The governor, on a two-day tour to the district's tribal areas, launched the scheme in Udaipur town, 350 km from Shimla, by distributing the tablets among class 6-12 students.
The programme is already running in rest of the state.
Later, she visited Trilokinath and Mrikuladevi temples and offered prayers.
"Mahila mandals" (women groups) accorded Singh a traditional welcome at both places and honoured her with a cap and shawl. Legislator Ravi Thakur accompanied her.
Appreciating the scenic charm, she said the Buddhist monasteries and temples of Lahaul-Spiti attract tourists from India and abroad and the area has a vast potential for tourism development.
It is also a favourite destination for adventure lovers, she added.
Singh said the culture of Lahaul valley has its own uniqueness and should be preserved. She stressed on generating environment-protection awareness to protect the area's natural beauty.
The landlocked Lahaul valley remains cut off for at least five months from November-December owing to heavy snow accumulation at the Rohtang Pass (13,050 ft) -- the only road connecting Manali in Kullu district.
It reopens once the snow starts thawing towards April-end.