I've heard this many times, and it makes sense to me - athlete's foot is one of many possible signs of yeast overgrowth, specifically candida yeast. You don't want to simply cure the symptoms when unchecked candida causes so many problems over time, but that said, you shouldn't have to suffer in the meantime needlessly. Going barefoot as much as possible (removing the warm, damp environment for yeast growth), especially in the sun, is supposed to be the best cure. ACV should help, too, since it's antifungal, as is coconut oil.
For helping with the candidiasis, there are several diets that claim to help, but the best approach I've found is just exactly what we're doing primally, and the most reknowned diets for "healing the gut" - the ones that really work (not the Yeast Connection diet which illogically eliminates fungus simply b/c it's another fungus - like eliminating yogurt if you have an e. coli infectxicon), like SCD, GAPS, BED, Maker's Diet - do the same thing. That is, eat only real, unprocessed food, add in probiotic foods (yogurt, real sauerkraut, other fermented foods), and skip all the grains & sugars, which feed the yeast.
If you have a candida overgrowth, it may be very, very hard to eliminate the grains & sugars b/c the yeast cries out for more of its grainy food. I have a specific protocol I've used to battle candida and found it very effective and can share it if you're interested.
5'4" 39yo mother to five sweeties & married to their AMAZING DaddyGrok
Current Weight: 175lb__________________________________Goal: 135lb
Deadlift: 240lb________________________________________Back Squat: 165lb
Bench: 130lb__________________________________________Pre ss: 85lb
***Winning a 20-year war against binge eating disorder***