Kids ate less artificial trans fat over 10 years, and their cholesterol got better — but the study couldn't say for sure if that was because of less trans fat or other changes in their diet.

When kids eat less butter and more olive oil or fish, their bad cholesterol goes down — especially if they were eating a lot of saturated fat to begin with.

When kids eat more saturated fat (like butter and fatty meats), their 'bad' cholesterol goes up a little bit — even at age 6.

Kids who eat the most saturated fat are more likely to have cholesterol levels that doctors worry about — even at age 6.

Eating less saturated fat, like from butter and red meat, tends to go along with lower levels of 'bad' cholesterol in the blood.

Over 10 years, Icelandic kids ate less butter and fatty meat, and their 'bad' cholesterol went down a little — showing that changing what kids eat can help their heart health.