Cooking and Carcinogens

<h3 >Cooking and carcinogens</h3>

In a human epidemiological analysis by <a href="http://en.wikipedia.org/wiki/Richard_Doll" title="Richard Doll" >Richard Doll</a>and <a href="http://en.wikipedia.org/wiki/Richard_Peto" title="Richard Peto" >Richard Peto</a> in 1981, diet was estimated to cause perhaps around 35% of cancers.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-14" >[15]</a> Some of these cancers may be caused by carcinogens in food generated during cooking process, although it is often difficult to identify the specific components in diet that serve to increase cancer risk. Many food, such as beef steak and broccoli, contain low concentrations of both <a href="http://en.wikipedia.org/wiki/Carcinogens" title="Carcinogens" class="mw-redirect" >carcinogens</a> and <a href="http://en.wikipedia.org/wiki/Anticarcinogen" title="Anticarcinogen" >anticarcinogens</a>.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-carcinogens_and_anticarcinogens-15" >[16]</a>

Several studies published since 1990 indicate that cooking meat at high temperature creates <a href="http://en.wikipedia.org/wiki/Heterocyclic_amine" title="Heterocyclic amine" >heterocyclic amines</a> (HCAs), which are thought to increase cancer risk in humans. Researchers at the<a href="http://en.wikipedia.org/wiki/National_Cancer_Institute" title="National Cancer Institute" >National Cancer Institute</a> found that human subjects who ate beef rare or medium-rare had less than one third the risk of stomach cancer than those who ate beef medium-well or well-done.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-amines-16" >[17]</a>

While eating meat raw may be the only way to avoid HCAs fully, the National Cancer Institute states that cooking meat below 212 <a href="http://en.wikipedia.org/wiki/Fahrenheit" title="Fahrenheit" >°F</a> (100 <a href="http://en.wikipedia.org/wiki/Celsius" title="Celsius" >°C</a>) creates "negligible amounts" of HCAs. Also, <a href="http://en.wikipedia.org/wiki/Microwaving" title="Microwaving" class="mw-redirect" >microwaving</a> meat before cooking may reduce HCAs by 90%.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-amines-16" >[17]</a>

<a href="http://en.wikipedia.org/wiki/Nitrosamine" title="Nitrosamine" >Nitrosamines</a>, present in processed and cooked foods, have also been noted as being carcinogenic, being linked to colon cancer.

Research has shown that grilling, barbecuing and smoking meat and fish increases levels of carcinogenic <a href="http://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon" title="Polycyclic aromatic hydrocarbon" >Polycyclic aromatic hydrocarbons</a> (PAH).

In Europe, grilled meat and smoked fish generally only contribute a small proportion of dietary PAH intake since they are a minor component of diet - most intake comes from cereals, oils and fats.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-PAH_in_diet-17" >[18]</a> However, in the US, grilled/barbecued meat is the second highest contributor of the mean daily intake of <a href="http://en.wikipedia.org/wiki/Benzo(a)pyrene" title="Benzo(a)pyrene" >benzo[a]pyrene</a> at 21% after ‘bread, cereal and grain’ at 29%.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-PAH_in_diet-17" >[18]</a>

Baking, grilling or broiling food, especially starchy foods, until a toasted crust is formed generates significant concentrations of <a href="http://en.wikipedia.org/wiki/Acrylamide" title="Acrylamide" >acrylamide</a>, a possible <a href="http://en.wikipedia.org/wiki/Carcinogen" title="Carcinogen" >carcinogen</a>.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-18" >[19]</a>

<h3 >Other health issues</h3>

Cooking dairy products may reduce a protective effect against colon cancer. Researchers at the<a href="http://en.wikipedia.org/wiki/University_of_Toronto" title="University of Toronto" >University of Toronto</a> suggest that ingesting uncooked or unpasteurized <a href="http://en.wikipedia.org/wiki/Dairy_product" title="Dairy product" >dairy products</a> (see also <a href="http://en.wikipedia.org/wiki/Raw_milk" title="Raw milk" >Raw milk</a>) may reduce the risk of <a href="http://en.wikipedia.org/wiki/Colorectal_cancer" title="Colorectal cancer" >colorectal cancer</a>.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-19" >[20]</a> Mice and rats fed uncooked sucrose, casein, and beef tallow had one-third to one-fifth the incidence of <a href="http://en.wikipedia.org/wiki/Adenoma" title="Adenoma" >microadenomas</a> as the mice and rats fed the same ingredients cooked.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-20" >[21]</a><a href="http://en.wikipedia.org/wiki/Cooking#cite_note-21" >[22]</a> This claim, however, is contentious. According to the <a href="http://en.wikipedia.org/wiki/Food_and_Drug_Administration_(United_States)" title="Food and Drug Administration (United States)" class="mw-redirect" >Food and Drug Administration</a> of the United States, health benefits claimed by raw milk advocates do not exist. "The small quantities of antibodies in milk are not absorbed in the human intestinal tract," says Barbara Ingham, Ph.D., associate professor and extension food scientist at the University of Wisconsin-Madison. "There is no scientific evidence that raw milk contains an anti-arthritis factor or that it enhances resistance to other diseases."<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-22" >[23]</a>

Heating sugars with proteins or fats can produce <a href="http://en.wikipedia.org/wiki/Advanced_glycation_end_product" title="Advanced glycation end product" class="mw-redirect" >Advanced glycation end products</a> ("glycotoxins").<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-kosch-23" >[24]</a>These have been linked to ageing and health conditions such as diabetes.

Deep fried food in restaurants may contain high level of <a href="http://en.wikipedia.org/wiki/Trans_fat" title="Trans fat" >trans fat</a> which is known to increase level of <a href="http://en.wikipedia.org/wiki/Low-density_lipoprotein" title="Low-density lipoprotein" >low-density lipoprotein</a> that may increase risk of <a href="http://en.wikipedia.org/wiki/Coronary_disease" title="Coronary disease" >heart diseases</a> and other conditions. However, many fast food chains have now switched to trans-fat-free alternatives for deep-frying.<a href="http://en.wikipedia.org/wiki/Cooking#cite_note-McDs-24" >[25]</a>