My Life as a 20ish Single

By now, most people know they should be eating more vegetables. But are there ways to get more from the vegetables you already eat?

A growing body of research shows that when it comes to vegetables, it's not only how much we eat, but how we prepare them, that influences the amount of phytochemicals, vitamins and other nutrients that enter our body.

The benefits are significant. Numerous studies show that people who consume lots of vegetables have lower rates of heart disease, hypertension, diabetes, eye problems and even cancer. The latest dietary guidelines call for 5 to 13 servings - that is two and half to six and a half cups a day.

Surprisingly, raw and plain vegetables are not always best. In The British Journal of Nutrition next month, researches will report a study involving 198 Germans who strictly adhered to a raw food diet, meaning that 95% of their total food intake came from raw food. They had normal levels of vitamin A and relatively high levels of beta carotene.

But they fell short when it came to lycopene, a carotenoid found in tomatoes and other red-pigmented vegetables that is one of the most potent antioxidants. Nearly 80 percent of them had plasma lycopene levels below average.

"There is a misconception that raw foods are always going to be better," says Steven K. Clinton, a nutrition researcher and professor of internal medicine in the medical oncology division at Ohio State University. "For fruits and vegetables, a lot of times a little bit of cooking and a little bit of processing actually can be helpful."

The amount and type of nutrients that eventually end up in the vegetables are affected by a number of factors before they reach the plate, including where and how they were grown, processed and stored before being bought. Then, it is up to you. No single cooking or preparation method is best. Water-soluble nutrients like vitamin C and B and a group of nutrients called polyphenolics are often lost in processing. For instance, studies show that after six months, frozen cheries have lost as much as 50% of anthocyanins, the healthful compounds found in the pigment of red and blue fruits and vegetables. Fresh spinach loses 64% of its vitamin C after cooking. Canned peas and carrots lose 85% to 95% of their vitamin C, according to data compiled by the University of California, Davis.

Fat-soluble compounds like vitamins A, D, E and K and the antioxidant compounds called carotenoids are less likely to leach out in water. Cooking also breaks down the thick cell walls of plants, releasing the contents for the body to use. That is why processed tomato products have higher lycopene content than fresh tomatoes.

In January, a report in The Journal of Agriculture and Food Chemistry concluded that over all, boiling was better for carrots, zucchini and broccoli than steaming, frying or serving them raw. Frying was by far the worst.

Still, there were tradeoffs. Boiling carrots, for instance, significantly increased measurable carotenoid levels, but resulted in the complete loss of polyphenols compared with raw carrots.

That report did not look at the effects of microwaving, but a March 2007 study in The Journal of Food Science looked at the effects of boiling, steaming, microwaving and pressure cooking on the nutrients of broccoli. Steaming and boiling caused a 22& to 34% loss of vitamin C. Microwaved and pressure-cooked vegetables retained 90% of their vitamin C.

Excerpt from NYT: Finding the Best Way to Cook All Those Vegetables