Long term exposure to pollutants from vehicle exhaust is linked to a heightened risk of the common eye condition — age-related macular degeneration or AMD, says researchers.
AMD is a neuro-degenerative condition that affects the middle part of the retina, known as the macula. It is one of the most common causes of poor vision in older people and is most likely caused by an interplay between genetic and environmental risk factors.
The study, published in the Journal of Investigative Medicine, shows that exposure to the highest levels of air pollutants was associated with an almost double risk among those aged 50 and older.
For the study, the researchers from Asia University in Taiwan analysed national health insurance and air quality data from 1998 to 2010 to see if there might be a link between long term exposure to the pollutants nitrogen dioxide and carbon monoxide and a heightened risk of AMD.
As the condition is more common among older age groups, the researchers focused on 39,819 people aged 50 and above. During the monitoring period, a total of 1,442 people developed cases of AMD. Those with the highest level of exposure to nitrogen dioxide were nearly twice as likely (91 per cent) to develop AMD than those exposed to the lowest level.
Those exposed to the highest level of carbon monoxide were 84 per cent more likely to develop AMD than those exposed to the lowest levels.
According to the researchers, this study has implicated nitrogen dioxide in cardiovascular and neurological ill health and as the retina is part of the central nervous system, there is a plausible biological explanation for its vulnerability to this pollutant. (IANS)
Caffeine may offset some of the negative effects of an obesogenic diet by reducing the storage of lipids in fat cells and limiting weight gain and the production of triglycerides, researchers have found.
Published in the Journal of Functional Foods, the research team from University of Illinois in US picked mice for the study and found that rats that consumed the caffeine extracted from mate tea gained 16 per cent less weight and accumulated 22 per cent less body fat than rats that consumed decaffeinated mate tea.
The effects were similar with synthetic caffeine and that extracted from coffee.
Mate tea is an herbal beverage rich in phytochemicals, flavonoids and amino acids that’s consumed as a stimulant by people in southeastern Latin American countries.
The amount of caffeine per serving in mate tea ranges from 65-130 milligrams, compared with 30-300 milligrams of caffeine in a cup of brewed coffee, according to the study.
“Considering the findings, mate tea and caffeine can be considered anti-obesity agents. The results of this research could be scaled to humans to understand the roles of mate tea and caffeine as potential strategies to prevent overweight and obesity, as well as the subsequent metabolic disorders associated with these conditions,” said study researcher said Elvira Gonzalez de Mejia.
According to the researchers, for four weeks, the rats in the study ate a diet that contained 40 per cent fat, 45 per cent carbohydrate and 15 per cent protein.
They also ingested one of the forms of caffeine in an amount equivalent to that of a human who drinks four cups of coffee daily.
At the end of the four-week period, the percentage of lean body mass in the various groups of rats differed significantly.
The rats that ingested caffeine from mate tea, coffee or synthetic sources accumulated less body fat than rats in the other groups.
In the rats, the accumulation of lipids in the adipocytes was significantly associated with greater body weight gain and increased body fat, according to the study.
To determine the mechanism of action, the scientists performed cell culture studies in which they exposed adipose cells from mice to synthetic caffeine or the coffee or mate caffeine extracts.
They found that regardless of its source, caffeine decreased the accumulation of lipids in adipose cells by 20 per cent-41 per cent.
The scientists also tracked the expression of several genes associated with obesity and lipid metabolism.
These included the fatty acid synthase gene (Fasn), an enzyme compound involved in the synthesis of fatty acids from glucose; and the lipoprotein lipase gene (Lpl), which codes for an enzyme that breaks down triglycerides.
In the rats that consumed the mate tea caffeine, expression of Fasn decreased by 39 per cent in their fat tissue and by 37 per cent in their livers, the researchers found.
The decreased expression of Fasn and two other genes in the liver evoked lower production of low-density lipoprotein cholesterol and triglycerides in the liver as well, according to the study.
“The consumption of caffeine from mate or from other sources alleviated the negative impact of a high-fat, high-sucrose diet on body composition due to the modulation of certain lipogenic enzymes in both adipose tissue and the liver,” de Mejia said. (IANS)