Not exactly. That old adage was a bit of folk lore or "wives tales" that derives from a longer version sourced from Wales in the 1860s. However, as with most "wives tales" there is some truth behind what was being said.
Apples contain many nutrients such as vitamin B, C, fiber, calcium, and potassium. A study published in Experimental Biology and Medicine shows that eating an apple can also improve your neurological health because it contains a high amount of quercetin, which reduces cellular death in the brain. Other studies have also found that eating apples can prevent dementia and reduce your risk of having a stroke and getting diabetes.