Vegetables are healthy,whether raw or cooked

The debate around vegetables has been whether they are best eaten raw or cooked. It was first proposed as early as the 1930s that raw food and cooked food might affect the body differently,when Dr Paul Kouchakoff presented his work on feeding experiments at the First International Congress of Microbiology.

Evidence suggests that cooked vegetables have some harmful effects,as cooking destroys nutrients and enzymes. However,cooking kills potentially harmful organisms and makes food safe,increases the bio-availability of certain nutrients and improves digestibility.

The truth is that vegetables are beneficial both in the raw and cooked state.

Cooking vegetables decreases water-soluble and heat-sensitive nutrients,such as Vitamin C,B-vitamins and folic acid. In fact,it was reported that salad and raw vegetable consumption has been found to be positively associated with higher levels of these nutrients among adults in the US population. It showed higher levels of these nutrients among salad eaters suggested better absorption.

Heat also destroys some enzymes. Garlic and cruciferous vegetables (like cauliflower,broccoli and brussel sprouts) contain special enzymes with anti-cancer properties. However,heating these vegetables destroys these properties. One of the common examples is garlic,which contains the enzyme alliinase that converts alliin to allicin. It is activated by crushing or cutting garlic and can be completely deactivated by 60 seconds of microwave heating. However,when garlic is crushed and allowed to stand for 10 minutes prior to being microwaved for 60 seconds,it retains some of its enzyme activity.

Increasing cooking time and temperatures of vegetables creates some harmful by-products called dietary advanced glycation end-products (AGEs). AGEs in our food can lead to several diseases including allergies,digestive disorders,arthritis,asthma,aches and pains and accelerate ageing.

In addition to loss of nutrients,enzyme activity and formation of AGEs,cooking vegetables is likely to affect their glycemic indices.

Glycemic index is the ability of carbohydrates in food to raise blood sugar levels. As the digestibility improves,the carbohydrate availability would also increase. Therefore,raw vegetables may be more useful for weight watchers and diabetics.

Most vegetables,when consumed raw,leave an alkaline ash which helps in better absorption of several nutrients. Raw vegetables have been found to be strongly associated with protection against cancer,particularly esophageal,gastric,and breast cancers than cooked vegetables.

While there are some losses during cooking,it also has some positive effects. Besides making it safer,cooking vegetables increases the bio-availability of Vitamin A.

A study found that heating tomatoes significantly increased lycopene content and anti-oxidant activity despite a decrease in Vitamin C. Studies of colorectal cancer showed both raw and cooked vegetables to be inversely associated with risk.

Make sure you have a good mix of both raw and cooked vegetables to maximise their benefits. Remember that salads,vegetable juices and raw vegetables can be a source of infection and eat these only at hygienic places.

Ishi Khosla is a former senior nutritionist at Escorts. She heads the Centre of Dietary Counselling and also runs a health food store. She feels that for complete well-being,one should integrate physical,mental and spiritual health. According to her: “To be healthy should be the ultimate goal for all.”