Well, this is a bit disturbing. I wonder if anyone else knows more on this topic?
I've spent a couple of hour digging into it and it seems legit. Research in the past few years suggests that pentadecanoic acid (C15:0) is likely to be an essential nutrient for human beings, being deeply implicated in longevity, prevention of diabetes and fatty liver syndrome etc. It also has recently been implicated in a new form of cell death resulting from fragile cell membranes interacting with iron homeostasis, both featuring in such diseases as metabolic syndrome.
Long story short, low levels of C15 can lead to cellular instability and may be a causal factor in a range of modern syndromes and disease.
www.ncbi.nlm.nih.gov
This is important for vegans because there is pretty much no C15 in most plant foods (or at least, so far I've not found any evidence there is a lot in plant foods, but I have read suggestions that leafy greens may be fair sources). C15 is found mainly in dairy and meat, though for most Westerners this can be a problem because those sources are also high in saturated fats.
www.mdpi.com
Anyways, there seems to be a growing concensus that C15 is an essential fatty acid and that modern Western populations may be at increased risk of disease from low circulating C15 levels. Some research suggests that C15 on its own may be a suitable option, becauae then it's not included in the whole food matrix that also contains high levels of sat fat. Apparently there are now C15 supplements available, including vegan options such as Fatty15.
www.nutritioninsight.com
Interestingly, the diet of Sardinians may be an example of the benefits of higher dairy consumption and hence greater intake of C15. Though their diet is sometimes unusual and they seem often to be in caloric deficiency, their preference for a mostly plant and dairy based diet may be what makes them especially long-lived.
journalofethnicfoods.biomedcentral.com
What do we do? Is this for real or just a scare story to promote the selling of supplements? Sure looks genuine to me.
I've spent a couple of hour digging into it and it seems legit. Research in the past few years suggests that pentadecanoic acid (C15:0) is likely to be an essential nutrient for human beings, being deeply implicated in longevity, prevention of diabetes and fatty liver syndrome etc. It also has recently been implicated in a new form of cell death resulting from fragile cell membranes interacting with iron homeostasis, both featuring in such diseases as metabolic syndrome.
Long story short, low levels of C15 can lead to cellular instability and may be a causal factor in a range of modern syndromes and disease.

Pentadecanoic Acid (C15:0), an Essential Fatty Acid, Shares Clinically Relevant Cell-Based Activities with Leading Longevity-Enhancing Compounds
Pentadecanoic acid (C15:0) is an essential odd-chain saturated fatty acid with broad activities relevant to protecting cardiometabolic, immune, and liver health. C15:0 activates AMPK and inhibits mTOR, both of which are core components of the human longevity ...

This is important for vegans because there is pretty much no C15 in most plant foods (or at least, so far I've not found any evidence there is a lot in plant foods, but I have read suggestions that leafy greens may be fair sources). C15 is found mainly in dairy and meat, though for most Westerners this can be a problem because those sources are also high in saturated fats.

The Cellular Stability Hypothesis: Evidence of Ferroptosis and Accelerated Aging-Associated Diseases as Newly Identified Nutritional Pentadecanoic Acid (C15:0) Deficiency Syndrome
Ferroptosis is a newly discovered form of cell death caused by the peroxidation of fragile fatty acids in cell membranes, which combines with iron to increase reactive oxygen species and disable mitochondria. Ferroptosis has been linked to aging-related conditions, including type 2 diabetes...

Anyways, there seems to be a growing concensus that C15 is an essential fatty acid and that modern Western populations may be at increased risk of disease from low circulating C15 levels. Some research suggests that C15 on its own may be a suitable option, becauae then it's not included in the whole food matrix that also contains high levels of sat fat. Apparently there are now C15 supplements available, including vegan options such as Fatty15.

C15:0 unveiled as essential fatty acid “we didn’t realize we were missing”
08 Jan 2021 --- US-based Seraphina Therapeutics has launched fatty15, a supplement touted as “the first and only” one to contain the pure fatty acid C15:0.C15:0, or pentadecanoic acid, is positioned as the first essential fatty acid to be discovered in the past 90 years, backed by a growing body...

Sardinian dietary analysis for longevity: a review of the literature - Journal of Ethnic Foods
Sardinia is one of the five Longevity Blue Zones (LBZs) in the world. Compared to other LBZs, the percentage of male centenarians in Sardinia is much higher. Due to the island’s isolation, the genetic traits of Sardinian people have shown that they are direct descendants of their Nuragic...

What do we do? Is this for real or just a scare story to promote the selling of supplements? Sure looks genuine to me.