Nutrient loss – a consequence of almost every cooking process that we subject our food to, yet one of the things that our largely nutrient deficient population can least afford. Heat, light and oxygen exposure alter the nutrients that we find in raw food, whilst methods involving water often mean that nutrients are leached/washed out and left behind.
Recently, I see more and more blogs about the “raw” diet. So I wanted to take a quick look at some of the different cooking methods that we typically use today and the impact that they have on the nutrients that we think we are getting from our food. Below is a quick and handy review for our Born2Perform family so that you can get the best nutrient gain from the foods that you are eating.
Heating mostly affects the vitamin and fat content within foods as well as the texture that they present prior to cooking. The “smoke point”, which is associated with impaired flavors, as well as burnt or unpleasant odours and most importantly, a reduced vitamin content. The “smoke point’ is the point at which a food items chemical structure is modified. Some fats are able to tolerate much higher temperatures before reaching their “smoke point”.
In addition to the fat structure being altered, the structure of proteins is also altered with heat. For example, you can clearly see the rearrangement of an eggs structural proteins between its raw and cooked states. However heating also makes certain nutrients more accessible for the body. For example the amount of carotenoids available in carrots is higher when carrots are boiled. Carotenoids have been demonstrated to kill off free radicals and have been associated with enhancing the human immune system.
When low fat diets became the craze, grilling was the method of cooking that was most heavily associated with it. Grilling allows for excess fat content to drip out onto a lower level baking tray whilst baking meat means that as the fat drips out of the meant it sits surrounding the meat and so might still end up on your plate. The funny thing is that science continually advances our understanding of the human body we are increasingly aware that low fat diets are not the bee all and end all. The human body requires fat (all be it healthy fats) to thrive and survive. Furthermore, during the 10-15 year period where low fat diets were most heavily promoted and during which time the food industry saw a drastic rise in the number of fat free products available on our shelves, we also saw a devastating increase in the worldwide figures for obesity and diabetes.
Why? Because low fat and fat free products saw an increase in the number of sweeteners, additives and stabilizers to give the products flavor and increase population purchase rates of these new “health focused” products that were in fact detrimental to health.
Back to grilling – the benefits of grilling are in the fact that we can reduce the amount of animal fat consumed, which could contribute to lower levels of bad cholesterol and thereby have a correlational effect on reducing risk of coronary heart disease. Furthermore the reduced time needed for cooking foods under the grill means that the loss of nutrients and minerals can again be reduced. However, exposure to higher temperatures especially at a surface level can create a greater degree in cell structure damage at a surface level meaning that the nutritional content is greater in the middle of the food but less at the surface. Furthermore, because of the higher temperatures at surface level food that is grilled can take on that singed flavor associated with carcinogenic compounds (explained in the BBQ section of this blog).
Baking is one of the most commonly used methods for cooking food. Destruction of one or more nutrients is inevitable during this process. The outer “crust” portion of food always sees the greatest demise in nutritional value as it is exposed to higher temperatures for longer periods of time. The interior part of the food rarely reaches the temperature within the oven and so the nutritional content remains more in tact.
Other factors that effect loss of nutrients during baking are time of baking required, food PH levels, moisture (water levels in food), light, oxygen, metals and possibly certain additives within the food.
However, yet again whilst baking might degrade the nutritional content of some vitamins and minerals, it turn makes others more accessible and useable by the body.
We all love a BBQ – the taste, the smells, the social atmosphere and if unless you live in a particularly unfortunate climate, the great weather. However, despite the great flavors and the very distinctive taste that occurs during the BBQ cooking process, it also presents some health risks. The most notable is the carcinogenic effect of cooking on a BBQ. 2 types of carcinogenic compounds are produced when food hits the BBQ grill, HCAs (heterocyclic amines) and PAHs (polycyclic aromatic hydrocarbons). These tend to be produced when the fat of the meat comes in to direct contact with the smoke or flame of the grill, which means that should you employ certain cooking methods then you can reduce the carcinogenic effects of one our favorite cooking methods. For example, use a leaner cut of meat with reduced fat, grill at lover temperatures and avoid flare-ups and overcooking, and finally try marinating the meat. It has been suggested that marinating the meat before grilling can provide a protective barrier against the reactions that induce HCAs.
WHAT’S THE ANSWER?
So is a raw diet the way to go? Not necessarily, cooking foods has its advantages. For example, cooking can reduce the number of possible malignant microbes, increase the digestibility of food and increase the availability of some phytonutrients, which are found in whole plant foods and may in part account for the benefits associated with cancer prevention. For example, both lycopene and carotenoids are easier to absorb after being exposed to heat.
There is no single right or wrong answer to cooking. The best answer is to utilize a variety of cooking methods throughout your daily and weekly intake of food. Alternating between steaming, grilling, baking, boiling, microwaving and eating raw fruits and vegetables to get the most out of your nutrients as possible