Welcome back. Let's briefly review Human Nutrition. Hippocrates, the ancient Greek physician said, "Let food be thy medicine and let thy medicine be thy food." So if we could give everybody the right amount of food, the right amount of nourishment, and exercise, not too little and not too much, we could have found the safest way to health. And that hasn't changed over thousands of years. People, before agriculture, usually hunted or gathered their food, and so they ate a mix of plants fish other types of foods including meats. These foods were packed with nutrients, and dietary fiber was generally higher compared to the modern diet, particularly in Western countries. Their primary sweet was honey, not refined sugar. So if you look at modern hunter gatherers today, they're noted for being in excellent cardiovascular health, metabolic health. So because they have very high activity levels, they also have very low obesity rates. And it's important to note that their diets are rich in fiber and different micronutrients. So in 1941, the US Department of Agriculture issued dietary guidelines, and they set up their first recommended dietary allowances. In 1946 the US Department of Agriculture issued a guide to good eating, and they recommended the basic food circle. This included seven different food groups, including vegetables, fruits, breads, and meats, and dairy products. They did not recommend specific serving sizes. But in 1992 to 2005 they developed what's called the food pyramid, and they recommended 6 to 11 servings of breads and pastas per day. And including two to four servings of fruits, multiple servings of vegetables, servings of dairy products and meats, and fats and sweets sparingly. Well, you can guess what happened after those recommendations. We'd had the obesity epidemic, now it's not entirely clear if it was due to Food Pyramid, but the food pyramid didn't help things. So from 2005 to 2011 the USDA came up with a new food pyramid, and this one included steps to indicate that you're supposed to exercise as well, and they didn't recommend specific amounts of servings, but just that you should get some of your nutrients from each one of these different food groups. And from 2011 onwards they now have a food plate. And so that food plate includes vegetables, fruits, grains, protein, as well as a dairy. So the question is, what is the optimum human diet? And in this cartoon, it demonstrates a food desert and people crawling on their bellies looking for healthy food. Now some people advocate for a vegetarian diet, and here's a vegetarian food pyramid with grains and vegetables and includes some eggs. Other people advocate for a raw food or vegan food diet and that includes a lot of water, leafy greens and other vegetables and raw fruit. So in 2004 Dan Buettner who is a journalist, was working with the National Geographic Society to find the people who were living the longest anywhere in the world. And they looked for people who routinely lived to be one hundred years old. And they found some that were living at 10 times the rate of people in other countries. And they identified these areas where people were living the longest as the blue zones. Now, what's interesting about the Blue Zone diets is that none of them were identical. In fact, they all varied in terms of the amount of vegetables, fruits, and proteins that they ate. But what was notable in all of them is that they were all high in fiber and none of them were strictly vegetarian or vegan. Now, you can live a very healthy life if you are vegetarian or even if you're a vegan, provided that you get the micronutrients that meats provide. But none of these diets were completely vegetarian or vegan. They all had a small amount of meat, poultry or fish as well as dairy products as well. Let's talk briefly about the Planetary Health diet. This commission convened scientists from 16 countries to develop targets for planetary health diets, ideally by 2050. The goal was to increase consumption of fruits, vegetables, nuts, and legumes. And they recommended in Western countries to eat smaller portions of meat and dairy products. So the Planetary Health Diet is flexible and is adaptable to different geographies and cultures and personal choices. In other words, no single diet is the healthiest diet. So health is based on what you eat, your individual genetics, the type of microbes that you have in you and on you. As well as how much you exercise and the environment in which you live. When we talk about the study of human nutrition, we must talk about Antoine Lavoisier who was a French nobleman and chemist. And he was considered the father of chemistry and nutrition, and he said that life is a chemical process. So the definition of nutrition is it's the supply of materials, also known as food, that are required by organisms to stay alive. Nutritional science is the study of food and nutrition. We focus generally on humans, although there are those who study the food and nutrition requirements of animals. This focuses on the biochemical processes through which these substances are converted into energy for the body to use. And the Blue Zone diets suggest that animal proteins are important for healthy diets, but only limited to small amounts. And the question is what are the nutrients that animal proteins provide? Animal products provide a number of important nutrients and that includes proteins, lipids, essential fatty acids, and micronutrients also known as minerals and vitamins. And the minerals include iron and zinc as well as these others. Vitamins include the B vitamins and even cholecalciferol, which is a D vitamin. They include other micronutrients as well. So proteins are the building blocks in our bodies, and they are essential for health and well-being. They make up our hair and our nails, our muscles, our immune system, our blood, our brain and nervous system, and even the enzymes that allow our body to function properly. And proteins, you can think of as a string of pearls that then are folded up into a variety of structures. And then you get these complicated structures and different chains then of proteins can be folded together to get a complex structure such as this one that's supposed to represent hemoglobin. So there are different protein rich foods. You can have it in animal proteins. You can get it in different types of beans and fruits. So if you don't get enough protein in your diet, you can develop a protein deficiency. And if you suddenly don't get enough particularly for young children, they develop a condition called Kwashiorkor or sudden protein deprivation. If you are starving of all nutrients including proteins, you get a condition called Marasmus, or in other words general starvation. Some of the iron-rich foods that you can eat include liver and broccoli and beans and nuts. You get iron deficiency when you don't eat enough foods that contain iron. So there's different recommended daily intakes of iron if you're a child or a young growing adult or a woman of childbearing age. And if you look at a blood smear under the microscope, this is what you would see if you have a normal blood smear. You've got a lot of red blood cells and they're pretty well red. But if you've got iron deficiency anemia, you don't have as many red blood cells and they look pale in the middle. So unfortunately iron deficiency affects as many as 1.6 billion people around the world. And it can impair brain development in children in poor countries. It's associated with maternal death in low-income countries as well. So iron deficiency anemia can involve a variety of different symptoms. And depending on how severe the anemia is the symptoms can either be mild or they can be severe. And here in the red you have severe anemia, and that includes fainting, chest pain, and even a heart attack. Some of the physical signs of iron deficiency anemia include a pale conjunctiva. This is a normal conjunctiva, which is nice and pink, and this is a pale conjunctiva, which shows that this person is anemic. Vitamin B12 which foods include fish and eggs and different types of meats. And vitamin B12 also known as cobalamin, is involved in red blood cell development, nerve development and maintenance, and normal brain functioning. So people who don't eat vitamin B12 rich foods are at risk of developing vitamin B12 deficiency, and that can include permanent nerve damage. So people who are vegans for example have to take supplements or enriched foods. So vitamin B12 deficiency again, you can also develop anemia. You can develop diminished cognitive function, low energy, and numbness in your hands and feet. You can develop infertility, severe depression, and other symptoms as well. Recent discoveries and research into the human microbiome show that the human body has ten times as many microbes living in it and on it as it does human cells. So they are as important to our health as any organ, such as our heart, our lungs, or our kidneys. And what we feed our microbes impacts our health. So we must realize that when we eat we are feeding our microbes as well as ourselves. And microbes do very well with a fiber-rich diet. Microbes will produce a thick mucus layer on top of your intestinal cells to help protect it against say autoimmune diseases such as inflammatory bowel diseases. So a fiber free diet as opposed to a fiber-rich diet produces very little mucus, and that can predispose intestinal linings to autoimmune attack. So a fiber-rich diet is much healthier than a fiber free diet. So the questions for this session include what is the definition of nutrition? What foods did the Blue Zone diets have in common? What foods did they minimize? And how did the Blue Zone diets compared to the Planetary Health Diet? What micronutrients are found in animal products? Which of these are also available in plant-based foods? Which foods are the most beneficial to the microbes in your gut and develop an optimum diet for you and your family? What foods would your diet include? And what foods would your diet exclude? And with that I'd like to thank you for watching this session.
