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The New Fat-Friendly Salad

Research shows how important healthy oils are to your diet

Hand pouring dressing

Violeta Pasat/Offset

Adding extra dressing actually can increase the absorption of eight different nutrients.

En español | You may feel a trace of guilt about putting dressing on your salad. Or are you in the habit of ordering it on the side, so you'll use less? It's officially time to let go of all that. A recent study by Iowa State University shows that the typical oil in dressing significantly boosts the nutrition you take in from veggies like carrots, tomatoes and leafy greens. And the more you pour on, the more benefit you'll receive. The study's lead author, Wendy White, describes it as “that rare, perfectly linear relationship” where doubling the dressing doubles the absorption of eight different nutrients, including cancer-fighting carotenoids and vitamins K, E and A.

The difference salad dressing makes turns out to be critical with nutrients such as, say, beta-carotene. “If you eat a baby carrot on its own, there's basically no absorption of the fat-soluble vitamins in it,” says White. And with only nine percent of American adults consuming the recommended two to three cups of veggies a day, “it becomes even more important to optimize the nutrients they do consume.” Beyond oils, studies have found that the healthy fats in items like eggs and avocado also can help you absorb the vitamins and antioxidants in the “nutritional powerhouses” that are salad vegetables, White notes.

For the study, White's team tested with soybean oil — the most commonly used oil in dressings bottled by the food industry. Years ago, in another frequently cited study, White had used canola to prove similar nutrient-boosting results. This time her research offered proof of additional nutrients that are better absorbed with a healthy oil, including the carotenoid lutein, which is key to preventing age-related macular degeneration.

White's work fits in with a larger nutritional push toward more healthy fats. It follows recent government nutrition guidelines lifting limits on total fats in our diets, as well as studies showing that low-fat diets don't promote the satiety you need to effectively maintain your weight. Still, White doesn't recommend going too nuts with the Italian. At 120 calories per tablespoon, she notes, oil is still a calorie-dense addition to your diet — and moderation would be wise.