Pentagon's immune-booster

A beta glucan so effective at strengthening the immune system the Pentagon has stockpiled it in case of biological attack could become a potent functional food ingredient, say scientists.

Beta glucan 1,3 1,6, a polysaccharide derived from the cell wall of baker's yeast, stimulates the body's innate immune system, the first line of defence against germs.

"These molecules activate the innate immune system very strongly in humans and other mammals, birds, fish and even crustaceans," claimed Dr Paul Clayton, former senior scientific advisor to the government's Committee on the Safety of Medicines. "I'm astounded it has taken the food industry so long to start looking at these beta glucans, but things are slowly beginning to change. I can't name names, but one large multinational food and drinks firm is planning a launch incorporating them this year."

Speaking at an RSSL event in London, he said: "1,3 1,6 is not the same as oat beta glucan [which many food firms are promoting on a cholesterol reduction platform]. That has a different molecular structure [1,3 1,4]."

We used to get 1,3 1,6 from beer and bread, but it's no longer present in these products, he said. "This may go a long way to explain why innate immune systems have become so vulnerable and ineffective. If a flu pandemic struck now, many of us would be uniquely ill-equipped to cope."

Companies wishing to make health claims about 1,3 1,6 such as 'strengthens the immune system' would probably have to prepare evidence under article 13.5 of the EU Nutrition and Health Claims Regulation, he said. "The evidence supporting this stuff is so compelling I think there's a powerful case for mandatory fortification of flour or other staple food products by government."

Beta glucan 1,3 1,6 is in aloe vera, echinacea and shiitake mushrooms. But brewer's yeast was the cheapest and most consistent source, said Clayton. In the late 1980s, the US army began tests to measure the immuno-protective effects of beta glucans and more than 100 immuno-stimulants, he said. In 2004, it concluded purified beta glucans were the most effective, protecting against bacteria, viruses and fungi and even radiation injury.