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A study published this week supports efforts to rid the United States' diet of trans fats. Women with the highest levels of trans fat in their blood have triple the risk of heart disease of those with the lowest levels.
"Humans cannot synthesise, or create, trans fatty acid. The only source is through diet," said study chief Dr Frank Hu of the Harvard School of Public Health in Boston.
The main source of trans fat in the diet is partially hydrogenated oils - plentiful in cookies, crackers, pastries and fried foods.
"Eliminating the use of partially hydrogenated oils and other sources of trans fat in the US diet - as long as saturated fat intake doesn't increase - will likely help reduce the burden of cardiovascular disease," he said.
Dr Hu and colleagues analysed blood samples obtained from 32,826 nurses between 1989 and 1990 as part of a long-term study that looked at the effect of oral contraceptives, diet and lifestyle on the development of heart and other diseases.
During six years of follow-up, 166 women developed heart disease and these women were matched to 327 healthy control women.
According to a report in the journal Circulation, the amount of trans fat in red blood cells correlated significantly with the amount of trans fat consumed, and was associated with increased levels of "bad" LDL cholesterol and decreased levels of "good" HDL cholesterol.
After adjusting the data for multiple factors that might influence the results, women with the highest trans fatty acid content in red blood cells were three times more likely to develop heart disease than women with the lowest trans fatty acid content.
This study, the authors say, provides further evidence of the potentially harmful effects of trans fats on heart health.
"Trans fat intake," says Dr Hu, "has been substantially reduced in European countries, whereas intake in the US is still relatively high.
"Recent efforts to eliminate trans fats from many foods and even from restaurant meals in cities such as New York and Philadelphia should have a beneficial effect on the population as a whole."
- REUTERS
