Bird Flu

The next global flu pandemic is coming. Klaus Stohr of the WHO Global Influenza Programme recently stated ‘There will be another pandemic. In the best case we expect billions to fall ill, with 2 to 7 million deaths – but it could be far worse.’ Here in the UK, our very own Department of Health predicts as many as 750,000 deaths. Why are the experts so pessimistic?

History shows that flu pandemics occur every 30 years or so. After this time the genetic makeup of a flu virus has changed so much that immunity built up from previous strains becomes irrelevant; so that herd immunity, our main defence against pandemics, has become negligible.

There were three pandemics in the 20th century, and all spread worldwide within a year of being detected. The Spanish flu in 1918-19 killed up to 50 million people. In the 50’s the Asian flu pandemic killed a mere million, and in ’68 Hong Kong flu killed another million or so. That was 36 years ago – so we’re due for the next one. Prime candidate is the bird flu now gathering momentum in Asia, and which has already shown human-to-human transmission.

Antibiotics are no use in treating viral infections, and the right vaccines to protect us against the new strain of bird flu won’t be ready until at least 6 months after the epidemic has started, which will be too late for many. Our benevolent and all-wise government has decided to purchase anti-viral treatments for 14 million Brits – about 1 in 4 of the population. That decision was based on two assumptions: firstly, that the emergency could be managed, and secondly that the anti-viral drugs will be reasonably effective. Both of these assumptions are very questionable. Our ability to deal with the fall-out of a contagious and highly lethal viral epidemic is, realistically, inadequate. And the efficacy of the anti-virals (which was never very high) is being seriously under-mined by Government-backed schemes in China to give the anti-viral drug amantadine to infected flocks of poultry. Nothing is more likely to breed new drug-resistant viruses. The WHO has asked for urgent ‘clarification.’

Let us assume, however, that the anti-viral drugs are still at least partially effective when the time comes, and the emergency plans will actually work. One in four people deemed sufficiently important (army, police, medical personnel and the political classes) will be protected. What should the rest of us, the expendable folk, do?

The best defence against viral infection is to prep your innate immune system, which is the body’s first line of defence against invasion by bacteria and viruses. Unlike the acquired (or adaptative) immune system, the innate immune system does not recognise every possible antigen. Instead, it is geared up to recognise and react to a small number of highly conserved molecules which are present in the cell walls of many pathogens; including LPS (gram negative bacteria), lipotechoic acids (gram positive bacteria), and 1-3, 1-6 beta glucans (bacteria and fungi).

Once stimulated, the innate immune response mounts both cellular and humoral responses. These involve:

1. Phagocytic cells. These include macrophages and related cell species such as Langerhans cells in the epidermis, Kupffer cells in the liver, microglia in the brain and osteoclasts in bone.
2. Cells that produce inflammatory mediators (mast cells, eosinophils and basophils)
3. Natural Killer cells
4.  Mediator molecules such as complement proteins, acute phase proteins and cytokines. These include tumor necrosis factor (TNF), interleukins 1 and 6, hydrogen peroxide, and gamma interferon, all of which fight against invading pathogens.

Of all the natural compounds known to stimulate the innate immune system, the best documented and most effective are the 1-3, 1-6 beta glucans, generally derived from brewer’s yeast (Kernodle et al ’98, Wakshull et al ‘99). These molecules activate the innate immune system very strongly indeed; in humans and other mammals, and in birds, fish and even crustacea (Mansell et al ’75, Hahn & Albersheim ’78, Robertsen et al ’94, Song & Hsieh ‘94).  Macrophages have receptors which specifically recognise 1-3, 1-6 beta glucans (Czop & Austen ’85), because they occur in the cell walls of many bacteria and fungi. This means that when you ingest beta glucans your innate immune system thinks, not unreasonably, that an enemy has arrived and it rises to the challenge. This important first line of defence is now fully activated, and several well-conducted research papers have shown that resistance to infection is greatly enhanced (Onderdonk et al ’92, Kernodle et al ’98, Vetvicka et al ‘02).

The beta glucans’ ability to activate macrophages has been extensively tested (Rasmussen et al ’85, ’87, ’89, ’90, ’91, ‘92); and has been shown to protect animals such as mice against otherwise fatal infections (Williams & Deluzio ’78, ’79, ’80, ’83, Leibovich & Danon ’80, Lahnborg et al ’82, Deluzio & Williams ’83, Browder et al ’83, Rasmussen & Seljelid ’91, Tzianabos & Cisneros ’96). Trials have shown the same substantial protective effects in human infections also (de Felipe ’93, Babineau & Hackford ‘94, Barbineau & Marcello ‘94, Dellinger et al ’99).

A glance at the references above shows that most of the key studies had already been completed by the mid – 90’s, but the work was not thought to be commercial, and was not developed for clinical use. Antibiotics still ruled the roost, and were highly profitable for the drug companies, while brewer’s yeast extracts were cheap and belonged to everybody. This meant that none of the drug companies was interested in investing in them.

The US army, however, was taking careful note. Starting in the late ‘80’s, they ran an exhaustive test programme to measure the immuno-protective effects of beta glucans and over 100 other immuno-stimulants, and as recently as 2004 reported that the beta glucans were the most effective of them all. Not only did they protect against infection with bacteria, viruses and fungi, they also conferred protection against radiation injury (Patchen et al ’87, Patchen & McVittie ’85).

Given that soldiers may at any time face an unpredictable range of biological weapons and even, in the worst case, radiation, the US army began to stock-pile beta glucans. To this day Washington keeps significant amounts of beta glucans in readiness, to be issued as and when circumstances dictate. (To put this in context, all cases of ‘bacterial warfare’ reported in the US to date - such as the notorious ‘anthrax by post’ episode – were identified as being internal affairs!)

I personally think that these valuable compounds are too good to be left to the armed forces. As bird flu continues to advance, I have put up a couple of kilos of purified beta glucans on the top kitchen shelf. When the time comes I will give them to my children, at a dose of 500 mg of beta glucans per day; armed with the knowledge that they are safe (Williams et al ‘88) and effective prophylactic agents. In trials with pigs, beta glucans reduce the harm done to the lungs after infection with swine flu virus, and reduce replication of the virus itself (Jung et al ‘04). As pigs and people have a good deal in common (metabolically and physiologically speaking), the pig model is very relevant to our own situation. When one looks at the UK government’s flu management strategy, George Orwell’s porcine metaphors seem more appropriate than ever.

WHICH BETA GLUCAN?

It is no easy to ascertain which beta glucan preparation is most effective. Surprisingly, the actual amount of beta glucan per capsule is not critical; particle size is as or more important, with particles of around 100 k.daltons found to be the most effective immuno-stimulants. Another key criterion is purity, generally expressed as a low or negligible protein and ash content. This will minimise the risk of an allergic reaction, a potential hazard in allergic and atopic individuals.

As there are some very shoddy materials on the market, I prefer to work with beta glucans from companies with a strong research background and an established track record. One of the best is Fibona, a German company working in association with the University of Berlin who have done large scale studies using beta glucans to replace antibiotics as growth promoters. Fibona’s beta glucan products (distributed in the UK by Vitalize Health Products) satisfy the most stringent quality criteria, which is why I have decided to support them.

HOW SHOULD I TAKE BETA GLUCANS?

A few well-intentioned nutritionists, with little understanding of immunology or evolutionary theory, have suggested that immuno-stimulants should only be taken for short periods of time. However, there is overwhelming evidence, derived from extensive vetinary trials, that beta glucans work best when taken continuously. The idea that chronic immuno-stimulation could be harmful (as opposed to the natural state of affairs) was finally squashed by a recent report which clearly showed that life-long exposure to immuno-stimulants actually extended life (Brousseau & Miller ‘05).

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