A new reports states that one in five, or about 20 percent, of American kids have unhealthy levels of cholesterol.

Cholesterol levels are even worse for children who are obese as over 43 percent of obese kids have bad cholesterol levels.

Among this group, teenagers have the worst cholesterol levels; 27 percent are aged 16 to 19 years old. Heart disease with artery clogging blockages can start as young as age 3.

About 21 percent of American children and teens have some form of "abnormal" cholesterol. And nearly 14 percent of kids have unhealthily low levels of “good” cholesterol. Cholesterol levels in children are mainly associated with diet, obesity, and heredity.

Cholesterol is a waxy, fat-like substance that is found in the cells of our bodies. We naturally produce cholesterol because it makes other essential substances such as vitamin D or hormones. It also makes substances to help with digestion. However, cholesterol is also found in the food we consume such as poultry, meat, and dairy products.

Consuming foods that are high in saturated and trans-fats makes our liver produce more cholesterol than we need. Too much cholesterol causes plaque to develop in the walls of the arteries. Increased cholesterol levels can eventually lead to serious health problems such as blood clots, stroke, or heart attack.

There are two types of cholesterol: good cholesterol and bad cholesterol. “Bad cholesterol” is also known as low-density lipoprotein (LDL) cholesterol. High levels of LDL cholesterol create a buildup of plaque in the artery walls, which can cause the arteries to become blocked. This can result in atherosclerosis, blood clots, heart attack, stroke, and peripheral artery disease.

“Good” cholesterol is also known as high-density lipoprotein (HDL) cholesterol. HDL cholesterol helps remove LDL cholesterol from the artery walls. Good levels of HDL cholesterol help protect us from heart attacks and strokes. However, low HDL cholesterol levels may increase the risk of developing heart disease.

When should your child have their cholesterol levels checked? It is recommended that children start screening as early as age 2, but no later than age 10. If the fasting lipid profile is normal, they should be screened again in three to five years.

For kids who are overweight or obese and who have a high blood-fat level or low level of "good" HDL cholesterol, the first form of treatment is to lose weight. This can be done by eating a healthier diet, getting more physical exercise and often times getting nutritional counseling.

Tips for children to improve cholesterol levels

• Exercise regularly. Regular aerobic exercise, such as running, biking, and swimming, can help raise HDL levels which lowers the risk for heart disease.

• Eat a healthy diet. Eat foods low in total fat, saturated fat, trans-fat, and cholesterol. Make sure to eat a variety of foods in order to get all the essential nutrients.  

Dr. Samadi is a board-certified urologic oncologist trained in open and traditional and laparoscopic surgery and is an expert in robotic prostate surgery. He is chairman of urology, chief of robotic surgery at Lenox Hill Hospital and professor of urology at Hofstra North Shore-LIJ School of Medicine. He is a medical correspondent for the Fox News Channel's Medical A-Team and the chief medical correspondent for am970 in New York City. Learn more at roboticoncology.com. Visit Dr. Samadi's blog at SamadiMD.com. Follow Dr. Samadi on Twitter and Facebook.