Yet the major finding from the foremost avian flu research center in the world is that the H5N1 virus is distinguished from milder flu viruses by its ability to hyperinduce the production of tumor necrosis factor (TNF) and other proinflammatory cytokines in the cells of the immune system, particularly the macrophages. This discovery, from the University of Hong Kong Dept. of Microbiology, was extended last August to specify the main mechanisms (1). Meanwhile, in nearby Taiwan, government scientists reported at about the same time that the main metabolite of vitamin A “could reduce…TNF-a production” and that “vitamin A may protect…patients from proinflammatory cytokine-mediated damage” (2). These findings were reported exclusively by Truthseeker last November (click HERE for his world scoop).

The ability of vitamin A to inhibit TNF in macrophages had long been known. Researchers at M.D. Anderson Cancer Center reported in 1994 that the major vitamin A metabolite “almost completely inhibited the production of TNF by macrophages” (3).

The Harvard review of Vitamin A mentioned above does not cite any of these studies but does review a number of other studies showing that vitamin A inhibits TNF (see section on Monocytes and Macrophages). It also references a clinical trial from Norway, which found that vitamin A supplementation at 6500 units a day (slightly above the daily requirement) resulted in “a significant decrease in TNF-a levels” – actually cutting them in half (4). Significant inhibition of TNF was also found in clinical trials of vitamin A (and other antioxidant vitamins) conducted in Italy (5) and Greece (6).

1. D. Lee et al. Hyperinduction of tumor necrosis factor alpha expression in response to avian influenza virus H5N1. J. Virol. 79:10147-54, Aug. 2005.

2. L. Ho et al. Retinoic acid blocks pro-inflammatory cytokine-induced matrix metalloproteinase production… Biochem. Pharmac. 70:200-8, 2005.

3. K. Mehta et al. Inhibition by all-trans-retinoic acid of tumor necrosis factor and nitric oxide production by peritoneal macrophages. J. Leukoc. Biol. 44:336-42, 1994.

4. P. Aukrust et al. Decreased vitamin A levels in common variable immunodeficiency. Eur. J. Clin. Inv. 30:252-259, 2000.

5. G. Mantovani et al. Reactive oxygen species, antioxidant mechanisms and serum cytokine levels in cancer patients: impact of an antioxidant treatment. J. Cell. Mol. Med. 6:507-82, 2002.

6. T. Vassilakopoulos et al. Antioxidants attenuate the plasma cytokine response to exercise in humans. J. Appl. Physiol. 94:1025-32, 2003.