Archive for November, 2009

Multivitamins & minerals may improve brain functions in kids

Sunday, November 22nd, 2009

Daily supplements of multivitamins and minerals may improve the brain function of children, says a new study from British and Australian researchers.

Twelve weeks of supplementation with vitamins and minerals was found to boost the attention scores of children, according to results published in the British Journal of Nutrition.

“This represents the first observation of acute behavioural effects of vitamins/minerals in human subjects,” wrote the researchers, led by Professor David Kennedy from Northumbria University in Newcastle.

“Naturally, these observations require replication in larger cohorts, but they do suggest that this matter should be given some priority,” cautioned the researchers.

Study details

The Newcastle-based researchers, in collaboration with scientists from Swinburne University in Australia, and the University of Westminster in London, recruited 81 children (average age 11) to participate in the randomised, double-blind, placebo-controlled, parallel groups investigation.

The children were reportedly all healthy and free from food allergy. In addition, none of the children used other dietary supplements during the three months prior to the study. Participants were randomly assigned to daily multivitamin and mineral supplements or placebo for 12 weeks. The study used Pharmaton SA’s Pharmaton Kiddi blend of multivitamins and minerals. The Swiss company also provided funding for the study.

Cognitive performance was measured using a battery of laboratory assessments. Measures were taken before the study, after one and three hours after the first dose, and after 12 weeks.

Kennedy and his co-workers report that the children in the vitamin/mineral group performed more accurately on two tests of attention. Indeed, the researchers noted the first signs of improvement only three hours after the first dose on the first day.

“The most surprising facet of the improvement in attention task performance seen here is that it became evident by three hours post-dose on the first day,” they wrote.

“To the best of our knowledge, the possibility that vitamins or minerals could exert behavioural effects after a single dose has not been explored,” they added.

However, no effects were observed on measures of the children’s mood, they added.

Science behind the claims?

The researchers noted that the study was aimed at testing the claims of the manufacturer that the multivitamin and mineral could improve the physical development and neural performance of the children.

“The combination of vitamins, minerals and amino acids present… in the present study does not allow the results presented to be attributed to any one component,” wrote the researchers.

“Further work in this area could examine the constituent parts of this treatment in more detail, perhaps focusing on attentional measures and including acute, as well as chronic, assessment,” they added.

Source: British Journal of Nutrition

Green tea extracts show promise for sleep-disordered breathing

Monday, November 9th, 2009

 

Antioxidant-rich extracts from green tea may reduce the effects of oxidative stress caused by breathing problems while people are sleeping, according to US researchers.

Obstructive sleep apnea (OSA) occurs when people stop breathing while they are sleeping, often for a minute or more, and this may many hundreds of times during a single night’s sleep. It is usually caused when the soft tissue in the rear of the throat collapses and closes during sleep, according to the American Sleep Apnea Association.

As such, people with this disorder are said to be at risk of oxidative stress and exhibit changes in their brain tissue in areas involved in learning and memory.

Supplements of green tea extracts may counter the cognitive deficits that may occur, suggests a new study with rats, published in American Journal of Respiratory and Critical Care Medicine.

If the results of the study can be repeated in humans, green tea and its extracts may offer a potential interventional strategy for people with the disorder, reported to be in the region of 12 million or so people in the US, according to the National Institutes of Health.

“OSA has been increasingly recognized as a serious and frequent health condition with potential long-term morbidities that include learning and psychological disabilities,” wrote lead researcher David Gozal from the University of Louisville.

Study details

Human OSA was modelled in rats by intermittently depriving the animals of oxygen during 12-hour “night” cycles for 14 days - intermittent hypoxia (IH). The researchers divided the 106 male rats into two groups, with one group assigned to receive drinking water containing green tea polyphenols.

The University of Louisville researchers, in collaboration with scientists from Soroka University Medical Center, then tested the animals for markers of inflammation and oxidative stress, in addition to using a water maze to test their performance in spatial learning and memory tasks.

They report that rats that received the green tea polyphenol (GTP)-supplemented water performed significantly better in a water maze than the rats that drank plain water.

Moreover, levels of malondialdehyde (MDA), a reactive carbonyl compound and a well-established marker of oxidative stress, were 40 per cent lower in the GTP-supplemented animals, added the researchers.

“GTP-[supplemented] rats exposed to IH displayed significantly greater spatial bias for the previous hidden platform position, indicating that GTPs are capable of attenuating IH-induced spatial learning deficits,” wrote Gozal.

“Because oxidative processes underlie neurocognitive deficits associated with IH, the potential therapeutic role of GTP in sleep-disordered breathing deserves further exploration,” he added.

Antioxidant activity

The benefits of the green tea extracts were attributed to the antioxidant properties of green tea polyphenols. “Recent studies have demonstrated the neuroprotective activity of GTP in animal models of neurodegenerative conditions such as Parkinson’s and Alzheimer’s disease,” wrote Gozal.

Green tea is said to contain over four times the concentration of antioxidant catechins than black tea (green tea leaves that have been oxidized by fermentation), about 70 mg catechins per 100 mL compared to 15 mg per 100 mL for black tea.

The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.

Source: American Journal of Respiratory and Critical Care Medicine
Volume 177, Pages 1135-1141, doi:10.1164/rccm.200701-110OC
“Green Tea Catechin Polyphenols Attenuate Behavioral and Oxidative Responses to Intermittent Hypoxia”
Authors: I.C. Burckhardt, D. Gozal, E. Dayyat, Y. Cheng, R.C. Li, A.D. Goldbart, B.W. Row