Part 1
Children with autism have 10,000 times as many gram negative bacterias as typical children.
Part 2
Explanation for this increase in bacteria
Part 3
Do antibiotics decrease the harmful bacteria?

Children with autism have 10,000 times as many gram negative bacterias as typical children.

Several studies have found out that compared to typical children, autistic children have more pathogenic intestinal flora. Several types of bacteria have been found to be abnormally abnormally elevated in the guts of ASD kids. Sophie Rosseneu and collaborators examined the GI bacteria in 69 children with regressive autism and constipation. They found the following result:
95% of children with autism had 10,000x normal level of E. coli (Aerobic Gram Negative Bacteria) and 40% also had overgrowth of similar bacteria (Aerobic Gram Negative Bacteria).

Aerobic Gram Negative Bacteria have a very potent endotoxin (LPS) that can cause damage to the gut, brain, thyroid, liver and other parts of the body.

Explanation for this increase in bacteria

It is astonishing that children with autism would have 10,000 times as many gram negative bacterias as typical children. We know from biology that the food supply is a very important determinant for the number of organisms that may survive. We also know that gram negative bacteria (the bacteria that contain LPS )are carbohydrate eaters. The majority of ASD children have carbohydrate malabsorption [2]; thus they have problems digesting starch and other complex carbohydrates because their guts are extremely damaged. Thus the gram negative bacteria will flourish, feasting on a multitude of available unabsorbed carbs and consequently emit the LPS which poisons the gut and brain.

The complex carbohydrates are much more difficult to digest than simple carbohydrates because they must be split into simple sugars before entering the blood stream. This is a problem for a compromised digestive system. Carbohydrates not absorbed into the blood stream become available food for harmful gut bacteria. Only monosaccharide carbohydrates do not become food for the bacteria. The monosaccharide are the type easy to digest because once absorbed, they vanish into the bloodstream before the bacteria can access them.

The following research articles demonstrate how the difficult to digest carbs increase gut bacteria when the body cannot absorb them and they remain as food for gut pathogens.

Two out of the following three research articles use The Hydrogen Breath test to measure amounts of anaerobic bacteria. ("anaerobic" is a technical word which means without air )

ABOUT THE HYDROGEN BREATH TEST
The hydrogen breath test utilizes the hydrogen measurement in the breath to diagnose several conditions that cause gastrointestinal symptoms.

Anaerobic bacteria are the only bacteria in the colon capable of producing hydrogen in humans. The gas develops as the result of exposure to unabsorbed food, particularly sugars and other carbohydrates like starch. Limited hydrogen is produced from the small amounts of unabsorbed food that normally reach the colon. Even larger amounts of hydrogen are present when there is a problem with food digestion and absorption in the small intestine. An environment is created that allows more unabsorbed food to reach the colon. Large amounts of hydrogen can also occur when colonic bacteria move back into the small intestine. ( "bacterial overgrowth" of the small bowel.) Once exposed to unabsorbed food, the bacteria are unable to completely traverse the small intestine to become fully digested and absorbed. Instead, some of the hydrogen produced is absorbed into the blood as it flows through the wall of the small intestine and colon and travels to the lungs. This hydrogen is released along with exhaled breath and can be measured.

The information above was taken from this website:
http://www.medicinenet.com/hydrogen_breath_test/article.htm

Supporting Research from PubMed:

Scientific Article #1

An important scientific experiment shows that the sugars that are prohibited from the SCD diet feed the anaerobic bacteria in the gut.

When patients with GI problems consumed complex sugars, the hydrogen test showed increases bacterial counts. (There is one exception: fructose). Fructose is a simple sugar; yet that sugar which is not complex also produces an increase in bacterial levels. Today's fructose is made from corn starch and impurities remain and fructose that is used for experiments is now made from corn, so it acts like a complex sugar.

Websites about how fructose is manufactured from corn:
http://ific.org/nutrition/sugars/index.cfm?renderforprint=1

The following research paper shows that the sugars that have a disaccharide molecular structure (they must be split into simple sugars before entering the blood stream. )lead to an increase in bacterial count. These sugars are not well absorbed and contribute to digestive problems:
View this article in PubMed
1: Isr Med Assoc J. 2000 Aug;2(8):583-7.

Carbohydrate malabsorption and the effect of dietary restriction on symptoms of irritable bowel syndrome and functional bowel complaints.

Goldstein R, Braverman D, Stankiewicz H.

Gastroenterology Institute, Shaare Zedek Medical Center, Jerusalem, Israel.

BACKGROUND: Carbohydrate malabsorption of lactose, fructose and sorbitol has already been described in normal volunteers and in patients with functional bowel complaints including irritable bowel syndrome. Elimination of the offending sugar(s) should result in clinical improvement. OBJECTIVE: To examine the importance of carbohydrate malabsorption in outpatients previously diagnosed as having functional bowel disorders, and to estimate the degree of clinical improvement following dietary restriction of the malabsorbed sugar(s). METHODS: A cohort of 239 patients defined as functional bowel complaints was divided into a group of 94 patients who met the Rome criteria for irritable bowel syndrome and a second group of 145 patients who did not fulfill these criteria and were defined as functional complaints. Lactose (18 g), fructose (25 g) and a mixture of fructose (25 g) plus sorbitol (5 g) solutions were administered at weekly intervals. End-expiratory hydrogen and methane breath samples were collected at 30 minute intervals for 4 hours. Incomplete absorption was defined as an increment in breath hydrogen of at least 20 ppm, or its equivalent in methane of at least 5 ppm. All patients received a diet without the offending sugar(s) for one month. RESULTS: Only 7% of patients with IBS and 8% of patients with FC absorbed all three sugars normally. The frequency of isolated lactose malabsorption was 16% and 12% respectively. The association of lactose and fructose-sorbitol malabsorption occurred in 61% of both patient groups. The frequency of sugar malabsorption among patients in both groups was 78% for lactose malabsorption (IBS 82%, FC 75%), 44% for fructose malabsorption and 73% for fructose-sorbitol malabsorption (IBS 70%, FC 75%). A marked improvement occurred in 56% of IBS and 60% of FC patients following dietary restriction. The number of symptoms decreased significantly in both groups (P < 0.01) and correlated with the improvement index (IBS P < 0.05, FC P < 0.025). CONCLUSIONS: Combined sugar malabsorption patterns are common in functional bowel disorders and may contribute to symptomatology in most patients. Dietary restriction of the offending sugar(s) should be implemented before the institution of drug therapy.

PMID: 10979349 [PubMed - indexed for MEDLINE]

Research paper #2 proves that bacterial fermentation is caused by unabsorbed starches. Half of the volunteers were fed starches together with acarbose, an inhibitor that would make them unable to absorb the starches. The volunteers who took acarbose were unable to digest their starches and showed signs of having increased bacterial counts in the colon. The starch inhibitor artificially rendered carbohydrate malabsorption to these volunteers

View this article in PubMed
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi? cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3053313&query_hl=11 1: Gastroenterology. 1988 Dec;95(6):1549-55.

Effect of starch malabsorption on colonic function and metabolism in humans.

Scheppach W, Fabian C, Ahrens F, Spengler M, Kasper H.

Department of Medicine, Wuerzburg University, Federal Republic of Germany.

To study the impact of starch on colonic function and metabolism, 12 healthy volunteers consumed a controlled diet rich in starch for two 4-wk periods. In one of the study periods they received the glucosidase inhibitor acarbose (BAY g 5421) and placebo in the other. Stool wet weight increased by 68%, stool dry weight by 57%, fecal water content by 73%, and the mean transit time by 30% on acarbose. Breath hydrogen was significantly higher on acarbose, indicating stimulated carbohydrate fermentation in the colon. Fecal bacterial mass (+78%), total stool nitrogen (+53%), bacterial nitrogen (+200%), and stool fat (+56%) were higher in the acarbose than in the control period. The stimulation of fermentation in the human large intestine may be important in colonic and possibly other diseases.

Explanation of fermentation

http://en.wikipedia.org/wiki/Fermentation_%28food%29

Sorbitol is another carb that is very dificult to digest. This research paper shows that consumption of Sorbitol produced an increase of bacterial counts on the hydrogen test.

View this article in PubMed

Sophie Rosseneu and collaborators also made a treatment study to try to eliminate the AGNB (Aerobic Gram Negative Bacteria). 11 children were treated with special antibiotics for 3 months. The antibiotics eliminates the Aerobic Gram Negative Bacteria. The constipation was cured or greatly improved and behavior improved greatly (3.7 -> 7.2/10).

But, when antibiotics stopped, AGNB returned, constipation returned, and behavior problems returned. A similar temporary benefit was seen when Vancomycin or oral Immunoglobulins were used.

The failure with medications has forced parents to use diet to starve out the pathogenic bacteria.