Make Your Vegetables Even Healthier With ... Fatty Salad Dressing?

Skip the lite dressing and go straight to the fatty kind to get the most out of your vegetables.

Ditching the fat-free dressing can improve your body's intake of healthy carotenoids.


Kristen Bonardi Rapp/Flickr

In our eternal -- some might say hopeless -- quest to shed weight, salads are often hailed as the perfect weapon. Vegetables, whether cooked or raw, are a great source of nutrients like vitamins and carotenoids, and they help limit our intake of unhealthy fats. It follows that picking a low- or no-fat dressing to go along with your salad is a wise choice -- or at least, it might seem that way.

But new research suggests there may be benefits to swapping the no-fat dressing for something heftier. That's because the higher fat content of richer dressings actually helps unlock vegetables' nutritional potential as they're being digested, say scientists from Purdue University. Although our impulse is generally to assume that low-fat or fat-free salad dressings are better for us, the researchers have found that different salad dressings can have an influence on a salad's nutritional value.

In a small study, test subjects were fed salads with three different kinds of dressing: one based on saturated fat (butter), one from polyunsaturated fat (vegetable oil) and one from monounsaturated fat (canola oil). Researchers then measured the subjects' blood for carotenoid absorption. Carotenoids, which include lycopene and beta-carotene, have been proven to help reduce the risk for heart disease and other chronic illnesses, so the more you get, the better. They found that subjects who had eaten the canola oil dressing had the highest levels of carotenoids in their bloodstream. Moreover, those who'd had dressings based on butter or vegetable oil needed more dressing to achieve the same benefits.

The study, published this week in Molecular Nutrition and Food Research, implies that there's a sweet spot involving both the amount of dressing you apply as well as the type of fat the dressing is made of.

"If you want to utilize more from your fruits and vegetables, you have to pair them correctly with fat-based dressings," said Purdue food science professor Mario Ferruzzi and the study's lead author. "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."

So if you're looking for a reason to ditch that bland and fat-free excuse for a salad dressing in your fridge, this looks like a pretty good one. It's more evidence that our bodies, which are hardwired to seek out flavor, can sometimes be surprisingly good at picking what's best for it.

We already know that some types of fat are better than others. Trans fats and saturated fats are the enemy, for example, while unsaturated fats can protect your organs and overall health. Now we're discovering that not only are some fats good for you -- they can also make already healthy foods even more nutritious.