Weirdly this just happened to me too! Two days ago every single one of my nails broke. That's never happened to me before.
The only thing I changed in my diet lately is that I've cut back on dairy (I was eating too much - now I just consume a little). About a week ago, I started taking supplements and eating bone broth daily. Weird. Could it be a shedding or something...?
"I think the basic anti-aging diet is also the best diet for prevention and treatment of diabetes, scleroderma, and the various "connective tissue diseases." This would emphasize high protein, low unsaturated fats, low iron, and high antioxidant consumption, with a moderate or low starch consumption.
In practice, this means that a major part of the diet should be milk, cheese, eggs, shellfish, fruits and coconut oil, with vitamin E and salt as the safest supplements."
- Ray Peat