TED Talks · Listen with Dr Jen Gunter

Healthy Bones

Believe that drinking milk with all its calcium and vitamin D is the one thing you need for strong and healthy bones.

Level: C1 · 71 sentences

Transcript

  1. Believe that drinking milk with all its calcium and vitamin D
  2. is the one thing you need for strong and healthy bones.
  3. And it's a really nice message that's sold a lot of milk over the years.
  4. But it's just not scientifically accurate.
  5. When we focus on milk,
  6. we lose the bigger picture of bone health.
  7. So let's start at the beginning.
  8. Adults have 206 bones that form the main part of the skeletal system.
  9. They're the support structure or cage that protects our organs.
  10. But they do so much more.
  11. They work with our muscles to move our bodies.
  12. They store important minerals.
  13. They produce hormones.
  14. And they even make our blood.
  15. Many people think of a Halloween skeleton when they imagine bone.
  16. But that only gives us a one-dimensional view.
  17. Bone actually has three layers.
  18. On the outside, there's the periosteum,
  19. a tough membrane that covers and protects.
  20. There's a thick layer of compact bone the white hard smooth part
  21. that most people are familiar with but inside there is spongy
  22. or trabecular bone and an inner core filled with bone marrow
  23. which contains stem cells that make blood
  24. and are constantly dividing most people understand
  25. that our bones grow when we're kids and adolescents
  26. We reach our peak bone mass in our 20s.
  27. What many people don't know is even after we stop growing,
  28. we are constantly removing old bone and replacing it with new.
  29. One estimate is enough bone is removed and replaced
  30. that a new skeleton is made every 10 years.
  31. Years. After we reach our peak bone mass,
  32. bone removal starts to outpace replacement.
  33. This can eventually affect the integrity of the bone
  34. and lowers the bone mass or the amount of bone that we have.
  35. The bone disease osteoporosis is an extreme version of this process.
  36. Bone loss outpaces replacement.
  37. And combined with other changes, this can lead to so much fragility
  38. that even small bumps or falls can create fractures.
  39. Another cool fact about bones is they store calcium.
  40. So if intake is low, meaning not enough in our diet,
  41. the body draws calcium from the bone.
  42. This can also contribute to bone loss.
  43. So we need enough dietary calcium to maintain our bone.
  44. Vitamin D fits into the picture because it helps our body absorb calcium.
  45. When we think of calcium and vitamin D,
  46. many of us picture a frosty glass of milk.
  47. Milk is not the only good source of calcium out there.
  48. Humans are creative omnivores.
  49. We can get calcium from a lot of other sources.
  50. Yogurt and cheese, for example.
  51. But also look for leafy greens like spinach and kale.
  52. Cruciferous vegetables like broccoli and cabbage.
  53. And proteins like tofu, nuts, beans, eggs, and fish.
  54. Fortified cereals and orange juice are also good too.
  55. And chia seeds.
  56. And vitamin D is plentiful in fatty fishes
  57. and our skin makes it from the sun.
  58. However, some people may need supplements.
  59. Another important factor for bone health is exercise.
  60. Mechanical loading stimulates the cells that build bone
  61. and muscles pulling on the bone may do this as well.
  62. In fact, any activity that puts stress on your bones,
  63. like walking, jogging, dancing, racquet sports,
  64. even strength training, like doing weights,
  65. stimulates extra deposits of calcium and growth of new bone.
  66. In addition, stronger muscles can help with balance.
  67. And one of the best ways to prevent a hip fracture,
  68. reducing falls with better balance.
  69. If milk is your thing, that's completely okay.
  70. But don't forget that bone health
  71. is so much more than just milk.