Monday, June 01, 2009

Western diet linked to teen's poor mental health

As we see from the original journal abstract following the article below, the study was more sophisticated than most in that there was some attempt to take social class into account. Maternal education is controlled for. It is however primarily paternal education that influences social class and there are other factors as well. So we have not escaped the influence of the fact that working class people eat more junk food and have poorer health generally. What they found could therefore have been a class effect, not a food effect.

I also suspect the factor-analytic approach used. I know factor analysis well, which is why I rarely use it. Factor identities are usually far from clear and relationships with them can be substantially altered by removing just one or two items from them. Conclusions derived from them are usually therefore pretty arbitrary. That one of the factors is identified as Western, whereas all or most of the participants were presumably Western, tends to raise the eyebrows a bit. Such a general appellation suggests that the factor was highly heterogeneous in its loadings, thus making generalizations about it very shaky. Looking at the individual foods and their relationships with behaviour would be much less inferential -- though appropriate error-rate adjustments would have to be made, of course (Let me hazard a guess that an experiment-wise error rate approach would have shown no statistically significant relationship between any food and any measure of mental health!). Identifying fruit and vegetables as the critical element in a factor that apparently comprised around 100 different foods is certainly an act of faith rather than a committment to rigorous hypothesis testing

A NEW study in WA has shown a link between Western-style diets and more mental health problems in teenagers. The research paper, from WA's Telethon Institute for Child Health Research, has just been published online in the respected international journal Preventive Medicine. Report author and leader of Nutrition studies at the Institute, Dr Wendy Oddy, said the results were based on detailed analysis of diet records and behaviour checklists that were collected from more than 1600 West Australian 14-year-olds in the Raine Cohort Study.

“Our analysis found that higher levels of behaviour and emotional problems were associated with a more Western-style way of eating, namely a diet high in takeaway foods, red meat, confectionary, soft drinks, white bread and unrefined cereals,” Dr Oddy said. “We also showed that these problems were less among teens with a more healthier style of eating, specifically those who ate more fruit and vegetables. “This suggests that if we want to reduce the high rates of mental health problems among young people, then improving their overall diet could be a good place to start.”

The study participants' food intake was assessed using a 212-item food frequency questionnaire. The Child Behaviour Checklist was used to assess internalising mental health problems, such as withdrawn and depressed behaviours, and externalising mental health problems, such as delinquent and aggressive behaviours.

Dr Oddy said previous studies have shown that one in five children are expected to develop some form of mental health problem by the time they reach adulthood, and that 50% of all adult mental health problems develop during adolescence. “We know that since 1985, children and teenagers have been increasing their energy intake by consuming more soft drinks and processed foods.

The number of overweight adolescents has doubled and obesity has tripled in that age group. At the same time there have been marked increases in sedentary behaviours such as TV viewing and computer use,” Dr Oddy said. “Investigating factors that influence mental health in young people must be a high priority. These findings show that there is a need to look at the overall diet, rather than concentrate on individual nutrients.”


The association between dietary patterns and mental health in early adolescence

By Wendy H. Oddya et al.

Objective: To investigate associations between dietary patterns and mental health in early adolescence.

Method: The Western Australian Pregnancy Cohort (Raine) Study is a prospective study of 2,900 pregnancies recruited from 1989-1992. At 14 years of age (2003-2006; n=1,324), the Child Behaviour Checklist (CBCL) was used to assess behaviour (characterising mental health status), with higher scores representing poorer behaviour. Two dietary patterns (Western and Healthy) were identified using factor analysis and food group intakes estimated by a 212-item food frequency questionnaire. Relationships between dietary patterns, food group intakes and behaviour were examined using general linear modelling following adjustment for potential confounding factors at age 14: total energy intake, body mass index, physical activity, screen use, family structure, income and functioning, gender and maternal education at pregnancy.

Results: Higher total (b=2.20, 95%CI=1.06, 3.35), internalizing (withdrawn/depressed) (b=1.25, 95%CI=0.15, 2.35) and externalizing (delinquent/aggressive) (b=2.60, 95%CI=1.51, 3.68) CBCL scores were significantly associated with the Western dietary pattern, with increased intakes of takeaway foods, confectionary and red meat. Improved behavioural scores were significantly associated with higher intakes of leafy green vegetables and fresh fruit (components of the Healthy pattern).

Conclusion: These findings implicate a Western dietary pattern in poorer behavioural outcomes for adolescents. Better behavioural outcomes were associated with a higher intake of fresh fruit and leafy green vegetables.

Preventive Medicine, Article in Press

Cherry juice could be the new sports drink after scientists found it helps ease pain after running

Maybe it is a natural analgesic -- like aspirin. This did not seem to be a double-blind, study, though

People who drank the unsweetened juice while training for a long distance relay reported much less duress after exercise than those who did not. Scientists believe cherries' benefits are likely because of the fruit's natural anti-inflammation power – attributed to antioxidant compounds called anthocyanins which also give cherries their bright red colour. As well as recommending it as a new 'sports drink', they say the findings could have far-reaching benefits for the millions currently taking over-the-counter medication to reduce muscle pain.

A growing body of research suggests cherries could reduce inflammation related to heart disease, arthritis and may even help maintain muscle strength for those suffering from fibromyalgia a common and chronic widespread pain disorder.

In the study, sixty healthy adults aged between 18 and 50 years who drank 10.5 ounces cherry juice twice daily in the week before the long-distance race had far less muscle pain than those who consumed another juice. On a scale from 0 to 10, they had a two point lower self-reported pain level at the completion of the run – a clinically significant difference.

While more research is needed to fully understand the effects of tart cherry juice the early findings, presented at the American College of Sports Medicine Conference in Seattle, indicate cherries may work like common medications used by runners to alleviate post-exercise inflammation.

Dr Kerry Kuehl, sports medicine physician at Oregon Health and Science University, said: "For most runners, post-race treatment consists of RICE – rest, ice, compression and elevation – and traditional NSAIDS (non-steroidal anti-inflammatory drugs). "But NSAIDS can have adverse effects – negative effects you may be able to avoid by using a natural, whole food alternative, like cherry juice, to reduce muscle inflammation before exercise."


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