Prof. Mcdonald today we are going to start our new section on nutrition and cover the aspects of food systems related to health, food access, food insecurity, and the impact of the food system on the environment. That is going to be the section we are going to cover for this last part of the course. Today we are going to start out by talking a little bit about nutrition and how we got to the point of what we know what to eat or what we should eat, and how that impacts the food system and drives what we do. This is all the information that is in Chapter Seven of your textbook. We are going to give a little bit of a background of the connection between food and health. How do we know we have this relationship . Where did it start . Where did it come from . We will talk about the discovery of nutrients and the role of the usda in how nutrition policy is started. We will do a whole other section on policy and nutrition, and cover it in great depth. We will talk about nutrient requirements, what they are, where they came from. How the public is educated about nutrition and supplemental nutrition programs, with the whole idea of eventually getting to the idea of nutrition and chronic disease. Thats where we are headed with the rest of this section of the course, talking about obesity and other chronic diseases. Lets start with this idea. Youve probably all heard this. Hippocrates says, let food be thy medicine and medicine be thy food with back in bc 400 or 300. They didnt understand much about the food system. They did know what was in food or what diseases were caused by, but there is this link between what we ate and how we felt and lived our lives, and how long we lived and what diseases we might have gotten. They have this connection. Eventually there were discoveries made of things that were in plants and animals that could cure diseases. The most advanced of these was chinese traditional medicine, which is still active today, discovering how things that are extracted from a plant ginseng, some of the mushrooms, things that were naturally growing in the environment could be used to prevent an illness or treat a condition or healing wound. This we think of today will be talk about dietary supplements. We see now kind of a resurgence and looking at natural compounds and how they might affect our health. You can go into any Grocery Store or drugstore, and there is a whole shelf of dietary supplements. Some of those are based on what was known from traditional chinese medicine. Others are newer discoveries. But there is this link between something in food or plants and health. So now we are in a new kind of environment. Just do a Google Search of nutrition and health and look at the books that will come up. We have an overwhelming bursting of information about how we should eat so that we can have ideal health, and ideal life, a perfect body, all the energy we need to get through our day. How did that get started . How did we get to this point where we are looking for food and ways to eat that are supposed to give us the Optimal Health . We have always had that connection, but we dont seem to still have all the answers. Do we know what the optimal diet is . I dont we do yet. We know a lot more than we did back in hippocrates day, but we are not there yet. How do we use food in a way that is optimal for our health, agricultural systems, and our environment . That is where we are headed in this course. Where are we going from where our health needs are to how do we raise the right kind of food and communicate what people should eat to ensure that health is maintained . When you think about nutrition i have been a nutritionist for 30 something years we are moving along a continuum. We started out trying to figure out what it is we need in our food to live, to have prevention of disease. We figured out what nutrients were in food and the quality of that. Thing we moved it to taste, convenience, things like microwave meals, tv dinners, soda that had is in it best that that had fizz in it. We talked about different ways that we process food to store it and keep it safe. Now we are at a point where he see chronic diseases being linked more and more to our food. This connection between what we eat and the kinds of diseases we get that arent acute diseases not something you can cure with a medicine, things like type two diabetes, some types of cancer, obesity, Heart Disease our excess food related diseases that we are seeing more of. We have moaned that we have moved along this continuum to get where we are today we have moved along this continuum to get where we are today. There are still a lot of people in the world and in the United States that dont have access to adequate food. We talk about that. We will have a whole section on food access. I am not saying these are all solved, but this is moving along the continuum of how we think about nutrition and the research that we do. Best to start with some of the basics. We know about macronutrients and micronutrients, but how . How did this all get started . In your book you have got some descriptions about little this a little bit of this history come a starting mostly with european scientists, german and french scientists who developed techniques to think about what was in food. What is it that we are consuming, and how what happens to it will we eat at . One of the ways they did this study was a balance study. How would you define a balance study . Just think about what we are saying here. What goes in and what comes out, right . You do a balance study, measure everything that goes in you have to have a marker it would need to be carbon for carbohydrates or nitrogen for protein. You measure those elements, and the techniques were available to do this fairly crudely, and what went into the animals diet, and you measure what comes out. How would you do that . You collect urine, feces, not so much breath, but we do that today. That is a balance study. We still do those, but these were the early scientists using that tool to say, carbon goes in, only a certain outcomes out. Or this amount of nitrogen when in, this much comes out. That meant it was retained, and they learned that growth require nitrogen. Body tissues were built up of nitrogen. They were able to say, ok, it takes this much nitrogen to make this much muscle, or to have this much growth were this month recovery from injury. Talents studies were very important in figuring out what nutrients were in food and what the body was doing with those. Eventually it was discovered that heat was generated, that the body was always warm. Theres lots of miss lots of myths about how Different Things in food were converted to heat, but it was eventually understood as oxidation, a burning of those fuels in the body. So the measurement of calories became the next focus of trying to understand what nutrients are required by the body. A way to do that is this idea of calorimetry, the measure of heat. Scientists began in germany and france, able to build isolated rooms or spaces and actually detect the amount of heat that was being generated by the body. Pretty sophisticated when you think about it. We have these kinds of facilities today using modern techniques, the back in the 1800s, 1900s, it was pretty sophisticated to be able to do that in a very precise way. But from those kinds of studies, by putting people or animals into these rooms and measuring heat produced, we generated some important information. It was determined that you could generate four kilocalories a unit of energy used in nutrition still, even though we dont think about that so much in our daily lives with one gram of protein. A United States scientist, part of the usda, received one of the first nutrition grants to do research on understanding what energy was produced from food. He expanded on the one gram of protein producing metro kilocalories to say that one gram of carbohydrates also produces four kilocalories, but that fact was a that fat was a higher generating fuel. These are important things we know today, that one gram of carbohydrate or printing generates four kilocalories or protein generates four kilocalories, and that one gram of fat generates nine kilocalories. This is how much energy is being produced from fuel from food, and they were used in early days of the usda to generate some information about what was in food, and the caloric value. It was instrumental in doing food composition. He was one of the first scientists engaged in that. There are some pieces of the text that were generated by he and his colleagues at the usda. You can see in this table here, this is a group of vegetables he did analyses on. You can see they ran the number of samples that they ran, the refuge the nonedible part discarded, water, fat, carbohydrates, protein, and ash. That is what food composition consisting of when we were figuring out what nutrients were in food. With that be sufficient today to be able to do any kind of diet balance for people . Know, is missing a whole bunch of nutrients no, it is missing a whole bunch of nutrients. But it was instrumental. At this point, it wasnt really understood that there were requirements for nutrients. The only one that was released sort of understood was protein from the work that had been done in germany and france and the balance studies. There was a lot of interest in how much protein someone would need to stay healthy because protein was considered to be one of the most important nutrients because it was so closely associated with physical fitness and activity. If you were on a protein deficient diet, you would lose muscle mass. That was considered to be unhealthy. Trying to find the balance of protein was one of the key drivers for early work on food composition. There was actually a lot of debate about how much protein needed be consumed because, as we know now today, not orthosis not all sources of dietary protein are equal in their quality of what they provide to our body for nutrition, and they didnt understand that at the time. But then we began to gain more understanding of this idea of quality. Protein was measured by nitrogen. That was one of the main ways they detected it. It was eventually discovered that an amino acid is the backbone of a protein, and an amino acid contains the Nitrogen Group and some other side group, and that these were all very different kinds of amino acids, but also into the same basic but all fell into the same basic structure. By 1900, scientists had been able to identify six different amino acids. They all had the same family, the same structure, but different chains. From that early chemistry, scientists could start to detect what happened when people animals, and this case when eating these proteins and how that affected health. Another invention that came into play and Nutrition Research at this time was the use of animal models. To study on people takes a lot of time. Back in those days, they werent too worried about restrictions on using people for experiments. It wasnt such a hindrance as it would be today. Obviously we cant do certain things on people that we could have done back in those days. Animals were quicker and faster and cheaper. Some of the research that was being done to discover the nutrients started using rats as an experiment of model. This quickly advanced to field because you could do a study on a growing rat within a couple of weeks, and you would know, were they getting enough nutrients . Did they die . Did they get a disease . Did they grow adequately . Did they lay in their cage and not move . You could discover that pretty quickly with these different diets that could be made. From those kinds of research, by the 1930s, the understanding of something called an essential amino acid was made. Something that was required in the diet, one of these compounds and to be present in order for that animal to grow normally. This is an important term. Is essential. Is the first understanding that there are things in our diet it is essential. It is the first understanding there are things in our diet that our body cannot synthesize. It has to be coming to us from the food that we. That we eat. The first essential nutrients were the essential amino acids. We were still focusing on the macronutrients carbohydrates, fat, and protein. Quickly thereafter, from using purified diets and looking at these rat studies, it was understood that there is also a requirement racer fatty acid requirement for a certain fatty acid. Ribonucleic acid was discovered using the animal models that were being used at the time, linoleic as it was discovered using the animal models that were being used at the time, but it wasnt until the 1970s that it was discovered these are also necessary for human health. There was always a little bit of a trace amount of lipid in the diets being used, and we didnt have a very big requirement for these essential fatty acids. It was very tricky to figure out what humans needed for fatty acid requirements. Then eventually, once more sophisticated chemistry was available and methods to extract and characterize lipids, we learn that it is not actually the linoleic acid. We can convert the linoleic to a recondite acid to a racodonic acid, and that is the one we actually need in our diet. It took 40 years to get from seeing it in an animal model to really understanding how it was working in humans. The real reason this became more evident was when we were starting to introduce infant formulas. And thats that were being fed strictly on purified formulas, not breastmilk, starting to see fatty acid deficiencies. Then we figured out that they have a requirement for linolenic or racodonic acid. Science moves slowly sometimes when you dont have all the tools you need to be able to characterize and study things. Those were the macronutrients. Remember what those are . Protein, carbohydrates, and fat. We were starting to understand that these were important for health. And one thought, ok, we are good. We know now there are essential amino acids, essential fatty acids. We know carbohydrates are important for the diet. We really dont have an essentiality for carbohydrates. So scientists were making diets and saying, we just need to figure at the right ratio. How much protein, carbohydrate, and fat to be need for animals to grow and be healthy . But along the way, they were making these very clean diet that just set carbohydrates, fat, and protein, and the animals werent growing. There were problems. It was clear that these macronutrients were not the only thing in the food that animals needed to grow. That led eventually to this understanding of these accessory factors. They were called vita amenes, because people thought that proteins were the most important part of the diet. We now call them vitamins. They were discovered to not be protein, but the name stuck. Thats why we use the term vitamin. That led to the separation of the b vitamin family, which are watersoluble primarily, and the a,d, k, and e categories that are not. The discovery of vitamins took place very rapidly because we had animal models that we were able to study. Science was moving very quickly in the field of chemistry and biochemistry and human metabolism was being understood more carefully. Being able to isolate and purified compounds and then put them back into the diet one at a time became possible. From those kinds of studies, vitamins were being discovered premuch every year pretty much every year. It happened all very quickly. By 1949, it was really evident that we had a whole host of vitamins in addition to the macronutrients, and also some minerals were being identified as being essential. Iron, calcium, potassium were being identified. For each of these, a key part of Nutrition Research is that for each of those nutrients, they were all essential because if you took them out of a diet, a disease happened. Something happened in the animal. You probably all would be familiar with that. If you take toussie them out, what is going to happen . If you take calcium out what is going to happen . You are going to get osteoporosis. Your bones dont grow. We know these things. At the time, they didnt know that. They were discovering these by doing that. The idea you take the nutrient out, get the symptoms, but the nutrients back and cure the symptom. That makes the connection between that nutrient and that cause or that affect. From this discovery, this whole work was the creation of the field of Nutrition Research, trying to figure out what is in our food, what components are there that affect disease. It was really connected to biochemistry. Biochemistry and nutrition came up very similarly because at the same time we were trying to figure out what was in the food and was causing disease, we were learning about human metabolism. What is it that vitamin a actually does anybody . What does vitamin c actually do . What pathways is it associated with . Those were happening concurrently and developing very quickly. A lot of early nutritionists were in biochemistry and for and trying to figure out those pathways. Between the 1800s and 1900s, we learned a lot about what was in our food and how it was connected to diseases. I have got on this slide some really common nutritional deficiency diseases that were everywhere. It wasnt uncommon to see people with one of these diseases and a group of your friends and family. I was having a conversation with my mother, who is in her 80s. We were talking about some things about nutrition, and about iodide salts. I was like, well, that is an interesting way they discovered soldiers coming from the midwest had a higher rate of goiter. She said there were people in my town that had goiter. And that was only one generation for me, for you two generations ago, when people had goiter. Goiter is a swelling of the thyroid gland caused by an adequate amount of eye by an inadequate amount of iodine in the diet. Now we have iodine salt to prevent that must we dont see goiter. We have a iodine and diets in other ways, as well. Rickets was also very common. You might way back figured out the cowboy with the bowed legs riding a horse, and thats why he has bowed legs. The reality is the bowed legs were happening because bones were weak. Children, infants, and toddlers who werent getting enough calcium or vitamin d in their diets, when they started to walk, their bones were like twigs, and it just bowed out. They couldnt hold up the weight of the child, so bowed legs became fairly common. You would see that in children Walking Around because they didnt have enough vitamin d or calcium in their diet as infants. We dont see that very much anymore. I and efficiency, anemia we already mentioned. Scurvy is another iron deficiency and anemia we artie mentioned. Scurvy is another we already mentioned. Scurvy is a great example. They knew vitamin c prevented scurvy from happening. On to talk about i want to talk about the blogroll about hol pellagra. You probably havent seen it in your lifetime. I havent seen it in my lifetime. It was one of the First Public Health crises in Young America that was happening as people were moving into different parts of the United States and starting to try and live off the land. There was poverty. There were people that didnt have access to healthy diets. This was a disease that was becoming very common in some parts of the southeastern United States, there were insane asylums everywhere because people were progressing through this disease of pellagra. One of the ways that the government responded to this was to send a team of epidemiologists in the early days of understanding medicine down to figure it out. What is causing this . It must have been an Infectious Disease, something in the air or water that was causing people to get this disease. Joseph goldberger was one of the early Public Health physicians. He took his team down to the southeast part of the United States and started to figure out what it was. One of the things he had to do initially was figure out, is it an Infectious Disease are not . Based on what he had seen in the population, he did not think it was an Infectious Disease. It wasnt being transferred from person to person he thought like like he thought it should. It was in families, but not in school classes, for example. He did some gross things that we were probably not recommend the day, but he exposed himself and his team to secretions from people that had pellagra. Rubbed it on their skin, it on their skin, ate it, exposed themselves to it to prove that it was not infectious. From doing the kind of work that we do investigative leave now, he questioned people. What did you eat . What were you exposed to . What were your Living Conditions like . He came to the conclusion that people who didnt have access to be vitamins were more likely access to b vitamins were more likely to develop pellagra than those who were wealthier. He did the next he did next experiment where he major people have access to b vitamins in their diet and they did not get pellagra. This is a great example of how you could use nutrition to prevent a very big problem in that part of the country. And now it is gone. We dont see that today at all. From all of this work, then, we started to get this idea that food and health are connected. The United States is developing, agriculture is booming, we are starting to see companies develop. I wanted to talk about three examples of how this was the start of the food industry, this idea that we could do things with our food that will help us be healthier. The first thing i want to talk about our graham crackers. Does anybody like graham crackers . I am sure you will have all had one at some point in your life. This is named for reverend sylvester graham, who is a real person, who was very involved with spirituality. He connected spirituality with. With food. He felt if you eight certain ate certain foods, you would be closer to god. He promoted this idea of a diet that was very vegetable based. Fruit, vegetables, whole wheat, and encouraged his followers to avoid eating too much meat, eggs, butter, cheese, things like that. What he did that was so innovative is he created a new fluoour called grandma flour. Graham flour. They tasted good. They were connected to health. A company was born from this idea of having a better way of eating food. The kind of graham crackers we have today are not exactly the same. They still use graham processes, but they have changed over the years. This is the start of why are we eating these kinds of crackers now . Because someone in the 1800s thought it was healthy for us to eat these. Another example is kellogg. The kellogg story is very classically american. There were two brothers, john harvey and will keith kellogg. They were running a sanitarium. Not a hospital exactly, but more of a rehabilitation center. People had a variety of illnesses, and they would go to the sanitarium and try to get well while they were there. John harvey in particular thought it was all about their intestinal tract. Does that sound familiar . What are we talking about today all the time . Our microboimes, what is in our digestive tract . Will kellogg was ahead of time. He thought everything in health had to do with what is going on in our digestive tract. He had no idea about micro volumes microbiomes, but still if you eat a healthy diet of nuts and vegetables and grains, you would be healthier. He went on this plan for those in his care, and he had to make food. That is not what people were typically consuming, fruits, festivals, and wholegrain. One of the things that he made was wheat flakes, and people like them. If remember our last chapter, we were talking about milk production and dairy. People were starting to put milk on their serial. This was the start of the kelloggs cereal company. Cornflakes was the first product they launched initially. And the Company Still making all kinds of cereal, got its start from thinking about what was going on in our digestive tract and how we can be healthier by eating a certain kind of diet. The third i want to cover is crisco. Probably an odd one. You are probably thinking, why crisco . Crisco is a funny story. Remember we talked about butter and hydrogenation, this idea that there was a conflict between people producing butter and people making Vegetable Oil and converting it into solid fat . The Crisco Company was founded by two guys, procter and gamble. They were brotherinlaws. They were candle makers. Their company was all about wax. They eventually made soap, which is another extension of that same technology. Then they discovered they can do hydrogenation of oil and make this solid cooking material that would replace butter. They decided in order to market the crisco, they would have to use science and technology in a really big way. They were not only marketing this product as being healthier than butter, they wanted to make it in a clean environment. Crisco was white, not yellow like butter. Cities clean. All of their factories are very clean. They had people in white uniforms making the product, and they advertised it very heavily as being hightechnology. It was advertised as being not absorbed as well as butter from your body, more digestible than butter, or lard, which was the other product commonly used for cooking. The other thing they did that was really smart was they started to take advantage of what was going on at universities. Remember we talked about Home Economics and agricultural experiment stations and growing as a way of getting information out to the public . The Crisco Company took advantage of that idea and hired home economists that would go out into the public and give presentations, cooking demonstrations here is how you use crisco, heres the kind of food you can make. They got all kinds of people to convert to this new technology, to use this new product. It was a clever advertising approach to take science, some of the new technologies in hydrogenation and clean manufacturing, and couple that with education, coming out of universities, Home Economics and learning stations, taking that i to the public. Out to the public. Putting the science, technology, and the public image of how this was marketed. Getting back to figuring out what we are doing with nutrients. At water was one of the first usda nutrition scientists and was doing food computational tables. Between the 1890s and 1975, actually 1963, we started to develop books about nutrient composition. That is what is called handbook 8. This book was published in 1963, so it is a historical document. I like to show people that this is what we knew about food composition the 1960s. It has vitamins, it has saturated fats, it has calcium phosphorus i will pass this around so you can take a quick look. You guys will do an assignment using the super tracker. That is where the data came from. You can go online now and search information, but this is where it all started in handbook 8. First way we started to publish information about what was in food, breaking it down by vitamins, minerals, and macro nutrients. It has been updated many times. We now have 80 different nutrients in the database for nutrient composition. The laboratory responsible for this work is the Nutrient Data laboratory, part of the usda. Their sole mission is to update databases about nutrition, nutrient composition of food. Do you think that is necessary . For their new foods . All the time. Are there new foods . Trying to figure out, what is the nutrient composition, how do we use that in our diet . Theres lots of updating going on, lots of food items, and you can search this online. When you do your homework assignment, you are going to super tracker and you are going to use foodopedia, based on the data in that book, and it will break down the food that you put in. You will see the nutrient composition. These are the basics, but you can see all of the nutrients in that apple. And you will see bioactive compounds that arent nutrients that you will see in a second. I wanted you to understand that it started with atwater in his data composition book. It went to handbook number 8, is now we have this whole unit of the usda whose sole mission is to do these analyses. We now have on the left side, of the essential nutrients carbohydrates, fats, vitamins and minerals. We need to consume them in our food. But now beyond that, nutrition is moving past those essential nutrients and we are realizing there are other things in food, just like when they found vitamins and minerals were required, we find it is not just proteins, fats, carbohydrates, vitamins, and minerals, there are other things include. Hair is fiber there is fiber, these bioactive compounds. We dont know how much they need. Remember i showed you the chemical structure of blueberry, all those chemicals . How do we know what all of those chemicals do . There are thousands of chemicals in any one food source. How do we understand that . I want to take a second to point out that one of these databases that, in addition to the Nutrient Database that can that handbook 8 has in it, we have bioactive compounds in it. The isoflavones was done at Iowa State University. Isoflavoens are found where . What is the source of an isoflavone . Soybeans. These are the estrogenic compounds that are found in soybeans and other legumes that we were very interested in around 2007, trying to figure out what do the eight do in the bodyy what do they do in the body . Dr. Murphy developed the techniques to another these include. Measure these in food. You can go out and search that database on the usda website and you can be proud that that came from Iowa State University work. I have the others on this chart. They are on the databases as well, and there is more. Than we have to figure out, how do we get from preventing disease to Optimal Health . We know enough about nutrition now, what should we be eating to make sure we have Optimal Health, and we are not missing nutrients, having too much how do we go to understand this in more detail . We are going to talk about, how do we get nuclear get nutrient requirements, how do we educate the public, and how do we deal with supplemental nutrition programs . Those are the three things we will talk about relative to this section. Before we do that i want to make sure you are aware of the agencies that are involved in food and health and nutrition. We have talked a lot about the usda, the food and nutrition service. We will talk of more about what they do. Also involved is the National Institute of health. The nih is based on disease and medicine, drugs and treatment of diseases. They have a role to play in nutrition as well. The center for Disease Control and prevention, the cdc, overseas food safety in addition to nutrition issues in the public sector. And of course the fda. Those are some of the key agencies you want to keep in mind when we talk about who is regulating and overseeing nutrition. First thing i want to talk about is, how do we know how much of a nutrient to consider . To consume . Once we have the analysis done of nutrients and food, the next step is to say, we know how much is in the food, how much do i need to eat to prevent from getting a disease . We went back to this idea of a deficiency and started to do research okay, if we have this nutrient and we know it causes deficiency disease, lets trace back and figure how much of the nutrient we need to provide to nature of the disease doesnt happen. Lots of research was done to create this whole body of literature about how much nutrient was needed, quantifying and measuring the disease rate. From that came the recommended dietary allowances. The recommended dietary allowances and i have two books here. These are ancient history from my personal library. Because i am ancient. This is from 1980. This is from 1989. Two different versions of the rda. As a nutritionist, this is like your bible. You had to memorize these books. Each one comes with a pullout that you had to memorize. How much nutrient was required for children, and all of the nutrients were listed across the top. This is what is called the recommended dietary allowances. I will pass those around too. Why did this get started . Was happening in the 1930s . The depression, poverty, people were worried about children not getting enough food to eat. So we were very concerned about taking what was known about food composition and understanding diseases and nutrients and figuring out, what do we need to feed people so they dont get nutritional deficiency . The 1930s was the start of trying to get those numbers down on paper, try to define nutrient requirements. That was done. Nutrient requirements were defined for those key vitamins and minerals. In 1840, what was happening around that time . The start of world war ii, r ight . We are looking at military service. What should we feed our soldiers . There was an committee on food and nutrition at the National Academy of sciences. In 1941 president roosevelt made it an issue of national defense. Is important to understand how to feed soldiers and keep them healthy going off to war, and thinking about what was going on in the public to prevent nutritional deficiencies from becoming a problem in society. Within 10 years or so, the first recommended dietary allowances were published. Was the start of the early books. Those are subsequent versions from the 1980s. The purpose of the dietary standards were to prevent diseases associated with starvation to feed the army and to maintain the health of the public. It was important that working people were healthy, not just the soldiers and children, but those that were involved in keeping the country going at that time. The rdas were a source of public nutritional recommendations. They never were meant to be personal individual nutrient requirements. They are meant to be for populations. We have used the rda open until the 1990s as the main source of how much you trade we need to stay healthy as nutrient you need to stay healthy is a population. It has been updated many times. How the rda works is a process that involves using evidence in literature. You have to have proof that the nutrient does whatever it is you are trying to prevent. As we got more sophisticated, we are not just looking at scurvy or osteoporosis, but looking at metabolic pathways and measuring enzyme activity and detecting what nutrients were doing at the cellular level. That over time. And a lot of work was done to put people on purified diets, watch what happens to them, figure out what dose is required to prevent him from having symptoms, biomarkers or whatever was being measured, and do that enough times for reproducibility. We also have to think about bio availability . What happens when you eat it, how much gets into your blood or tissue. It is not a 1to1. Somethings have to be converted to other things. Betacarotene has to be converted to vitamin a. You dont have a onetoone transition. You have to worry about how it is metabolized, how it is broken down in storage. We need to worry about toxicity. Some of the minerals for example iron is very toxic. You cant take a lot of iron and not have a negative consequence on your health. We had to learn all those things. Eventually using statistics to figure out, what is a safe range . What should be in the rda book . That is where the data got generated. This was done repeatedly, updated every couple of years. Scientists would get together and look at this information. They generated this rda book every couple years. It became apparent that the rda wasnt sufficient. The rda was a little confusing. It is a range of values, but it comes down to one number for ages and gender. In 1994, scientists from the u. S. And canada said, we need to do Something Different in how we define Dietary Intake recommendation. They came up with this idea of dietary reference intake. It is 4 different measures. An estimated average requirement, recommended dietary allowance, which is the rda, adequate intake, and tolerable upper intake level. That can be somewhat confusing. This graph makes it simple to understand. This is in your textbook as well. If you look at this vertical line going from low risk of deficiency to high risk of deficiency, oyou see that the rda is set at a place where almost no one would show a deficiency. 2 of the population would be at risk of deficiency if they follow the rda. The average estimated requirement is said to be at the 50 level. It is not as stringent as the rda, but you estimate about half the population would be meeting their nutrient requirement at that level. On the other side we see toxicity. No toxicity to high toxicity. The tolerable upper level is since of the where the most sensitive population would experience a toxicity. It was very protective of the population. The average intake, which is not shown here, is used to replace the rda four things we dont have enough data to define an rda. It is equivalent to an rda, but not based on enough science. If you can see from this that there is a range how we can define nutrient requirements. Why would you think it is important to have this difference between the era and the rda . Does that make any sense . One is careful and stringent, one is not so much. Why would you think that would be important . [indiscernible] prof. Macdonald yeah, you are looking at preventing the population from getting a nutrient deficiency, where is your looking at generally relative intake. One thing we know about food is that we dont need all the the nutrients all the time. That is why rda this challenging to meet. If you try to meet rda, you probably wont reach it every day. Chances are over a couple days you will consume the nutrients you need to meet that average requirement. If you are trying to meet intake at the rda level every day, that is challenging if not impossible, whether if you aim for 50 of the population, that is doable. We have to be more realistic and how people actually eat. [indiscernible] prof. Macdonald that is what this means. Only 2 would be at risk. So 98 would meet the requirement. The idea is very conservative, whereas the era is not so conservative. Now we have all these numbers. We have books, we have composition tables, we have rda s, we have all this data. How do we get the information into the hands of the people . How do we help the public understand what they should be eating . The rda was not for the public. Was for dietitians, doctors, people doing foodservice for children for school, Hospital Food Service management it wasnt for the public. We did have to have some way of doing that. We are going to talk about dietary guidelines and nutrition labeling. The focus begins even back then they were generating dietary recommendations for the public. They focused on children in the early 1900s. We saw the first use of food cooking, food grouping, the five food groups. As we moved into the 1930s, depression, worrying about nutrition deficiencies in children, and the cost of food, the usda generated guidance on using certain kinds of foods that were lower in cost but could still meet nutrient needs. We moved from that into the seven guides which was more of a wartime nutrition guide based on the rda to Health People balance their diet. By 1956 we had changed it again. We have four food groups, meat, milk, fruits and vegetables, and grain. There are lots of different ways people were trying to convey information to the public. Which one of these do you remember from your childhood . Which was the first one you saw . Which pyramid . The black one . Anyone remember the 1992 one . Some of you probably. Some may know this one, myplate. It evolves over time. What does this mean to you when you first saw it . What did you take away from the pyramid
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