Laurie's Blogs.

I remember back in the day when it was said, “you can’t turn fat into muscle”.   You had to lose fat and gain muscle.  The two were different substances.  While that’s still true, it doesn’t account for the infiltration of fat into atrophied muscles.  Let’s discuss that topic a bit more.

From Hildebrandt, M., Fankhauser, G., Meichtry, A. et al. Correlation between lumbar dysfunction and fat infiltration in lumbar multifidus muscles in patients with low back pain. BMC Musculoskelet Disord 18, 12 (2017). 

So, studies have shown that people with back pain also tend to have atrophy of their multifidus muscles.  Further studies reveal that the atrophied multifidus muscles also have fatty infiltration, so much so that the cross sectional area of the fatty multifidus might actually ‘measure’ the same as a person without back pain.  

Additional studies have looked at patients with injuries, such as hip fractures.  It’s been shown that a limb with a significant injury will have a higher percentage of low-density muscle (low quality muscle tissue with fatty infiltrate) and a lower percentage of high-density muscle (normal muscle tissue).

In these instances, muscle does ‘sorta’ turn into fat!  Yikes!  If you’ve been contemplating becoming a couch potato, perhaps you should reconsider!

I did a blog on a review paper a while back (December 2022), that was looking at whether the fatty infiltrate was reversible.  

https://www.fourleg.com/Blog?b=597  

The consensus there was ‘no’, you can’t reverse this with 8 – 16 weeks of exercise.  However, I thought, what about animal studies, and in particular studies on mice.  Mice age faster… so perhaps exercising for a shorter ‘real-world’ follow up time would be like long term follow up in a person, and somewhere in between in a dog.

What did I find?  (Not tons… but here’s what I did find)

• Histologic analysis showed that high intensity interval training (HIIT) prevented and reversed muscle atrophy and fatty infiltration.
• Vitamin D supplementation improves muscle loss and muscle functioning.
• β3 Adrenergic agonists (amibegron) may serve as a new pharmacologic modality to treat rotator cuff muscle atrophy and fatty infiltration
• Activating intramuscular brown fat can decrease fatty infiltration and muscle atrophy

HOW can we do this?

Brown fat foods and compounds that boost activity or induce the browning of white fat include turmeric, green tea, chili peppers, fish oil, resveratrol, berberine, and cinnamon. Other ways to activate brown fat include cold exposure and moderate exercise.

All in all, I think the answer is ‘maybe’.  Perhaps it’s that I WANT the answer to be 'maybe'.  I’d like for there to be things that we can do to help with this phenomenon.  Some HIIT, supplements, and cold exposure might also be of benefit!  It's all worth a try anyways!

Until next time…

Cheers!

References:

1. Hildebrandt, M., Fankhauser, G., Meichtry, A. et al. Correlation between lumbar dysfunction and fat infiltration in lumbar multifidus muscles in patients with low back pain. BMC Musculoskelet Disord 18, 12 (2017). 
2. Yazici A, Yerlikaya T, Oniz A.  Evaluation of the degeneration of the multifidus and erector spinae muscles in patients with low back pain and healthy individuals.  Journal of Back and Musculoskeletal Rehabilitation, vol. 36, no. 3, pp. 637-650, 2023.
3. Takahiro F & Shigeharu T.  Skeletal muscle tissue composition ratio in patients with hip fracture: Comparison of fractured side and non-fractured side.  Journal of Back and Musculoskeletal Rehabilitation, vol. 36, no. 3, pp. 669-676, 2023.
4. Zhou H, Wang Z, Chen C, et al. Effect of High-Intensity Interval Training on Fatty Infiltration After Delayed Rotator Cuff Repair in a Mouse Model. Orthop J Sports Med. 2023 May 19;11(5):23259671231170192. 
5. Cheung WW, Hao S, Wang Z, et al. Vitamin D repletion ameliorates adipose tissue browning and muscle wasting in infantile nephropathic cystinosis-associated cachexia. J Cachexia Sarcopenia Muscle. 2020 Feb;11(1):120-134. 
6. Wang Z, Liu X, Jiang K, et al. Intramuscular Brown Fat Activation Decreases Muscle Atrophy and Fatty Infiltration and Improves Gait After Delayed Rotator Cuff Repair in Mice. Am J Sports Med. 2020 Jun;48(7):1590-1600. 
7. Foods that Activate Brown Fat for Healthier Metabolism.  https://thenutritioninsider.com/fitness-weight-loss/foods-that-activate-brown-fat-for-healthier-metabolism/  (Accessed June 24, 2024).