For a long time, alternative medicine doctors have told patients they have a "Candida overgrowth", sometimes based on a stool test, sometimes only a guess based on various symptoms that an excess of Candida is supposed to cause. And they diagnose "dysbiosis", meaning the microorganisms in the person's gut are of the wrong kind. They prescribe probiotics, prebiotics - which are substances like inulin and fructooligosaccharides that (hopefully) primarily feed good bacteria - they prescribe anti-Candida diets, etc.
This has been somewhat validated by research, actually. Gary Huffnagle, who investigates the interaction between gut flora and the immune system, found that mice with an artificially induced Candida overgrowth developed allergies when exposed to allergens. Also Candida causes gastric inflammation in mice if other bacteria are depleted. Also the presence of Candida affects recovery of the good bacteria after treatment with broad-spectrum antibiotics (in mice). The gut flora plays a role in allergies and asthma, and probiotics can help with allergies.
The anti-Candida diets that alt-med doctors have prescribed, emphasize limiting sugar, fruit, and they may limit carbohydrates in general. This isn't what Gary Huffnagle recommends. He wrote a popular book The Probiotics Revolution. He does recommend limiting sugar, but recommends fruit and vegetables because they have prebiotics (I'm not sure if too much fruit is considered to be bad). It's not a lowered-carb diet - complex carbohydrates like grains are included. Also probiotics like kefir and yogurt.
I'm not sure what research there is on what consuming a lot of sugar does to the microorganisms in the gut, whether it tends to encourage Candida or not. Sugar is quickly broken down into glucose and fructose in the gut. The fructose tends to be the more problematic part, apparently - it tends to increase intestinal permeability and probably has other bad effects. Glucose tends to be absorbed quickly into the blood - if you eat a glucose pill, it'll be absorbed in the stomach, so it won't reach the small intestine where the Candida are.
I went to an allergist in NYC recently to try to get some help for my puzzling and very severe problems. I developed a terrible allergy to dog dander, probably cat too. So bad that if I just get a whiff of dog, like if a dog approaches me, I get sick. I also have a huge number of food allergies, and I'm very sensitive to tiny amounts of allergens orally. I got sick for a couple of days recently, after a dentist stuck a local anesthetic containing corn products into my mouth before I noticed. I can't live in my house right now because it has dog dander in it - I'm living in a motel and my dog's in a boarding kennel while I try to help my health problems.
The pattern is that I have hypersensitivity in my mucous membranes in my nose and my gut. I used to have positive allergy tests but I don't any more. So my allergies have "gone local". Also I tend to get UTI's - bladder and kidney infections. Since the bladder is lined by a mucous membrane, that might be connected to my allergies. Mucosal immunity is connected to what goes on in the gut.
So among other things, the allergist suggested probiotics, reducing sugar, maybe reducing carbs, antifungal drugs like diflucan.
So I'm trying to find out what the scientific evidence is, that my kind of problems could be caused by candida overgrowth or dysbiosis in general.
I've been eating a lot of sugar. That's how I get myself to go out when I'm sick with allergies! And I hadn't realized that might be making the allergies worse long-term. It's difficult because eating sugar really does help me feel a little more able to do things and cope when I'm sick.
I've also been on antibiotics long-term, to prevent the UTI's. They aren't broad-spectrum antibiotics, they are selective for UTI bacteria, and the doctors have assured me that they wouldn't mess up my gut ecosystem. But I don't know if this is true or not. Broad-spectrum antibiotics aren't usually used for a long time.
I would almost surely have an allergic reaction to commercial probiotics, because they're all cultured on foods I'm allergic to. But, probably I can grow my own probiotics :)
There's a prebiotic I'm probably not allergic to, Metamucil Clear & Natural, which is inulin.
And I've been drinking pau d'arco tea. It's a candida-killer and it seems not to affect the good bacteria Bifidobacterium and Lactobacillus.
I got quite sick for about a week from the pau d'arco tea. I felt quite spacey and unreal, and I was very wiped out and I spent a lot of time in bed. Which strongly suggests that part of what's been bothering me so much, has been intestinal fungi.
I cut way down on the sugar, and I've been limiting fruit and eating a lot of vegetables.
It does seem that eating a lot of sugar, and possibly the antibiotics, might be part of the cause of my problems. Probably not the whole cause: early in 2010 I came down sick with my dog and mold allergies, and at that time I'd been eating a low-fructose diet with lots of vegetables for several months.
I'm trying to avoid being sick with allergies, by staying in the motel - hoping my nose will recover if I avoid allergic reactions.