FROM:
Alternative Medicine Review 1999 (Dec); 4 (6): 403–413 ~ FULL TEXT
Lyn Patrick, ND
Introduction
HIV infection involves a progressive immune dysfunction and loss of
CD4 T cells leading to opportunistic infection, wasting syndrome, malignancies,
or CD4 depletion significant enough to qualify as CDC-defined AIDS. Several
research studies have indicated that the apoptosis of CD4 cells contributing
to HIV progression does not result solely from HIV infection, but largely
from antioxidant imbalances in the host. [1–3]
Activation of latent HIV state can be stimulated in the presence of reactive
oxygen species (ROS) through the stimulation of oxygen-responsive transcription
factors, specifically NF-kB, which induces HIV replication in the infected
T-lymphocyte. The number of reactive oxygen species can be reduced by restoring
proper redox balance through adequate availability of antioxidants.
Micronutrient deficiencies are common in HIV, both in early and late
stages of the disease. Tomaka [4] found in
129 patients with stratified T-cell counts all cohorts had similar prevalences
of nutrient deficiencies. Among the three subgroups (CD4>500, CD4 200–500,
CD4<200), each had similar occurrence of deficiencies: 38, 41, and 42
percent, respectively. Beta carotene and selenium figure prominently in
these deficiency pictures. Their role as antioxidants provides a logical
explanation for the widespread deficiencies of these nutrients seen in
HIV and their therapeutic relevance.
Beta Carotene in HIV/AIDS
Beta Carotene Deficiency
Beta carotene, a fat-soluble antioxidant, is a well-known scavenger
of the singlet oxygen radical [5] and can
decrease free-radical induced lipoperoxidation damage in HIV. [6]
Deficiencies of serum and plasma beta carotene and other carotenoids
(including lutein and lycopene) have been observed in multiple studies
in both HIV-positive and AIDS patients. [4, 7, 8]
Depression of serum beta carotene levels is usually indicative of fat malabsorption
and diarrhea, common complications of AIDS, secondary to general malabsorption,
infection, and altered gut barrier function. [9]
While pancreatic function appears to be normal in HIV/AIDS,10 enterocyte
function and villous atrophy occur even without intestinal infection. [11]
Ullrich, [7] in a cohort of 116 HIV-infected
individuals, found serum carotene concentration did not differ significantly
between AIDS-diagnosed individuals who had diarrhea and those who did not:
77 percent of both groups had abnormally low carotene levels. In addition,
serum carotene levels did not differ between HIV/AIDS patients with or
without the presence of infectious agents in the stool or on intestinal
biopsy: 76–percent infected and 77–percent noninfected individuals had
abnormal serum carotene levels. The presence or absence of weight loss,
fever, or secondary extra-intestinal infection did not correlate with alterations
in serum carotene level. See Table 1.
In this study, CD [4] percentages (r=0.364;
95% CI, 0.194–0.513; p<0.001), CD4 count (r=0.28; 95% CI, 0.101–0.441;
p=0.0013) and the CD4/CD8 ratio (r=0.38; 95% CI, 0.212–0.526; P<0.001),
(but not leukocyte, lymphocyte, or CD8 counts) in peripheral blood correlated
with serum carotene levels.
Favier et al [6] examined a cohort of 25
asymptomatic HIV-1 seropositive subjects in CDC stage II (mean CD4 396/mm3)
and 18 HIV-1 seropositive subjects in CDC stage IV (mean CD4 56/mm3) and
followed changes in their antioxidant status for six months. They found
severe deficiencies of plasma carotenoids and beta carotene in both groups,
and a significantly more rapid fall in the level of beta carotene in the
CDC II group than the CDC IV group. The authors related this difference
to increased levels of peroxidation in CDC stage II patients. Their malondialdehyde
(MDA) and hydroperoxide levels were significantly higher (P<0.05) than
in those subjects who had more advanced disease (CDC stage IV). They concluded
the reduction in carotene levels was the result of increased antioxidant
activity at this stage of HIV infection due to overproduction of oxygen
radicals by polymorphonuclear leukocytes in CDC stage II. See Table
2.
Whether carotene depletion is due to malabsorption or increased free
radical load or both, it appears to be consistently deficient in HIV-positive
subjects. Omene [12] measured beta carotene
levels in 15 African-American and Hispanic children. Those with HIV had
6.5 times lower levels of serum beta carotene than age-matched HIV-negative
controls; the children with AIDS had a 13–fold lower level than HIV-negative
controls. There were no significant differences in the levels of serum
vitamin A or E in any of the groups. Periquet et al [13]
looked at 21 HIV-1 positive children and found deficiencies of plasma levels
of both lycopene (p=0.002) and retinol (p=0.023) but not beta carotene
in the AIDS-diagnosed children (n=10).
Serum beta carotene and vitamin A levels were measured in 74 pregnant
HIV-1 positive women in the first trimester and compared to pregnant HIV-negative
women, also in the first trimester. [14] HIV-infected
women with CD4 counts below 200 had 37–percent lower mean serum vitamin
A and beta carotene levels when compared to controls (p<0.001). Both
serum beta carotene and vitamin A levels correlated with percentage of
CD4 lymphocytes, CD4 counts, and CD4/CD8 ratios (p<0.001). Lacey [8]
found a significant depletion of plasma carotenoids in 35 HIV-positive
individuals compared to controls (p<0.001). Plasma levels of four of
the individual carotenoids were correlated with CD4 count, but beta carotene,
and vitamins A, C, and E were not.
An evaluation of nutrient supplementation in 64 HIV-1 infected adults [15]
revealed that even though 63–73 percent claimed they were taking some form
of multi-vitamin, plasma levels of total carotenoids were still lower than
the HIV-negative controls (p=0.009). Lower CD4/CD8 ratios were correlated
with lower carotene levels (p=0.02). Although the patients in this study
who were taking antioxidant supplements had consistently fewer low concentrations
of antioxidants no matter what their disease stage status (p=0.0006), 29
percent still had subnormal levels of one or more antioxidant.