Chloride, potassium, magnesium, sodium and free fatty acids diffuse through intestinal cells. Amino acids, fatty acids, glucose, minerals, and vitamins also cross through cells, but they do it by another mechanism called active transport.
There's a third way substances can pass through. The spaces in between the cells that line the intestines are normally sealed. These tight junctions are called desmosomes. When the intestinal lining becomes irritated, the junctions loosen and allow unwanted larger molecules in the intestines to pass through into the blood. These unwanted substances are seen by the immune system as foreign (because they aren't normally present in blood). This triggers an antibody reaction.
When the intestinal lining becomes further damaged, even larger substances, such as disease-causing bacteria, undigested food particles, and toxins, pass directly through the damaged cells. Again, the immune system is alarmed and antibodies and substances called cytokines are realeased. Cytokines alert white blood cells to fight the particles. This fight produces oxidants, which cause irritation and inflammation throughout the body.
Symptoms of Leaky gut syndrome / Intestinal permeability
Symptoms include: abdominal pain, asthma, chronic joint pain, chronic muscle pain, confusion, fuzzy or foggy thinking, gas, indigestion, mood swings, nervousness, poor immunity, recurrent vaginal infections, skin rashes, diarrhea, bed-wetting, recurrent bladder infections, poor memory, shortness of breath, constipation, bloating, aggressive behavior, anxiety, fatigue, feeling toxic.
Leaky gut syndrome is associated with the following conditions:
- Autoimmune disease
- Celiac disease
- Crohn's disease
- Environmental illness
- Inflammatory joint disease / arthritis
- Intestinal infections
- Pancreatic insufficiency
- Ulcerative colitis
- Chronic fatigue syndrome
- Food allergies and sensitivities
- Liver dysfunction
- Rheumatoid arthritis
- Irritable bowel syndrome
- Chronic stress
- Intestinal infections
- Small intestine bacterial overgrowth
- Environmental contaminants
- Excess alcohol
- Poor diet
- NSAIDS and other medications
The standard test for leaky gut syndrome is the mannitol and lactulose test. Both are water soluble molecules that the body can't use. Mannitol is easily absorbed by people with healthy intestinal linings. Lactulose is a larger molecule and is only slightly absorbed. A person drinks a solution contain both mannitol and lactulose. Urine is collected for six hours and the amount present in urine reflects how much was absorbed by the body. A healthy test shows high levels of mannitol and low levels of lactulose. If high levels of both molecules are found, it indicates a leaky gut condition. If low levels of both molecules are found, it indicatioes general malabsorption of all nutrients.
Lipski, E. Digestive Wellness, Keats Publishing/McGraw Hill, 2001.