Researchers at Ohio State University paid about a dozen people to eat salads (this is America, you've got to PAY people to eat salad) with or without avocado, one of the healthiest sources of fat, and then measured the amount of carotenoids that made it into everyone's bloodstream. Those eating a salad including half an avocado absorbed about 10 times more carotenoids than those eating the fat-free salad!
The other salad enhancement study recently took place at the Universitia di Urbino in Italy. With the understanding that it's the antioxidants that give fruits and vegetables their anticancer, antiviral, and anti-inflammation properties, scientists experimented with adding different fresh herbs to salads and measuring their resultant total antioxidant content. They found that adding just a single sprig of fresh herbs (the weight of 3 paper clips worth of thyme, sage or marjoram--a kissing cousin of oregano) literally doubles the antioxidant power of a bowl of salad. It's almost like eating two salads for the price of one!
The researchers conclude: "We stress the need to introduce aromatic herbs as a seasoning supplement in the diet of every age group." Read more: http://www.drgreger.org/june2005.html.