We all know the importance of getting our 5-9 servings of fruits and vegetables each day in order to reduce our risk of certain chronic diseases such as cancer. But are you really getting the maximum impact from the vegetables you eat or are you cooking away all the vitamins, nutrients, and antioxidants?
Eg;-A recent study conducted in the U.K. showed boiling vegetables that are members of the cruciferous family, including cabbage, broccoli, and Brussels sprouts, significantly reduces their anticancer properties. The active anticancer ingredient, which is destroyed by the boiling process, is called gucosinolate. Glucosinolate is an important compound that converts inside the body to a cancer-fighting chemical called isothiocynate, which helps to remove cancer-causing components from our system. When cruciferous vegetables are boiled, most of this important compound is destroyed along with the cancer protective properties.
Vegetables are a crucial component of a nutrient-rich diet. While eating them raw is an excellent way to get all the vitamins and nutrients they have to offer, some vegetables are impossible to eat raw, and some people cannot tolerate raw vegetables.
Benefits of Cooking
Cooking has also some beneficial effects. It improves the appearance and palatability of foods and confers new flavors. Cooing also destroys harmful food borne microorganisms. Digestibility of several foods, particularly of starch improves on cooking. During cooking starch swells and cell walls burst making it easy for the enzymes in the digestive juices to have access to starch and digest it. Cooking eggs helps in destroying avidin, which is known to bind biotin and make it unavailable. Some legumes contain trypsin inhibitors, particularly Soya bean. Protein digestibility is reduced by trypsin inhibitor. Heating or autoclaving the legumes help destroy the trypsin inhibitor and improve protein quality. Similarly duck eggs also contain a trypsin inhibitor in the white portion. Prolonged boiling or autoclaving can destroy this inhibitor. In general, quality of proteins improves after cooking since their access to enzyme and their digestibility improves.
Common Ways of Losing Nutrition That You Should Avoid
- Wash the vegetables rid them of pesticides, but do not soak them. Water takes away nutrients
- The most effective way of retaining all of the vitamins in a vegetable is the eat a clean fresh vegetable as it is, without cooking or heat.
- Buy the freshest produce possible. Vegetables start losing nutrients the moment they are harvested. Check out the local farmer's market for the freshest selection
- Cook the vegetables soon after buying them. The longer they sit in the refrigerator, the more nutrients lose.
- Cook the vegetables with very little water.Put the water that is left after steaming into a soup or sauce, to take advantage of all of the vitamins and minerals leached out during steaming nutrients they lose.
- Frozen vegetables have just as many nutrients as fresh vegetables do. Often they are frozen shortly after being picked, so they are packed with nutrients.
- Use a lid to avoid steaming away precious vitamins.
- Avoid cutting vegetables up into very small pieces. Wash vegetables before cutting though washing after cutting will lose certain nutrients such as vitamin C,folic acid, thiamine etc
- Use a sharp knife when cutting fresh vegetables; bruising vegetables can deplete them of valuable vitamins
- Cut off only the inedible parts of vegetables. Sometimes the best nutrients are found in the skin (or just below the skin and in the leaves).
For any foods that grow under the ground, a lot of the vitamins and minerals are found just under the skin. For example, potatoes – most of the nutrition is just under the skin. So just by peeling them, we peel past the thin layer under the skin and lose a lot of the main vitamins, minerals and nutrients. On the other hand, in the case of foods that grow above the ground, the nutrition is mainly in the core or centre. Avoid peeling vegetables such as potatoes and beets until after cooking
Put away the peeler. When apples and cucumbers are peeled, their antioxidant content decreases by 33% to 66%.
Good cooking methods retain more vitamins, minerals and other nutrients
The high fiber content, the vitamins and the minerals are the main reasons to eat vegetables. However, cooking them the wrong way may diminish their nutrients. Steaming is the best way
probably the best method for preparing vegetables to preserve their vitamin and anticancer properties is to Steam your vegetables. Steaming vegetables in a steamer or double boiler cooks without bleeding the nutrients. Both metal and bamboo steamers can be used. Steaming allows the vegetable to retain its nutrients because it does not come in contact with the water. If you do not have a steamer, use a double boiler with a slotted pan on top. Leafy vegetables like spinach steam for about four minutes, denser vegetables such as broccoli can steam for up to 15 minute
If you have neither a steamer nor slotted double boiler, you can steam vegetables in the microwave to the same effect. Use as little water as possible and cook on a low power level for a short amount of time. When micro waving, leave the vegetables in larger pieces so as to absorb less water.
Stir-frying considered a healthy cooking method because vegetables are cooked without water, in small amount of oil and only a few minutes on the high heat. Vegetables and meats should be sliced thin in order to heat fast. Because it’s fast, stir-frying sears the outside of what’s being cooked, locking nutrients inside The key to stir frying is cutting the vegetables into small enough pieces so that they cook quickly. The less time in the heat, the less chance of nutrient breakdown
Boiling is the most common cooking method but this method causes the greatest loss of nutrients in vegetables. Many of the vitamins and minerals are leached out into the cooking fluids and can be lost forever if those fluids are thrown away. You can restore most of the vitamins if you will use water, in which your vegetables were boiled, to make sauce, gravy or soup.
If cooked vegetables stored and then re-heated later, most of their vitamins will be destroyed and vitamin C content will be near zero.
A vitamin loss during boiling process also depends on the type of vegetables. The greatest losses occur in leafed vegetables, seed-vegetables lose less of their vitamin content, and root-vegetables the best retain their nutritional content. If you use lots of water and boil for long time, you’re going to lose more nutrients than if you boil quickly and use relatively little water.
B. Baking and Roasting
When dry heat is used during cooking it’s called baking if we do it to the bread and if we do it to the meat it’s called roasting. Baking of the bread and roasting of the meat also leads to destructions of nutrients.
During simple baking of the bread, content of vitamins in flour is decreasing. Studies are showing that around 30% of thiamine content destroyed in bread when it’s baked. When baking powder is added than half of the thiamine content can be destroyed. Remember, toasting of the bread leads to the further loss of vitamins. If you wish to minimize vitamin loss, than chose light toasting for your bread.
Roasting, frying and grilling are the best cooking methods for meats because there is no water where valuable nutrients can leach into. Studies are showing that roasted or grilled meat losing 20% of its vitamins and boiled or stewed meat losing 50% of its vitamin content.
When you will use juices of roasted meat for gravy or something else, that way you will restore most of the lost vitamins. Overcooking of the meat leads to great destructions of vitamins and minerals.
Deep frying method uses hot oil and that is very destructive for nutrients and it also adds calories to the food that is cooked. Especially destructive this method for the vitamin E. Studies have shown that cooking food in fats and oils destroys between 70% and 90% of vitamin E.
Frying causes great distractions of vitamin A in margarine. After 5 minutes of frying margarine losses 40% of vitamin A and 70% lost in 15 minutes