By Margaret Badore for DietsInReview.com
The raw food trend is getting a lot of media attention lately, both on DietsInReview and in the wider health community. The raw diet tied for the second best diet for weight loss in U.S. News‘ assessment, and raw cleanses are a hot trend that’s gaining popularity both for its promises of detoxification and weight loss.
Supporters of the raw diet believe that raw fruits, vegetables and nuts are the richest sources of vitamins, minerals, enzymes and other nutrients. Some people who follow the raw food diet also include meat and dairy, but many are strict vegans. While a plant-based raw diet is certainly very healthy, cooking some plants actually increases some nutrients and can make others more bio-available.
Once you start into the question of raw vs. cooked foods, it immediately becomes a complex matter. Nutrition science has become quite sophisticated, yet there’s still only a limited amount of research available on this subject. Some vitamins may be lost during the cooking process yet other nutrients are enriched by cooking and exposure to heat. However, there are still many gray areas when it comes to the importance of many vitamins, minerals and other phytochemicals, and even more uncertainly when you want to compare their values before and after cooking. Below are some of the facts that we do have about raw and cooked foods, organized by nutrient.
“Heat readily destroys thiamine (B-1) and vitamin C,” says Mary Hartley, RD, MPH Nutritionist for Calorie Count. Scientific American reports that cooking tomatoes for just two minutes decreases their vitamin C content by 10 percent. Vitamin C is a highly unstable compound that is quickly degraded through oxidization and cooking. “Foods high in thiamin include whole grain and enriched grain foods, fortified cereals, lean pork, wheat germ, legumes, and organ meats,” says Hartley. “Vitamin C is found in many fruits and vegetables, especially red and green peppers, oranges, cantaloupe, broccoli, Brussels sprouts, baked potato, and cabbage.” She suggests eating a raw source of vitamin C every day.
Lycopene is an essential nutrient found in tomatoes and other red berries and fruits. A diet rich in lycopene is associated with lower rates of cancer. One study published in the British Journal of Nutrition found that one kind of lycopene is made more bioavailable by cooking. “Lycopene is a carotenoid, and all carotenoids, along with phenolic acids and flavonoids, are enhanced by cooking,” says Hartley. She adds that studies have shown that carotenoid-rich foods are best eaten in the presence of fat or oil.