Having a salad is almost always a healthy choice, but it turns out that the kind of salad dressing you choose can make a difference in how healthy it is.
The vegetables in salads are full of important vitamins and nutrients, but their benefits are controlled by using the right type and amount of salad dressing.
Purdue University researchers fed subjects salads topped off with a variety of dressings. Some were saturated, monounsaturated and polyunsaturated fat-based dressings. The subjects were then tested for absorption of fat-soluble carotenoids – compounds such as lutein, lycopene, beta-carotene and zeaxanthin in their blood.
Those carotenoids are considered very healthy since they are associated with reduced risk of several chronic and degenerative diseases such as cancer, cardiovascular disease and macular degeneration.
The study found that monounsaturated fat-rich dressings required the least amount of fat to get the most carotenoid absorption. What does this mean, exactly? It means that a fat-free salad dressing is not necessarily the best choice.
"If you want to utilize more from your fruits and vegetables, you have to pair them correctly with fat-based dressings," said Mario Ferruzzi, the study's lead author and a Purdue associate professor of food science. "If you have a salad with a fat-free dressing, there is a reduction in calories, but you lose some of the benefits of the vegetables."
Overall, pairing with fat matters, the researchers found. You can absorb significant amounts of carotenoids with saturated or polyunsaturated fats at low levels, but you would see more carotenoid absorption as you increase the amounts of those fats on a salad.
The findings coincide with a 2004 Iowa State University study that determined carotenoids were more easily absorbed by the intestines when paired with full-fat dressing as opposed to low-fat or fat-free versions.