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Researcher sees link between vitamin D, autism

August 26th, 2010

The growing prevalence of autism is one of the biggest scientific whodunits in the medical world, with few clues for its rising incidence.

But a U.S. researcher is advancing a controversial hypothesis: that autism is related to vitamin D deficiency during fetal development and early childhood.
Dr. John Cannell, a psychiatrist and prominent vitamin D advocate, says flagging levels of the vitamin in pregnant women and young children could be the elusive factor explaining the rising rate of autism.

The evidence for such a link is circumstantial, and autism experts describe the hypothesis as speculative. But Dr. Cannell, founder of the Vitamin D Council, a non-profit advocacy group, says autism rates have skyrocketed in lockstep with medical advice given to the public since the late 1980s to avoid all exposure to bright sunshine.

“If it’s true, I can’t think of another situation where medical advice was so damaging to such a large number of people,” says Dr. Cannell, who practises at Atascadero State Hospital in California.

The vitamin D link “is an interesting speculation,” says Dr. Wendy Roberts, a professor of pediatrics at the University of Toronto and one of Canada’s leading autism experts.

Because the cause of autism is such an enigma, Dr. Roberts says researchers should investigate vitamin D, but the public should treat the idea more cautiously.

“You like to be able to have something that is firm and clear before you get parents all excited and doing something and then, once again, being disappointed,” she said.

Although Dr. Cannell is something of a maverick in research circles, he has credentials. Last year, he published an important peer-reviewed paper linking low vitamin D levels to an increased susceptibility to influenza, based on research at his hospital.

But for his autism hypothesis, he is now jeopardizing his chances of publication in a scientific journal by e-mailing the Vitamin D Council newsletter outlining the idea to thousands of U.S. autism activists – a possible violation of the rules of publication.

Dr. Cannell said he decided to disseminate his hypothesis now to encourage the public to increase its sun exposure during the warmer part of the year.

“If only 10 pregnant women go outside and sunbathe a little bit, they may be saved a lifetime of misery,” he said.

The idea that vitamin D deficiency may have a link to autism isn’t as farfetched as it once might have seemed because the deficiency is also emerging as a possible cause of many diverse illnesses, ranging from multiple sclerosis to cancer.

Last month, the Canadian Cancer Society recommended adults start taking the sunshine vitamin to reduce their risk of cancer.

Autism refers to a spectrum of conditions that involve repetitive behaviours and difficulty communicating and interacting socially. Autism manifests itself in the first few years of life and is thought to be some kind of neurological disorder affecting brain function.

One discredited theory is that the mercury-containing preservative thimerosal once used in childhood vaccines causes autism. Studies have failed to find any link.

The cause of autism is further clouded because some scientists speculate that part of the apparent increase in incidence – in the United States it is being diagnosed about 10 times more frequently now than in the early 1990s – may reflect improved reporting by doctors more aware of the condition.

The current Canadian estimate is that about 60 children out of every 10,000, or about 1 in 165, have autism and related conditions. Up until the 1990s, the prevalence was thought to be far lower, at only 4 or 5 children in 10,000.

If there is a vitamin D link, incidence rates around the world would probably vary by latitude. Rates would be lower in equatorial areas, where sun exposure is higher, than in northern latitudes, but studies investigating geographical differences in diagnosis haven’t been done.

Dr. Cannell says some of the strongest evidence vitamin D may have a hand in the disorder is that the vitamin is converted in the body to a steroid hormone, which in animal experimentation has been found to influence brain development. If vitamin levels are low, whatever brain development it is linked to will be skewed.

Startling trend
The occurrence of autism spectrum disorders (the most sever of which is autism) has risen sharply during recent years.
Rate per 10,000
UNITED STATES
1980s: 4-5
1990s: 30-60
2000A: 67
CANADA
2001B: 60
SOURCES: ENVIRONMENTAL HEALTH PERSPECTIVES
A- CENTRES FOR DISEASE CONTROL
B-CAIRN

Binge on broccoli to boost the brain

August 24th, 2010

From DNAindia.com:

Eating certain fruit and vegetables could boost the memory, particularly broccoli, according to British research.

The study conducted by King’s College London,provides scientific backing to the theory and has major implications for the prevention and treatment of Alzheimer’s disease, the Royal Pharmaceutical Society said.

Extracts found in five fruits and vegetables —broccoli, potatoes, oranges, apples and radishes — were found to contain substances that act in the same way as drugs used to treat the disease. Broccoli had the most.

Alzheimer’s, for which there is no cure, is the most common form of dementia among older people.

It seriously affects their ability to carry out daily activities, impairing parts of the brain that control thought, memory and language. Most of the drugs used to treat the disease act as inhibitors of acetylcholinesterase, the enzyme responsible for the breakdown of the neurotransmitter acetylcholine.

It has been previously suggested that some common vegetables might have anti-acetylcholinesterase activity, but no detailed investigation has ever been carried out. The King’s College London research confirms this activity in all five of the fruit and vegetables.

Broccoli was found to have the most potent activity and was taken forward for further tests to identify the agent responsible.

These were found to be glucosinolates, a group of compounds found throughout the cabbage family. “As yet, it is unproven that eating broccoli, for instance, would have a beneficial effect on Alzheimer’s disease.

“As yet, it is unproven that eating broccoli, for instance, would have a beneficial effect on Alzheimer’s disease,” said professor Peter Houghton, from King’s College London.

“But the long-term effects of regularly consuming these compounds in vegetables belonging to the brassicaceae might certainly be beneficial in reducing a decline in acetylcholine levels in the central nervous system.”

UV radiation, not vitamin D, might limit multiple sclerosis symptoms

August 15th, 2010

From ScienceNews.org:

Ultraviolet radiation from sunshine seems to thwart multiple sclerosis, but perhaps not the way most researchers had assumed, a new study in mice suggests.

If validated in further research, the finding could add a twist to a hypothesis that has gained credence in recent decades. The report appears online March 22 in the Proceedings of the National Academy of Sciences.

Scientists have hypothesized that MS is rare in the tropics because people synthesize ample vitamin D from exposure to the UV radiation in equatorial sunlight. What’s more, MS is more common in the high latitudes of northern parts of Europe and North America than in regions farther south. That pattern has led to the assumption that higher levels of vitamin D might prevent people from developing MS, what became known as the latitude hypothesis.

But a direct cause-and-effect relationship between vitamin D deficiency and MS has never been established. In past experiments, giving vitamin D supplements to mice with an MS-like disease required giving the animals harmful amounts of the nutrient, notes Hector DeLuca, a biochemist at the University of Wisconsin–Madison.

“It just didn’t add up,” he says. “We decided to go back and see if maybe UV light by itself was doing something.”

In MS, the fatty myelin sheaths that insulate nerves in the central nervous system are damaged by attacks by the immune system. In a series of experiments in mice, DeLuca and his team induced a condition comparable to human MS by injecting the animals with proteins that instigate similar myelin damage.

The researchers exposed some mice to UV radiation before and after giving the animals the damaging injection. Another group of mice got the injection but not the UV exposure.

The mice exposed to UV rays suppressed the effects of MS-like disease better than the control mice, the researchers found, even though the amount of radiation wasn’t enough to greatly increase the animals’ blood concentrations of vitamin D.

In another test, the researchers gave injected mice varying doses of vitamin D supplements, but no UV radiation. The supplements failed to control the disease onset, severity or progression.

“We concluded that UV light is doing something beyond [making] vitamin D,” DeLuca says.

There’s no question that the latitude hypothesis has merit, says George Ebers, a neurologist at the University of Oxford in England. “MS risk is geographically related.” But that risk is more complicated than exposure to UV radiation during an MS attack, as this mouse model used. For example, previous research has shown that children in northern latitudes who are born in May, after their mothers had spent a winter with little sunshine, are more likely to develop MS than are kids born in November, he says.

Ebers notes that mice in this study were exposed or not exposed to UV over a matter of weeks and were in the throes of an MS-like disease during the study. “That’s completely separate … from the question of whether your risk is boosted or diminished by where your mother lived,” he says.

Apart from the timing issue, MS risk might well be influenced by a biological mechanism apart from vitamin D blood levels, but many questions remain, Ebers says. Those include how UV radiation might inhibit MS and, more specifically, what is the effect of UV rays in suppressing the immune system. “It’s quite possible that UV exposure will have a number of other mechanisms and be involved in hormonal circuits,” he says.

DeLuca and his colleagues speculate that UV radiation is playing a mysterious role in MS that is independent of vitamin D production. “We’re doing experiments trying to find out what it is,” he says.

ADHD and Obesity: Is There a Link?

August 13th, 2010

From HealthCentral.com:

There are many behaviors seen in children and adults with ADHD that just make sense, when you consider that the core symptoms are, among other things, inattention, impulsivity, distractibility and more. People with ADHD typically are sensory seeking, even though it may not always look that way, especially if the individual has the inattentive sub-type.

For example, many who are impulsive might find themselves having problems in the area of high risk behaviors, such as brief but many sexual encounters, over-spending, and gambling.

A hyperactive individual might get involved in dangerous activities like car racing. Or they might have an exercise addiction.

An inattentive person’s need for stimuli might be harder to see, but usually it’s there. It might be seen in the areas of internet, TV or even video game addiction.

Those who study ADHD and addictions have begun to look at the connection between eating disorders and ADHD and lately and more specifically, ADHD and obesity. For many, eating can be either stimulating or sedating…or even both.

There have been a few studies in recent years showing a correlation between obesity in children/adolescents and having ADHD. However, there has been little research on the possible link between ADHD and obesity in adults.

A new study, recently published in the journal Eating and Weight Disorders, explored why some adults have difficulty staying on weight loss programs. The researchers at the Centre of Addiction and Mental Health and the University of Toronto (Canada) administered ADHD tests to 75 women who had been referred to an obesity clinic. The average age of the women was 40 and the average Body Mass Index (BMI) was 43, which is considered to be in the severely obese range.
The ADHD tests included self-reports of retrospective childhood symptoms and a rating of current ADHD symptoms.

Their findings were interesting. Compared to the general population, the researchers found that 26.6% of the obese subjects were classified as having ADHD, whereas in the general population, 3-5% of adults are known to have ADHD. The researchers found the statistics significant.
Researchers J.P. Fleming and colleagues wrote: “While the current study does not allow us to ascertain the cause of the deficit, it is striking that a very high percentage of this sample of severely obese women report very substantial problems with the set of symptoms that we classify as reflecting ADHD.”

What prompted the study was an observation that a significant number of obese clients had tremendous difficulty keeping accurate records of their diet planning- planning and preparing their meals- as well as eating and exercising regularly. These observations prompted the team to research the reasons behind this, thus the discovery of the ADHD/obesity connection.

The researchers noted that, “while the current study does not allow us to ascertain the cause of the deficit, it is striking that a very high percentage of this sample of severely obese women report very substantial problems with the set of symptoms that we classify as reflecting ADHD.”

Too Much, Too Young – Excess brain growth may be the first sign of autism

August 9th, 2010

From ScientificAmerican.com:

The average age at which children are diagnosed with autism is between three and four, but scientists have long suspected that the disorder starts much earlier. A key piece of evidence is a phenomenon known as brain overgrowth. Autistic toddlers tend to have large brains for their age, and researchers have shown a correlation between the degree of excess growth and the severity of autism symptoms. Eric Courchesne, director of the Autism Center of Excellence at the University of California, San Diego, helped to pioneer the overgrowth hypothesis. Now he and his colleague Cynthia Schumann have published data that suggest the excess brain growth starts in the first year of life, if not sooner.

The study, published in a recent issue of the Journal of Neuroscience, is the first to evaluate brain growth and autism throughout early development. Using cross-sectional MRI scans, the U.C.S.D. researchers found overgrowth in autistic subjects as young as one and a half. At two and a half, the autistic subjects’ brains were 7 percent larger on average than the control group’s. Al though why, exactly, excessive brain growth is related to autism remains a mystery, the new work helps to confirm that signs of the disorder appear early—knowledge that could lead to detection and treatments, such as behavior therapy, at a younger age. “The earlier the intervention, the better the outcome,” Courchesne says.