The Journal of Health, Population and Nutrition
Vol. 35, No. 1, 2016, pp. 1-7
Bioline Code: hn16008
Full paper language: English
Document type: Research Article
Document available free of charge
The Journal of Health, Population and Nutrition, Vol. 35, No. 1, 2016, pp. 1-7
© Copyright 2016 - The Journal of Health, Population and Nutrition
Tryptophan depletion in context of the inflammatory and general nutritional status of a low-income South African HIV-infected population|
Bipath, Priyesh; Levay, Peter F. & Viljoen, Margaretha
Background: The essential amino acid tryptophan cannot be synthesised in the body and must be acquired
through dietary intake. Oxidation of tryptophan, due to immune induction of the enzyme indoleamine 2,3-
dioxygenase (IDO), is considered to be the main cause of tryptophan depletion in HIV infection and AIDS.
We examined plasma tryptophan levels in a low-income sub-Saharan HIV-infected population and compared it to
that of developed countries. Tryptophan levels were further examined in context of the general nutritional and
Methods: This cross-sectional study included 105 HIV-positive patients recruited from the Kalafong Hospital in
Pretoria, South Africa, and 60 HIV-negative controls.
Results: Patient tryptophan levels were in general markedly lower than those reported for developed countries. In
contrast to reports from developed countries that showed tryptophan levels on average to be 18.8 % lower than
their control values, tryptophan levels in our study were 44.1 % lower than our controls (24.4 ± 4.1 vs. 43.6 ±
11.9 μmol/l; p < 0.001). Tryptophan levels correlated with both CD4 counts (r = 0.341; p = 0.004) and with proinflammatory
activity as indicated by neopterin levels (r = −0.399; p = 0.0001). Nutritional indicators such as albumin
and haemoglobin correlated positively with tryptophan and negatively with the pro-inflammatory indicators
neopterin, interleukin 6 and C-reactive protein. The most probable causes of the lower tryptophan levels seen in
our population are food insecurity and higher levels of inflammatory activity.
Conclusions: We contend that inflammation-induced tryptophan depletion forms part of a much wider effect of
pro-inflammatory activity on the nutritional profile of HIV-infected patients.
Tryptophan; HIV/AIDS; Malnutrition; Sub-Saharan; Pro-inflammatory activity
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