Possible Environmental causes of Autism
Although genetics plays an important role in autism, environmental factors are also involved. There is no general consensus on what those environmental factors are . Since the word “autism” is only a label for people who have a certain set of symptoms, there are likely to be a number of factors that could cause those symptoms. Some of the suspected environmental causes for which there is limited scientific evidence include:

Childhood vaccinations: The increasing number of vaccines given to young children might compromise their immune system. Many parents report their child was normal until vaccinations.

MMR Vaccine: Evidence of measles virus has been detected in the gut, spinal fluid and blood. Also, the incidence of autism began rising significantly when the MMR was introduced in the US (1978) and in the U K (1988). Thimerosal (a mercury-based pre-servative) in childhood vaccines. The number of vaccines given to children has risen over the last two decades, and most of those vaccines contained thimerosal, which is 50% mercury. The symptoms of mercury poisoning in children are very similar to the symptoms of autism.

Excessive use of oral antibiotics: Can cause gut problems, such as yeast/bacterial overgrowth, and prevents mercury excretion. Maternal exposure to mercury (e.g., consumption of seafood high in mercury, mercury dental fillings, thimerosal in RhoGam shots).

Lack of essential minerals: Zinc, magnesium, iodine, lithium, and potassium may be especially important.

Co-occurring conditions
Mental Retardation: Although it has been estimated that up to 75% of people with autism have mental retardation, research studies have frequently used inappropriate IQ tests, such as verbal tests with nonverbal children and, in some cases, estimating the child’s intelligence level without any objective evidence. Parents should request non-verbal intelligence tests that do not require language skills, such as the Test for Nonverbal Intelligence (TONI). Furthermore, regardless of the result, realise that autistic children will develop more skills as they grow older, and that appropriate therapies and education can help them reach their true potential.

Seizures: It is estimated that 25% of autistic individuals also de-velop seizures, some in early childhood and others as they go through puberty (changes in hormone levels may trigger seizures). These seizures can range from mild (e.g., gazing into space for a few seconds) to severe, grand mal seizures. Many autistic individuals have subclinical seizures which are not easily noticeable but can significantly affect mental function.

Chronic Constipation and/or Diarrhoea: An analysis of the ARI’s autism database of thousands of cases show over 50% of autistic children has chronic constipation and/or diarrhoea. Diarrhoea may actually be due to constipation — i.e., only liquid is able to leak past a constipated stool mass in the intestine. Manual probing often fails to find an impaction. An endoscopy may be the only way to check for this problem. Consultation with a pediatric gastroenterologist is required.

Sleep Problems: Many autistic individuals have sleep problems. Night waking may be due to reflux of stomach acid into the esophagus. Placing bricks under the head of the bed may help keep stomach acid from rising and provide better sleep. Melatonin has been very useful in helping many autistic individuals fall asleep. Other popular interventions include using 5-HTP and implementing a behaviour modification program designed to induce sleep. Vigorous exercise will help a child sleep, and other sleep aids are a weighted blanket or tight fitting mummy-type sleeping bag.

Pica (Mud eating): Approximately 30% of children with autism have moderate to severe pica. Pica refers to eating non-food items such as paint, sand, dirt, paper, etc. Pica can expose the child to heavy metal poisoning, especially if there is lead in the paint or in the soil.

Low Muscle Tone: A study conducted by the first author found that 30% of autistic children have moderate to severe loss of muscle tone, and this can limit their gross and fine motor skills. That study found that these children tend to have low potassium levels. Increased consumption of fruit may be helpful.

Sensory Sensitivities: Many autistic children have unusual sensitivities to sounds, sights, touch, taste, and smells. High-pitched intermittent sounds, such as fire alarms or school bells, may be painful to autistic children. Scratchy fabrics may also be intolerable, and some children have visual sensitivities. They are troubled by the flickering of fluorescent lights. If the child often has tantrums in large supermarkets, it is possible that he/she has se-vere sensory oversensitivity. Sensory sensitivities are highly variable in autism, from mild to severe. In some children, the sensitivities are mostly auditory, and in others, mostly visual. It is likely that many individuals who remain non-verbal have both auditory and visual processing problems, and sensory input may be scrambled. Even though a pure tone hearing test may imply normal hearing, the child may have difficulty hearing auditory details and hard consonant sounds.