The Celtic midfielder divulged in an interview with the UEFA website that Italian football is rife with racism.
Nakamura turned out for Reggina for three seasons before joining Celtic in 2005, and for him, there were difficulties adapting when he moved from Japan to Italy.
"It's very difficult for a Japanese player coming to Europe," said Nakamura.
"There are so many factors in different countries, ranging from the style of play to the obvious cultural differences.
"Sometimes you get racism as well, not in Scotland, but in Italy, which is not nice, and that probably explains why so few Japanese players have made it here."
Nakamura's stint in Italy was impressive and he helped Reggina retain their top flight status every season he was there. After three seasons, he left for Scotland to play for Celtic in 2005.
Compared to Italy, Nakamura says he is more settled in Glasgow. And, that is helped by his wife and young son joining him in Scotland.
"My son is now two-and-a-half years old and going to nursery in Glasgow. He speaks better English than I do," joked the midfielder.