Yes. You would need to find a financial institution that can facilitate these currencies in a retirement account. Many are unable to do so, as their systems are not programmed to perform the currency conversion necessary to satisfy IRS tax reporting requirements, which must be done in U.S. dollars.
To learn more, see Wading Into The Currency Market.
Question answered by Denise Appleby, CISP, CRC, CRPS, CRSP, APA