CHEMICALS DERIVED FROM BROCCOLI SPROUTS SHOWS PROMISE IN TREATING AUTISM
Results of a small
clinical trial suggest that a chemical derived from broccoli sprouts -- and
best known for claims that it can help prevent certain cancers -- may ease
classic behavioral symptoms in those with autism spectrum disorders (ASDs).
The study, a joint
effort by scientists at MassGeneral Hospital for Children and the Johns Hopkins
University School of Medicine, involved 40 teenage boys and young men, ages 13
to 27, with moderate to severe autism.
In a report published
online in the journal Proceedings of the National Academy of Sciences during
the week of Oct. 13, the researchers say that many of those who received a
daily dose of the chemical sulforaphane experienced substantial improvements in
their social interaction and verbal communication, along with decreases in
repetitive, ritualistic behaviors, compared to those who received a placebo.
"We believe that
this may be preliminary evidence for the first treatment for autism that
improves symptoms by apparently correcting some of the underlying cellular
problems," says Paul Talalay, M.D., professor of pharmacology and
molecular sciences, who has researched these vegetable compounds for the past
25 years.
"We are far from
being able to declare a victory over autism, but this gives us important
insights into what might help," says co-investigator Andrew Zimmerman,
M.D., now a professor of pediatric neurology at UMass Memorial Medical Center.
ASD experts estimate
that the group of disorders affects 1 to 2 percent of the world's population,
with a much higher incidence in boys than girls. Its behavioral symptoms, such
as poor social interaction and verbal communication, are well known and were
first described 70 years ago by Leo Kanner, M.D., the founder of pediatric
psychiatry at The Johns Hopkins University.
Unfortunately, its
root causes remain elusive, though progress has been made, Talalay says, in
describing some of the biochemical and molecular abnormalities that tend to
accompany ASD.
Many of these are
related to the efficiency of energy generation in cells. He says that studies
show that the cells of those with ASD often have high levels of oxidative
stress, the buildup of harmful, unintended byproducts from the cell's use of
oxygen that can cause inflammation, damage DNA, and lead to cancer and other chronic
diseases.
In 1992, Talalay's
research group discovered that sulforaphane has some ability to bolster the
body's natural defenses against oxidative stress, inflammation and DNA damage.
In addition, the chemical later turned out to improve the body's heat-shock
response -- a cascade of events used to protect cells from the stress caused by
high temperatures, including those experienced when people have fever.
Intriguingly, he says,
about one-half of parents report that their children's autistic behavior
improves noticeably when they have a fever, then reverts back when the fever is
gone. In 2007, Zimmerman, a principal collaborator in the current study, tested
this anecdotal trend clinically and found it to be true, though a mechanism for
the fever effect was not identified.
Because fevers, like
sulforaphane, initiate the body's heat-shock response, Zimmerman and Talalay
wondered if sulforaphane could cause the same temporary improvement in autism
that fevers do. The current study was designed to find out.
Before the start of
the trial, the patients' caregivers and physicians filled out three standard
behavioral assessments: the Aberrant Behavior Checklist (ABC), the Social
Responsiveness Scale (SRS) and the Clinical Global Impressions-Improvement
scale (CGI-I). The assessments measure sensory sensitivities, ability to relate
to others, verbal communication skills, social interactions and other behaviors
related to autism.
Twenty-six of the
subjects were randomly selected to receive, based on their weight, 9 to 27
milligrams of sulforaphane daily, and 14 received placebos. Behavioral
assessments were again completed at four, 10 and 18 weeks while treatment
continued. A final assessment was completed for most of the participants four
weeks after the treatment had stopped.
Most of those who
responded to sulforaphane showed significant improvements by the first
measurement at four weeks and continued to improve during the rest of the
treatment. After 18 weeks of treatment, the average ABC and SRS scores of those
who received sulforaphane had decreased 34 and 17 percent, respectively, with
improvements in bouts of irritability, lethargy, repetitive movements,
hyperactivity, awareness, communication, motivation and mannerisms.
After 18 weeks of
treatment, according to the CGI-I scale, 46, 54 and 42 percent of sulforaphane
recipients experienced noticeable improvements in social interaction, aberrant
behaviors and verbal communication, respectively.
Talalay notes that the
scores of those who took sulforaphane trended back toward their original values
after they stopped taking the chemical, just like what happens to those who
experience improvements during a fever. "It seems like sulforaphane is
temporarily helping cells to cope with their handicaps," he says.
Zimmerman adds that
before they learned which subjects got the sulforaphane or placebo, the
impressions of the clinical team -- including parents -- were that 13 of the
participants noticeably improved. For example, some treated subjects looked
them in the eye and shook their hands, which they had not done before. They
found out later that all 13 had been taking sulforaphane, which is half of the
treatment group.
Talalay cautions that
the levels of sulforaphane precursors present in different varieties of
broccoli are highly variable. Furthermore, the capacity of individuals to
convert these precursors to active sulforaphane also varies greatly. It would
be very difficult to achieve the levels of sulforaphane used in this study by
eating large amounts of broccoli or other cruciferous vegetables.
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