Two men who have been synonymous with Coca-Cola for years — one who helmed the beverage giant and the other who protected its secret formula — are leaving the company’s board of directors.

Donald Keough, Coca-Cola’s president and chief operating officer from 1981 to 1993, and James Williams, former chairman and chief executive officer of SunTrust Banks, will not seek re-election at Coca-Cola’s annual meeting in April, the company said Thursday.

“Many of our current Coca-Cola leaders learned this business under Don, and I have personally benefited from his guidance, mentorship and friendship for more than 30 years,” Coca-Cola Chairman and Chief Executive Officer Muhtar Kent said in a release. “Likewise, Jimmy has been a great adviser to me and the Board, and we have all gained from his clear direction and wise counsel.”

Keough and Williams leave the board two years after some shareholders complained about the age of board members. Keough is 86, and Williams is 79. After these retirements the average age of the board members will be 66.

At least 10 of the 17-member board are age 70 and above, including Barry Diller and Peter Ueberroff, said Ken Bernhardt, a marketing professor at Georgia State University who has led a roundtable that has included Coca-Cola executives.

“This is an opportunity to get a couple of younger board members who are more in tune with some of the changes in the industry,” said Bernhardt.

He added, however, that Keough and Williams “are pillars of understanding of what Coke stands for” and that their knowledge of marketing and finance will be missed on the board.

Keough has held many positions at Coca-Cola, including leading its foods division from 1971 to 1973 and as chairman of bottler Coca-Cola Enterprises between 1986 and 1993. He also was chairman of Columbia Pictures, which Coca-Cola once owned. Keough retired as president and chief operating officer of the company in April 1993.

Williams has served as a director at Coca-Cola since 1979 and has been chairman of the board’s Finance Committee since 1985. Coca-Cola said his role as director has been to connect the company and SunTrust, which financed the sale of Coca-Cola in 1919 and guarded its secret formula in a vault for more than 80 years.