The Japanese government has formally listed reishi as a supplement to be used for people with cancer. They have studies showing that reishi protects against radiation. If you've ever had radiation treatments, you should consider taking it as a supplement. I would also recommend it for cancer protection or in cases of remission.

Maitake (Grifola frondosa)
Maitakes are becoming quite popular for one isolated substance they contain called D-fraction, a registered trademark of Maitake Products, Inc. D-fraction has been shown to have anti-tumor activity and also supports the immune system in general. But so does the complete mushroom. One study showed that maitakes blocked the growth of tumors in 86 percent of mice. People and mice are different, of course. But the history of medicinal mushrooms indicates that once again, the whole mushroom may contain co-factors that either enhance the absorption of D- fraction or add to its usefulness as an immune supporter. One Japanese study using rats showed that powdered maitakes lowered cholesterol and increased the excretion of bile, a substance we need to digest fats. This means that maitakes could help with fat digestion. Maitakes have been used in ancient China for respiratory problems, poor circulation, liver support, weakness, exhaustion, and to strengthen the life force (Chi).

It appears that using D-fraction may be more like using an over-the- counter medication, while taking the complete mushroom is more like eating a food that enhances immunity and helps the body function more effectively. Each has its place in your immune-boosting program.

Cordyceps (Cordyceps sinensis)
Cordyceps sinensis is one of the most interesting species of medicinal mushrooms. It is a small, finger-shaped fungus that, in its natural habitat, takes over caterpillar and insect larvae with its spores. The spores germinate, emerging from the parasitized larva. This fungus has been reported to have anti-tumor activity and strong immune properties. In this country, Cordyceps are grown in sterilized mediums without the insect larvae, and appear to have the same kind of protective effects as those found in the wild.

Cordyceps seem to be a lung and kidney tonic. They help relax smooth muscles, making them the nutrient of choice for people with asthma and respiratory problems. Like the other medicinal mushrooms, Cordyceps has been used as an anti-cancer agent. In the Orient, one study showed that they strengthened legs in frail older people and reduced their dizziness. For people like me with a history of coughs accompanying chest colds, Cordyceps are ideal. They have the added ability to help recover more quickly from strenuous exercise, and are an excellent supplement for all athletes, including people who only work out on weekends.

Using medicinal mushrooms
While different medicinal mushrooms have slightly different properties, all contain beta glucan, a form of sugar called a polysaccharide. Beta glucan supports immunity by communicating with your immune system, telling it to defend you against harmful viruses and bacterium. Some mushroom products contain concentrated quantities of beta glucan, while others contain the whole mushroom with beta glucan and all the co-factors that help beta glucan and other substances work. Just remember that the complete mushroom powder or extract is a supportive food, while products that emphasize one ingredient are similar to over-the-counter medications.