In today’s episode we explore a topic that evolved out of a conversation between Dr. Stephen Gasior and Lissa McNeil about how to keep your bones healthy as you age. It turned out to be a deep and fascinating conversation with many twists and turns that we’re sure you’ll enjoy. Below is a short list of terms and their definitions to help you navigate the discussion. Enjoy!
osteocytes -- cells that maintain bone; live in lacunae
lacunae -- small pits or cavities in bone
osteoblasts -- cells involved in building bone
osteoclasts -- cells involved in breaking down bone
senescence -- a state of cells in which they become largely inert
senolytics -- a compound that causes a senescent cell to self-destruct
resorption -- when bone is broken down and its minerals are released into the blood
ostoporosis -- a state of bone characterized by holes and brittleness
ostopenia -- a state of bone characterized by low bone mass or low density
apotosis -- when cells self-destruct
Lynne: Welcome today to the Ageless Mind Project podcast, "Voices from the Field", where we talk with a wide variety of proactive agers and experts to explore how each of us can design our own version of an ageless mind: one that's alert, curious, creative and ever growing.
These podcasts are meant to give you tools to increase your well-being and quality of life at any age. Today, Steven Gasior Ph.D, our resident expert on the science of aging, has returned to answer questions from one of our subscribers, Lissa McNeil. Lissa has asked us to explore the subject of bone health, something that's crucial for physical stability in both men and women. Falls are one of the top causes of disability and even death, especially as we age. So learning how to take care of our bones is a key part of designing an ageless mind — sound mind in sound body. Lissa, please introduce yourself and go ahead with your questions for Stephen.
Lissa: Thank you Lynne. Good morning, Dr. Gasior. I also work with Lynne promoting healthy body, mind and spirit. My first question for Dr Gasior is: how are calcium and vitamin D connected, and what hormones are important in bone health?
Dr. Gasior: Good morning and happy be here again to talk about healthy aging. And you point out one of the really key materials in the body that are important: both calcium as a major component of bone, as well as the regulation of how bones form and grow and maintain strength throughout life. So, bones you can think of as that main structural scaffold of the body, just like the steel girders are in a building. If you don't have a good strong framework and matrix for which things can also use leverage and build off of, then you don't have a sound structure — and bone, in terms of being a kind of — what are the components of bone and how is it actually formed —it really is primarily a mixture of an organic and inorganic set of compounds, and the inorganic is a crystal or mineral of calcium and phosphate, and so that's really where the main structural density of it comes from.
Then also collagen, which is an important connective tissue in the body, is what forms the majority of the organic part. Bones play this important role in that they are a structural point where other things get leveraged from them, and so muscles also have to work well with bones. So with calcium being an important component, and you get calcium from your diet as well as phosphate, the key role of vitamin D is to help with the absorption of those minerals from your diet into your body, and so that's why vitamin D plays a very important role. As a secondary role, vitamin D is also important for muscle health and muscle strength, and so your bones, that whole combination of the muscle and skeletal structure, relies upon vitamin D for overall strength and health.
Lissa: Thank you. Just as a follow-up to that first question, there seems to be a balance between calcium and phosphate being incorporated into the bone matrix and being taken out of the bone for use in other body processes like metabolism. Is that called resorption?
Dr. Gasior: Yes, that is resorption, and it's a pretty critical process for the body, because calcium in particular is used for a lot of enzymes and chemical reactions in the body, and then phosphate is also used as a buffering system in terms of maintaining the right pH in your blood and within cells, and so the body has to maintain adequate amounts of that within those cellular processes and the bone can act as a reservoir, that if you need some more you can draw it from the reservoir.
The regulation of when resorption happens is actually very interesting. That one of the best examples of maintaining this balance is in pregnant women. and so in order to form a new being there's a lot of reallocation of bodily resources including calcium and phosphate, and so that's something that can happen is that you can have a pregnancy related decrease in bone density, which usually comes back with a healthy diet and healthy living after the pregnancy.
Lissa: Well that's encouraging, and something to watch out for when you're pregnant. As we age, what happens to the cells that create bone tissue?
Dr. Gasior: So yeah, so bone like everything in your body that's structural, it is somehow being formed by cellular processes, cells that are dedicated to that function of building bone, healing bone, maintaining bone and also basically taking bone back apart. So, let me give a couple of names here.
First is osteocytes. These are cells that live within bones and are important for maintaining the structure of them, and they live within little holes within bones, and they're also very good at sensing what the bones need, whether they're undergoing stress or undergoing a loss of minerals.
Now osteoblasts are a specialized type of cell that are primarily involved in laying down and building that new bone matrix. And so, especially when you're young you have lots of osteoblasts being active in order to lengthen and grow the bones. They're also present when you get a bone that's broken-- they come in and try and lay down new bone in order to, you know, refashion it to a nice strong bone.
And then the third class are osteoclasts. These are the type of cells that break down bone tissue because, again, while you're doing growth or while you're doing a healing process, there can be excess that's built there, but also of course it's important that you have osteoclasts being active in those cases where you need calcium and phosphate back for other cellular processes. One of the key things to understand in the body — and as we're talked about in aging — is that the ability of each of these cells to do that role can change over time.
One thing we know is that when we're young and have lots of growth hormones coursing through our bodies, then of course the osteoblasts are highly active. Then, as we get older, how well the body regulates the osteoblasts and osteoclasts can start to change. Osteocytes can also start to age and lose some of their ability to maintain bone structure.
Lissa: Do they become senescent or, like, dormant?
Dr. Gasior: That is a really good question because the process of senescence, which is something that we know is associated with aging, is a process where cells start to lose their identity, lose their ability to function in the way they're supposed to. It is a commonality of aging in many different ways.
In looking through the literature and seeing what's known specifically about senescence in osteocytes and osteoblasts, there hasn't been a lot of definitive work that's been done yet. I think the positive things in the field are that people have started to look at senolytics as a way to treat osteoporosis or other bone function, things that, say, come from usage injuries or arthritis, and so there are actually a lot of exciting clinical trials going on. But right now, it's very much at a nascent phase of understanding this association. However, if you were to ask me to lay some bets on it, I think it would be a pretty easy bet that there will be some degree of association and some benefit from looking at it from a senolytic perspective.
Lissa: That's encouraging and something to look forward to. Thank you. I have one final question for you Dr Gasior. How does exercise help us strengthen our bones and joints?
Dr. Gasior: This is a great question because, while the field of thinking about drug interventions for bone health is still very new in terms of aging, we've known for the longest time that doing exercise, doing things that have impact on bones is a great way to maintain healthy bones. The key part, as I've mentioned before, is that when you think about osteocytes and osteoblasts, bones have an incredibly unique structure. They're one of the few types of compounds where the more you use them the stronger they get, right? When you think about a building with steel girders, eventually with enough wind and ground shifting and usage, it is always more likely to fail. Whereas with bones, the more you use them - the more you introduce micro fractures, the more you introduce stress points — the more you activate osteocytes to respond to that stress by laying down more matrix. And that's actually what leads to stronger and more dense bones via exercise.
It's been known for a long time that —especially for young women — the more you increase your bone density as a young person, the more of a reservoir of strong healthy bones you have as you go through life. But the other important thing to keep in mind when one's doing exercise, especially for bone health and density, is that the mere fact that you're using your muscles and creating stress and tension on bones means you are helping maintain their strength. And so this combination of doing exercises that have impact and movement is very important for helping build bone density as well as muscle strength. And those feed back on each other.
Finally, it's always important to keep in mind that maintaining good flexibility of your joints, which is based on the tendons and ligaments that are the tissues connecting all these together, helps maintain bone health as well. The other thing I will say - as a kind of little side story - is that for people who have difficulty exercising, there have been lots of studies showing that vibrations can actually help increase muscle and bone density. That's because the body’s cells are reacting to this vibration that's moving through the body. They've shown in mice that you can increase bone and muscle density by having them stand on a plate that's just vibrating at a high frequency. So there are multiple ways to think about helping maintain bone and muscle strength, even if exercise in some cases can be a problem.
Lissa: That's really good to know, and I agree we can all use some good vibes. Well thank you very much, Dr Gasior. Any tips for our listeners on what they can do to maintain their bone health?
Dr. Gasior: So, the main things are to make sure you're eating a good healthy diet that includes the components of vitamin D, you know, calcium phosphate compounds. Vitamin D is something that you also get from sunlight.
A key thing to keep in mind is that there was a scourge of a disease called rickets in Europe when people were avoiding sunlight : so, vitamin D. One of the main ways that we build it in our body is through exposure to UV light, and so those are all things that are good. But maintaining healthy exercise movement, making sure you're doing exercises that have some degree of strength or impact component to them, are really important for the body’s health.
Lissa: Excellent, thank you for your time and we'll look forward to another podcast.
Dr. Gasior: I'm looking forward to it too. Thanks for your questions. This has been an excellent discussion.
Lynne: Stephen and Lissa, thank you for letting us sit in on your conversation. Actually it raised a lot more questions for me about how I can do things for my bones at the age of 85, so I'd like to have you both back to talk about some of those questions.
And to our subscribers, do you have questions you'd like to ask Stephen? Put them in the comments below or send them to us at AgelessMindProject@gmail.com. Maybe you'd even like to come on the show to ask your questions.
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Voices From the Field - Exploring Bone Health