Kamis, 15 Desember 2016

como prevenir cancer de colon

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welcome back. as we've seen plant based diets can have many health benefits. however, when one omits all or most animal foods from their diet, there's potential nutrition issues, and certain nutrients that can be lacking or even absent from your diet. vegan diets that omit all animal foods, can be nutritionally sound. but it does require awareness of potential issues, and planning. in this segment, we'll talk about nutrients and dietary components of concern. and as we talk about them, i'll also offer some strategies to help boost intake of these nutrients, and avoid

possible inadequacies of these. i've given you a link here to position paper. the academy of nutrition and dietetics which was formerly known as the american dietetic association, puts out position statements or position papers, they call them, on a variety of nutrition related topics. these papers are kind of the consensus of what we know to date. and also kind of gives the american dietetic or the academy of nutrition dietetics stands on certain issues, on certain nutritional concepts, and vegetarian diets is one of those. so, if you go to this link, not only will you go to the link for this particular

position paper, but you'll see a list of others there, that you know, can potentially give you some good information. some good background and some good suggestions, in terms of how that all fits into a healthy diet. now the position of you, academy and nutrition and dietetics, on vegetarian diets is that they can be healthful, they can be adequate, but they do potentially require careful planning. particularly as you move down towards the spectrum towards a vegan type lifestyle. vegetarian diets can be appropriate really for any age individual at any life stage. but, as i noted, dependent on how, quote,

strict the diet might be, there may be some potential nutritional concerns. so we're going to look at a few of those and kind of walk through those. the potential concerns tend to be surrounding somewhat protein. however, as we'll see in a minute, that's not always really a concern particularly if people are eating a wide variety of food, and getting adequate calorie intake. iron, zinc, calcium, vitamin d, riboflavin, vitamin b12, omega-3 fatty acids, and iodine. so, we'll look at each one of these individually, and just talk about why potentially, the issue may exist. what some of the strategies are, and some

of the potential concern for that one. i've also given you a link [sound] to the dietary reference intakes. these are tables that will provide you what's recommended, in terms of, a host of all the nutrients, and dietary constituents. that what we know to date in terms of what people need, in terms of age, gender, life stage. and rather than going into the specific numbers for each of these vitamins, minerals, dietary constituents, i've given you a link here where if you're interested you can go and see the specific numbers so, so to speak. these come out from the institute of medicine, they've been released over the

last decade or so. and they not only are intended to prevent deficiency, but also to promote our health and prevent disease. so the levels are set at a level that helps you know, keep us healthy and potentially prevent disease states. so these can be a great resource although sometimes it's hard to know exactly how to put these numbers into effect. when we talk about protein, which was the first nutrient quote of concern on our list, the main thing for this slide here with the different nutrient needs, is to say our actual protein needs, are not as high as most people think. this shows the amount that we need per kilogram of body weight.

well, a kilogram is equivalent to about 2.2 pounds. so, almost you can cut these numbers and half, if you thinking of it in terms of pounds. so, you need less than half a gram for most adults for our protein needs. so, if somebody weighs a 150 pounds, they really need less than 75 grams a day in total protein. and most americans eat well over 100 grams. we eat much more in general, than what our body actually needs to meet its protein requirements. now that's a diet, this quote a western diet, that would include animal foods. so sometimes when you take animal foods

out, which is a primary source of our protein, about 70% in the typical diet. there is the risk of cutting back too far on protein rich foods. so, you know, in a, the us, males consume almost twice the amount of protein they need a day and consu-, and women consume about 20 grams more than they need a day. and this is again just the typical diet. and as i mentioned, about 70% comes from meats, milk, and other animal products. so this sets the stage for potentially when you switch to a plant based diet, that protein intake could fall. when you talk about protein, and we're not going to get a whole lot into all the physiology and aspects of protein. but for a protein to be able to be

utilized by your body, for you be able to support tissue growth, maintenance, repair, you have to have all the essential amino acids present. there are nine essential amino acids. the other amino acids, the quote non essential, are ones that can be produced by the body. produced by other amino acids so you don't necessary have to have a dietary source. but we do have to have a dietary source of these essential amino acids. when you look at foods, certain foods are considered complete proteins, and that means, they contain all the essential amino acids. animal foods are quote, naturally a

source of all the amino, essential amino acids. they are complete proteins. whether it be meat, poultry, fish, dairy foods, eggs, all of those are examples of complete protein. now there are plant foods, that are also complete proteins. soy products, tofu, edamame, soy milk would all provide all the essential amino acids. quinoa, which is a, a grain. that's a high quality protein, and provides all nine essential amino acids. and then there's even a blue green algae that provides all the essential amino acids. and when we hear from our vegan student a

little later, she'll tell you about how she uses this, and some of the other products in her diet. however, when you're looking at complete proteins, you can also take plant foods that have complementary amino acids, combine them, and get a complete protein. for example when you combine beans with a grain, it forms a complete protein with all spectrum of the essential amino acids. so every plant food has its own unique profile of amino acids. and you can meet your protein needs, just by eating a variety of plant foods and combining some of these complementary plant foods, that will yield complete proteins.

so, you can get a sufficient amount. you don't even necessarily have to eat them at the same time, but sort of within the context of a day. that when you combine these foods, you will have the spectrum of amino acids you need to build tissues, to repair tissues, to maintain tissues and essentially meet the needs of protein in your body. this just shows some examples of complimentary proteins hummus and pita, beans and rice so you can just, you can see corn and beans. that there's different aspects of foods that you can just put together, and make complementary proteins. and this is really a mainstay of vegan diets.

diets that, particularly ones that exclude all animal foods, is to just include when you see succotash which is a combination of lima beans and corn, that these type foods combined. and it's interesting too, if you look at populations around the world, many of which that either don't have much meat, use it as a condiment, or even avoid meat completely. that you see inherent in many of their cultural dishes, some of these combinations that come together to make complete proteins. another nutrient that can be a potential concern in a vegetarian or vegan diet is iron. the most bio-available form of iron is

found in meat and in animal foods. we do can get iron through plant foods. it's a non heme form that is not as bio-available, which means your body can't utilize it as effectively. thus, when you look at dietary reference intakes for the needs of vegetarians, they tend to be remarkably higher for iron, about 80% higher. because they're taking in their iron from this non-heme source, that is not as bio-available, so therefore, you need more. so when, like a young female, for example, that excludes all animals foods and including in that, of course, red meat, which is one of the most bio-available forms of iron.

unless she takes care, to include say foods fortified with iron, or eat foods that are inherently higher in iron content, she runs the risk of not having sufficient intake of iron. and consequentially, potentially getting anemia, iron deficiency anemia. now you do find iron in your beans and your legumes fortified grains, cereals are a excellent source of iron, so including those, when you combine iron foods with a vitamin c source. it enhances how much iron is absorbed. so you know, iron is important consideration in some cases, vegetarians and vegans may need an iron supplement in addition to their diet. but just again, it all kind of evens out,

if you're eating a wide spectrum of foods including some fortified foods that provide some of these nutrients. zinc is another nutrient that is predominantly found in animal foods, meats, fish, poultry. you do have some zinc in whole grains as well, which tends to be a big portion of many plant food diets. however again it's not as bio-available as the animal sources of zinc. zinc has many functions in the body. it plays a role in over 200 enzymes in terms of their function. it has a role in growth, hearing, as do all the essential nutrients. so you want to make sure the you have adequate zinc intake.

and you can see when you exclude all animal foods, the potential for not getting enough of these nutrients, is certainly there. now zinc, however, when you look at zinc of vegetarians, it tends to be similar but again, there's that risk of deficiency or marginal deficiency. so you do want to continue use foods, that provide a good source of zinc and be aware of those type things. calcium's another one that often comes to mind, particularly for vegetarians that are excluding all dairy and milk products. your lacto-ovo vegetarians, rarely have any issue with too low of calcium intakes, but vegans can fall below.

what's interesting though, is that when you don't overdo on protein, particularly animal protein, you don't tend to need quite as much calcium. so there's a ratio there in terms of need. and so population groups around the world, that don't eat a lot of animal protein, and actually sometimes have a lower overall intake of protein, and you also have a lower intake of calcium, you don't see some of the issues related to low calcium intake. and that may be because, your calcium needs may change with lower protein intake, and less animal protein. calcium needs can be met, through using calcium fortified products.

you see calcium fortified orange juice, you see calcium fortified foods, many of your soy milks, your alternative milks, in the vegetarian type market place, are fortified with calcium, often time equivalent to the level that you would find in regular cows milk, so you can get it through there. also leafy grains tend to be a great source of calcium as does broccoli. again the bio-availability of calcium from plant foods, does not tend to be as high as it is, say in dairy foods. when you look at different sources, i've made a list here of some of the ways you can find calcium, certainly dairy foods for lacto-ovo vegetarians. but for individuals that exclude dairy

foods, there are some plant base sources. and that you'd also need vitamin d, which we'll talk about in a moment, along with your calcium, in order for the calcium to be utilized and absorbed by the body. vitamin d is another nutrient that sometimes, there's some concern in terms of vegetarian diets. particularly stricter vegan type diets, that may be low in vitamin d. vitamin d we think of as the sunshine vitamin, because you can synthesize it when you're exposed to ultraviolet light. and it's recommended that we do get a certain amount of sunlight per day, for our vitamin d status. certainly not to the point where we run any risk of, of skin cancer, but vitamin

ds essential for calcium utilization, for bone growth it plays other roles in the body. and deficiency disease of vitamin d is certainly not unheard of. we see rickets in children, which is low calcium levels demineralization of the bone, and as individuals age you see bone loss, potential osteoporosis. you get calcium, i mean vitamin d, excuse me, through fortified milk. the us fortified all milk with vitamin d, 40, 50 years ago to help curb the prevalence of rickets, which it did a great job of it doing so. you get it from cod liver oil, butter, cream, egg yolks, fish. which all are animal foods.

so you know, you do have to look for fortified products, that have vitamin d. adequate sunlight, look for soy products that have been fortified, and potentially too a supplement of vitamin d might be necessary. now with low vitamin d status it can affect bone health so you do need to look for other sources, and definitely supplementation if your exposure to sunlight is limited. and if you're not using vitamin d fortified type foods. now riboflavin is a b vitamin, vitamin b2 specifically. it plays an important role in energy metabolism, vision, skin health. our primary source of ribo, riboflavin in

the american diet is through milk. the next source would be through meats, you do find it in certain green vegetables, and in whole grain as well. but by far in the u.s., the majority of riboflavin in our diet comes through milk. so when individuals give up diary foods, stop consuming dairy foods and other animal foods, they run the risk of not getting sufficient riboflavin. but again, you see many products fortified with, with b vitamins. and if you're eating a varied diet that does include whole grains and green vegetables, it's unlikely that you will develop any kind of riboflavin issues. but again it's one just to be aware of,

particularly because of the way we typically get it, through meat and milk. this is a study that i've given a reference for as well. and some studies have shown, you know, that the benefits of different spectrums of vegetarian diets may vary. some studies certainly show benefits of vegan, eliminating all animal foods in terms of its impact on cancer and cardiovascular disease. other studies find different things. and in this study, this study actual found better health benefits, with a diet that did include some dairy foods. so you know, this is partly to say there's no hard and fast, you know, bottom line, that we know emphasizing

plant foods, is a wise idea, for pretty much all of us. how far we go in terms of eliminating all animal foods, is going to be a personal decision. that may be belt, based on health parameters, but certainly one that should not be taken lightly. and thought about with some of these nutritional considerations that we're looking at here. vitamin b12, is probably one that comes to mind for many people. the only source of vitamin b12 in our diet, is through animal foods. so therefore, when individuals exclude animal foods they must have an alternative source of vitamin b12, or

potentially a deficiency can develop. many vegetarian type products are fortified with vitamin b12, there's certainly vitamin b12 supplements out there. and another consideration with b12 is that as we age, absorption declines. so, it's even more of an issue, more of a concern, in older vegetarians, to make sure that they're getting adequate b12. particularly if they're la, omitting all animal foods. i've included here a link to a fact sheet from the national institute of health, that provides a lot of great information on b12. some of the background information, source information, consideration

information that you may find very helpful, if you're interested in looking more at vitamin b12. or if you are currently following, or plan to follow, a diet that emits all or most animals foods, that might be something that'll be interesting to you. you'll find many products, again, that are fortified with b12. many of them will say so on the label. if they make a claim of such on the label, you'll be able to find the content of b12 on the label. so therefore, the link i included earlier to the dris, can give you some information in terms of your particular b12 needs. when you look at supplements, when you

look at fortified foods, and the amount that you would need to take in each day, to avoid any kind of potential deficiency or inadequacy in b12. another interesting potential nutrient of concern in vegetarians, is omega-3 fatty acids. our primary source of omega-3's is through marine fish. marine fish, marine oils, and vegetarian diets tend to be rich in omega-6 fatty acids, which is just another one of the essential amino acids. but it can be low in omega-3s, particularly with the exclusion of all fish type products. plant foods do have a source of omega through 3.

however, it's not converted as efficiently to the more active forms of omega-3. you find omega-3's in walnuts, in flax seed, in soy, and in certain algae's. so including those can help and it also may be helpful to look for foods that are fortified with epa and dha. because plant foods are going to have the ala form of omega-3 fatty acids. and including those will help somewhat boost your intake of omega-3s versus omega-6. in general, most health authorities feel we need about a ratio of 4 parts omega-6, to one part omega-3. the typical american diet is 10 parts omega-6, to one part omega-3.

so even within a regular diet that doesn't exclude fish, that ratio is off. and within vegetarian diets we also risk that kind of imbalanced ratio. so finding ways to get more omega-3s in our diet, is a better way to kind of improve that ratio. i've given you here just a little information in terms of epa, dha, ala, the different omega-3 fatty acids. many health benefits from including sufficient amounts of omega-3 fatty acids, in relation to heart disease, in terms of blood pressure and other functions in the body. so certainly this is another consideration, is to look for alternative sources and foods that are rich in the

ala, so that at least you're getting some good sources of omega-3 fatty acids. i've included a chart here for you, just with some information about content, how that works into our needs, and many, some of these are animal sources, but several are plant sources. so you can kind of see what some of the sources might be. flax seed, walnut. some of those can very rich sources of your omega-3 fatty acids in the form of ala. finally the last nutrient that is possibly of concern, is iodine. iodine, the predominant source in the american diet, is through iodized salt. with the incidence of goiter,

particularly in mid-america, in the early part of the 1900's, another public health campaign, just like vitamin d to milk, was adding iodine to salt to reduce the incidence. and it was a huge success in terms of inc, reducing incidence of goiter. you will see on all your labels of salt, when you buy a container of salt, iodized salt. if it's not iodized, it will also say that. now one reason that sometimes we see issue with vegetarians. is that in the vegetarian diet particularly if they're using sea salt, kosher salt, these may or may not be iodized.

so they may not be a very rich source of iodine. also whole food, plant based diets tend to minimize processed foods. processed foods tend to be high in salt. and often times the salt, that manufacturers are using, is the iodized salt. so it, it can just potentially be an issue where iodine intake can fall. this is not common. it's a possibility. you do get iodine too through the soil, particularly in coastal areas, that can get into the, the plants that you're consuming, so you can get some iodine that way. but just being aware that if you're using

sea salt, you're using kosher salt and completely omitting iodized salt and processed foods, that you might want to find some ways to get a little iodine in through your diet. either through some use of iodized salt, or looking for a sea salt that's been iodized. that was just a look at some of the nutrients and food constituents, that individuals who exclude or who significantly limit animal foods, need to be aware of. and they need to consider, as they plan their diet, when you make your food choices, and when you evaluate whether you're going to use dietary supplements, and what's the role of fortified foods in

your diet. a registered dietitian can certainly be a great resource. and i encourage many individuals, particularly those that are adopting a vegan lifestyle, that a consultation with a dietitian to talk about some of the nutritional considerations. how they might be individualized for you, is always a great idea. but do remember it's certainly possible, and you know, with good planning, with wise food choices, that even the quote, strictest vegetarian diet can be helpful and adequate.

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