From: Dr. Chun Wong
There have been a couple of reports about Vitamin D in “Scientific American” magazine which both have bearings on autism.
Vitamin D Deficiency Affects the US
The first report was about how Vitamin D deficiency is soaring in the US, according to a study published in the “Archives of Internal Medicine”. The study claimed that a whopping three quarters of US teens and adults have a deficiency of vitamin D – that’s quite an incredible figure and makes you wonder why.
The study’s author, Adit Ginde, from the University of Colorado Denver School of Medicine, puts this vitamin D deficiency down to skin cancer prevention measures such as wearing long sleeves and using sunscreen ( sun protection of just factor 15 can cut the skin’s ability to manufacture vitamin D by 99%) and points out that there are actually very few dietary sources of vitamin D. Vitamin D is known as the “sunshine vitamin” because the skin produces vitamin D when it is exposed to the sun. By protecting ourselves from sun exposure, to reduce our risk of melanoma, we are cutting our levels of vitamin D.
Is There a Link between Lack of Sun and Autism?
But what has all this got to do with autism? Doesn’t a vitamin D deficiency lead to bone problems, such as rickets, osteoporosis and arthritis, not autism?
Well, yes, but experts are now wondering if a growth in vitamin D deficiencies has got something to do with the growth in autism. This theory is the result of two preliminary studies in Minnesota and Sweden, and the findings of these studies are discussed in the second article in “Scientific American” magazine.
Both Sweden and Minnesota have large Somali immigrant communities who seem to be overrepresented in the total number of children with autism in each area. In Minnesota, Somali families began arriving in 1993 and the number of children with autism in their community has jumped from 0 out of 1,773 in 1993, to 43 out of 2,029 in 2007. In Sweden, records of Somali children born in Stockholm between 1988 and 1998 have been studied and researchers concluded that Somali children in Stockholm were 3-4 times more likely to suffer with autism than non-Somali children in the city.
The Somali communities in both cities just can’t understand it. In Stockholm, the Somali people call autism “The Swedish Disease” because they had never seen it in Somalia, and Huda Fara, a Somali molecular biologist working in Minnesota, says “We never saw such a disease in Somalia. We do not even have a word for it.”
So why is autism hitting the Somali community so badly?
The only link that researchers could see was to do with sunlight. Both Minnesota and Stockholm are northern latitude countries and so have less hours of sunlight than equatorial Somalia. This means that the Somali communities were having less sun exposure in their new countries and therefore less vitamin D. Adit Ginde also points out that people with darker skins synthesize vitamin D more slowly. It has also been noted that Somali women (including pregnant women) were covering themselves completely when going outside in their new communities, much more than they would have done back in Somali where their whole community was Muslim. Their dress obviously affected their sun exposure levels.
Some experts are arguing that the increase of rates of autism in the Somali communities is just because autism was not being diagnosed in Somalia, due to a lack of awareness, but others are arguing that there may be a vitamin D link with autism. Proponents of this theory put forward the findings of a 2007 review, by Tulane University’s Allan Kalueff, on 20 different studies on animals and humans. Kalueff concluded that vitamin D was essential in gestation and early infanthood for “normal brain functioning”.
Another study that backs up the vitamin D theory is research carried out by Cornell University and published in “Archives of Pediatrics and Adolescent Medicine” in November last year. This study found that children who lived in counties in Washington, Oregon and California, where there were more overcast days and more rain, were twice as likely to have autism than children living in drier counties in the same state. Michael Waldman, co-author of the study, said “Our research is sufficiently suggestive of an environmental trigger for autism associated with precipitation, of which vitamin D deficiency is one possibility. Further research focused on vitamin D deficiency is clearly warranted.”
Research into vitamin D and autism is ongoing, including a pilot study by Gene Stubbs (associate professor emeritus of psychiatry and pediatrics at Oregon Health & Science University) with pregnant women. Stubbs is giving 5,000 IUs of vitamin D3 to pregnant women who already have at least one child with autism. He is then going to give the women 7,000 IUs while they are breastfeeding. It will be interesting to see the results of this study.
What Can You Do?
If you are pregnant, you may want to consider taking a special pregnancy supplement which contains vitamin D and making sure that you eat plenty of vitamin D rich foods, such as milk, fatty fish and eggs. However, the best source of vitamin D is the sun, so try and get a little sun each day. Experts agree that 10-15 minutes of sunlight a day, at breakfast time or in the evening when the sun’s rays are not so damaging, can boost vitamin D levels without harming the skin.