Last week, researchers from Purdue University released a study that showed why fat is an essential part of any salad. They argued that low- and no-fat salad dressings made the vitamins and nutrients in greens and veggies less available to the body. That's because carotenoids -- a class of nutrient that includes lutein, lycopene, beta-carotene and zeaxanthin -- is fat soluble and can't be absorbed by the body unless it's delivered with some fat as well.
But that doesn't mean you should pull out the Ranch and blue cheese dressing just yet. Researchers discovered that certain types of fats were more efficient at drawing out the nutrients, meaning that a salad didn't have to become a high-fat affair.
"You can absorb significant amounts of carotenoids with saturated or polyunsaturated fats at low levels, but you would see more carotenoid absorption as you increase the amounts of those fats on a salad," said lead researcher Mario Ferruzzi, an associate professor of food science at Purdue, in a statement. The secret? Using monounsaturated fats, which aided nutrient absorption, even in a small portion size of three grams.
We covered the study here and readers weighed in about their favorite salad fats in the comments. Using those and a host of other options culled from the USDA database, we've compiled a list of great fats to include in your next salad to maximize vitamin absorption without overstepping your daily allowance:
An avocado has <a href="http://www.webmd.com/diet/features/8-healthy-facts-about-avocados" target="_hplink">30 grams of unsaturated fat</a>, and while estimates vary, <a href="http://www.peertrainer.com/DFcaloriecounterB.aspx?id=2022&v=1" target="_hplink">about 16 of those are monounsaturated</a>. That means that you need just one-quarter of one fruit -- to get optimal lycopene, beta-carotene and other antioxidant absorption.
Just a third of a teaspoon will yield 3.3 grams of monounsaturated fats and, along with it, <a href="http://www.livestrong.com/article/182045-monounsaturated-fat-content-of-foods/" target="_hplink">polyphenols and vitamin E</a>.
Though they pack a salty wallop with 400 milligrams of sodium per 10 olives, that same serving offers 3.5 grams of monounsaturated fat.
Half an ounce, or about nine cashews yields 4 grams of monounsaturated fats -- as well as a healthy dose of magnesium and phosphorous, which are essential to good bone health. The nut also includes tryptophan, which can help regulate sleep cycles and is thought to enhance mood. Not bad for a salad topper.
A third cup of whole milk ricotta includes 3 grams of monounsaturated fats, <a href="http://www.nal.usda.gov/fnic/foodcomp/Data/SR20/nutrlist/sr20w645.pdf" target="_hplink">according to a USDA database</a>. For less fat per volume, try half a cup of part-skim ricotta or two ounces of whole milk mozzarella.
One tablespoon of tahini <a href="http://www.nal.usda.gov/fnic/foodcomp/Data/SR20/nutrlist/sr20w645.pdf" target="_hplink">contains 3 grams of monounsaturated fat</a>, along with a healthy serving of magnesium.
Chopped Macadamia Nuts
Macadamia nuts are so rich in monounsaturated fat that you'd need only a fifth of an ounce -- or about two nuts -- to reach 3 grams of monounsaturated fats.
One third tablespoon of canola oil, half a tablespoon of peanut oil and just over a tablespoon of sunflower oil all contain about 3 grams of monounsaturated fat.