One in five Americans kids have unhealthy cholesterol levels, and more than 8 percent have the most worrisome high cholesterol levels, a new survey finds. 

Older children and teenagers had the worst cholesterol levels -- nearly 27 percent of 16- to 19- year-olds had at least one measure of unhealthy cholesterol, the National Center for Health Statistics found. And the heavier children were more likely to have unhealthy cholesterol measures. More than 43 percent of obese kids had bad cholesterol levels. 

“While it’s not a surprise that they have more abnormalities than nonobese kids, it is pretty frightening,” said Dr. Julie Brothers, a preventive cardiologist at Children’s Hospital of Philadelphia, who was not involved in the study. 

Unhealthy cholesterol levels can mean arteries are already being blocked with hardening “plaques” that can cause heart attacks and strokes. 

Many studies have shown heart disease starts young — with artery-clogging blockages starting sometimes as young as age 3. Ultrasound examinations of children as young as 10 have shown they can have arteries that are already as clogged as those in some middle-aged people. 

Sugary and Fatty Foods are to Blame

Kids can inherit a genetic form of high cholesterol called familial hypercholesterolemia, but a bigger cause of high cholesterol is a poor diet. Sugary and fatty foods can both boost cholesterol levels.  Lack of exercise can skew cholesterol levels, too.

The NCHS team looked at data from 2011 to 2014 taken from a very large survey of health in the U.S. 

“One in five youth had high total cholesterol, low high-density lipoprotein (HDL) cholesterol, or high non-HDL cholesterol,” they wrote.  Thirteen percent had low levels of high-density lipoprotein (HDL or “good” cholesterol). HDL scoops up the “bad” cholesterol and carries it away, so having high levels is important. It’s linked most with poor diet. 

Another 8.4 percent had high LDL -- the low-density or LDL cholesterol that is the bad actor in clogging arteries. More than 14 percent of children aged 6 to 8 had abnormal cholesterol levels and 26.9 percent of teens aged 16 to 19 did, they found.

Brothers said it’s never too soon to start turning things around for a child. “I always start with diet, even with familial hypercholesterolemia,” she said. Cutting back on sugary drinks and fatty foods can help. 

Lack of Fiber and Exercise is Another Cause

Brothers also recommends that kids eat one fruit or vegetable with every meal or snack to try to get to the five-servings-a-day recommended minimum. This enables them to increase fiber intake. 

“The vast majority of the overweight or obese kids that I see do not need medicine,” Brothers said. “I wish I could tell them there is a little pill they can take. The only pill really is hard work.” Adding exercise is one important factor. 

Exercise can also raise HDL levels, she said. “I work with those kids to really focus on aerobic activity. It’s important for everything,” she said.

But some children do have dangerous cholesterol levels and for them, cholesterol-lowering drugs can be important, Brothers said. 

“We want our kids to live longer than we do and at this point they are not going to,” she said.