Absorption
The traversal of nutrients from the small intestine through the cells lining the small intestine and subsequently into the blood vessels. The small intestine breaks down ingested food into fats, proteins (amino acids), and carbohydrates. Specific areas of the small intestine then absorb these nutrients through the cell walls.
Adenosine
A molecule made inside cells from folate, amino acids (glutamine, glycine, and aspartic acid), respiratory carbon dioxide, and the sugar ribose. It is one of several similar molecules called "purine nucleosides," made during purine synthesis. Guanosine and inosine are others. When phosphates are added, nucleosides become nucleotides. Adenosine becomes adenosine monophosphate (AMP), diphosphate (ADP), or triphosphate (ATP). Adenosine as ATP can join methionine to form S-adenosylmethionine (SAM).
Amino Acids
The building blocks of proteins. The body makes many amino acids, but others are required from nutrients in order to manufacture proteins in the liver. Within the small intestine ingested proteins are broken down into amino acids, which can then be absorbed into the small intestinal cells.
Antibodies
The specialized proteins produced by white blood cells that circulate in the blood recognizing and binding to foreign proteins, microorganisms, or toxins, in order to neutralize them. They are a critical part of the immune response.
Antigen
Any substance that causes your immune system to produce antibodies against it. The antigen may be a foreign substance from the environment (such as chemicals, bacteria, viruses, or pollen) or formed within the body (such as bacterial toxins or tissue cells).
Autoimmune Disease
The body's normally protective immune system causes damage to its own tissues. The body responds as if normal tissues are infected or somehow abnormal.
B cell
A lymphocyte that produces antibodies in response to antigens.
Bowel Dysbiosis
A state of living with intestinal flora that have harmful effects. It can be described as being due to putrefaction, fermentation, deficiency, or sensitization. A number of inflammatory diseases within the bowel, the skin, or the connective tissue have been reported in association with dysbiosis.
Casein
One of several proteins found in all mammalian milk. It is known to break down into molecules with opioid properties, called casomorphine. If the enzymes designed to digest milk are not functioning properly, the resulting peptides can still be biologically active--that is, they can function as opioids (possibly explaining some of the behavioral symptoms we see in autism). If this happens, most of the peptides should be dumped harmlessly into the urine, but some of these peptides cross the blood-brain barrier and cause serious neurological problems.
Catechol-O-methyltransferase (COMT)
An enzyme that catalyzes the degradation of catecholamines, including the neurotransmitters dopamine, epinephrine, and norepinephrine. A genetic polymorphism (a common normal variant) in COMT contributes to the responses to pain and stress.
Celiac Disease
A digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have celiac disease cannot tolerate a protein called gluten, which is found in wheat, rye, and barley. When people with celiac disease eat foods containing gluten, their immune system responds by damaging the small intestine, specifically the villi.
Cell-mediated response
Part of an immune response involving a T-cell attack on an antigen.
Central Nervous System (CNS)
The brain and the spinal cord.
Cerebrospinal fluid (CSF)
A watery substance that provides a cushion that protects the brain and spinal cord.
Chelate/Chelation
The combination of a metal with an organic molecule forms a ring-like structure known as a chelate. Chelation is used clinically to increase the removal of metals from the body.
Colon
The part of the large intestine that extends from the cecum to the rectum.
Cysteine
A sulfur-containing amino acid that is synthesized from homocysteine. Its levels are rate-limiting for the synthesis of glutathione.
Cytokines
Small protein molecules that are the core of communication between immune system cells. They are actively secreted by immune cells. There are a lot of known cytokines that have both stimulating and suppressing action on lymphocyte cells and immune response. Some of the better known cytokines include: histamine, prostaglandin, TNF (tumor necrosis factor), IL-1, and IL-6.
Duodenum
The first part of the small intestine, where secretin is excreted.
Dysmotility
When the muscles of the gastrointestinal tract (esophagus, stomach, small and large intestines) do not work normally (hence the term dysmotility). Food does not move normally through the stomach and intestines, there is often distention of the stomach and intestines as fluid collects, and there is frequently pain.
Endoscopy (including ileo-colonoscopy, upper GI endoscopy, capsule enteroscopy)
A term referring to the use of a fiber-optic scope to evaluate the presence of disease in the GI tract, small intestine, and colon.
Enterocolitis
Inflammation of the small and large intestine. In the ASD population the most common symptoms include fever, abdominal swelling, diarrhea, failure-to-thrive, food malabsorption, constipation, abnormal posturing, and abdominal pain.
Enzyme
A biological catalyst. That is, a substance that increases the speed of a chemical reaction without being changed in the overall process. Enzymes are vitally important to the regulation of the chemistry of cells and organisms.
Eosinophils
Eosinophils are white blood cells active in allergic diseases, parasitic infections, and other disorders.
Epithelial Cells
The inner portion of any structure of the body is lined with epithelial cells.
Esophagus
A soft muscular tube that connects the throat to the stomach.
Folate (folic acid)
Folate and folic acid are forms of water-soluble B vitamins. Folic acid refers to the synthetic vitamin used in supplements, whereas folate is the form found in foods. The term comes from the Latin "folium" which means leaf. This makes sense because folate is found in leafy vegetables. Critical for the proper development and maintenance of cells, especially during times of rapid cell division such as fetal development and childhood, it was discovered several years ago to be critically important for avoiding neural tube birth defects. Folic acid supplementation is recommended for all women who are pregnant or may become pregnant.
Folinic Acid
Also known as 5-formyl tetrahydrofolate; it is an active form in a group of vitamins known as folates. In contrast to folic acid, which is a synthetic form of folate, folinic acid is one of the forms of folate found naturally in foods. Folate deficiency is believed to be the most common vitamin deficiency in the world due to food processing, food selection, and intestinal disorders. In the body folinic acid may be converted into any of the other active forms of folate. Folate coenzymes are also needed in the formation of heme, the iron-containing protein in hemoglobin, and the formation of the amino acid methionine from homocysteine (vitamin B-12 as methylcobalamin is also needed for this conversion). Folinic acid is commonly prescribed under the name Leucovorin.
Gastric
Refers to the stomach.
Gastrointestinal Tract
Begins with the mouth, leads to the esophagus and extends through the stomach, small intestine (duodenum, jejunum, and ileum), and large intestine (colon). During the journey, food is broken down and nutrients absorbed. Finally, within the large intestine, water is resorbed and the remaining fecal matter is expelled. If inflammation is present, motility (movement) is impaired, resulting in constipation and/or diarrhea.
Glial cells
A supportive cell in the central nervous system -- the brain and spinal cord. Glial cells do not conduct electrical impulses (as opposed to neurons, which do). The glial cells surround neurons and provide support for them and insulation between them. Glial cells are the most abundant cell types in the central nervous system. There are three types of glial cells: astrocytes, oligodendrocytes, and microglia. Astrocytes are concerned with neurotransmission and neuronal metabolism. Oligodendrocytes are involved in the production of myelin, the insulating material around neurons. And microglia are part of the immune system.
Glutathione (GSH)
A tri-peptide, made from glutamic acid, cysteine, and glycine. It is the major anti-oxidant species in cells, and along with cysteine, it is critical for binding and detoxifying heavy metals. Levels of GSH are low in autism and the ratio of GSH to its oxidized form (GSSG) is low, indicating the presence of oxidation stress. GSH is also required for synthesis of methyl B12, so low levels can contribute to reduced methionine synthase activity.
Gluten
The proteins found in the plant kingdom subclass of Monocotyledonae, the grass family of wheat, oats, barley, rye, and triticale. Derivatives of these grains include malt, grain starches, hydrolyzed vegetable/plant proteins, textured vegetable proteins, grain vinegar, soy sauce, grain alcohol, flavorings, and the binders and fillers found in vitamins and medications. Like casein, gluten breaks down into molecules with opioid traits, called gluteomorphine. As with caseomorphin, it too can retain biological activity if the enzymes needed to digest it are not functioning properly.
Heavy Metals
Mercury, lead, cadmium, and other heavy metals cannot be metabolized by the body and if accumulated, can cause toxic effects by interfering with various physiological functions. These substances are called "heavy metals," a term applied to metallic elements whose specific gravity is about 5.0 or greater, especially those that are poisonous.
Heterozygous
Referring to a gene pair in which two alleles (any of the alternative forms of a gene that may occur at a given locus) do not code for the same trait.
Histamine
A kind of cytokine that causes an inflammatory response to an injury, resulting in redness, swelling, warmth, and pain.
Homocysteine
A sulfur-containing amino acid, which is an intermediary in the metabolism of another sulfur-containing amino acid, methionine.
Homozygous
Referring to a gene pair in which the two alleles code for the same trait.
Ileum
The final section of the small intestine.
Immunoglobulin (IG)
Immunoglobulins (antibodies) are proteins produced by plasma cells. They are designed to control the body's immune response by binding to substances in the body that are recognized as foreign antigens (often proteins on the surface of bacteria or viruses.) Antibodies are diverse, with more than 1010 possible variations, yet each antibody is designed to recognize only a specific antigen. The antibodies are released into the intercellular fluid where they bind to the infecting antigen, identifying it for destruction by the immune system. Immunoglobulins also play a central role in allergies when they bind to antigens that are not necessarily a threat to health and provoke an inflammatory reaction. There are five main types of antibody: IgA, IgD, IgE, IgG, and IgM are the most common.
Inflammation
Inflammation is a process in which the body's white blood cells and chemicals protect us from infection and foreign substances such as bacteria and viruses. When inflammation occurs, chemicals from the body's white blood cells are released into the blood or affected tissues to protect you from foreign substances. This release of chemicals increases the blood flow to the area of injury or infection and may result in redness and warmth. Some of the chemicals cause a leak of fluid into the tissues, resulting in swelling. This protective process may stimulate nerves and cause pain. In some diseases, however, the body's immune system triggers an inflammatory response when there are no foreign substances to fight off.
Jejunum
The middle section of the intestines, between the duodenum and the ileum.
Lamina Propria
A thin vascular layer of connective tissue beneath the epithelium of an organ.
Large Intestine (colon)
Receives the liquid residue after digestion and absorption are complete. This residue consists mostly of water, as well as materials (e.g. cellulose) that were not digested. It nourishes a large population of bacteria (the contents of the small intestine are normally sterile). Most of these bacteria are harmless. Bacteria flourish to such an extent that as much as 50% of the dry weight of the feces may consist of bacterial cells. Reabsorption of water is the chief function of the large intestine. The large amounts of water secreted into the stomach and small intestine by the various digestive glands must be reclaimed to avoid dehydration. If the large intestine becomes irritated, it may discharge its contents before water reabsorption is complete, causing diarrhea. On the other hand, if the colon retains its contents too long, the fecal matter becomes dried out and compressed into hard masses, causing constipation.
Leaky Gut Syndrome
An abnormal level of intestinal permeability is suspected as a major factor in a wide range of food and chemical sensitivities, arthritis, asthma, headaches, digestive problems of varying seriousness, and chronic fatigue. It has been linked to many of the problems experienced in patients with severe candida albicans overgrowth, since it was known that candida, in its fungal form can put down "roots" into the gut wall, allowing comparatively large molecules to pass through into the bloodstream. Whether these are food molecules, bacteria, or chemical toxins, the result is the same: an immune response by the body, an attack by antibodies, and the start of a cycle of immune response, inflammation, and antibody-antigen reactions.
Liver
The liver has many important jobs. It makes a substance called bile which aids in digestion, and other substances needed by the body to fight disease. The liver also removes certain types of poisons and wastes (detoxification).
Lymphocyte
A type of white blood cell involved in the human body's immune system. There are two broad categories of lymphocytes, namely T-cells and B-cells. Lymphocytes play an important and integral part of the body's defenses. In the presence of an antigen, B-cells become much more metabolically active and transform into plasma cells. Plasma cells are large lymphocytes with a large nuclear to cytoplasmic ratio and are the form of B-cell lymphocytes that produce antibodies. An increase in lymphocytes is usually a sign of a viral infection.
Lymphoid nodular hyperplasia
A form of chronic lymphadenitis (inflammation of one or more lymph nodes) occurring as an immunologic response and characterized by transformation of T cells to lymphoblasts (an activated lymphocyte that has been transformed in response to antigenic stimulation), endothelial cell hypertrophy, and the presence of a mixed leukocyte infiltrate.
Macrophage
A large cell that is derived from a white blood cell called a monocyte, that ingests bacteria and other foreign cells, and that helps white blood cells identify microorganisms and other foreign substances.
Methionine
An amino acid, one of the 20 building blocks of protein. A dietary essential amino acid, methionine provides methyl groups and sulfur for normal metabolism.
Methionine Synthase (MTR)
The MTR gene provides instructions for making an enzyme called methionine synthase reductase (MTRR), a mitochondrial precursor. This enzyme activates cobalamin-dependent methionine synthase. Methionine synthase is involved in processing amino acids (the building blocks of proteins). Specifically, it carries out a chemical reaction that converts the amino acid homocysteine to another amino acid, methionine. Methionine is used by the body to make proteins and other important compounds.
Methylation
The transfer of a methyl group to another molecule. It makes adrenaline from norepinephrine, and melatonin from serotonin. It is critical for the transcription of DNA.
Methylcobalamin
An active form of B12. Vitamin B12 comes in several forms, but only the methyl form is used in the central nervous system. Cyanocobalamin (the form used in vitamin supplements) is converted by the liver into methylcobalamin, but not in therapeutically significant amounts. Vitamin B12 deficiency is caused by a wide range of factors including low gastric acidity, excessive laxative use, poor absorption from the intestines, lack of calcium, and heavy metal toxicity. The most frequent cause of B12 deficiency is a vegetarian diet without supplementation (B12 is derived from animal sources). When B12 is deficient, SAM becomes deficient, and SAM methylates myelin.
Methylenetetrahydrofolate Reductase (MTHFR)
The enzyme which converts folic acid to the biologically active form of folate. A single nucleotide polymorphism (SNP) affects the ability of the enzyme to work appropriately.
Natural Killer (NK) cell
A large white blood cell that can react against and destroy another cell without prior sensitization to it. Natural killer (NK) cells are part of our first line of defense against cancer cells and virus-infected cells. NK cells are small lymphocytes that originate in the bone marrow. NK cells look for a "banner" flown by normal cells. If the NK cell recognizes the "banner," it spares that cell. If the "banner" is absent, the NK cell attaches to the target cell, releases a burst of chemicals that penetrate the target cell's wall, and the target cell breaks up (lyzes).
Opioids
The class of drugs to which morphine belongs, opioids have powerful analgesic capacity but are highly addictive and have potent effects on the central nervous system (CNS). In the early 1980s, it was noted that the behavior of animals under the influence of opioid drugs was similar to that of some people with autism. Dr. Jaak Panksepp proposed that autistics might have elevated levels of naturally occurring opioids in their CNS. There are several such naturally-occurring compounds. The best known of these are the beta-endorphins which produce the so-called "runner's high." These substances bind to opiate receptor sites in brain cells and mimic some of the pharmacological properties of opiate drugs. At about the same time, work by Swedish autism expert Christopher Gillberg showed elevated levels of "endorphin-like substances" in the cerebrospinal fluid (CSF) of some autistics. It is particularly interesting that levels are high in those autistic children who are insensitive to pain and those who engage in self-injurious behaviors. Reichelt in Norway and Shattock in England confirmed the presence of compounds with opioid characteristics in the urine of autistic children. These are believed to be the products of the incomplete digestion of certain food proteins (especially gluten and casein).
Peptide
A chain of amino acids.
Protein
One or more peptides linked together. Proteins are required for the structure, function, and regulation of the body's cells, tissues, and organs, and each protein has unique functions.
S-adenosylmethionine (SAM)
SAM is what gives methyl groups to substances in the process called "methylation". Seventy percent of SAM's methylation duty goes to form creatine.
Secretin
A hormone that controls digestion. Secretin stimulates the pancreas to secrete digestive enzymes, the stomach to produce pepsin, and the liver to produce bile.
Small Intestine
The section of the intestines between the stomach and the colon. It is divided into three major sections: the duodenum, the jejunum, and the ileum. Digestion within the small intestine produces a mixture of disaccharides, peptides, fatty acids, and monoglycerides. The final digestion and absorption of these substances occurs in the villi, which line the inner surface of the small intestine.
Sulfation
Detoxification is a vital biological process that renders toxic substances harmless and allows them to be excreted from the body. In order for this to occur, the toxin is often transformed into a new substance altogether. Often this transformation is accomplished by adding one molecule to a toxic one, making the original one larger but benign. This process is called conjugation. Adding sulfate to a molecule is a common form of detoxification. In ASD children this biological function is often impaired. Research by Rosemary Waring has shown that an enzyme critical for sulfation, phenol sulfur transferase, is deficient. If the sulfation system is atypical in any way, one would expect effects on the bodyıs immune system.
T cell
A thymus-derived lymphocyte that helps stimulate an immune response against an antigen.
Thimerosal
A preservative which contains nearly 50% ethyl mercury by weight. The FDA estimates that throughout the 1990s it was used in more than thirty licensed vaccines and biologics marketed in the US. During this time the vaccine schedule for infants included as much as 187 mcg of mercury in the first six months of life--far exceeding levels accepted as safe. Many symptoms of ASD closely resemble those of mercury poisoning. It is no longer used in most vaccines.
Tumor Necrosis Factor (TNF)
A member of a superfamily of proteins, each with 157 amino acids, which induce necrosis (death) of tumor cells and possess a wide range of proinflammatory actions. Tumor necrosis factor is a multifunctional cytokine with effects on lipid metabolism, coagulation, insulin resistance, and the function of endothelial cells lining blood vessels. Blocking the action of TNF has been shown to be beneficial in reducing the inflammation in inflammatory diseases such as Crohn's disease and rheumatoid arthritis.
Villus (pl: Villi)
A tiny finger-like protrusion on the lining of the small intestine. Nutrients from food are absorbed into the bloodstream through villi. Without villi, a person becomes malnourished, regardless of the quantity of food eaten.
Yeast
Unicellular fungus whose colonies resemble those of bacteria.
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