1 00:00:00,000 --> 00:00:06,000 Thanks, Jennifer. Hi, my name is Scott Smith. I'm the lead for NASA's Nutritional Biochemistry Laboratory. 2 00:00:06,000 --> 00:00:10,000 Jennifer provided you some great background information on the importance of good nutrition. 3 00:00:10,000 --> 00:00:14,000 Based on the information she provided, can you come up with a definition for nutrition? 4 00:00:14,000 --> 00:00:18,000 What is your daily nutritional need for calcium? How are you meeting that need? 5 00:00:18,000 --> 00:00:21,000 In your groups, take a few minutes to answer the questions. 6 00:00:21,000 --> 00:00:24,000 Your teacher can now pause the tape so you can collaborate with your peers. 7 00:00:24,000 --> 00:00:29,000 Nutrition is the study of how the body uses nutrients, like calories, vitamins, and minerals, 8 00:00:29,000 --> 00:00:31,000 and how much of each of those nutrients the body needs. 9 00:00:31,000 --> 00:00:33,000 While good nutrition is important for everybody, 10 00:00:33,000 --> 00:00:39,000 NASA scientists at the Nutritional Biochemistry Laboratory look at how astronauts' nutrient needs are affected by spaceflight. 11 00:00:39,000 --> 00:00:42,000 One area that is very important is the role of nutrition in keeping bones healthy. 12 00:00:42,000 --> 00:00:48,000 Not eating foods that include nutrients such as calcium and vitamin D can result in weak bones. 13 00:00:48,000 --> 00:00:54,000 You can find good sources of calcium and vitamin D in dairy products such as milk and cheeses, broccoli, and spinach. 14 00:00:54,000 --> 00:00:58,000 Calcium is probably the most important nutrient that comes to building strong bones. 15 00:00:58,000 --> 00:01:01,000 More than 99% of the calcium in your body is stored in bones, 16 00:01:01,000 --> 00:01:06,000 and when you don't get enough calcium in your diet, it comes out of bones to help the other tissues. 17 00:01:06,000 --> 00:01:12,000 If you do that long enough, what happens is the bones become weak and brittle, and can lead to diseases such as osteoporosis. 18 00:01:12,000 --> 00:01:15,000 Osteoporosis is a disease where the bones become fragile and break. 19 00:01:15,000 --> 00:01:21,000 The best way to counteract or prevent getting osteoporosis is to eat well and exercise when you are young. 20 00:01:21,000 --> 00:01:24,000 So why are we concerned about bone loss during spaceflight? 21 00:01:24,000 --> 00:01:27,000 Astronauts actually lose bone mass during spaceflight. 22 00:01:27,000 --> 00:01:32,000 This is especially significant for long missions such as the astronauts that serve on the International Space Station, 23 00:01:32,000 --> 00:01:34,000 or on future missions to other planets. 24 00:01:34,000 --> 00:01:36,000 When astronauts return from long missions, 25 00:01:36,000 --> 00:01:41,000 they have an increased risk of fractures and other health problems because they lose bone mass and calcium. 26 00:01:41,000 --> 00:01:43,000 Do you have any idea why this occurs? 27 00:01:43,000 --> 00:01:46,000 Does that mean they get osteoporosis while they're in space? 28 00:01:46,000 --> 00:01:49,000 The human body gets used to operating in Earth's gravity field. 29 00:01:49,000 --> 00:01:54,000 When humans are removed from this environment, as when they travel in space, many complex changes take place. 30 00:01:54,000 --> 00:01:56,000 While living and working in a microgravity environment, 31 00:01:56,000 --> 00:02:01,000 your body senses that it doesn't need as much bone mass to support the body, so bone mass decreases. 32 00:02:01,000 --> 00:02:03,000 When you return to Earth's gravity environment, 33 00:02:03,000 --> 00:02:08,000 your body senses it needs more bone mass to support the body, so bone mass will begin to increase. 34 00:02:08,000 --> 00:02:11,000 Because it takes a long time to regain the lost bone, 35 00:02:11,000 --> 00:02:14,000 this is the period when you have a higher risk of bone fractures 36 00:02:14,000 --> 00:02:18,000 because your body's skeleton has a tougher time supporting your body against Earth's gravity. 37 00:02:19,000 --> 00:02:23,000 Here at NASA, we conduct research to understand how much calcium is being deposited into bones 38 00:02:23,000 --> 00:02:25,000 and how much calcium is being taken out of bones. 39 00:02:25,000 --> 00:02:29,000 This research involves mathematics, especially measurement and estimation skills. 40 00:02:29,000 --> 00:02:32,000 For example, let's take a look at the following system diagram. 41 00:02:32,000 --> 00:02:35,000 Suppose Norbert was to consume 1,000 milligrams of calcium, 42 00:02:35,000 --> 00:02:39,000 which is the daily recommended allowance, in the form of a large glass of milk. 43 00:02:39,000 --> 00:02:44,000 This diagram shows the path that calcium and other nutrients follow as they enter Norbert's body from the mouth. 44 00:02:45,000 --> 00:02:50,000 The milk enters the stomach and is broken down in the stomach and small intestine by chemical processes. 45 00:02:50,000 --> 00:02:55,000 Approximately 80% of the calcium, or 800 milligrams, leaves the body as solid waste. 46 00:02:55,000 --> 00:02:59,000 The remaining 20%, or 200 milligrams of calcium, enters your bloodstream. 47 00:02:59,000 --> 00:03:02,000 The calcium will help many of your body functions 48 00:03:02,000 --> 00:03:05,000 and, importantly, will prevent calcium from being taken out of bones. 49 00:03:05,000 --> 00:03:08,000 This is what happens when you don't eat enough calcium. 50 00:03:08,000 --> 00:03:11,000 About 5%, or 50 milligrams of the remaining calcium, 51 00:03:11,000 --> 00:03:14,000 enters your kidneys and is released as liquid waste. 52 00:03:14,000 --> 00:03:16,000 Some of the calcium will be taken up into bone, 53 00:03:16,000 --> 00:03:19,000 and some will also be released by bone back into the bloodstream. 54 00:03:19,000 --> 00:03:25,000 Finally, a small percentage of calcium flows from the bloodstream into the large intestine and out as solid waste. 55 00:03:25,000 --> 00:03:29,000 To estimate how much calcium bones are absorbing and how much calcium is being taken out of bones, 56 00:03:29,000 --> 00:03:32,000 we can give Norbert a tiny amount of a special form of calcium. 57 00:03:32,000 --> 00:03:35,000 For this case, let's call it blue calcium. 58 00:03:35,000 --> 00:03:37,000 Over time, usually 10 to 14 days, 59 00:03:38,000 --> 00:03:42,000 we collect biological samples of solid waste, liquid waste, and blood. 60 00:03:42,000 --> 00:03:46,000 We can determine how much calcium, regular or blue, is in each sample. 61 00:03:46,000 --> 00:03:49,000 By mathematically analyzing the data, we can actually estimate 62 00:03:49,000 --> 00:03:51,000 the amount of calcium absorbed by the intestines, 63 00:03:51,000 --> 00:03:53,000 how much calcium is filtered by the kidneys, 64 00:03:53,000 --> 00:03:56,000 how much calcium is being deposited into bone, 65 00:03:56,000 --> 00:03:58,000 and how much calcium is being taken out of bone. 66 00:03:58,000 --> 00:04:01,000 By studying the flow of calcium before, during, and after spaceflight, 67 00:04:01,000 --> 00:04:06,000 we can tell how the body is changing during flight and what is happening to the calcium. 68 00:04:06,000 --> 00:04:10,000 From our estimates, we can conclude that the amount of calcium that is deposited into bone 69 00:04:10,000 --> 00:04:14,000 and the amount of calcium released by the bone back into the blood is about the same. 70 00:04:14,000 --> 00:04:16,000 This changes when astronauts are in space. 71 00:04:16,000 --> 00:04:20,000 The amount of calcium absorbed by the bone is less than the amount of calcium released by the bone. 72 00:04:20,000 --> 00:04:24,000 Finally, when astronauts return to Earth and recover over time, 73 00:04:24,000 --> 00:04:28,000 the amount of calcium deposited into bone and the amount of calcium released by bone stabilizes 74 00:04:28,000 --> 00:04:30,000 and returns to pre-flight levels. 75 00:04:30,000 --> 00:04:34,000 Understanding the specific means of how bone and calcium use change during flight 76 00:04:34,000 --> 00:04:37,000 can help us figure out how to counteract it and also help prevent bone disorders on Earth, 77 00:04:37,000 --> 00:04:39,000 such as osteoporosis. 78 00:04:39,000 --> 00:04:41,000 Are you beginning to understand the importance of nutrition 79 00:04:41,000 --> 00:04:43,000 and how nutrition can be important for your health? 80 00:04:43,000 --> 00:04:46,000 Have you changed any of the answers to the questions I asked earlier? 81 00:04:46,000 --> 00:04:49,000 Now would be a great time to stop the tape and review your answers.