Broccoli
I’ve written in the past about the the anti-cancer properties of cruciferous vegetables, and indeed broccoli is a great source of sulforaphane, a component in which laboratory studies have found it has impressive anti-cancer capabilities. The enzyme myrosinase, which is found in broccoli, is essential to the formation of sulforaphane. If you destroy this enzyme while over-cooking brocolli, you also damage the anti-cancer properties of this vegetable. A research presented in November 2013 at the American Institute for Cancer Research (AICR) compared between regular cooking, microwave cooking and steaming of broccoli and found that steaming the vegetable for up to five minutes is the best way to preserve the enzyme myrosinase. Cooking and heating in the microwave for a minute or less destroyed most of the enzymes. A study published two years earlier in the journal “Nutrition and Cancer” found that eating broccoli sprouts that contain large amounts of the enzyme myrosinase with broccoli increased the formation of sulforaphane.
Tomatoes
Tomatoes contain a powerful antioxidant called lycopene which is associated with reducing the risk of various types of cancer. According to the American Institute for Cancer Research, it is recommended to cook tomatoes for a few minutes, as such cooking releases a form of lycopene that is better absorbed than lycopene found in tomatoes that haven’t been cooked. Adding a little bit of olive oil to cooked tomatoes will further increase the amount of lycopene absorbed in the body.
Garlic
If you crush or chop garlic and then wait 10-15 minutes before exposing it to heat, a phytochemical called allicin is formed which helps to fight many diseases. Allicin is created in a chemical reaction between a component called alliin and the enzyme alliinase. When the garlic is whole, the alliin and the alliinase are separated, but when chopping or mincing the garlic it makes them mix together and create allicin. So before exposing the chopped garlic to heat, it’s best to wait because heat destroys the enzyme alliinase, so let the enzyme do its job for a while before cooking the garlic.
Potatoes
Potatoes are one of the foods that create a chemical called acrylamide in certain cooking methods. Studies have found that high levels of acrylamide may increase the risk of cancer in animals, and many experts believe that it is likely that this is also the case in humans. In general, the chances of acrylamide formation increase when the food is prepared for longer periods in high temperatures, such as frying, grilling or baking. Recommendations published by the Food and Drug Administration (FDA) in November 2013, don’t recommend to store potatoes in the refrigerator because this may increase the formation of acrylamide while baking or frying. It is recommended to store potatoes in a cool dark place such as a cupboard or pantry. In addition, it is recommended to soak the potato pieces in water for 15-30 minutes before frying or baking them to reduce the amount of chemicals that will be created in the process.
According to the FDA, when comparing frying, grilling and baking potatoes, frying causes the largest formation of acrylamide. However cooking in water and microwave preparation of whole potatoes in their skins don’t form acrylamide.
Note – if you choose to fry potatoes, for example chips, fry them until they are golden but not brown, as brown areas contain more acrylamide.
Bread
As with potatoes, over-heating bread forms acrylamide. Therefore the FDA recommends to prepare the toast until it is a light brown color and not dark brown. If there are very dark areas, avoid eating them.
Meat
Studies show that there is a link between the extent of meat preparation to the risk associated with various types of cancer. Heating meat at high temperatures causes the formation of components that can harm our DNA and increase the risk of cancer. The best way to avoid this is to prepare the meat at a lower temperature. Prefer cooking and baking meat over frying and grilling, especially grilling over charcoal. If you do decide to grill the meat over the charcoal, it is recommended to grill over coals that had been turned gray and not over the flames and remove burnt parts to reduce the damage. To help prevent the formation of cancer-causing components, it is advisable to turn the meat often and keep fanning it. According to the American Institute for Cancer Research, marinating meat with herbs and spices before grilling it may reduce the formation of carcinogens.
Herbs
Herbs not only add flavor and color to food but they also have powerful medicinal properties. New studies raise the possibility that herbs may also play a role in cancer prevention. For example, experts in the American Institute for Cancer Research say that rosemary contains a substance known as carnosol which may inhibit the growth of cancerous tumors.
Fruits and vegetables
Eat fruits and vegetables with their skins. The skin is loaded with anti-cancer phytochemicals. For example, if you eat an apple with its skin, you receive 75 % more quercetin, which is an anti- cancer component, in comparison to a peeled apple.
Cooking vegetables for a long time causes them to lose water-soluble vitamins, such as vitamin C and folic acid and some phytochemicals. To maximize the anti-cancer potential of vegetables, the American Institute for Cancer Research recommends that you steam them, bake them in the oven or stir fry them. If you still want to cook the vegetables, add enough water just to cover the bottom of the pot and cook just until the vegetables are tender.
It is also recommended to add to vegetables a little bit of healthy fat – like olive oil, avocado, tahini and nuts – because fat helps absorb healthy nutrients like beta-carotene and fat soluble vitamins such as vitamin A, E and K.
