Skip to main content

What You Should Know About Autism, Vitamins and Supplements

From the Interactive Autism Network

Vitamins and other nutritional supplements are substances that are either
essential for normal body functions or are thought to enhance the body's
functioning. Vitamins and minerals are required in small amounts by all humans
for normal growth and development. For the most part, adequate amounts of
vitamins and minerals are obtained by eating a healthy diet.

Essential fatty acids and amino acids are also required by the body and
obtained from certain foods. Inadequate amounts of these important nutrients can
lead to illness. In recent years, all of these essential nutrients have become
available as a pill and can be found on almost any supermarket shelf. Specific
foods are no longer the only source of vitamins, minerals, essential fatty
acids, and essential amino acids. In addition to the required nutrients, many
other nutritional supplements are now available on the supermarket shelf and/or
over the internet.

The growing use and availability of nutritional supplements, along with
numerous reports of their potential benefits, have gained the attention of the
scientific community. Many of these products are now being being studied with
the same rigor and scrutiny which has traditionally been applied to drugs and
medications used to cure, treat, and/or prevent illness. In addition, the intake
of large amounts or "mega" quantities of vitamins and other required nutritional
elements is undergoing increased investigation, both for potential benefits
and/or harm. For a valuable resource about nutritional supplements, their
proposed benefits, and available research findings, refer to the nutritional
supplements index at

Use of Vitamins and Supplements: Children with ASDs

There are several reasons to suspect that children on the autism spectrum may
not be getting sufficient nutrients, including chronic diarrhea or constipation,
gastrointestinal inflammation, and a tendency to restrict food choices. 1 In
addition, the possibility exists that children with autism do not break down or
process the nutrients they do consume in expected ways.

Mega-vitamin therapy and other nutritional supplements are commonly used to
treat children with ASD. Recent studies show that over 30% of parents are giving
their children extra Vitamins C and B6, and over 25% are using essential fatty
acids and magnesium. Other nutritional supplements reported in use by more than
10% of parents include Vitamin A, mega-vitamin therapy (non-specific), DMG
(dimethylglycine), and L-glutamine. 2 The
rationale for use and the expected benefits of many of these supplements vary,
as does the evidence supporting them. In regards to maintaining a general state
of good health, the use of a daily multi-vitamin is widely accepted and
supported for children with ASD, especially given the self-restricted diets many
of these children consume. Vitamin therapy and nutritional supplements beyond
this, however, are not fully supported and need to be further studied.

Vitamin C

Children with ASDs have not been found to suffer from a severe lack of
Vitamin C. 3,4
Any beneficial impact its use may have for children on the spectrum is therefore
not due just to making up a vitamin deficiency. What, then, might its effect be?
There are several possibilities. Vitamin C, also known as ascorbic acid, is
believed to influence the functioning of the human body and brain in many ways,
including regulation of cellular immune function; as an antioxidant; and via its impact on
the neurotransmitterdopamine. 5,6

It is a fact that children with ASDs have been shown to suffer from increased
oxidative stress in a number of studies. 7,8,9
"Oxidative stress" occurs when molecules that do not have a balanced number of
protons and electrons --called free radicals-- "steal" an electron from
another molecule to achieve balance and stability. Unfortunately, the molecule
stolen from now becomes a free radical itself, and will go on to steal an
electron from another molecule, and on and on, in what has been called "an
electron-stealing frenzy." 10 To
some degree, this constant exchange of electrons is natural, and the body can
cope. When the process goes out of balance, however, antioxidants like Vitamin C
help by "donating" electrons to molecules that lack one in a non-damaging way
that stops the chain-reaction. The central nervous system, which includes the
brain, is thought to be more sensitive to free radical attack than other systems
in the body. It is therefore not surprising that "free radicals have been
implicated in a variety of neuropsychiatric conditions." 11 In
theory, children with autism suffering from "oxidative stress" might be helped
by receiving Vitamin C or other antioxidants. No studies have yet been done to
test this specific theory with regard to autism, however.

So far, only one double-blind, placebo-controlled study has
explored the effectiveness of Vitamin C as a therapy for autism. It was
specifically directed at Vitamin C's involvement in the regulation of dopamine,
a crucial neurotransmitter, and did indeed show a decrease in stereotypic
behaviors. 12 It
was, however, a small study involving only 18 subjects, and its findings have
not so far been replicated -- that is, confirmed in another study. (To learn
about evaluating research studies, see "Gold
Standard of Evidence: the Randomized Controlled Trial."

More research is still needed to see if Vitamin C truly helps children with
autism and, if so, through what mechanism.

Vitamin B6 and Magnesium Combined Therapy

The use of large doses of vitamin B6 (pyridoxine) was first reported to
improve speech and language in children diagnosed with "autism syndrome" in the
late 1960s. 13
Over the next three decades, a variety of studies were conducted in attempts to
show that children with autism significantly improved on a regimen of Vitamin B6
with magnesium. (Magnesium was added to counter negative side effects that can
come with large doses of Vitamin B6, such as irritability, hypersensitivity to
sound, and bed-wetting.) Most of these reported positive outcomes, and called
for more research to be conducted. 14,15,16
At least two studies found that children with autism had high levels of B6 in
their blood -- evidence that their bodies were not efficiently converting the
vitamin, and providing a reason why more B6 might prove helpful. 17,18

Unfortunately, most of these studies were not conducted in an ideal way. They
were either non-randomized, had no control group, were not "blind", or were very
small. Two more recent studies, which were randomized, double-blind, and
placebo-controlled, suggested that B6 and magnesium did not have a statistically
significant effect. 19,20
Another, which focused on children with Asperger's Syndrome and PDD-NOS, found
Vitamin B6 appeared to increase verbal IQ scores, although it did not improve
social functioning. 21 In
brief, results of various studies on the usefulness of Vitamin B6 and magnesium
have been contradictory and confusing.

In 2006 the Cochrane
, an independent, not-for-profit, organization dedicated to
producing and distributing high quality reviews of published clinical trials on
a variety of treatments and disorders, published a complete review of suitable
studies on the efficacy of vitamin B6 and magnesium for treating the core
deficits of autism. Using strict guidelines for evaluating study design, only 3
clinical trials were deemed acceptable for inclusion in the review. Other
studies were excluded because they were not being conducted in a way that met
the standards set by the reviewers. The final conclusion of the Collaboration
was that no recommendation could be given regarding the efficacy of vitamin
B6-Magnesisum as a treatment for autism. Enough high quality research has simply
not been carried out. 22


Dimethylglycine (DMG) is not a vitamin, per se, but is sold as a nutritional
supplement. It has been suggested that DMG is an immune enhancer in addition to
being "metabolized in the liver, ultimately to glycine, an excitatory
neurotransmitter." 23 Although
DMG has been widely used to treat children with ASDs, the two double-blind,
placebo controlled studies conducted to test it did not show it to be effective.
These were very small studies, however. Considering the large numbers of parents
treating their children with DMG, and the repeated claims of effectiveness
(especially in the areas of speech and behavior) made in the parent-advocacy
literature over a great many years,26
more research is warranted.

Essential Fatty Acids (Omega 3)

Essential fatty acids, which make up about 20% of the dry-weight of the
brain, are now believed to be crucial to the brain's optimal functioning. Called
"essential" because they cannot be manufactured by the body, but must be
acquired through the diet, these fatty acids have a major influence on a variety
of biochemical processes involving the neurons, or nerve cells, in the brain.
They can therefore impact both thought processes and behavior. 27,28
In addition, they are believed to help modulate the immune system 29 --
an interesting fact, considering that we now know some kind of immune
dysfunction may well be involved in autism. 30,31,32,33

There are two key essential fatty acids: Omega-3 and Omega-6. Our modern
diet, especially in the United States, is thought to include far too many
Omega-6 containing foods, and far too few foods containing Omega-3s. (Omega-3s
come mainly from fish oil -- not a big item in the Western diet.) One researcher
has written that humans evolved eating a diet where the ratio of Omega-6 to
Omega-3 was one to one, that is, for every Omega 6 people ate, they ate one
Omega 3. Omega-6 and Omega-3 were in balance. In modern diets, in contrast, we
are eating somewhere between 11 and 15 Omega-6s for every Omega-3. 34,35

Researchers have shown in recent years that deficiencies in Omega 3 fatty
acids may be linked to aggression,36
and schizophrenia. 40
They may also be linked to the Autism Spectrum Disorders (ASDs). For one thing,
symptoms of fatty acid deficiency -- such as excessive thirst and constant
drinking, 41 dry
skin, dry hair, dandruff, and soft and brittle nails -- have been documented in
ASDs. 42
For another, at least one study has shown that children with autism, when
compared to mentally retarded children without autism, had significantly lower
levels of Omega-3. 43

Indeed, looking at mental illness and developmental disorders as a whole,
scientists have begun to theorize that there may be some fundamental link
between a lack of essential fatty acids and a variety of neuropsychiatric
conditions, including the Autism Spectrum Disorders. 44,45
One group of researchers noted, for example, that the effects of a fatty acid
deficiency could partially explain the fact that there is a higher prevalence of
ADHD in males than females because males are more vulnerable than females to
certain fatty acid deficiencies. 46
They also noted that individuals with ADHD often have sleep problems, allergies,
emotional and mood disorders, motor coordination problems, and learning
disabilities. 47 It
is interesting to consider that, in the Autism Spectrum Disorders, males also
far outnumber females, and that many individuals with ASDs also experience the
other challenges identified. Could there be one unified explanation for these
and other disorders?

Researchers are taking on the issue, especially with an eye to treatment. Can
supplementing the diet with essential fatty acids -- which would be fairly easy
and inexpensive to do -- improve the condition of individuals with ASDs? For
now, studies are few and very small. 48
One randomized, double-blind, placebo-controlled pilot study recently
demonstrated that children with autism receiving an Omega-3 supplement showed
improvement, especially in hyperactivity and repetitive behaviors. (Please note,
however, that this study involved only thirteen children.) 49
Another small study showed that parents of children with ASDs who took
fish oil supplements for six months reported improved cognitive and motor
skills, concentration, eye contact, sociability, and sleep, as well as reduced
hyperactivity and aggression. A few, however, reported an increase of
hyperactivity and behavioral problems. 50

Clearly, this is an area where more extensive research is called for.

View References
for this Article

Copyright the Kennedy Krieger Institute, 2009


Popular Video