Thursday, May 19, 2011

To Cook or Not to Cook?: "Raw?" is the Question

We all know we have got to eat our fruits and veggies. Sure, you can get plenty of fibre, perhaps more than enough for the day, from whole grains and fibre supplements, but fresh fruits and veggies are packed with vitamins, minerals and antioxidants which are potent disease fighters. In today's world - you need those guys on your team.

When it comes to fruit, we don't typically cook it (unless we're making some kind of dessert) but veggies are consumed in a variety of ways. And yet the decision to cook veggies is being questioned more and more - so what is actually best? Raw or cooked? Unfortunately, the answer is less than simple: "it depends". Darn.

What does it depend on? Firstly, from a food science perspective, we have to consider what the fibres are like in the foods we're eating. The nutrients, enzymes and juices that we seek out of fruits and veggies are locked within their cellular structures like little ziplock bags. If our bodies are able to break them down and open those 'bags' up, we can effectively absorb those nutrients and utilized those enzymes without having to cook the food in question. However, if the fibres and cell walls are tough and rigid, meaning we can't break them down without a little help, they will pass right through our bodies or we will only absorb a small fraction of all that goodness. So what can we do?

Cooking helps to break down the cellular structure of fruits and veggies. That's why produce shrinks and wilts when it is exposed to heat - those little 'ziplock bags' burst and break down, releasing those juices and nutrients. Cooking also improves food safety by destroying potentially harmful pathogens that might be lurking on the surface of your food. Who knows what happened anywhere along the way from the farm to your store? But just as raw is one extreme, there is another extreme when it comes to cooking - overcooking! It's great for jams and fruit fillings for pies, not so great for veggies at dinner.

Since we know that the colour of fruits and veggies is due to their antioxidant pigments, brighter or more intense is better. Dull is what needs to be avoided. Overcooking fruits or vegetables causes their nutrients to leach out into their cooking environment in addition to destroying active enzymes, when the goal is for them to be released inside of your body. The best way to cook veggies is to gently steam or saute them or just blanch them in boiling water until their colour intensifies. They should be 'al dente' just like properly cooked pasta; little softer on the outside with a tougher 'bite' on the inside.

Consuming too many raw vegetables may lead to the accumulation of homocysteine in the body, a compound that builds up when a person lacks B12, B6 and folic acid which are present in whole grains and dark leafy greens. Unfortunately, if those nutrients can't be absorbed in high enough quantities, we end up with nutritional deficiencies. Individuals who eat mostly raw foods tend to be deficient in vitamin B12 in addition to having lower bone densities, meaning they aren't absorbing enough calcium. As with all things, we can't forget that balance is key.

Some produce that is healthier when cooked includes: spinach, tomatoes, kale, butternut squash, pumpkin, red peppers, carrots and sweet potatoes. Cartenoids, a group of antioxidant phytochemicals found in these foods, responsible for yellow and orange colours, are easier to absorb when foods are cooked. The same is true for lycopene, another antioxidant pigment found in tomatoes.

On the flip side, sulphurophanes found in broccoli, in addition to folate and vitamin C are destroyed by heat. However, with gentle cooking, you're more likely to break the cell structures down and actually absorb more nutrients overall even though some might be destroyed. It's a bit of a trade-off.

The rest boils down to personal preference and health status - if you're getting all you need out of your diet and you're in good health, congratulations and all the power to you. For me, I don't like my broccoli raw but I like raw carrots. Am I going to be less healthy than a raw foodie? Probably not.

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