Aidan:
Hello and welcome to the Ideal Nutrition Podcast. This is episode 202 where we’re going to be talking about nutrition requirements through aging. And we’re going to be covering a range of topics. We’re going to be talking about things like anabolic resistance, calcium, iron changes, other micronutrients. As a quick disclaimer, we obviously can’t cover everything. So we’re going to try and cover as many key points as we can. One of the biggest examples in this disclaimer is we’re not going to go into specific areas in detail.
For example, when I was writing this up, like the notes for ourselves in advance, I was thinking, I was like, what could be missed in this podcast? And one of the clearest examples that came to my mind is menopause. And we probably won’t talk too deeply about menopause in this. And one of the reasons is I, if I talk about that, I really want to do it justice. And I don’t really want to do it in passing. That’s my own two cents. That’s how I create content. That’s how I think about things, but we’re going to try and do a broad coverage of a lot of other things and maybe a tiny bit on that of how nutrition changes through aging.
Leah:
So the first thing we are going to touch on that happens as we age is the concept of anabolic resistance. So as we age, our muscles actually become less responsive to the usual signals that trigger muscle growth, like protein intake and resistance training. And this is like termed anabolic resistance. And there are several mechanisms that we can point to that cause this over time although a really large one is likely the reduction in certain hormones as we age. So things like testosterone and oestrogen.
So again, as Aidan said, we’re not gonna go too deeply into menopause, but there is definitely a lot to talk about there in regards to anabolic resistance. So in practice, this means that like older adults may actually need more protein to have the same anabolic effect or same impact on muscle protein synthesis in a single meal than a younger person.
So for example, a younger person may be able to consume 20 grams of protein in a meal and this will have a really great anabolic effect. And then maybe the equivalent for an older person with reduction in testosterone, oestrogen and other factors, they may actually require like 30 to 40 grams of protein in that meal to have an equivalent impact on muscle protein synthesis.
So this is a concept that is generally well accepted in the evidence-based space, but it’s also important to note that the overall daily protein requirement to like quote unquote maximise muscle growth is pretty much the same across the board, whether you’re a younger person or an older person. And generally we are aiming for that over 1.6 gram per kilo body weight mark. So rather than getting too caught up in the idea of anabolic resistance, I’d recommend you focus on a few key points.
So the first one would be just generally eating enough total protein each day. So ideally over that 1.6 number, spreading it out across meals if possible, staying active, especially incorporating some level of resistance training, and then also getting an adequate amount of calories overall.
Aidan:
Calcium is another one that changes throughout the lifespan as well, where up until 50 for both men and women, it is at around milligrams per day for the recommended daily intake. Post 50 for women, it changes to 1300 milligrams, but that’s a very un-nuanced way of saying that post menopause it changes.
So post menopause, when oestrogen has dropped, bone marrow density typically declines. And that is actually a major concern that we would want to address or try to minimise the risk of. If somebody went on HRT, that would in like that would address that to a degree because oestrogen wouldn’t drop. But without that, but without that, we’re looking at a few things that can help bone marrow density.
Calcium is obviously the one that is top of mind for everyone, which is why there is that increase. But there’s so many other variables. Like if we’re looking at from a nutrition perspective, there’s things like vitamin D, vitamin K, potassium, magnesium, phosphorus, and overall protein intake as well. Another massive one is that the stimulus on the bones
Arguably matters even more than nutrition. Staying active is a huge thing and staying active in multiple ways. For example, like just walking and stuff like that is a great step. But if you’re doing some form of resistance training, even better, one that often goes missing relatively early in life is some form of plyometric activity or jumping. The longer you can keep that in your routine in some way, or form, the better bone marrow density tends to be.
But even just resistance training, like I see, we obviously have a DEXA scanner at ideal nutrition and everyone I see who lives why it’s typically has good bone real density. There’s such a strong correlation and it seems to matter more than a lot of other things. So this calcium thing does matter. But one of the reasons I’ve actually added so many layers of context there is I do not think many people are going to be getting 1300 milligrams of calcium. And it’s actually one of the few things that I’m less pressed to address than other things.
I think people shouldn’t be super, super far away from that. But say somebody was at 700 to 800, I’m less concerned with getting them to 1,300 milligrams than I am if somebody was at like, I don’t know, 60 to 70% of another recommended daily intake of another nutrient.
Leah:
The next one that can shift over time and as we age is iron requirements. So we can talk about this in regards to life stages as well, but also again, just generally as we age. is this something that does shift?
So for adult men and postmenopausal people, the recommended daily intake for iron is eight milligrams per day, which is generally pretty easy to meet through a quote unquote balanced diet. For premenopausal people, however, so people that have a regular menstrual cycle, the RDI increases to 18 milligrams per day due to the iron losses, again, through menstruation.
There is quite a large degree of like there’s a spectrum here. Like if you have really heavy, very frequent periods, your iron requirements may be higher than that. If you’re someone that has very light periods or uses hormonal contraception to skip periods or anything like that, then your needs are likely lower. So again, there’s a spectrum, but the RDI is 18 milligrams per day. So a little bit higher than the recommended intake for people that don’t have a menstrual cycle.
And this is why a lot of people with a cycle do and can become iron deficient because 18 milligrams per day is actually a pretty large amount, but not quite as large as during pregnancy. So obviously not everyone gets pregnant as they age, but it’s like a life stage in which your iron requirements do shift. So there is a pretty sharp rise to 27 milligrams per day and it’s pretty unlikely that this is going to be met through just diet alone.
So supplementation is typically recommended. So just talking about generally as we age, there can be an issue with a decrease in absorption and chronic illness and medications and things like that can actually increase your need for iron because maybe you’re not absorbing enough, maybe there’s kind of issues through that gastrointestinal system. So even though you might be going from the requirements of like 18 milligrams a day as a premenopausal person and then as you no longer have a cycle, those needs decrease, they may start to increase again, kind of as you head into like later stages of life.
So we’re thinking like 60, 70, 80 kind of age ranges. So there can be an issue with that and then that can lead to deficiency over time. And then kind of just a side note is that again, not a life stage or an aging thing, but plant-based diets also increase your, your needs for iron due to the lower absorption of non-heme iron versus he mine that you’re going to be finding in your animal based foods. And then we would just times the RDI by 1.8 in those circumstances.
Aidan:
B12 is an interesting one where the recommended daily intake is listed as 2.4 micrograms for all stages of life or for all adults onwards. actually don’t know what they are below 18, but 2.4 all the way through from like 18 through to 70 plus. But it’s interesting to me because it’s quite rare for somebody to be deficient at a younger age unless they’re plant-based and not supplementing or other people would like they can have deficiencies.
It’s just quite rare, but I spoke about this on a previous podcast that like in aged care homes in Australia, greater than 10% of people are deficient and around 30% are close to being deficient. We know very clearly that absorption of B12 typically decreases over the lifespan. So it was interesting that the technical needs and according to the RDI don’t change, but you could make a very strong argument for needing to pay more attention to that as you age.
That could be as simple as a blood test though, just checking in on that regularly just to see. And then if it is starting to drop or anything like that, you can just address that through either dietary changes or supplements.
Leah:
The final point we’re going to touch on is less nutrient-based, but just talking about general appetite as we get older. So appetite often does decrease as we age, which can make it harder to meet nutritional needs. So again, this is probably more talking in the context of like elderly people.
So, I don’t even want to add a number to that. Well, I’m not going to add a specific number, but I’m just thinking like, obviously, if you’re someone who is 50 and gone, my appetite stay the same or is increased. It’s like, okay, we’re probably not quite reaching the age in which this would maybe take a large dip just yet. So we can get, again, this decrease in appetite.
Typically this is going to be linked to reduce physical activity, changes in body composition, but it is still crucial to meet your caloric needs to support strength, immunity, quality of life, kind of generally, quote on quote, healthy aging. Cause as we get into the later stages of life, malnutrition is a lot more common.
Another interesting thing is the concept of a healthy weight also shifts with age. So although BMI is not like this perfect measure that has no issues whatsoever, the optimal range tends to move from 18.5 to 25 in younger adults as being kind of the quote on quote healthy range to around 22 to 27 or even up to 30 in some cases for like older adults. So this shift is linked to better outcomes in general quality of life and health.
So things like lower risk of falls and fractures, largely due to there being better muscle and bone retention with that slightly higher body weight. That being said, much of the benefit of the slightly higher body weight can also come from staying physically active, trying to maintain your muscle mass the best that you can rather than from the weight alone.
Aidan:
If we have any listeners who are 70 plus years old, feel free to get in contact. Love to hear from you.
Leah:
Yeah. And do you consider yourself elderly and at what stage?
Aidan:
Let us know. Even my Instagram, email, whatever way you want to get in touch. I personally, so I used to work a lot in that age range in previous jobs. And so I found it a little bit conflicting at times would be if somebody was in that age range and they were like borderline, what would be considered healthy by standard BMI metrics or anything like that, but wanted to lose weight.
And let’s say hypothetically, they didn’t have any health conditions, obviously above a certain age, most people will have some form of health condition. And they just wanted to do it just to either improve health, vanity reasons, whatever it is. It is a conflicting one, particularly if they were not super active or did not want to be super active or were not able to be super active, because it would make me wonder, is this improving their health?
Or is this increasing the risk of falls and fractures and a few other things as well? So like I find that interesting challenge and the BMI quote on quote like range like it does tend to increase the physical activity one is the main one. Like if you can do that, you do have stronger bones, you do have stronger muscles. It helps with everything like that. Is there anything else we should cover or do you reckon that covers everything we want to talk about today?
Leah:
I think that covers everything.
Aidan:
Well, this has been episode 202 of the Ideal Nutrition Podcast. As always, you have not already, if you could please leave a rating and review, that would be greatly appreciated.