Comprehensive Nutritional and Dietary Intervention for Autism Spectrum Disorder

Nutritional and dietary treatment has been shown to be of benefit in treatment of ASD, as the disorder is marked by nutritional imbalances, metabolic impairments, and digestive problems. Short term studies on individual treatments/supplements are widespread. This single-blind, randomized and controlled trial tested the use of a comprehensive treatment combining these individual methods for improvement of ASD symptoms, digestive problems and overall functionality. 67 ASD-diagnosed individuals were enrolled and randomized into a treatment and non-treatment group alongside a control group of neurotypical individuals (n = 50), with ages ranging from 3 years to 58 years. The study hypothesized that all aforementioned symptoms stand to show greater improvement through the synergist effect of a combination nutritional/dietary intervention comprising the following individual nutrient groups/diets:

1. Vitamins and Minerals

The rationale for a customized vitamin and mineral supplementation comes from previous studies that have shown this dietary intervention to be of significant benefit in ASD patients. These include studies citing the presence of impaired methylation (important for epigenetics), lack of glutathione (an important anti-oxidant) and increased oxidative stress in ASD children. One trial comparing ASD children with neurotypical children found that the former had significantly lower levels of metabolic and energy production biomarkers like: biotin, glutathione, methylation status, ATP, NADH, NADPH, sulfate (free and total), and neurotransmitters like: tryptophan, and GABA; and high levels of oxidative stress markers and plasma glutamate. The study was followed by a treatment trial that resulted in improvement of most of these markers to normal or near-normal level, indicating improved metabolic status, except for sulfate, for which additional treatments may be needed. Supplement group had shown improvement in autism symptoms as well.

Methods and Treatment Protocols: Drawing from the above-mentioned literature, the study enrolled 67 ASD-diagnosed individuals with ages ranging 2.5-60 years, who had not attempted to change either developmental or behavioral treatments in the previous 12 months, or used nutritional supplements or special diets for the last 2 months. Outcomes were measured through various clinical assessment tools for autism severity. In addition, biomarkers for vitamins in blood and urine were tested in a blinded manner at the start and end of the study. Nutritional status evaluation included standard measurements of blood chemistry like ammonia, lactic acid, creatine kinase, albumin, etc., Complete Blood Count (CBC) with differential, and a thyroid panel (TSH, T3, T4), urinary iodine, RBC elements, RBC fatty acids, C-Reactive Protein, and homocysteine-related metabolites (homocysteine, cysteine, methionine).

After initial evaluation of autism severity, overall functioning, physical examination and sample collection for blood and urine tests, treatment was begun in a sequentially-administered manner. Methodology will be the same for every nutrient/diet mentioned later except for the timing of the start of the individual treatment. Vitamins and minerals were started on Day 0.

Treatments and Doses: The study used an improved variation of a supplementary regimen used in a previous study. Doses were adjusted to bodyweight and slowly increased over the course of 4 weeks. For convenience, it was split into three doses corresponding to breakfast, lunch and dinner, or two doses with breakfast and dinner.

Constituent vitamins and doses are as follows:

1.      Vitamin A (85% beta carotene and 15% palmitate, IU) 6500

2.      Vitamin C (from calcium ascorbate, mg) 500

3.      Vitamin D3 (cholecalciferol, IU) 1000

4.      Vitamin E (as alpha-tocopherol, IU) 150

5.      Vitamin K (K1 and K2, mcg) 55

6.      Vitamin B1 (thiamin hydrochloride, mg) 20

7.      Vitamin B2 Riboflavin (mg) 40

8.      Niacin (71% inositol hexanicotinate & 29% niacinamide, mg) 35

9.      Vitamin B6 (50% as P5P pyridoxal 5 phosphate, 50% as pyridoxine hydrochloride, mg) 40

10.  Folate (as folic acid, folinic acid, and L-5-methyltetrahydrofolate, mcg) 600

11.  Vitamin B12 (50% as methylcobalamin & 50% as cyanocobalamin, mcg) 500

12.  Biotin (mcg) 225

13.  Pantothenic Acid (calcium d-pantothenate, mg) 30

14.  Iodine (potassium iodide, mcg) 100

15.  Lithium (mcg) 350


16.  Choline (from choline bitartrate, mg) 250

17.  Inositol (mg) 100 Calcium (mg) 70

18.  Magnesium (magnesium citrate, mg) 100

19.  Zinc (zinc gluconate, mg) 15

20.  Selenium (selenomethionine and sodium selenite, mcg) 40

21.  Manganese (manganese amino acid chelate, mg) 1

22.  Chromium (chromium amino acid chelate, mcg) 70

23.  Molybdenum (sodium molybdate dihydrate, mcg) 100

24.  Potassium (from potassium chloride, mg) 50

25.  MSM (methylsulfonylmethane, mg) 500

26.  Vitamin E as mixed tocopherols (mg) 100

27.  CoQ10 (mg) 50

28.  N-acetyl-cysteine (mg) 45

29.  Acetyl-L-carnitine (mg) 200

30.  Vanadium (mcg) 25

31.  Boron (mcg) 250



Results and Explanations: Use of vitamin supplements resulted in worsening of behavior (moderate severity) in 2 participants who stopped use after 4 months due to this adverse effect. They had abnormally low levels of B12, and relatively lower levels of methyl-B12, riboflavin and beta-carotene: this may have made them extremely sensitive to supplements, or they may have an underlying metabolic problem. 20% of the people complained about the taste, but it was helped by mixing the supplement with juice or taking it in capsule form.

Compliance was relatively good overall – about 85% missed 1 or less dose per week.

Autism symptoms improved and are discussed later under the heading of ‘Clinical assessment of ASD symptoms, gastrointestinal symptoms and overall functionality’.

It was one of the highest rated treatments in terms of effectiveness, consistent with the fact that most improvement in patients occurred in the first three months. >85% of families agreed to treatment continuation in the future.

As for quantification through medical tests, most of the RBC measurements did not change. Slight decrease in RBC and slight increase in MCV was observed. Biomarkers for Vitamin B2, B5, folic acid, B6, B12 (greater increase for cyanocobalamin form and none for methyl-cobalamin form) and CoQ10H2 were significantly increased. Meanwhile there was no improvement in other vitamin levels, which shows that larger doses or use of more bioavailable forms of supplements may be needed for more therapeutic effect. Dose increase of Vitamin D is of special importance.

Treatment group further showed significant increase in RBC selenium and chromium. Large significant decrease was observed in homocysteine levels, which may be because of B12 and folic acid as well as B6 supplementation (enzymatic cofactors involved in homocysteine metabolism), whereas methionine and cysteine levels showed no great changes.


2. Essential Fatty Acids

These include polyunsaturated fatty acids (PUFAs) like omega-3 and omega-6. Studies have shown EFAs to be decreased in psychiatric disorders like schizophrenia, ADHD, depression, bipolar disorder, dementia. Supplementation has documented benefit in all these disorders in addition to Rett’s syndrome (a disorder with autistic symptoms). EPA is more effective than DHA.

PUFAs are beneficial for intestinal membrane function and gastrointestinal problems, which have a documented relation with ASD. A meta-analysis of 15 studies showed that in comparison to neurotypical people, ASD individuals had lower eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA), and a lower ratio of total omega-3 to total omega-6 fatty acids; these differences were primarily found in children and not adults. Placebo-controlled trials showed omega-3 FA supplementation (at doses 0.5 – 1.5 g/day) to improve social withdrawal and repetitive behavior in ASD patients. Short duration of the studies may not have allowed for full effect to show, as fatty acids take 6 months to build steady levels within RBCs.

Supplementation with higher doses and long-term duration may be helpful as levels of fatty acids appear to be decreased in ASD.

Methods and Treatment Protocols: Same criteria, clinical assessment measures and laboratory parameters (pre and post) as for vitamins/minerals were applied. Supplementation with Fatty Acids was begun on day 30.

Treatment Doses: ProEFA-Xtra by Nordic Naturals, a concentrated blend of fish oil (for omega-3 FAs) and borage oil (for omega-6 FAs) was used. Fish oil is one of the most absorbable sources of fatty acids. According to bodyweight, doses were as follows: 30–50 pounds (14–23 kg): 2 capsules/day, 51–100 pounds (23–45 kg): 3 capsules/day, 100+ pounds (45+ kg): 4 capsules/day.

Moreover, each capsule contained: 609 mg omega-3 fatty acids (425 mg EPA, 110 mg DHA, 74 mg other omega-3 fatty acids), 198 mg omega-6 fatty acids (including 128 mg GLA), and 15 mg omega-9 fatty acids. Treatment was started at 1 capsule/day and increased to required doses over 2-4 weeks.

Results and Explanations: The treatment showed good safety and no adverse events were reported except for taste issues which were resolved by mixing the supplement with juices and taking them in capsule form.

Treatment effectiveness was the one of the highest rated, and more than >85% families agreed to continuing the treatment.

PUFA levels in RBCs were significantly increased. Percentage increase was 6 times larger for EPA than DHA, consistent with the 4:1 EPA:DHA composition of the fish oil used.

BMI showed no significant changes. There were large increases in EPA and DHA for treatment group compared to non-treatment group, and a small decrease in arachidonic acid that may contribute to reduced pro-inflammatory eicosanoid production and may be of benefit in ASD. However, there were no significant changes in CRP for either group, which is a marker for systemic inflammation. Levels of linoleic acid, dihomo-γ-linoleic acid, elaidic acid and palmitoleic acid were reduced as well, probably because of competitive absorption with omega-3 fatty acids. Most treatment effectiveness was reported in those participants with the lowest initial linoleic acid levels.

Conclusively, higher doses of essential fatty acids may be warranted.


3. Sulfate

The evidence for this treatment comes from several previous studies. Sulfate is biochemically useful for detoxification, synthesis of brain tissue, inactivation of catecholamines, sulfation of mucin proteins lining the gastrointestinal tract and more. Free and plasma sulfate levels in ASD patients are found to be low; in trials, ASD participants had lower sulfation capacity than controls demonstrated by a low capacity to detoxify acetaminophen. Urine sulfate in ASD is found to be high and there may be urinary wasting. Low plasma ATP levels correlating with low sulfate levels have been found; as kidneys need ATP to reabsorb sulfate, this may partly explain the wasting effect. There is also a reduced capacity for sulfite conversion to sulfate reflected in a high urinary concentration of sulfite, and a study showed some degree of improvement (38% participants) in conversion with molybdenum supplementation. Vitamin and mineral supplements have been shown to be helpful in increasing levels but additional sources of sulfate like Epsom salt baths (composed of magnesium sulfate) may be needed.

Methods and Treatment Protocols: Epsom salt baths, an internally researched effective way for raising sulfate levels, were begun on day 60.

Treatments and Doses: Participants were asked to take a 20 min warm bath twice a week using 2 cups of Epsom salt and half a cup of baking soda.

Results: No adverse events were reported. Epsom salt baths ranked lowest in treatment effectiveness as rated by families and 70% planned to continue with the treatment.


4. Carnitine

Carnitine is essential for fatty acid metabolism and energy production as it carries long chain fatty acids (fuel) into the mitochondria and toxic organic acids out of the mitochondria to be eliminated from the cell. Studies have suggested that ASD patients commonly have mitochondrial disorders, a generalized impairment of function not to be confused with mitochondrial ‘diseases’. Evidence for this treatment comes in the form of studies that have found low levels of carnitine in ASD individuals as well as a trial that concluded carnitine supplementation to be beneficial for ASD. The latter study showed improvement with Childhood Autism Rating Scale 2 (CARS-2) and Clinical Global Impression (CGI) Scores, and increase in cognition and speech were also noted. Carnitine therapy was well-tolerated and effective in raising serum concentrations of carnitine and a strong correlation between free serum carnitine and clinical benefit was reported. Therefore, it is believed that carnitine therapy is of benefit as it improves impaired mitochondrial function in ASD children.

Methods and Treatment Protocols: Supplementation was started on Day 90.

Treatments and Doses: Based on a previous study involving L-carnitine, a safe and effective dosage of 50 mg acetyl-L-carnitine/kg bodyweight-day to a maximum of 2 grams/day was used. Dose was gradually increased to the full dosage over 4 weeks, and was split evenly between morning and dinnertime.

Results and Explanations: One parent reported discontinuation on account of the treatment making their child feel sick. Compliance wise, 82% of families missed doses only once (or less) a week. Treatment effectiveness was rated lower than vitamins/minerals, EFAs, healthy-gluten-casein-soy-free-diet, and 44% reported willingness to continue with the treatment.

Blood chemistry showed a small decrease in Blood Urea Nitrogen concentrations in treatment group. Serum L-carnitine showed significant increase while acetyl-L-carnitine showed non-significant increase; reported treatment effectiveness had a non-significant inverse correlation with initial levels of acetyl-L-carnitine.

Increase was observed more in L-carnitine level while supplementation was in acetyl-L-carnitine form, which suggests there is interconversion between the two forms in the body. Moreover, based on two previous studies that showed better improvement in levels and clinical symptoms with the L-carnitine form (compared to the modest benefit observed in the current study), it was concluded that the L-carnitine form is better absorbed in the body and should be used in the future.

One exceptional case of improvement was related to carnitine. A moderately obese, severely autistic 9-year-old who had difficulty with physical activity and low energy levels showed vast improvement in endurance and strength. By 6-12 months into the study she was able to do things she’d previously been unable to do like get in and out of vans by herself, walk for 2 miles without the use of wheelchair and attend outings without tiring. Her diet had previously been limited in beef and pork (primary dietary sources of carnitine) and improvement seemed to coincide with the start of high-dose carnitine supplementation at 4 months. Her levels of carnitine before and after the study were also drastically different: from 68% of normal, after treatment they averaged 18% above normal levels. The case study showed that nutritional deficiencies and food intolerance may have significant effects, and thus a treatment with dietary supplements may be beneficial in treating some intractable problems.


5. Digestive Enzymes

Gastrointestinal problems like chronic constipation, diarrhea, abdominal pain and inflammation are common in ASD patients, and correlate with autism severity. These problems can, in part, be due to deficiencies of digestive enzymes. One study found severe deficiencies of disaccharidase enzyme activities in endoscopic biopsies, of which lactase and maltase were the most frequently deficient. Another study conducted on biopsy samples from ASD children observed similar deficiencies: 62% had deficiencies in lactase, 16% were deficient in sucrase, and 10% were deficient in maltase. Levels were similar for children and adults indicating a lifelong impairment. An open-label study has found wide range of benefits from digestive enzymes while results from randomized controlled trials are mixed.

Methods and Protocols: Supplementation began on Day 180.

Treatments Doses: A digestive enzyme complex for proteins (low-medium enzyme activity), carbohydrates and starches (medium level activity), and fats (medium-high activity) was used. The dosage was one capsule for a snack or small adult meal, two capsules for a typical adult meal, and three capsules for a large adult meal. Composition of one capsule was as follows:

  1. Amylase 3500 DU
  2. Peptidase 13,000 HUT
  3. Glucoamylase 50 AGU
  4. Xylanase 7000 XU
  5. Protease 4.5 22,000
  6. HUT Protease 3.0 35 SAPU
  7. Amylase 1500 DU
  8. Invertase 800 SU
  9. Alpha-galactosidase 100 GalU
  10. Lactase 500 ALU
  11. Lipase 500 FIP

Results and Explanations: One participant could not tolerate the treatment and discontinued it after one month. Another participant, despite observing benefit for constipation and behavior, stopped using it after a developing a facial rash with long use. Compliance was such that 78% people reported missing one or less dose per week. Treatment effectiveness was not amongst the highest rated, and only 44% families were inclined to continue with the treatment. It appears that more research on which particular blend of enzymes may show maximum benefit is needed.


6. Healthy Gluten, Casein and Soy Free Diet

The rationale for this treatment was again based on the gastrointestinal problems seen with ASD. Data exists to show that ASD patients may have an abnormal immune response to certain foods like gluten (wheat, rye, barley and oats), casein (dairy products) and soy. Food sensitivities are more common in ASD children than neurotypical children, which may be indicate an underlying increased gut permeability. 87% of ASD children had antibodies to gluten compared to 1% of age and gender matched controls, and 90% had antibodies to casein vs. 7% of controls.

Several studies have shown that special diets can benefit individuals with ASD including one short-term study employing an allergen-free diet for 8-weeks. Another longer-term study using a 12-month (or longer) treatment with gluten and casein free diet resulted in 81% improvement by the third month and sustained improvement over the course of the treatment. These improvements pertained to the social isolation, mutism, stereotypic behavior and hyperactivity characteristic of ASD. Another long-term trial also found improvement in communication.

Methods: Healthy gluten and casein free diet was started on day 210.

Treatment Protocols: Participants were educated on the diet through written instructions, a 1-hr PowerPoint presentation and a 1-hr personal consult with a nutritionist with permission to ask additional questions. The major principles of the diet include adequate intake of a variety of vegetables, fruits, quality protein, non-excessive caloric intake, replacement of junk food with healthy snacks, avoidance of artificial colors, preservative and flavors, and a healthy gluten-free, casein-free, and soy-free diet (HGCSF diet). Parents made the final decision on adherence to these guidelines in meal plans.

Results and Explanations: One parent reported increased aggression, inability to problem solve and spinning behavior in their child, which may have been due to removal of favorite foods. 33% families reported 90% or higher compliance with healthy diets, 60% reported 80% compliance and 7% reported a 60% compliance. This treatment was rated amongst the top three for high effectiveness (even with lower compliance than other treatments) and 63% people planned to continue with it.

Significant improvement was seen in one special case with a HGCSF diet. A 27-year-old participant with severe ASD who had a history of treatment-resistant severe urinary retention, kidney stones and UTIs requiring routine catheterization and occasional hospitalization, responded very well to this treatment. Within 4 days of the start of treatment, his urinary retention improved and the need for catheterization ended. Patient relapsed with accidental intake of dairy products on a few occasions, but strict adherence thereafter dramatically improved his urinary symptoms and the overall quality of life.

Another 7-year-old boy in the study with severe pica also responded to HGCSF diet very favorably; within one week of starting treatment, there was complete resolution of pica. This showed that a comprehensive dietary treatment may be key to resolving certain intractable problems associated with ASD.

A limitation of the study was that HGCSF diet treatment could not be blinded. There is a need for further research on this treatment method.


Clinical assessment of ASD symptoms, gastrointestinal symptoms and overall functionality

The effectiveness of this combination therapy was measured through the following clinical assessment tools for autism related symptoms, taken at the start and end of the study.

Autism Diagnostic Observation Schedule (ADOS) and Reynolds Intellectual Assessment Scales (RIAS) were two assessments done in a blinded manner, and hence ensured maximum reliance. RIAS indicated that there was significant increase in Non-verbal IQ in treatment group but no significant improvement in Verbal IQ or memory.

Childhood Autism Rating Scale (CARS-2) and Severity of Autism Scale—Professional Evaluation (SAS-Pro) were assessments done on a semi-blind basis and both showed significant improvement in treatment group as opposed to non-treatment group.

Vineland Adaptive Behavior Scale II (VABS-II) was also conducted in a semi-blind manner over a phone interview. Treatment group gained an average of 18 months of developmental age compared to 4 months increase in developmental age in the non-treatment group, with significant improvements in Communication, daily living skills, and social skills domains. However, developmental age still remained below biological age.

Some clinical assessments showed that there is significant improvement in gastrointestinal health with the use of this combination nutritional therapy. These included 6-item Gastrointestinal Severity Index (6-GSI) and PGI-2 subscale for Stool/GI symptoms.