The Baylor team took a different approach by focusing on a protein called Sox9, a key regulator of gene activity in aging astrocytes. When they increased Sox9 levels in mice that had already developed memory problems and plaque buildup, the results were striking. Astrocytes became more active and began clearing the plaques.

https://scitechdaily.com/researchers-discover-boosting-a-single-protein-helps-the-brain-fight-alzheimers/

Okay, so what foods would support Sox9 in my brain?

Dr RC (Gem):

SOX9 is not a dietary protein. It is not found in food, nor can it be obtained through supplementation.

Because SOX9 is a specialized internal protein produced by your own body, it cannot be "eaten" to increase its levels.
What is SOX9?

SOX9 is a transcription factor—a type of protein that acts as an "on/off switch" for specific genes within your cells. Its name stands for SRY-box transcription factor 9. 

    Internal Production: It is produced internally by the body's own genetic machinery, primarily during embryonic development and throughout adult life in specific tissues.

    Role in the Body: It is critical for the development of bone, cartilage, reproductive organs, and the maintenance of certain stem cell populations. Because it regulates how cells develop and function, it is essential for the structure of your skeleton and the repair of tissues.

Why You Cannot Find It in Diet

    Biological Function: As a transcription factor, SOX9 functions inside the nucleus of your cells, where it binds to DNA to regulate gene expression. It is not a structural protein like collagen or a nutritional protein like those found in meat, beans, or dairy. 

    Digestion: Even if you were to consume a protein that had the same name or structure, the digestive process would break it down into basic amino acids long before it could ever reach your cells or perform any function related to cartilage or skeletal development.

Summary

If you have seen references to SOX9 in the context of joint health, cartilage, or tissue repair, these references are talking about the internal biological process that your body performs naturally. Scientists study SOX9 to better understand how to potentially trigger the body's own repair mechanisms for conditions like osteoarthritis or skeletal disorders. There is no "SOX9-rich" diet.

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Debbie says it'll soon be available at Walmart, Target, Walgreens, & GNC as a supplement.

Well.... high levels of Sox9 are associated with arterial plaque and other issues, so you want the right levels, not higher levels.

However, the fact that it cannot be increased through diet coupled with the fact that you wouldn't necessarily want to increase it in no way decreases the chance of it being sold in 250 tablet bottles in Walmart.

By the way, this is a general problem with the epidemiology of supplements. Often supplements show no benefit, but sometimes thats because there is almost always no benefit, but other times that's because most of the study population is getting enough, some are getting too little, and some are already getting too much so it all balances out. For part of that population, though supplementation is hugely beneficial and for part it may be detrimentall

For things like D3, iron, B12 where both insufficiency and surplus are bad, it's always best to start with a blood test. I haven't had blood work in years, but it's on my 2026 To Do list. In general, though, I'm in the safe range with the three above and I supplement modestly to try to be in the middle to high end of the range.