Raw orange, red, yellow, and dark green vegetables contain vitamin E and K as well as carotenoids, such as beta-carotene, which the body converts into vitamin A. Mixing a bit of healthy plant oils with your greens helps unlock fat-soluble nutrients. But how much oil do you need to drizzle on your salads to get thatbenefit?
In a small study in the American Journal of Clinical Nutrition, 12 healthy female volunteers ate five salads at different times after overnight fasting. The test salads contained the same mix of vegetables, but with salad dressings that contained different amounts of soybean oil. The study found that, starting at a bit less than a teaspoon of oil, increasing “doses” of oil in the salads steadily boosted the amount of vitamins that the women absorbed. The maximum amount of oil used was about 7 teaspoons (a bit more than 2 tablespoons, containing 288 fat calories).
Even in this small group, the amounts of vitamins that individual women absorbed varied. But it does provide additional support for tossing raw vegetable salads with a generous amount of oil, and may help to explain why unsaturated oils like soybean support a healthy diet pattern.