Article

raw versus cooked: eating clean

We have all become a little obsessed with eating ‘clean’ these days. I actually love the term ‘clean food’. Yes, definitely, I want to eat clean food! I’m not a huge fan of ‘dirty’ food! The five second rule doesn’t really sit well with me! That aside, what does ‘clean food’ really mean and is raw food better for us than cooked food?

Raw food menus and diets have attracted a lot of attention, in part due to the belief that cooking reduces the nutritional value of our foods. This has meant more people choosing fresh and seasonal produce and less processed and fast foods, which is great! However, cooking can bring great benefits to our health and wellbeing and in some cases, can increase the healthiness of a meal.

One of the most important roles of cooking is to destroy potentially harmful microorganisms that are present in the food supply, particularly in poultry and ground meats (like hamburgers) which should always be thoroughly cooked. Also, to eliminate chemicals, pesticides and bacteria, the surface of all fruits and vegetables should be carefully washed before eating. There have been several cases in the past few years where eating raw fruits and vegetables has led to food poisoning. In Victoria alone, not long ago we were in a tizz about the dangers of our frozen berry supply and its link to an hepatitis outbreak. Soon after we had a contaminated lettuce scare, and just recently we were advised against eating rock melon which had been linked to 80 cases of salmonella poisoning. This occurs because fruits and vegetables can carry bacteria (E.coli, salmonella and listeria) within the layers of their leaves or on their surface. Fruits and vegetables are often washed after harvesting and this water may be contaminated. The soil may have been contaminated or, further, contamination can occur in the packaging and transportation stage or even by handlers at the marketplace. Who knows, even fellow shoppers sneezing and coughing over foods can pass on nasty germs. Either way, there is a small, but real risk.

Following these safety measures can help prevent Salmonella poisoning:

  • Wash your hands before preparing food and after handling raw meats
  • Cook meat and eggs thoroughly until they reach an internal temperature of 160 F (71 C)
  • Do not eat foods containing raw eggs or milk, such as undercooked French toast
  • Avoid cooking raw meat in the microwave, as it may not reach a high enough internal temperature to kill Salmonella bacteria and may be unevenly cooked
  • Avoid bringing uncooked meat into contact with food that will not be cooked (i.e. salad)
  • Wash hands with soap after handling reptiles or animal feces
  • Always wash your hands after going to the bathroom

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So, providing raw fruits and vegetables are thoroughly washed, they add many nutritional benefits such as vital vitamins and minerals, antioxidants and fibre. All of these things have been linked to reducing the risk of many chronic diseases such as some cancers, heart disease and illnesses associated with obesity. However, cooking some vegetables, fruits and grains can decrease their nutritional value. Vitamin C and folate in particular are two highly volatile micronutrients that are damaged when exposed to heat. Boiling vegetables will cause the greatest loss in these nutrients (up to 80% can be lost) and even greater losses will result if the cooking water is discarded as the vitamin C and folate ‘leaches’ into the surrounding water. The more coloured the cooking water, the more nutrients lost. Steaming for brief periods is far better and using the cooking water to make sauces and soups will help to retain some of the lost benefits.

Typical Maximum Nutrient Losses (as compared to raw food)
Vitamins Cook Cook+Drain
Vitamin A 25% 35%
  Lycopene 25% 35%
  Lutein+Zeaxanthin 25% 35%
Vitamin C 50% 75%
Thiamin 55% 70%
Riboflavin 25% 45%
Niacin 40% 55%
Vitamin B6 50% 65%
Folate 70% 75%
Vitamin B12 45% 50%
Minerals Cook Cook+Drain
Calcium 20% 25%
Iron 35% 40%
Magnesium 25% 40%
Potassium 30% 70%
Sodium 25% 55%
Zinc 25% 25%

Cooking vegetables, fruits and grains can also be beneficial and increase the nutritional value of a food.

Some advantages of cooking are:

  • Makes food tastier
  • Breaks down indigestible parts of food, releasing more nutrients from the food
  • Destroys bacteria and harmful micro organisms
  • Increases availability of phytochemicals eg cooked tomatoes have higher lyceine
  • Adds variety to the diet

Of course, there are many additional social, emotional, psychological and economic benefits to cooking foods in our daily lives.

Overcooking foods can lead to poor nutrition quality as well as soggy, tasteless food. Many people inadvertently overcook their food for fear of undercooking it. In these circumstances it is important to remember that foods can always be cooked for longer if necessary but can’t be ‘less cooked’ once they are overdone. Nutritional quality of meats, proteins and grains is less affected by overcooking however overcooking vegetables can result in a decrease in nutrition quality. Optimal cooking times and techniques for foods will depend on many factors such as the size and thickness of the food pieces and also the ripeness of the foods. Here are some general cooking suggestions:

Steaming vegetables for short periods will minimise the loss of nutrients from vegetables. Generally, greens should be cooked for no more than 1 minute. The vegetables should still have a lovely bright colour when cooked. If your beans turn brown, you’re in for a mushy, tasteless experience. They should also be slightly crisp, but softer on the outside for that initial bite. Microwaving is a good method. “Really?” I hear you say? Well, yes. This is because the ultra-quick cooking time means less nutrient loss. For best results, use microwave-safe cookware rather than plastic containers or plastic wrap.

Chargrilling and barbecuing are such popular methods of cooking, especially in the summer months. The flavours of vegetables like of eggplant and capsicum are beautifully enhanced by grilling. To avoid the health risks of smoke, coat the food in oil before placing on the grill, rather than spraying oil over the food grill. The more fat that drips onto the flame, the more smoke you will produce.

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Roasting is a mess-free cooking choice and a good way to enhance flavours, especially from starchy tubers or coloured root vegetables. Roast or bake vegetables on slightly lower temperatures to give you more room for error as well as ensuring the inside of the vegetable cooks at a similar time to the outside. Also, watch the oil! Using baking paper and spraying your vegies with a little olive oil before roasting and cook until golden and tender, not charred and shriveled.

Stir-frying also is a great option as the fast cooking time involved with stir-frying means more nutrients are retained. As long as you do keep it quick. Simply spray a hot wok or frying pan with oil and add vegies, such as carrot and capsicum. If cooking a variety of vegetables in one dish make sure to think about how long each of the vegetables may take to cook. Cut longer to cook vegetables smaller to decrease their cooking time and shorter to cook vegetables bigger. It may not work to add all vegetables to the cooking pan at once – add longer cooking items before shorter cooking ones. This means everything will be ready at the same time. This technique can take some practice and knowledge of different ingredients.

Either way, raw or cooked, if you are filling your plates with a variety of vegetables, consuming a couple of pieces of fruit and a small amount of meat, you can pretty much say you are eating CLEAN FOOD!

You can visit the Center for Disease Control and Prevention) or Department of Health (http://www.health.gov.au/internet/publications/publishing.nsf/Content/gug-director-toc~gug-foodsafety) to learn more about how to prevent food-borne illnesses.

Other helpful sites:

http://foodauthority.nsw.gov.au/foodsafetyandyou/special-care-foods/fresh-fruit-and-vegetables

http://www.health.gov.au/internet/publications/publishing.nsf/Content/ohp-enhealth-manual-atsi-cnt-l~ohp-enhealth-manual-atsi-cnt-l-ch3~ohp-enhealth-manual-atsi-cnt-l-ch3.8