Former Yukos owner Mikhail Khodorkovsky was put in a solitary confinement cell on March 17 for violating the food rule. His lawyers protested against the regulation in court, calling it an "affront to human dignity."
However, prosecutors said infringements to human dignity were clearly defined by international law, and that this rule in no way violates prisoner rights.
The oligarch's lawyer, Yury Shmidt, said: "We were seeking to have these rules annulled. The stakes were very high on this issue. So far, Khodorkovksy has had two penalties." The attorney said he intended to appeal the Supreme Court's decision.
Khodorkovsky has also been put in solitary confinement for holding prohibited documents and drinking tea in an unsanctioned area, but a court ruling later acknowledged that the first punishment was ungrounded.
Shmidt said he had insisted the court acknowledge that the food rule infringes human dignity, and called for improvements to the living conditions of prisoners.
Inmates who repeatedly violate such rules can be denied the chance of an early release.
Khodorkovsky has now served three years of an eight-year sentence for fraud and embezzlement in a Siberian penal colony. Shmidt, who visited his client on October 25, said the complaints against Khodorkovsky merely showed the desire of prison staff to please their bosses.
