**1. Introduction**

Everyone has yeasts like *Candida* spp., mostly Candida albicans, in their intestines, and only seriously ill people will get sick. In contrast, other therapists fear life-threatening diseases if these germs are detected [1].

Many patients are completely unsettled. These are very seriously ill patients such as cancer or AIDS patients whose defense is extremely weakened [2]. In their cases, the internal organs can fail due to a fungal attack. Fungal diseases and intestinal mycoses have actually increased in recent years. Gynecologists observe that more and more women suffer from vaginal mycoses.

The reasons for this increase are, for example, nutritional errors such as too much sugar and white flour products or nutritional deficiencies causing a dysregulated immune system [3]. However, treatments with cortisone and antibiotics and the increase in environmental pollutants are also contributing factors. All of these factors weaken our immune system and thus promote the spread of the fungi. If, for example, antibiotics have damaged the natural intestinal flora, *Candida* yeasts can spread because important physiological germs are lacking as opponents.

Unfortunately there are only nonspecific symptoms that can have many other causes. In the foreground are diarrhea and constipation—often alternating—flatulence, an abdominal distension, and abdominal pain. Affected people reported migraines, depression, liver diseases, and skin changes. But symptoms may or may not be due to *Candida*.

When referring to the intestinal yeasts, it is usually of *Candida* genus. Yeasts can be found practically everywhere in nature: they colonize the mucous membranes of humans and animals, adhere to objects, and can be found in water and soil. *C. albicans* are commonly found in the intestine. These yeasts were previously found in 80% of all intestinal yeast infections. In contrast to other *Candida* species, *C. albicans* adheres to the mucous membranes of warm-blooded humans and animals. Their transmission takes place directly through physical contact. In healthy people, however, this is completely unproblematic. But there are also numerous other types of *Candida* that have been on the rise recently. Yeasts find optimal living conditions in the intestine as the environment meets their requirements and provides them plenty of food [4].

People with weakened immune systems are particularly at risk of contracting *Candida*. Older people (elderly), whose defenses are weakening, are also considered a high-risk group [5].

The role of intestinal gut microbiota in health and disease is gaining more attention and is increasingly recognized [6]. The philosophy of alimentation might give us a clear start to see the patient as a whole again. It cannot only be drugs and medicine to treat the diseases [7].

### **2.** *Candida* **spp. as member of the human gastrointestinal tract microbiota**

In the normal human gastrointestinal tract microbiota, *Candida* species are part of and can be found in the oropharynx, esophagus, gastrointestinal tract, and vagina. When the immune system is compromised from different reasons, a local or invasive infection can be developed [5, 8].

*Candida* species are among the most common yeast, and as fungi in stool cultures, the most common germ is *C. albicans*. *C. albicans* is one of the optionally pathogenic fungi that only trigger a disease under certain conditions [1, 9, 10]. However, numerous other types of fungi can also be detected in healthy intestinal flora in small numbers of germs using modern methods. With reduced immune defense like with HIV disease, but also with diabetes mellitus or cancer and with therapies with immune inhibitors (immunosuppressive therapy, e.g., with steroids [cortisone]), the amount of *Candida* in the intestine can increase significantly, so that a serious disease becomes possible [2].

Overgrowth of the intestine (over 1,000,000 fungi/g stool) is often accompanied by annoying gas, intestinal cramps, and/or diarrhea. If such symptoms occur in patients with a weakened immune system, overgrowth with *Candida* should also be considered [11–13].

*The Influence of* Candida *spp. in Intestinal Microbiota; Diet Therapy, the Emerging Conditions… DOI: http://dx.doi.org/10.5772/intechopen.92791*
