When experts discuss what keeps the Cuban economy afloat, they usually focus entirely on tourism, overseas remittances and the export of nickel, tobacco and rum not to mention the big chunk from Venezuelan subsidies.

Less talked about is Cuba’s foreign policy and its importance to the economy.

In the early 1990s, the Castro government learned a crucial lesson: that Havana’s diplomatic ties around the world could play a key role in generating cash by becoming a useful partner to a growing number of nations.

That’s the essence of “doctor diplomacy” ranging from the thousands of physicians in Venezuela to Brazil’s recent hiring of 4,000 Cuban doctors through the Pan-American Health Organization.

And these doctors have an additional skill: they speak Portuguese, thanks to their experience in places like Angola, Cape Verde, Guinea-Bissau, Mozambique and Timor-Leste.

South Africa is another prime example. In 2012, the number of Cuban doctors there jumped from 119 to 213 in the wake of an exodus that has seen half of that country’s physicians emigrate to Canada and elsewhere.

The South African government is also sending scores of students to Cuba, paying for their scholarships to become doctors.

In addition, Cuba’s close friends Brazil, China and others are eyeing Cuba’s biotech and pharmaceutical potential, especially given the lower prices of Cuban products compared to their U.S. and European rivals.

Cuba not only provides medical services to Haiti but also produces millions of vaccines to fight meningitis in Africa, often in joint ventures with Brazil and other countries.

Similar ventures are funding the construction of four hospitals in Haiti, while Venezuela is financing the rebuilding and expansion of an international airport in Cap-Haitien by Cuban experts.

In coordination with Venezuela and the Economic Community of West African States (ECOWAS), Cuba has built factories for the production of biolarvicides to fight malaria and dengue in countries like Ghana, Gabon, Côte d’Ivoire, Nigeria and Equatorial Guinea. And in Latin America, Cuban biofertilizer plants are rising in Ecuador and El Salvador.

South Africa now one of Cuba’s top customers for biotech and medical products is funding similar projects at home and in Tanzania. President Jacob Zuma recently cancelled Cuba’s $159 million debt and approved a $41 million aid package to Cuba.

Angola, another “brother in arms,” finds Cuba to be a useful and not too expensive partner. Cubans can be found from Cuando Cubango (“the end of the world” as the Portuguese colonists used to call it) to Huambo, Luanda, Bengo and other Angolan cities, building roads, highways, bridges and hospitals.

Wealthy Arab states, following in the footsteps of Qatar, are also linking up with Cuba.

Ibrahim Abdulaziz Al-Assaf, the Saudi minister of finance, recently awarded Cuba a $30 million grant to renovate Havana’s water supply system. Likewise, the Kuwait Fund for Arab Economic Development is paying for the complete reconstruction of the water systems of Santiago de Cuba and Holguín.

In 2011, Cuba and Saudi Arabia opened embassies in each other’s capitals, and in 2012 Foreign Minister Bruno Rodríguez Parrilla visited Riyadh along with Dr. Carlos Manuel Gutiérrez Calzado, CEO of Biopharm-Cuba  a clear indication that these very rich markets also view Cuba as a useful partner.