Vegetables are the foundation of good eating. No healthy meal can be complete without vegetables. Not only do vegetables fortify our health, they also add visual appeal, flavour and crunch to the meal.
Loaded with antioxidants, phyto-chemicals, vitamins, minerals and fibre, this low calorie high nutrient group is one of the most valuable elements in our current lifestyles. You can eat as much of them as you want without worrying much about calories. They can almost be treated as free foods with the exception of potatoes, sweet potatoes, and other starches which need to be watched.
Whether vegetables are beneficial raw or cooked has been the subject of debate and much interest. Evidence suggests that cooking vegetables has some harmful effects, as it destroys nutrients and enzymes. However, cooking helps as well as it kills potentially harmful organisms and makes it safe. It also actually improves the bio-availability of certain nutrients and improves digestibility.
The truth is that vegetables are beneficial in both raw and cooked state.
Cooking vegetables decreases water-soluble and heat-sensitive nutrients, such as Vitamin C, Vitamin B and folic acid. In fact, it was reported that consumption of salad and raw vegetable has been found to be positively associated with higher levels of these nutrients among adults in the US population. It also showed that higher levels of these nutrients among salad consumers suggested better absorption.
Some enzymes too are destroyed by heat. Garlic and cruciferous vegetables, which include 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 the garlic and can be completely inactivated 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; it can also accelerate ageing.
Most vegetables when taken raw leave an alkaline ash which helps in better absorption of several nutrients. In fact, 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. Cooking vegetables increases bio-availability of Vitamin A. Studies of colorectal cancer showed both raw and cooked vegetables to be inversely associated with risk.
Vegetables are a must for good health. Ensure you have a good mix of both raw and cooked vegetables to maximise their benefits, but by no means overcook them. Remember, however, that salads, vegetable juices and raw vegetables can be a source of infection. Consume them only when highest levels of hygiene are being maintained.