Among dietary factors, learning and behavior are influenced not only by nutrients, but also by exposure to toxic food contaminants such as mercury that can disrupt metabolic processes and alter neuronal plasticity. 

Neurons lacking in plasticity are a factor in neurodevelopmental disorders such as autism and mental retardation. Essential nutrients help maintain normal neuronal plasticity. Nutritional deficiencies, including deficiencies in the long chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, the amino acid methionine, and the trace minerals zinc and selenium, have been shown to influence neuronal function and produce defects in neuronal plasticity, as well as impact behavior in children with attention deficit hyperactivity disorder. 

Nutritional deficiencies and mercury exposure have been shown to alter neuronal function and increase oxidative stress among children with autism. These dietary factors may be directly related to the development of behavior disorders and learning disabilities. 

Mercury, either individually or in concert with other factors, may be harmful if ingested in above average amounts or by sensitive individuals. High fructose corn syrup has been shown to contain trace amounts of mercury as a result of some manufacturing processes, and its consumption can also lead to zinc loss. Consumption of certain artificial food color additives has also been shown to lead to zinc deficiency. Dietary zinc is essential for maintaining the metabolic processes required for mercury elimination.

Since high fructose corn syrup and artificial food color additives are common ingredients in many foodstuffs, their consumption should be considered in those individuals with nutritional deficits such as zinc deficiency or who are allergic or sensitive to the effects of mercury or unable to effectively metabolize and eliminate it from the body. 

Reference:

Dufault R, Schnoll R, Lukiw WJ, Leblanc B, Cornett C, Patrick L, Wallinga D, Gilbert SG, Crider R., Mercury exposure, nutritional deficiencies and metabolic disruptions may affect learning in children, Behav. Brain Funct. 2009 Oct 27;5(1):44.

Most studies on sick building syndrome (SBS) are cross-sectional and have dealt with symptoms among office workers. There are very few longitudinal cohort studies and few studies on SBS in relation to domestic exposures. The aim of this study was to investigate changes in SBS symptoms during the follow-up period and also to investigate changes in different types of indoor exposures at home and relate them to SBS symptoms in a population sample of adults from Sweden. We also wanted to investigate if there was any seasonal or regional variation in associations between exposure and SBS.

 A random sample of 1,000 people of the general population in Sweden (1991) was sent a self administered questionnaire. A follow-up questionnaire was sent in 2001.

An increased risk for onset of any skin symptoms (risk ratio (RR) 2.32, 1.37-3.93), mucosal symptoms (RR 3.17, 1.69-5.95) or general symptoms (RR 2.18, 1.29-3.70) was found for those who had dampness or moulds in the dwelling during follow-up. In addition people living in damp dwellings had a lower remission of general symptoms and skin symptoms.

Dampness in the dwelling is a risk factor for new onset of SBS symptoms. Focus on indoor environment improvements in dwellings can be beneficial both for the inhabitants and the general population. Reducing dampness in buildings is an important factor for reducing SBS symptoms in the general population.

Reference:
Sahlberg B, Wieslander G, Norbäck D., Sick building syndrome (SBS) in relation to domestic exposure in Sweden – A cohort study from 1991 to 2001, Department of Occupational and Environmental Medicine, Uppsala University Hospital and Uppsala University, Uppsala, Sweden, Scand J Public Health. 2009 Oct 22.

A new study in China has found that people with higher levels of pesticide exposure are more likely to have suicidal thoughts. The study was carried out by Dr Robert Stewart from the Institute of Psychiatry at King’s College London together with scientists from Tongde Hospital Zhejiang Province. 

The agricultural pesticides commonly used in China are organophosphates which are in wide use in many lower income countries but have been banned in many Western nations. It is well known that they are very dangerous if ingested as an overdose but there is also biological evidence that chronic low-grade exposure to these chemicals, which are very easily absorbed into the body through the skin and lungs, may have adverse effects on mental health. This study is the first epidemiological evidence to suggest possible effects on suicidal thoughts. 

The study was carried out in central/coastal China, a relatively wealthy area with a rapidly developing economy. In a very large survey of mental health in rural community residents, participants were also asked about how they stored pesticides. The study found that people who stored pesticides at home, i.e. those with more exposure, were more likely to report recent suicidal thoughts. Supporting this, the survey also found suicidal thoughts to be associated with how easily accessible these pesticides were in the home and that the geographic areas with highest home storage of pesticides also had highest levels of suicidal thoughts in their populations. 

Given the high level of pesticide exposure and the high suicide risk in rural China, clarification of the causal mechanisms underlying this association and the development of appropriate interventions should be priorities for public health and health policy. 

Dr Robert Stewart comments: ‘Organophosphate pesticides are widely used around the world although are banned in many countries because of their risk to health. They are particularly lethal chemicals when taken in overdose and are a cause of many suicides worldwide. Our research findings that suggest that higher exposure to these chemicals might actually increase the risk of suicidal thoughts provides further support for calls for tighter international restrictions on agricultural pesticide availability and use.’

Dr Jianmin Zhang, Associate Chief Psychiatrist, Tongde Hospital of Zhejiang Province, and Vice Director, Zhejiang Office of Mental Health, China added: “The findings of this study suggested potential causal links and might partially account for the much higher incidence of suicide in rural than urban areas of China. However, further studies particularly with more precisely defined and assessed exposure are critically needed, as awareness of safer access to pesticides is important both to policy-makers and pesticide users.”

Reference: King’s College London, Pesticides exposure linked to suicidal thoughts, October 22, 2009  

Notes:

Pesticide exposure and suicidal ideation in rural communities in Zhejiang province, China by Jianmin Zhang, Robert Stewart, Michael Phillips, Qichang Shi & Martin Prince was published in the October issue of the WHO Bulletin. The full article can be accessed on http://www.who.int/bulletin/volumes/87/10/08-054122.pdf 

The analysis involved data from a survey of a representative sample of 9,811 rural residents in Zhejiang province who had been asked about the storage of pesticides at home and about whether or not they had considered suicide within the two years before the interview. The Chinese version of the 12-item General Health Questionnaire (GHQ) was administered to screen for mental disorder.

Gluten-free diet a must for children with celiac disease 

Celiac disease (CD) is an inherited intestinal disorder characterized by life-long intolerance to the ingestion of gluten, a protein found in wheat, rye, and barley. Although CD can be diagnosed at any age, it commonly occurs during early childhood (between 9 and 24 months). Reduced bone mineral density is often found in individuals with CD. A new article in the journal Nutrition Reviews examines the literature on the topic and reveals that a gluten-free diet can affect children’s recovery. 

Metabolic bone disease remains a significant and common complication of CD. Reduced bone mineral density can lead to the inability to develop optimal bone mass in children and the loss of bone in adults, both of which increase the risk of osteoporosis. There also exists an additional risk of fracture in people with CD. 

However, evidence suggests that a gluten-free diet (GFD) promotes a rapid increase in bone mineral density that leads to complete recovery of bone mineralization in children. A GFD improves, although rarely normalizes, bone mineral density in adults. Children may attain normal peak bone mass if the diagnosis is made and treatment is given before puberty, thereby preventing osteoporosis in later life. 

Also, nutritional supplements consisting of calcium and vitamin D seem to increase the bone mineral density of children and adolescents with CD. 

“Our findings reinforce the importance of a strict gluten-free diet, which remains the only scientific proven treatment for celiac disease to date,” the authors conclude. “Early diagnosis and therapy are critical in preventing celiac disease complications, like reduced bone mineral density.” 

Reference: Wiley-Blackwell, Gluten-free diet reduces bone problems in children with celiac disease, October 8, 2009

Chemicals and Molds often associated with Sick Building Syndrome   

A study was performed to explore possible environmental risk factors, including indoor chemicals, mold, and dust mite allergens, which could cause sick building syndrome (SBS)-type symptoms in new houses. 

The study was conducted in 2004 and 2005 and the final study population consisted of 86 men and 84 women residing in Okayama, Japan. 

The indoor concentrations of indoor aldehydes, volatile organic compounds, airborne fungi, and dust mite allergens in their living rooms were measured and the longitudinal changes in two consecutive years were calculated. 

A standardized questionnaire was used concomitantly to gather information on frequency of SBS-type symptoms and lifestyle habits. About 10% of the subjects suffered from SBS in the both years. 

Crude analyses indicated tendencies for aldehyde levels to increase frequently and markedly in the newly diseased and ongoing SBS groups. Among the chemical factors and molds examined, increases in benzene and in Aspergillus contributed to the occurrence of SBS in the logistic regression model. 

Indoor chemicals were the main contributors to subjective symptoms associated with SBS. A preventive strategy designed to lower exposure to indoor chemicals may be able to counter the occurrence of SBS. 

Reference:  Takigawa T, Wang BL, Sakano N, Wang DH, Ogino K, Kishi R.,    A longitudinal study of environmental risk factors for subjective symptoms associated with sick building syndrome in new dwellings, Sci Total Environ. 2009 Sep 15;407(19):5223-8.