Transcripts For CSPAN3 History Of Diet And Nutrition Guideli

CSPAN3 History Of Diet And Nutrition Guidelines July 15, 2017

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 way back in bc 400 or 300. People are there was some connection between what they ate and their health. 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 heal a 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 think we do yet. We know a lot more than we did back in hippocrates day, but we are not there yet. What we are still trying to figure out is 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 we 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 moved along this continuum to get where we are today. Now that we have cured all of these along the way, we havent figured out how to prevent food insecurity. There are still a lot of people in the world and in the United States that dont have access to adequate food. We will 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 it . 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. To be really careful. You would measure everything that came out. 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 went in, this much comes out. That meant it was retained, and they learned that growth require d 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 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. One gram of dietary protein would generate four kilocalories of heat. We dont use that today. We going to talk a little bit more about gilbert atwater. He brought that to the United States. He was 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 fat was a higher generating fuel. These are important things we know today, that one gram of carbohydrate generates for 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. Would that be sufficient today to be able to do any kind of diet balance for people . 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 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 that we have to eat to grow, that we cant make. Our body cannot synthesize. It has to be coming to us from the food that we. 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 for a certain fatty acid. Ribonucleic acid was discovered using the animal models that were being used at the time. The 1970s that linoleic asd that it was discovered. 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 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 will 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 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. Quickly. 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 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. Scurvy is a great example. They knew vitamin c prevented scurvy from happening. 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

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