Why your salad needs dressing


Researchers at Iowa State University found that adding up to two tablespoons of soybean oil to vegetables increased the body's absorption of seven different micronutrients.


"Nutrients bind to fats which, when broken down by bile and digestive enzymes, allow the fatty acids and now accompanying fat-soluble vitamins to pass through the cell walls of our intestines and enter circulation,” explains Brian St. Pierre, R.D., CSCS, director of performance nutrition at Precision Nutrition in Scarborough, Maine.

“We analyzed a total of eight fat-soluble nutrients, including carotenoids, and vitamins A, E, and K, and found that absorption of these nutrients correlated to the amount of oil added to participants’ salads,” says Wendy White, Ph.D., the lead study author. “In turn, this means healthier skin and bones, better vision, an improved immune system, and even cancer prevention,” she says.


Any fat source will increase absorption of fat-soluble nutrients and options such as olive oil, avocado, and nuts are preferred over soybean oil, says St. Pierre, adding that soybean oil is over-consumed in the US from its frequent use in many highly-processed foods. To keep total fat and calorie intake in check, St. Pierre advises sticking to one to two thumb-sized portions (or tablespoons) of healthy fat per meal.