Adding a little dressing to your salad may boost its benefits, according to a study which found that fat from soybean oil promotes absorption of eight different micro nutrients in vegetables. Better absorption of the nutrients promotes a range of health benefits, including cancer prevention and eyesight preservation, researchers said. The study, published in the American Journal of Clinical Nutrition, noted that eating the same salad without the added oil lessens the likelihood that the body will absorb the nutrients. Researchers at Iowa State University in the US found that added oil aided in the absorption of seven different micro nutrients in salad vegetables. Those nutrients include four carotenoids - alpha and beta carotene, lutein and lycopene - two forms of vitamin E and vitamin K. The oil also promoted the absorption of vitamin A, the eighth micro nutrient tracked in the study, which formed in the intestine from the alpha and beta carotene. The study builds on previous research that focused on alpha and beta carotene and lycopene. Better absorption of the nutrients promotes a range of health benefits, including cancer prevention and eyesight preservation, said Wendy White, an associate professor of food science and human nutrition at Iowa State University. "The best way to explain it would be to say that adding twice the amount of salad dressing leads to twice the nutrient absorption," White said. The study included 12 college-age women who consumed salads with various levels of soybean oil, a common ingredient in commercial salad dressings. The subjects then had their blood tested to measure the absorption of nutrients.
Women were chosen for the trial due to differences in the speed with which men and women metabolise the nutrients in question. The results showed maximal nutrient absorption occurred at around 32 grammes of oil, which was the highest amount studied, or a little more than two tablespoons. However, White said she found some variability among the subjects. "For most people, the oil is going to benefit nutrient absorption. The average trend, which was statistically significant, was for increased absorption," White said.