be expected to exert a saturable response, viz. beneficial up to a certain level in correcting overt or sub clinical deficiency states, with diminishing returns thereafter. Some (such as vitamin A) may even be toxic at high doses. These are important considerations because they expose the flawed reasoning of those advocating unconsidered supplementation (of multi vitamins for example) as necessarily harmless.
Formulating policy for research and practice
It is a prime function of ASSAf to serve as an interface between scientists and policymakers. With regard to the current study, policymakers include those involved in health care delivery, and also those concerned with setting research policy. In other words, it has been the task of this panel not only to identify policy for best practice in relation to nutrition HIV/AIDS and TB, but also to define gaps in the evidence base as priority areas for further research.
One of the criticisms of a radical, purist evidence-based approach to medical decision-making and policy formulation is that professional caregivers and clinicians have expressed reservations that many years of hard-earned practical experience can potentially be discounted and undervalued in the evidence-based medicine (EBM).
Similarly, the National Department of Health might argue that they are accountable for the practical, real world (i.e. not the ivory tower) situation, and have special knowledge and skills relating to what can and cannot be done on a national level. The response of the panel to this has been to look at all the opinions, whether based on firm scientific evidence, or on clinical experience, or from the vantage point of a National Department of Health charged with the responsibility of forming and implementing policy on a national scale. The panel has looked at these 3 perspectives to identify commonalities or divergences of opinion, in the light of its own process and policy recommendations. The source material for each perspective is as follows:
Evidence-based guidelines from the consensus panel’s own studies and the 2005 1.
recommendations from the World Health Organization.
The 2006 guidelines from the Southern African HIV Clinicians Society.
2.
The 2006 guidelines from the National Department of Health.
3.
some 40 or so are considered to be essential constituents of a healthy balanced diet (13 vitamins, 17 elements, nine essential amino acids, and essential fatty acids and carbohydrates).
The complex field of phytochemicals and other food constituents, which may well exert profound effects on immune functions, has not been addressed. Both western pharmaceutical agents, (whose parent molecules may have originally been discovered as food or plant constituents), and traditional pharmacologically active compounds have been excluded in their entirety, not because they are considered unimportant or without potential value, but because in the view of the panel they fall outside the scope of nutrition. On the question of the immunologically beneficial effects or otherwise of traditional remedies and their constituents, the ethical societal rules pertaining to any potential or actual pharmaceutical product would appear to apply. Claims made in respect of such remedies should be subject to rigorous review before the scientific community can endorse them, and they must proceed through the same channels of description, characterization and chemical identification, and animal and human safety and efficacy trials as are necessary for any pharmaceutical product. The South African Medical Research Council has a policy and a dedicated research unit devoted to the study of Indigenous Knowledge Systems (IKS). A significant segment of the work of the South African MRC IKS Research Unit is focused on the process to be followed in respect of HIV interventions claiming benefits of one form or another.
The Study Panel unanimously endorses the view that specific antiretroviral agents are the only established direct weapon in the treatment of HIV infection itself; unfortunately, unlike the drugs used to treat active tuberculosis, and for a variety of complex reasons, they cannot (yet) be used immediately after diagnosis, creating the situation where indirect support and care must sustain infected subjects until (as well as after) antiretroviral drugs are applied.
The important intersection between nutrition and antiretroviral therapy (ART) has not been addressed in the current Academy of Science of South African consensus study because it has been reviewed comprehensively recently and was included in the recent World Health Organization Reports on Nutrition and HIV infection.
Microbial safety of foods, food preservation and/or preparation has not been addressed in this report, but much attention has been paid to food safety in the revised National Guidelines referred to in the chapter on policy guidelines. Similarly, examination of the social science evidence underpinning recommendations concerning food security have not been addressed in this study.
Three South African epidemics
This chapter reviews the South African epidemics of malnutrition, HIV infection and tuberculosis as separate entities. The prevalence of each epidemic is sufficiently high in South Africa to ensure significant overlap purely on mathematical grounds – in other words, even if there were no synergies between them. In fact, there is considerable prima facie evidence from observational studies to suggest that each epidemic reinforces the other two.