One out of every five U.S. teenagers has a cholesterol level that increases the risk of heart disease, federal health officials reported Thursday, providing striking new evidence that obesity is making more children prone to illnesses once primarily limited to adults.

A nationally representative survey of blood test results in American teenagers found that more than 20 percent of those ages 12 to 19 had at least one abnormal level of fat. The rate jumped to 43 percent among those adolescents who were obese.

Previous studies had indicated that unhealthy cholesterol levels, once a condition thought isolated to the middle-aged and elderly, were increasingly becoming a problem among the young, but the new data document the scope of the threat on a national level.

"This is the future of America," said Linda Van Horn, a professor of preventive medicine at Northwestern University who heads the American Heart Association's Nutrition Committee. "These data really confirm the seriousness of our obesity epidemic. This really is an urgent call for health-care providers and families to take this issue seriously."

Earlier research found that the obesity epidemic has been accompanied by an increase in a host of health problems in youths that were previously found mostly among adults, including high blood pressure, diabetes and arthritis. The new data detail the obesity's effect on cholesterol levels, which can increase the risk for a variety of illnesses, including diabetes and heart disease.

"The current epidemic of childhood obesity makes this a matter of significant and urgent concern," said Ashleigh May, an epidemic intelligence service officer with the federal Centers for Disease Control and Prevention's division for heart disease and stroke prevention, who led the analysis.

Although the latest government data suggest that the obesity epidemic might be leveling off after increasing for decades, at least one-third of youths are overweight or obese, and the heaviest boys continue to get heavier.

"People are worried that this generation is going to grow up to have more cardiovascular disease than the current generation," said Denise Simons-Morton of the National Heart, Lung and Blood Institute. "This problem is poised to negate all of the advances we've made in cardiovascular health."

In the new study, published in the CDC's Morbidity and Mortality Weekly Report, researchers analyzed data collected from 3,125 youths through the National Health and Nutrition Examination Survey, which is conducted every two years.

According to data from surveys conducted between 1999 and 2006, 20.3 percent had abnormal "blood lipid" levels, which includes low levels of high-density lipoprotein (HDL), or the "good cholesterol"; high levels of low-density lipoprotein (LDL), the "bad cholesterol"; and high levels of triglycerides, which can also clog arteries.

The percentage of teens with an abnormal blood lipid level varied by weight, ranging from 14.2 percent of those whose weight was normal to 22.3 percent among those who were overweight to 42.9 percent among those who were obese.

The findings support a 2008 recommendation by the American Academy of Pediatrics that children and adolescents get blood tests to see whether they need to be treated for abnormal lipid levels if they are at risk for heart disease because of a family history of high blood cholesterol or early heart disease or if they are at risk because they smoke, have high blood pressure or diabetes or are overweight.

Source: http://www.washingtonpost.com/wp-dyn/content/article/2010/01/21/AR2010012102481_pf.html

Trans fats are chemically altered vegetable oils. They are produced artificially in a process called hydrogenation which turns liquid oil into solid fat. This makes them saturated, which raises blood cholesterol.

Trans fats can be found in thousands of processed foods from sweets and biscuits to ready meals. They are used because they are cheap, add bulk to products, have a neutral flavour and give products a long shelf life. They have no nutritional value.

Are trans fats bad for you?
Trans fats have been linked to high cholesterol, which can lead to health conditions such as heart attacks and strokes.

A study suggests that trans fats can also increase the risk of fertility problems. Researchers from the Harvard School of Public Health in Boston, USA, say that consuming just 4g of trans fats every day can lead to infertility in women.

Avoiding trans fats
In the UK, there is no specific requirement for the trans fat content of products to be included on food labelling. However, some manufacturers have started to do so voluntarily.

Trans fats can be formed during a process called hydrogenation. Hydrogenated fats must be declared on the label so if a product contains hydrogenated fats, it may contain trans fats. Look out for the words partially hydrogenated on food labels these products may also contain trans fats.

If you want to avoid trans fats you should:

• avoid products that list hydrogenated or partially hydrogenated or shortenings on the label,
• include lots of fruit and vegetables in your diet,
• use fat-free or low-fat dairy products,
• avoid fast food, high and full fat margarine and baked goods such as doughnuts, pastries and biscuits,
• use lean cuts of meat and poultry and cook them without skin, without adding trans fats,
• use liquid vegetable oil for frying, and
• ask about trans fat content when eating at a restaurant or café.