3 Vegetables Made Healthier When Cooked

Cooking Veggies Releases Trapped Nutrients

Eating vegetables are an important part of a healthy diet. Athletes and fitness enthusiasts understand them as a valuable source of phytochemicals. These chemical compounds provide antioxidant properties, according to chronic research. Antioxidants are powerful substances stabilizing free radicals (cell-destroying atoms) in our body and helpful in disease prevention. Because of this benefit, consuming vegetables is linked to decreased incidence of cancer, heart disease, and degenerative illness.

Cooking Can Enhance Nutrient Value

Mixed vegetables
Some Veggies are Healthier When Cooked. Sawayasu Tsuji / Getty Images

It has been said eating raw vegetables provides the best nutrients. While this may be the case for most veggies, cooking actually increases nutrient value in some vegetables. There appears to be positive and negative feedback in current research with how veggies are prepared. According to an article published in the Journal of Agricultural and Food Chemistry, “many protective compounds are enhanced when vegetables are cooked.”

Tomatoes, broccoli, and carrots are three vegetables shown to have improved nutrient value when cooked. It appears beneficial phytochemicals are trapped in the cell wall without applying a heating method. We will be taking a look at how cooking enhances nutrients in each of these vegetables. 

Tomatoes

Yellow and red tomatoes with a knife on a wooden board
Cooked Tomatoes Provide More Lycopene. Westend61 / Getty Images

Tomatoes are scientifically labeled a fruit, but for cooking purposes referred to as a vegetable. They’re nutrient-dense and a rich source of vitamin C and lycopene. Lycopene is the phytochemical giving the tomato its red hue along with significant antioxidant properties.

The Journal of Agricultural and Food Chemistry published a study on the nutritional benefits of cooking tomatoes. Several cooking trials were conducted heating raw tomatoes to 88 degrees Celsius for two, 15 and 30 minutes. Vitamin C and lycopene values were measured at each interval. Research results indicated a significant drop in vitamin C but in contrast, a substantial increase in lycopene.

Steaming or boiling tomatoes is the preferred method of cooking to bring out more lycopene for optimal nutrition. Research indicates lycopene reduces the risk of cancer, improves heart health, and enhances neurological response. 

Broccoli

Organic Broccoli just harvested
Lutein Antioxidant Increased in Cooked Broccoli. Mint Images/ Tim Pannell / Getty Images

Broccoli is a cruciferous vegetable with superior antioxidant properties. Research has indicated broccoli contains phytochemicals carotenoids, polyphenols, and glucosinolates. It’s also a rich source of lutein and tocopherol. These chemical compounds are shown to decrease cancer by reducing inflammation in our blood vessels. Broccoli is well-known as a detox vegetable and superfood.

The International Journal of Food Sciences and Nutrition published an article on how cooking broccoli affects nutrient value. It was determined various heating methods reduced the nutrient levels of five glucosinolate antioxidant compounds. At the same time, significant increases in lutein, carotene, and tocopherols were reported cooking broccoli. In fact, longer heating time extracted even more.

According to research published in the Journal of Agricultural and Food Chemistry, cooking broccoli promotes the release of carotenoids. Carotenoids are “protein complexes, leading to better extractability and higher concentrations in cooked samples.”

Steaming and boiling broccoli are the preferred methods of cooking to enhance carotenoids like lutein and phytoene. Studies show phytoene reduces the risk of prostate cancer, improves heart health, and reduces inflammation in our blood vessels.    

Carrots

Organic Carrots
Antioxidant Value is Improved Cooking Carrots. Kevin Summers / Getty Images

Carrots are a popular root vegetable. They are a rich source of beta-carotene, fiber, and numerous vitamins and minerals. Carrots provide antioxidant health benefits attributed mostly from high concentrations of vitamin A and beta-carotene.

Research published in the Journal of Agricultural and Food Chemistry examined different cooking methods on the nutrient value of carrots. Antioxidant samples were measured after boiling, steaming, and frying. Carotenoids, polyphenols, glucosinolates, and ascorbic acid (vitamin C) were analyzed after cooking the carrots.

Research results indicated boiling carrots increased all carotenoids (antioxidants) by 14 percent. The other cooking methods caused a decrease in antioxidant value with frying reflecting the worst decline. Total antioxidant capacities (TAC) were compared during the cooking trial. Results agreed with prior research that “reported a significant increase of carrot TAC during a thermal treatment at 130 degrees Celsius for 20 minutes.”

Boiling carrots retained the most vitamin C and carotenoids. Research results also “suggest that for each vegetable a preferential cooking method could be selected to preserve or improve its nutritional and physicochemical qualities.”

Sources:

Dewanto V et al. Thermal Processing Enhances the Nutritional Value of Tomatoes by Increasing Total Antioxidant ActivityJournal of Agriculture and Food Chemistry. 2002.

Hwang ES et al. Effects of various heating methods on glucosinolate, carotenoid and tocopherol concentrations in broccoli. International Journal of Food Sciences and Nutrition. 2013. 

Miglio C et al. Effects of Different Cooking Methods on Nutritional and Physicochemical Characteristics of Selected Vegetables.  Journal of Agriculture and Food Chemistry. 2008.

Continue Reading