetes, are randomised to low CHO diets and isoenergetic balanced weight loss diets.

Vitamin D and Calcium Status in South African Adolescents with Alcohol Use Disorders

Adequate vitamin D and calcium are essential for optimal adolescent skeletal development. Adolescent vitamin D insufficiency/deficiency and poor calcium intake have been reported worldwide. Heavy alcohol use impacts negatively on skeletal health, which is concerning since heavy adolescent drinking is a rising public health problem. This study aimed to examine biochemical vitamin D status and dietary intakes of calcium and vitamin D in 12–16 year-old adolescents with alcohol use disorders (AUD), but without co-morbid substance use disorders, compared to adolescents without AUD. Substance use, serum 25-hydroxyvitamin D (s-25(OH)D) concentrations, energy, calcium and vitamin D intakes were assessed in heavy drinkers (meeting DSM-IV criteria for AUD) (n = 81) and in light/non-drinkers without AUD (non-AUD) (n = 81), matched for age, gender, language, socio-economic status and education. Lifetime alcohol dose was orders of magnitude higher in AUD adolescents compared to non-AUD adolescents. AUD adolescents had a binge drinking pattern and “weekends-only” style of alcohol consumption. Significantly lower (p = 0.038) s-25(OH)D (adjusted for gender, smoking, vitamin D intake) were evident in AUD adolescents compared to non-AUD adolescents. High levels of vitamin D insufficiency/deficiency (s-25(OH)D < 29.9 ng/mL) were prevalent in both groups, but was significantly higher (p = 0.013) in the AUD group (90%) compared to the non-AUD group (70%). All participants were at risk of inadequate calcium and vitamin D intakes (Estimated Average Requirement cut-point method). Both groups were at risk of inadequate calcium intake and had poor biochemical vitamin D status, with binge drinking potentially increasing the risk of the latter. This may have negative implications for peak bone mass accrual and future osteoporosis risk, particularly with protracted binge drinking.

High-dose vitamin D3 reduces deficiency caused by low UVB exposure and limits HIV-1 replication in urban Southern Africans.

Significance Vitamin D deficiency is associated with HIV/AIDS progression and mortality. Seasonal decline in UVB radiation, darkly pigmented skin, low nutritional vitamin D intake, and genetic variation can increase risk of deficiency. Cape Town, South Africa, has a seasonal UVB regime and one of the world’s highest rates of HIV-1 infection, peaking in young adults. In two ethnically distinct groups of young adults in Cape Town we found high prevalence of seasonal vitamin D deficiency resulting from inadequate UVB exposure. This deficiency was associated with increased permissiveness of blood cells to HIV-1 infection which was reversed by vitamin D3 supplementation. Vitamin D may be a simple, cost-effective intervention, particularly in resource-poor settings, to reduce HIV-1 risk and disease progression. Cape Town, South Africa, has a seasonal pattern of UVB radiation and a predominantly dark-skinned urban population who suffer high HIV-1 prevalence. This coexistent environmental and phenotypic scenario puts residents at risk for vitamin D deficiency, which may potentiate HIV-1 disease progression. We conducted a longitudinal study in two ethnically distinct groups of healthy young adults in Cape Town, supplemented with vitamin D3 in winter, to determine whether vitamin D status modifies the response to HIV-1 infection and to identify the major determinants of vitamin D status (UVB exposure, diet, pigmentation, and genetics). Vitamin D deficiency was observed in the majority of subjects in winter and in a proportion of individuals in summer, was highly correlated with UVB exposure, and was associated with greater HIV-1 replication in peripheral blood cells. High-dosage oral vitamin D3 supplementation attenuated HIV-1 replication, increased circulating leukocytes, and reversed winter-associated anemia. Vitamin D3 therefore presents as a low-cost supplementation to improve HIV-associated immunity.

Systematic review of the effects of iodised salt and iodine supplements on prenatal and postnatal growth: study protocol

Introduction Iodine is an essential micronutrient and component of the thyroid hormones. Sufficient ingestion of iodine is necessary for normal growth and development. If iodine requirements are not met, growth can be impaired. Salt iodisation and supplementation with iodine can prevent iodine deficiency disorders and stunted growth. No systematic review has yet collated the evidence linking iodine to growth. With an increased emphasis on stunting within the WHO Global Nutrition Targets for 2025, we propose a systematic review to address this question. Methods and analysis We will undertake a systematic review, and if appropriate, meta-analyses, evaluating the effects of iodised salt or iodine supplements on prenatal and postnatal somatic growth, until age 18. We will search a number of databases, including MEDLINE, EMBASE, Web of Science, CINAHL, PsychINFO, the Cochrane Library, including the CENTRAL register of Controlled Trials and also the WHO library and ICTRP (International Clinical Trials Registry Platform), which includes the Clinicaltrials.gov repository. We will also search Wanfang Data and the China Knowledge Resource Integrated Database. Included studies must have compared exposure to iodised salt, iodine supplements or iodised oil, to placebo, non-iodised salt or no intervention. Primary outcomes will be continuous and categorical markers of prenatal and postnatal somatic growth. Secondary outcomes will cover further measures of growth, including growth rates and indirect markers of growth such as insulin-like growth factor-1 (IGF-1). Ethics and dissemination The systematic review will be published in a peer-reviewed journal, and will be sent directly to the WHO, United Nations Childrens Fund, International Council for the Control of Iodine Deficiency Disorders and other stakeholders. The results generated from this systematic review will provide evidence to support future programme recommendations regarding iodine fortification or supplementation and child growth. Trial registration number PROSPERO CRD42014012940.

Iodised salt and iodine supplements for prenatal and postnatal growth: a rapid scoping of existing systematic reviews

BackgroundIodine deficiency can adversely affect child development including stunted growth. However, the effect of iodine supplementation or fortification on prenatal and postnatal growth in children (<18 years) is unclear. We identified the potential need for a systematic review to contribute to the evidence base in this area. To avoid duplication and inform the need for a new systematic review and its protocol, we undertook a rapid scoping review of existing systematic reviews investigating the effect of iodised salt and iodine supplements on growth and other iodine-related outcomes.MethodsWe searched TRIP and Epistemokinos (latest search date 15 December 2014). All English language systematic reviews reporting on the effect of iodine supplementation or fortification in any form, dose or regimen on any iodine-related health outcomes (including but not limited to growth) were included. Eligible systematic reviews could include experimental or observational studies in pregnant or lactating women or children to age 18. We tabulated the extracted data to capture the scope of questions addressed, including: author, publication year, most recent search date, participants, pre-specified treatment/exposure and comparator, pre-specified outcomes, outcomes relevant to our question and number and type of studies included. Methodological quality of included reviews was assessed using AMSTAR.ResultsNine hundred and seventy-six records were screened and 10 reviews included. Most studies were of moderate methodological quality. Outcomes included assessments of thyroid function, iodine deficiency disorders, mental development and growth. Populations studied included pregnant women, preterm infants and children into adulthood. Most reviews looked at direct iodine supplementation or fortification, though some reviews considered iodine status, including the relationship between iodine intake and iodine biomarkers. Although five reviews pre-specified inclusion of growth outcomes, none provided synthesised evidence on the effects of iodine supplementation or fortification on prenatal and postnatal somatic growth.ConclusionsOur rapid scoping review demonstrates a gap in the evidence base with no existing, up-to-date systematic reviews on the effects of all forms of iodine supplementation/fortification in all of the relevant population groups on relevant growth and growth-related outcomes. A new systematic review examining this question will assist in addressing this gap.

Breastfeeding policies and practices in health care facilities in the Western Cape Province, South Africa

Abstract The Baby-Friendly Hospital Initiative (BFHI) is a global effort to improve the role of maternity services and to enable mothers to breastfeed their infants, thus ensuring the best start in life for their infants. The foundation for the BFHI is the Ten Steps to Successful Breastfeeding (BF). It has been shown, however, that the selective implementation of only some of the steps may be ineffective and discouraging to successful BF practices. An initial study was therefore conducted to assess the extent of the implementation of the Ten Steps in both public and private maternity facilities. Poor performance for some steps led to a follow-up study to investigate the knowledge and attitudes of health care workers (HCWs) and mothers alike and to evaluate the exclusive BF (EBF) practices of mothers attending private BF clinics. Both studies followed descriptive, cross-sectional designs and were set in the Cape Metropole in the Western Cape. Twenty-six maternity facilities participated in the initial study, for which observation lists were completed and verified by interviewer-administered questionnaires to both HCWs and mothers. Eighteen private BF clinics participated in the follow-up study, which included observations and interviewer-administered questionnaires to 25 HCWs and 64 mothers. During the initial study, lower mean scores were noted for Steps 1, 2, 6 and 10. The overall implementation of the Ten Steps was average. The findings highlighted the importance of the establishment and implementation of BF policies, of appropriate and continuous BF training and better referral systems to ensure initiation and establishment of early BF, EBF practices and support on an ongoing basis to ensure the best start in life for infants.

Research evidence and policy: qualitative study in selected provinces in South Africa and Cameroon

BackgroundThe translation of research into policy and practice is enhanced by policymakers who can recognise and articulate their information needs and researchers that understand the policymakers’ environment. As researchers, we sought to understand the policymaking process and how research evidence may contribute in South Africa and Cameroon.MethodsWe conducted qualitative in-depth interviews in South Africa and focus group discussions in Cameroon with purposively sampled subnational (provincial and regional) government health programme managers. Audio recorded interviews were transcribed, thematically coded and analysed.ResultsParticipants in both countries described the complex, often lengthy nature of policymaking processes, which often include back-and-forth consultations with many diverse stakeholder groups. These processes may be influenced by political structures, relationships between national and subnational levels, funding and international stakeholder agendas. Research is not a main driver of policy, but rather current contextual realities, costs, logistics and people (clinicians, NGOs, funders) influence the policy, and research plays a part. Research evidence is frequently perceived as unavailable, inaccessible, ill-timed or not applicable. The reliability of research on the internet was questioned. Evidence-informed health decision-making (EIDM) is regarded as necessary in South Africa but is less well understood in Cameroon. Insufficient time and capacity were hindrances to EIDM in both countries. Good relationships between researchers and policymakers may facilitate EIDM. Researchers should have a good understanding of the policymaking environment if they want to influence it. Greater interaction between policymakers and researchers is perceived as beneficial when formulating research and policy questions as it raises researchers’ awareness of implementation challenges and enables the design of tailored and focused strategies to respond to policymakers’ needs.ConclusionsPolicymaking is complicated, lengthy and mostly done at national level. Provinces/regions are tasked with implementation, with more room for adaptation in South Africa than in Cameroon. Research evidence plays a role in policy but does not drive it and is seen as mostly unavailable. Researchers need a thorough understanding of the policy process and environment, how the health system operates, as well as the priorities of policymakers. This can inform effective dialogue between researchers and policymakers, and contribute to enhancing use of research evidence in decision-making.

Would an increase in vegetable and fruit intake help to reduce the burden of nutrition-related disease in South Africa? An umbrella review of the evidence

Abstract Evidence indicates that increased vegetable and fruit intake improves health. The intake of vegetables and fruit in South Africa is much lower than recommended. When considering the promotion of greater vegetable and fruit intake in South Africa, it is necessary to view the available evidence on the relationship between vegetable and fruit intake and disease risk reduction through a South African lens. This will help to determine whether or not interventions to optimise vegetable and fruit intake would contribute to reducing the burden of nutrition-related disease in South Africa. The aim of this umbrella review was to compile the best available evidence from multiple reviews and scientific reports on the link between vegetable and fruit intake and the nutrition-related burden-of-disease profile in South Africa. Vegetable and fruit intake has been associated with prevalent nutrition-related problems in South Africa, including vitamin A status and adiposity in children; and cancer, cardiovascular disease, type 2 diabetes and adiposity in adults. Reviewed evidence from systematic reviews and scientific reports has suggested that increasing vegetable and fruit intake in South Africa could potentially contribute to reducing the burden of nutrition-related conditions in this country. Increasing vegetable and fruit intake in preschool children could improve their vitamin A nutriture. Enhancing vegetable and fruit intake in adults could contribute to reducing the risk of certain prevalent cancers (lung and gastrointestinal) and cardiovascular disease (coronary heart disease, ischaemic heart disease and cerebrovascular accidents). It should be kept in mind that the methodological quality of the included systematic reviews ranged from low to high (AMSTAR), and most reviews did not assess the scientific quality of the included studies. This evidence supports the need to promote greater vegetable and fruit intake in South Africa.

An analysis of methods used to synthesize evidence and grade recommendations in food-based dietary guidelines

Abstract Evidence-informed guideline development methods underpinned by systematic reviews ensure that guidelines are transparently developed, free from overt bias, and based on the best available evidence. Only recently has the nutrition field begun using these methods to develop public health nutrition guidelines. Given the importance of following an evidence-informed approach and recent advances in related methods, this study sought to describe the methods used to synthesize evidence, rate evidence quality, grade recommendations, and manage conflicts of interest (COIs) in national food-based dietary guidelines (FBDGs). The Food and Agriculture Organization’s FBDGs database was searched to identify the latest versions of FBDGs published from 2010 onward. Relevant data from 32 FBDGs were extracted, and the findings are presented narratively. This study shows that despite advances in evidence-informed methods for developing dietary guidelines, there are variations and deficiencies in methods used to review evidence, rate evidence quality, and grade recommendations. Dietary guidelines should follow systematic and transparent methods and be informed by the best available evidence, while considering important contextual factors and managing conflicts of interest.

VITAMIN D FOR TREATMENT AND PREVENTION OF TB-HIV

Background Susceptibility to reactivate tuberculosis infection is influenced by immunosuppression. Amongst the greatest risk factors for active TB are HIV-1 infection and vitamin D deficiency. These risks factors are not mutually exclusive and may exacerbate each other. However, the phenotype of immunodeficiency induced by each is different. Vitamin D deficiency not only associates with TB risks, but it is greater in HIV-co-infected patients. The effects of vitamin D on the immune system are pleiotropic, being both anti-inflammatory and antimicrobial. Evidence suggests that vitamin D may not only reduce risk of TB by increasing anti-mycobacterial immunity and reducing inflammation, but it may also reduce HIV replication and the associated effects on innate and adaptive immunity; thus concomitantly reducing the associated risk of HIV on TB. Methods We investigated in vitro and ex vivo the effect of vitamin D supplementation on the response of monocyte-derived macrophages (MDM) and peripheral blood mononuclear cells (PBMC), respectively, to HIV-M. tuberculosis (Mtb) co-infection. The effects of pathogen growth and susceptibility to infection were correlated to cytokine, chemokine and antimicrobial peptide production, by expression, secretion and flow cytometry analysis. Results MDM differentiated in the presence of vitamin D metabolites, significantly restricted HIV-1 replication, alone and during co-infection with Mtb. Type 2 MDM were considerably more susceptible to HIV-1 infection than type 1. This correlated with the level of CCL2 production, which was significantly inhibited by vitamin D metabolites. PBMC isolated from healthy individuals in summer and in winter after receiving vitamin D, significantly restricted HIV-1 infection, compared to PBMC collected in winter before supplementation. There was a significant difference in circulating cell populations and serum cytokines/chemokines in summer, compared to winter, and these were investigated for correlations with HIV replication. Conclusions Vitamin D may prove a cheap, effective, tool for preventing TB-HIV disease progression and clinical trials are warranted in at-risk populations.