Duane Cristopher, longtime manager of the Brooks Street Health Food Co-op, died Sunday following a three-month battle with vitamin lung. 'Decades of inhaling a trace dust of vitamin supplements caused particles to accumulate over time in his lungs, ultimately cutting off his oxygen supply,' said Dr. Arthur Washington, Christopher's physician. 'We also suspect bee pollen may have been a factor.' At Christopher's funeral Tuesday, family and friends commented admiringly on how natural the 57-year-old's body looked. 