The Fungus Among Us

Yeast are interesting little creatures. If you’ve ever made bread, dinner rolls or pizza dough from scratch, you probably know a little about yeast. I don’t make bread very often, but I do make pizza dough with whole grains. I start the process by adding some yeast to warm water with a little bit of sweetener of some kind (honey for me). Then I add part of the flour to make a soft dough called a sponge.

The little “yeastie beasties” start feeding on the sugar and doing what all microscopic creatures love to do—multiply rapidly. In the process of feeding, they give off lots of carbon dioxide (CO₂) and a small amount of alcohol. This makes lots of tiny “air” bubbles, so when the sponge becomes all bubbly, I add the rest of the flour, salt and oil.

Oil and salt inhibit yeast growth so the process slows down a bit, but the yeast continue to feed at a reduced pace, making the dough rise. Kneading the dough activates the gluten, which makes the dough elastic, so it will hold more air. It also breaks big air bubbles into little ones, creating a finer texture.

Yeastie beasties aren’t just useful for making baked goods. They also produce beer, wine and other spirits. I’ve never done it, but it’s something I’d be interested in trying. Since yeast also give off alcohol as they feed, you simply need to leave them long enough in some kind of sugary or starchy liquid (such as grape juice or barley malt water) and they’ll convert the sugars to alcohol. By the way, the foam in the beer is created by the same CO2 that makes bread rise.

If you let the alcohol sit, then acetic acid-producing bacteria will feed off the alcohol and turn it into vinegar. Thus, yeast turns apple cider to hard cider and bacteria turn the hard cider into apple cider vinegar.

Yeast is also used as a food additive and flavoring agent. Yeast products like Vegemite and Marmite are popular in countries like the United Kingdom and Australia. They are made by adding salt to a yeast solution, which causes the yeast to break down releasing the protein and other nutrients.

Yeast is very high in nutritional value, by the way, which is why brewer’s yeast is a great “superfood.” It is one of the richest naturally-occurring sources of protein and B-complex vitamins. Brewer’s yeast is any yeast used in brewing that has been heated to kill the yeast.

Yeasts belong to the class of microbes known as fungi and obviously there are other forms of fungi besides yeast, such as mold and mushrooms. These fungi also have some useful properties.

For example, antibiotics like penicillin were derived from mold. Mold also makes certain cheeses like blue cheese. More specifically, molds from the penicillin genus are responsible for the blue veins in blue cheeses such as Roquefort, Gorgonzola and Stilton.

Mushrooms are another form of useful fungi. Of course, some are edible and some are deadly poisonous, so you have to know what you’re doing if you gather mushrooms. However, I really enjoy some good mushrooms. Plus, many very important immune-enhancing herbs are mushrooms or fungi, including ganoderma, reishi, miatake, kombucha and cordyceps.

Fungi and Soil Fertility

But the usefulness of fungi doesn’t stop with their role in nutrition. Both fungus and bacteria live in soil and are vital to soil health. There are about one billion bacteria and one million fungi in the average teaspoonful of soil. That fact will probably be enough to incite panic into anyone who suffers from germ phobia, but the fact is that these microbes are vital both to the health of the soil and to the health of our bodies, because they help make soil nutrients available to plants.

Fungi in particular have an important symbiotic relationship with plants. Certain fungi called mycorrhizae (myco means fungal and rhiza equals root) live partially in the plant root hairs and partially in the soil. The plant supplies food for the fungus and the fungus supplies moisture and nutrients (particularly minerals) to the plant.

A United Nations research project demonstrated that supplying soil with fungi and soil-living bacteria, instead of artificial fertilizers, improved crop yields, boosted harvests, and saved money for some developing world farmers. (UN News Center-23 March 2006) This is why compost is so good for the garden—it supplies microbe-rich organic matter, which improves a plant’s ability to utilize nutrients in the soil. Beneficial fungi in the soil are very helpful for breaking down dead plant material to recycle nutrients.

Friendly Flora and Yeast

Just as soil health involves fungi, our health does, too. Our body plays host to about 5,000 species of fungi. These microbes are at worst benign, but more likely are part of the overall ecology of our health, just as the friendly bacteria like acidophilus and bifidophilus are. Our intestines alone house about 2-4 pounds of friendly bacteria and fungi.

In both the soil and in our bodies, fungi and bacteria compete with each other and serve to keep each other in check. Lacto bacteria produce lactic acid, which inhibits fungi. Certain fungi produce antibiotics to inhibit bacteria. As long as balance is maintained, everything is fine.

However, if the immune system becomes compromised, the pH becomes too imbalanced or the friendly bacteria are destroyed, fungi can multiply out of balance, resulting in various yeast or fungal infections. The most common organism involved in these infections is Candida albicans or candida for short. (Everyone I know has always pronounced candida “can-DEE-dah,” but I recently learned that the correct pronunciation is “CAN-did-ah.”)

Candida albicans isn’t the only species in the candida genius. There are many others, including several that are also normally present in our intestinal flora. Other species in the candida genus that may be involved in yeast infections include C. tropicalis, C. stellatoidea, C. glabrata, C. krusei and others. Cryptococcus neoformans and Rhodortorula mucilaginosa are other non-candida species known to cause yeast infections, but 70% of all yeast infections appear to be caused by species in the candida genus. From what I’ve read, however, there may be close to 200 species of yeast that could be involved in yeast infections.