Rice starch is an essential addition in xenic cultures, and is ingested by D.fragilis trophozoites, together with bacteria.

In the cytoplasm, digestive vacuoles were common and contained rice starch, myelin or bacteria.

In stained smears, using higher magnification, food inclusions can be found and various bacteria, yeasts and Bacillus hominis may also be ingested.
D.fragilis: the unflaggelated human parasite. JJ Windsor & E.H.Johnson. Br.JBS 1999; 56: 293-306

Histochemical studies detected carbohydrates in the cyst wall and fat globules in the cytoplasm.
Morphology, histochemistry and infectivity of Blastocystis hominis cyst.
Abou El Naga IF, Negm AY.
J Egypt Soc Parasitol 2001 Aug;31(2):627-35

A distinct band of capsular material, or slime, may surround the cell and is apparent because it forms a transparent circle of variable thickness delinieated on the inside by the cell membrane and on the outside by bacteria, cells, and food debris in the fecal suspension.
Blastocystis hominis —
Past and Future
C.H. Zierdt Clin. Micro. Reviews.
Jan 1991, Vol. 4, No.1 (61-79)

The presence of membrane fusions of the cytoplasmic vesicles with the central vacuole indicated the accumulation of carbohydrates in the central vacuole.
Histochemical detection of carbohydrates of Blastocystis hominis.
Yoshikawa H, et al
J Eukaryot Microbiol 1995 Jan-Feb;42(1):70-4


Pattern of excretion of D.fragilis following dietary adjustments:-
Researchers placed an infected subject on a diet of mainly carbohydrates. Between day 1 and 30 - increased numbers of D.f. were found. The subject was then placed on a protein diet and retesting began at day 60. Between day 60 to 80 less D.fragilis were excreted.
(D.fragilis. A review with notes. J.Yang et al. AJTM&H 1977)

Diet & Parasites

Parasites survive by obtaining nourishment from their host. Dientamoeba fragilis and Blastocystis hominis ingest carbohydrates, bacteria and yeasts (see side bar for references).

An image of Dientamoeba fragilis ingesting rice starch.

people infected with these bugs find that limiting, or completely restricting, carbs greatly improves their symptoms.

Annie is another example of someone whose symptoms were helped by following a carb restricted diet. She was diagnosed with D.fragilis after putting up with symptoms for several years misdiagnosed as IBS:

"There was a period of two months in 2002 when I was able to exclude all sugar and grains from my diet, as I figured maybe it was candida. Just like the information on your website said, restricting carbs made me feel better. That's a pretty harsh way to live though and when I lost the willpower to stick to a very restrictive diet, all the symptoms returned, and have since been getting worse."

Karen in the UK had a similar experience. After suffering years of ill health D.fragilis was finally diagnosed by her naturopath. Her therapist, being unfamiliar with this common GI parasite, diagnosed the symptoms as Candida (a common misdiagnosis) and placed her patient on an anti-Candida diet restricting carbs and fruit:

"The diet caused immediate improvement in a way nothing else had. I was much less tired than I had been for 2 months. My head was clearer. (I had previously been eating refined sugars in an attempt to boost my energy). But I was still quite unwell.".

L. from the US was hoping for some relief after years of battling "fatigue, insomnia, dizziness, brain fog, diarhea/constipation, gas, mucousy stools, abdominal discomfort/inflammation, weight loss, depression". Like many people do, he turned to alternative medicine for answers. That's how he discovered that he felt better on a carb restricted diet:

"This is when I began seeing a series of alternative practicioners and adressing my digestive issues.  I discovered that if I stayed away from sugars and carbs that I felt much better.  I also noticed that I had developed quite a few food alergies. I did multiple herbal cleanses and colonic irrigations that seemed to improve things a little but it was always short lived.  I also tried many anti-parasitic herbal and homeopathic remedies with the same experience.  To date I have spent thousands of dollars on tests, treatments, and supplements to little or no avail." (Specialised stool testing revealed an infection with Dientamoba fragilis and Blastocystis hominis) April 07

Carbs & Starches:

Finding out which foods are contributing to the symptoms can be difficult because most foods contain varying amounts of either complex or refined carbs.

These following foods contain low/very low carbohydrate content, meaning that they should not aggravate the symptoms.

Pumpkin, artichokes, beetroot, cabbage, green peppers, tomatoes - grilled/fried, parsnips, summer squash, cabbage, cauliflower, Brussels sprouts, string beans, asparagus, onions, egg plant, salsify, okra, kohlrabi, endive, lettuce, tomatoes, cucumbers, celery, chard, spinach, broccoli, zucchini, onions (caramilised onions - ie. heated to a high temp as in frying - contain high levels of starch), salad greens, kale, spaghetti squash, bok choy, collard greens.

The following foods are high in carbohydrates/starches:

Grains including wheat, rye, oats, barley, corn, rice. Potato; sweet potato, dry beans and peas, tapioca, sago, peanuts, chestnuts, bananas; green peas.

Many prepared foods contain starches, including: couscous, breads, cookies, muffins, cakes, biscuits, pastas, and tabouli, breakfast cereals.

However, following a low carb diet long term can be detrimental to health:

There is a strong link between higher levels of nutrient intake and mental health. Researchers found significant correlation between Global Assessment of Functioning (GAF) with dietary intake of carbohydrates, fibre and other minerals. Nutrient Intakes Are Correlated With Overall Psychiatric Functioning in Adults With Mood Disorders. Karen M Davison, PhD, RD1; Bonnie J Kaplan, PhD. Can J Psychiatry. 2012;57(2):85–92


Chronic caloric restriction in young rats may lead to the development of depressive and/or anxiety disorders. Chronic food restriction in young rats results in depression- and anxiety-like behaviors with decreased expression of serotonin reuptake transporter Jeong Won Jahng et al. Brain Research.
Volume 1150, 30 May 2007, Pages 100–107.


In case you are tempted to starve your parasites into submission - don't waste your time. My Blasto. and D.fragilis survived three 10 day complete fasts (water and vitamins only). Plenty of others have tried and failed as well over the past 17 years. I don't recommended it at all. Why put yourself through all that suffering only to find that the parasites come back.

Another problem with fasting: When conditions aren't right for the parasites' survival - such as during a drug treatment or when fasting deprives them of food, parasites form cysts. It's often cysts that survive a treatment. Resuming a normal diet simply starts the cycyle again. Coffee enemas and fasting won't eradicate Blasto. or D.fragilis.

The only way to permanently get rid of these parasites is with a targeted drug treatment. Please see Treatment page for more info.

Jackie Delaney 2015