Everyone is aware of the common risks that come with working in a kitchen. Something could catch fire, a glass could break, or an appliance could malfunction, to name a few. However, even when everything is working properly there are still major health risks with the act of cooking itself. All over the world, people are continually cooking in order to provide a hot meal for their loved ones. Unfortunately, they do it unaware of the tremendous genetic risks to which they are exposing themselves.
The main risk factor related to cooking is the cooking oil. In a study by van Houdt et al. to determine possible genotoxicity of particles found inside the home, six samples were taken from various sources around the house, including the kitchen. The sample particles were tested in a Salmonella/microsome assay, which is a test to reveal abnormal change in the metabolic activity of the samples. Although tobacco smoke was the particle that caused the most genetic damage, other particles were also found to cause mutations. The kitchen particles caused many genetic mutations probably as a result of the vaporized cooking products.
Qu et al. found that particularly harmful cooking products include some cooking oils, such as rapeseed (canola) and soybean cooking oils. This was suggested by public health studies in Chinese women that showed that tobacco smoke was not the only risk factor for development of lung cancer. A case-control study showed that cooking fumes might also be a cause of lung cancer. Several different types of genetic tests were performed, which all came to the same conclusion that cooking oil fumes are in fact genetically harmful. However, it was only the fumes from rapeseed and soybean oil while the fumes from lard and peanut oil were not hazardous. Another study conducted by Yang et al. showed strong support for this hypothesis by showing that cooking oil fumes from frying fish can be carcinogenic. Interestingly, a third study by Wu and Yen showed that peanut oil fumes could cause oxidative stress in lung cells that can lead to cancer. This is contrary to the findings of Qu et al., which demonstrated that peanut oil did not cause genetic mutations. As both studies used different tests and assays to determine genotoxcicity, this highlights the difficulty in determining which tests are more clinically relevant for predicting cancer risk.
An alternative mechanism for increased cancer risk due to cooking oils was shown in a study done by Chang et al., which analyzed the effects of dienaldehydes, such as trans, trans-2, 4-decadienal. Dienaldehydes are abundant in heated oils and have been associated with lung cancer development in women due to their exposure to oil fumes when cooking. The result of adding dienaldehydes to lung cells was an increase in oxidative stress. Adding N-acetylcysteine, which is an antioxidant, prevented the cancerous cell growth and release of harmful proteins. This was additional confirmation that cooking oils induce oxidative stress in lung tissue.
A study detailing the hazards of cooking oil fumes has been conducted on restaurant workers. Cooking oil fumes are a complex mixture that includes polycyclic amines, fat aerosols, and particulate matters, which are all proven to be carcinogenic and mutagenic substances. This study showed that levels of these carcinogens are increased in urinary samples of restaurant workers compared to matched controls.
Aside from cooking oil fumes, there is risk associated with the methods used to generate heat for cooking. Women in third world countries who use biomass fuels such as wood, dung or crop residues, for cooking have an increased risk of stillbirths according to a study done by Mishra et al. According to a study about the risks of cooking smoke exposure to pregnant women, women cooking with biomass fuels are twice as likely to experience a stillbirth compared to those who use cleaner fuels. This is due to their increased exposure to carbon monoxide and particulates from the biomass smoke.
Pregnant women should also be aware that microwave ovens might present a risk factor for spontaneous abortions during the first term of pregnancy. In one study by Liu et al., 200 women who had spontaneous abortions were compared to matched controls. Many factors were analyzed and microwave oven use, mobile phone use, and emotional stress showed statistically significant association with spontaneous abortion. This does not imply a cause and effect but does raise the possibility of harm that should be studied further.
Hyperthermia is a known risk factor for neural tube defects in a variety of animal species. A study conducted by Suarez et al. looked at potential causes of hyperthermia and the risk of neural tube defects in Mexican-American women using a case-control study. They found an association with high fever, saunas, hot tub and electric blanket use and neural tube defects. Working in hot kitchens was of borderline statistical significance.
Besides the environmental risks posed by the hot kitchen, with biomass fuels, microwave energy and cooking oil fumes, the ingestion of certain cooked foods could result in genetic mutations. Several lines of evidence indicate that cooking conditions can contribute to human cancer risks through the ingestion of mutated compounds from heat-processed foods. Such compounds cause different types of DNA damage as mentioned in the case of cooking oil fumes. Examples include, genetic variations in a DNA sequence that occur when nucleotides in a gene are altered and the condition of having an abnormal number of chromosomes or having chromosomes with missing or extra pieces. In a study by Potential human carcinogens, present in the high-temperature cooking of meats, were investigated in human liver cells by Nauwelaers et al. Though rat liver cell tests for food carcinogens resulted in low levels of cancer, human liver cells results were 100 fold higher. This suggests significant potential genotoxicity.
Based on the various studies previously mentioned, it is clear that the act of cooking in the kitchen should not be treated lightly. People, especially women, must be careful about their choice of cooking oil, the temperature at which they cook their food, and their use of the microwave ovens when preparing even a simple meal. Although many of the studies require confirmation that they apply to the American kitchens, there is enough risk documented that every person who spends time in the kitchen should be concerned. The solution for a hot meal: eat out!
Bibliography
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