Lifting and Lipids: Exercise Reverses a Signature of Aging in Fat

When I say fat, you probably think of a blob of amorphous jiggly tissue that contains stored energy or stored calories. But the fat or lipids that fills and fluxes through our bodies is so much more complex. And there are thousands of different lipids, each with fascinating metabolic functions that we are still exploring. And a new paper in Nature Aging entitled "A conserved complex lipid signature marks human muscle aging and responds to short-term exercise" has discovered a lipid signature of aging as well as a simple way to reverse it. So let's dig in. Welcome to my channel. Stay curious. Now, to gain a better understanding of the lipid signature of aging, they started in model organisms, particularly mice, taking 10 different tissues— those you see here— from young mice, 3 months old, and old mice, 2 years old. And they identified over 1,200 different lipids. Over 21 different lipid classes and found that the top 10 lipids that were significantly enriched in most tissues in aging mice were all from the BMP lipid subclass. BMP stands for bismonoacylglycerol phosphate, and it's a complex lipid class implicated in neurodegenerative diseases, cancer, and other disorders. So in brief, they found that accumulating levels of BMP lipids constituted an aging signature in mice. But does this hold true for humans? To answer this question, the researchers took muscle biopsies, particularly muscle biopsies, from young 20 to 30-year-old or older 65 to 80-year-old human adults. And again, like in the mice, they found elevations of BMP lipids accumulating in the muscles as we age, as can be seen in this graph. Basically, the red dots here indicate lipids that accumulate with age, and those above the horizontal line in panel B are significantly enriched with age. And as you can see, there is a lot of BMP lipids And now for my favorite question addressed by the study, and maybe your favorite question too, if I may be so presumptuous. Can you rejuvenate your aging lipid signature? Can you attenuate, decrease BMP levels? Or are we just stuck with an aging lipid signature no matter what? Well, the answer is yes. You might have gathered from the title, we can rejuvenate our aging lipid signature, reduce BMP levels with exercise. So in a study, they took 12 overweight older women who underwent a randomized crossover trial through 3 phases. Each phase lasted 4 days, and there was a sedentary phase whereby women were sitting 14 hours a day, an exercise phase whereby they took one of those 14 hours and actually exercised vigorously during it, or moderate to vigorous exercise. So 13 hours sitting, 1 hour exercise. That was the second arm. And then they had a third arm whereby they were doing a little bit more standing and walking, but not vigorous exercise. And they wanted to see, would more standing or walking or more vigorous exercise reduce BMP levels, reverse the aging signature. And what they found was that moderate to vigorous exercise for just 1 hour a day for 4 days was able to significantly reduce BMP levels, reverse the aging signature, as seen here in this graph, which is super cool. Now, that said, these data do have some limitations. For example, in the human study, only short-term effects of exercise were examined. We don't really know what the chronic effects of exercise would be in chronic exercisers. I think overall the data are very strong, that a routine, an exercise routine, is very good for healthspan and longevity, but we don't know what the effects on BMP levels will be. I speculate that the more you exercise over time, the lower your BMP levels will be, the more you'll rejuvenate your lipid signature. Also, we only have muscle biopsy data. It's harder to get data from, say, a liver biopsy in generally healthy humans. So we only have one tissue in older adults, although I would suspect this would generalize across tissues as we saw in the mice. It's also not clear whether the BMP accumulation, the aging signature, is a cause or a consequence of the physiology of aging. That still needs to be worked out. Nevertheless, I think these data provide interesting new evidence that exercise is anti-aging and that this is an added benefit of exercise that can be measured in the lipid signature of the lipids circulating around, fluxing through our bodies, which is super cool. So that said, I will leave you with one final question and I want you to answer in the comments. What is your favorite form of moderate to vigorous exercise? And also, does does this video change your perspective on exercise, and is it going to change your exercise patterns? Let me know. So this video was pretty short. I thought I'd take some time to tack on some rapid-fire bonus questions or Q&A about an exercise-related topic, protein. So let's just dive into it, and you can let me know if you like this format and what questions you have, and if you want me to do another episode on protein or exercise and what topics I should cover there. And that said, let's go. How much protein someone should eat is a common question. The RDA, in my opinion, is very, very low at 0.8 8 grams per kilogram. I think that's way too low. From what I've heard from experts, 1.6 grams per kilogram will be sufficient for most protein needs. Now, if you go higher than that, there may be some benefits on things like satiety. You can play around with that. I don't think it's necessarily harmful provided you don't have kidney disease, but 1.6 grams per kilogram should be sufficient for most purposes. Moving on, do you need to space protein throughout the day? The answer is no, not really. There might be a tiny, tiny edge to spacing protein if you're like a very high-level, say, bodybuilder,. But in general, it's more about the total protein you eat over the course of the day. So you can block it into two large meals if you want. That's what I do. Now, as for plant versus animal protein, there's a lot of debate about this. People saying plant proteins are suboptimal, they have low bioavailability. I would say this is more or less a myth, but it's a myth based in some truth. As a class, plant proteins tend to have lower bioavailability than animal proteins and a slightly different amino acid profile. But the fact of the matter is there are plant proteins with high bioavailability. Say soy protein has much higher bioavailability than, say, peanut protein. And also Also, bioavailability isn't as important if you're not like teetering around the RDA. If you're, say, eating 1.6 or 1.8 grams per kilogram of protein, then you'd be getting enough protein whether or not you're eating animal protein or plant protein. As for plant protein and amino acid composition, plant proteins can have a different amino acid composition, but all plant proteins— listen to me here— all plant proteins contain all essential amino acids. And if you're eating a diversity of plant proteins and you kind of sum the amino acid profile over the day, it's not that different from eating animal proteins. So if you prefer to eat plant proteins for whatever reason. I prefer animal proteins, but if you prefer plant proteins, then I say go for it. I don't think it's going to negatively affect your muscle building or athletic performance, and I hope that myth will die. Don't know if it will, but hope it does. Another question— this is more exercise than protein— relates to keto adaptation and how long keto adaptation takes to get back exercise performance. And I would say it depends on the kind of exercise performance you're looking for. For steady-state cardiovascular exercise, generally about 6 weeks. After about 6 weeks, you'll have sufficient keto adaptation, fat adaptation on a strict ketogenic diet to recover your steady-state cardiovascular performance. Now, highly glycolytic activities, things like sprints, will take a little bit longer to recover because you want to recover your muscle glycogen stores, and that can take many months, even up to a year. Now, the fact of the matter is we don't have great data on long-term keto adaptation and highly glycolytic activities. So there is a gap in the evidence base there. But I would say in general, for steady-state cardiovascular, 6 weeks. For highly glycolytic activity, it can take much longer, months to maybe even a year. And it's not even clear then if your full performance will be recovered. I have my opinions. I think it can be, but that's still in the realm of unknown. And then the last exercise-related thing I wanna plug is on a video that I also just released on L-citrulline, an amino acid. So it does relate to protein. It was a super cool paper showing that L-citrulline can talk to osteocytes. In bone and help coordinate bone's response to mechanical loading. So things like running or weightlifting, you know, go do leg day. You really want your bones to remodel properly when you mechanically load them, and L-citrulline potentially can augment that effect, making your bones stronger in response to exercise. Go check out that video. It covers a fascinating new paper, and I hope you enjoy that as well. With that said, have a great day and go get some exercise.