Former Cuban leader Fidel Castro has returned to writing with a vengeance, publishing five columns since Jan. 5 and after a seven-week break that triggered a wave of rumors that the health of the 85-year-old had taken a turn for the worse.

A check of Castro’s writing record for 2011 showed several ups and downs in productivity, with 25 columns in January, February and March but none at all in December or August and only one in July.

The super-secretive Castro has never explained his occasional absences from the public eye or his bursts of activity, especially after emergency surgery forced him to surrender power to his brother Raúl, unofficially in 2006 and officially in 2008.

His sole public appearances in the past year or so have been through his columns, known as “Reflections of Fidel,” and photographs of his meetings with high-ranking foreign visitors.

Castro’s 52-day gap in publishing his reflections, from Nov. 14 to Jan. 5, sparked rumors of a health crisis that were doused when he wrote a column on one of his top subjects — the risks of nuclear war over Iran.

But Max Lesnick, a Miami radio commentator who knew Castro during their university years in Havana and now travels often to Cuba, said he saw Castro in late November and spoken to him by phone for 45 minutes during a December visit to the Cuban capital.

Lesnick said that during their meeting and phone conversation Castro appeared “stable, considering his age,” and remains mentally “alert and lucid” but walks “very carefully.”

“I sometimes go 20 days without writing in my own pages because I have other things to do besides writing, like Fidel,” Lesnick said. “That’s why I don’t think that those numbers are important.”

In recent months, Castro has been particularly interested in Moringa, a plant attributed with all kinds of medicinal benefits, he said. When they met in November, Castro said he had just left a meeting with about 80 farmers to discuss the plant.

Havana dissident Tania Diaz Castro wrote in late November that a truck had distributed scores of small Moringa plants in neighborhoods near Castro’s home in western Havana. She’s heard nothing more about plant distributions since, Diaz added Thursday.

A native of northwestern India, the plant is reputed to be full of vitamins, minerals, amino acids and antioxidants that boost the body’s defenses against infections, fight arthritis and diabetes and bring about a pleasant sleep.

Castro has a long record of enthusiastically plunging into scientific efforts to improve the Cuban economy by, for instance, trying to improve its stock of milk and beef cattle and pasture systems, and its strains of sugar cane.

Many of them did not pan out, and his famous campaign to produce a record 10 million tons of sugar during the 1970 harvest was a disaster, all but paralyzing the rest of country.