Salads are packed with healthy nutrients. But there is a catch. You also have to eat some fat so your body can absorb certain fat-soluble compounds such as lycopene from tomatoes and carotene from carrots. Previous research has suggested you absorb more nutrients by adding additional fat.
That means zero-fat salad dressings are counterproductive. You're consuming fewer calories, but you're also getting a lot less benefit from the veggies.
However, a new study by researchers at Purdue University suggests some fats are better than others when it comes to aiding the absorption of these nutrients.
Volunteers were fed salads topped off with saturated, polyunsaturated and monounsaturated-based dressings, and then their blood was tested for nutrient levels.
The results revealed that a relatively small dose of canola oil (three grams) was just as effective as a higher level (20 grams).
"You can get a significant amount of absorption with a lower level of fat," said Mario Ferruzzi, the lead author of the study, published in the journal Molecular Nutrition & Food Research.
Canola oil is a monounsaturate. Dr. Feruzzi said other monounsaturates, such as olive oil, may be equally effective, but studies must be done to know for sure.