Eat a lot of carrots or other beta-carotene-rich foods and your skin just might get a yellow tint, since beta-carotene is what gives these foods their color. You'll also gain health benefits, because beta-carotene acts as an antioxidant to lower your risk for cancer and heart disease and your body can use this natural plant pigment to form vitamin A. However, the way you prepare foods may affect how much beta-carotene your body can absorb.
Effect of Heat
Heating foods that contain beta-carotene doesn't destroy the beta-carotene. In fact, it makes it more available by breaking down the walls of the plant cells that contain beta-carotene. A study published in "Food Research International" in March 2013 found cooking Australian bush tomatoes to make tomato sauce increased the available beta-carotene by 14 percent compared to the amount in raw bush tomatoes.
Best Cooking Method
A study published in "Plant Foods for Human Nutrition" in December 2009 found that deep-fried sweet potatoes had the most available beta-carotene, followed by steamed or boiled sweet potatoes and then baked sweet potatoes. Each of these methods has its pros and cons. Deep-frying adds lots of fat and calories, but boiling can lower the amount of vitamin C in foods. Steaming tends to maintain more nutrients than boiling and may be a good way to maximize the amount of vitamins and minerals in your vegetables.
Cooking your food for too long can cause it to lose more nutrients as well as making it mushy and less flavorful. Boiling carrots for 15 minutes or less will help increase the amount of the most easily absorbed type of beta-carotene, but cooking them for longer may cause some of this beta-carotene to turn into a form that isn't as easily absorbed, according to a study published in "The Journal of Agricultural and Food Chemistry" in April 2010. So, don't overcook your vegetables.
You'll absorb more beta-carotene from pureed cooked carrots than you will from chopped raw carrots. However, to get the most benefit from your beta-carotene-rich foods you need to serve them with something that contains at least a small amount of fat. A study published in "The European Journal of Clinical Nutrition" in May 2002 found that 17 percent more beta-carotene was available from pureed carrots than chopped carrots, cooking the pureed carrots increased availability by another 6 percent and adding oil during cooking increased availability by another 12 percent. You'll be able to absorb two to five times as much beta-carotene from your vegetables if you cook them with oil instead of cooking them without oil, notes another study published in "Plant Foods in Human Nutrition" in 2004. However, only a small amount of oil is necessary. Using too much oil is unhealthy.
- University of Maryland Medical Center: Beta-carotene
- Plant Foods in Human Nutrition: Microstructure and In Vitro Beta Carotene Bioaccessibility of Heat Processed Orange Fleshed Sweet Potato
- Food Research International: The Impact of Thermal Processing on Bioactive Compounds in Australian Native Food Products (Bush Tomato and Kakadu Plum)
- Journal of Agricultural and Food Chemistry: Effect of Storage and Cooking on Beta-carotene Isomers in Carrots ( Daucus carota L. cv. 'Stefano')
- European Journal of Nutrition: Beta-carotene Bioavailability From Differently Processed Carrot Meals in Human Ileostomy Volunteers
- European Journal of Clinical Nutrition: Estimation of Carotenoid Accessibility From Carrots Determined by an in Vitro Digestion Method
- Plant Foods for Human Nutrition: In Vitro Accessibility and Intake of Beta-carotene From Cooked Green Leafy Vegetables and Their Estimated Contribution to Vitamin A Requirements
Based in Massachusetts, Jessica Bruso has been writing since 2008. She holds a master of science degree in food policy and applied nutrition and a bachelor of arts degree in international relations, both from Tufts University.