|MadSci Network: Medicine|
Aloha, Sharon, You ask a very interesting question. But, first I need to rework part of it for you. Fats do not dramatically increase the risk for cancer. It just isn't as simple as that, in spite of the public health messages that seem to get spread all over. As an academic nutritionist who teaches a lot of introductory nutrition students each semester, I am very uncomfortable with some of that information, too,...mainly because it is too simplistic and/or blatantly not correct. Some fat-like compounds in our food (some of the saturated fatty acids) seem to increase the risk for certain cancers; some fat-like compounds (such as conjugated linoleic acid, which is a bunch of a particular fatty acid hooked together) seem actually to decrease the risk for certain cancers; some fat-like compounds (some of the other saturated and unsaturated fatty acids) seem to have little/no effect on the development of cancer, especially in non-human animals. I don't think we have enough information in humans to make really definitive statements about cancer(s) and "fat" in the diet, although people who should know better do that all the time. What we do know is that excess energy (kilocalories) in the diet may increase the risk for cancer(s). But, too few kilocalories can also increase the risk for chronic disease, even cancer(s). Note that I keep writing "cancer(s)"...that is because there are about 100 different (but similar) kinds of diseases that we group together and call cancer. These diseases are similar because they all include cell growth that has gone 'nuts'...cells multiplying when they shouldn't, eventually to become malignant tumors. Anyway, too much fat in the diet can provide too many kilocalories...and people who get very heavy may have an increased risk for certain cancers, such as breast, testicular, and ovarian cancers, if they are genetically prone to them. Now to your question about vitamin E and fat. Vitamin E is a fat- soluble vitamin (micronutrient), and your body can't absorb it well if you don't have enough fat in the diet. Also, fat IS a nutrient. Your body just doesn't function correctly without enough...somewhere between 50-100 grams/day for most adults. Vitamin E IS also an antioxidant, just like you mentioned. So are other nutrients (e.g., minerals, like selenium, and vitamins, like vitamin C or the provitamin beta-carotene). These substances help our bodies fight off the damage that very reactive chemical substances (free radicals) can cause at the level of the cell. So, you see, nutrition isn't quite as simple as good/bad. Too much of anything, even vitamin E, is not good; too little of anything, even fat, is not good. The amount really makes the difference. The take-home message, I think, is that we need all the nutrients in the 'right' amounts...and almost all of those can be gotten from our food (there are exceptions, like getting enough iron and folate during pregnancy...supplements are advissed). The best practical advice that I can give, as a nutritionist is to eat a wide variety of foods, in modest amounts...and enjoy your food!
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