Brewing giant Anheuser-Busch InBev, one of five alcohol companies underwriting a $100 million federal trial on the health benefits of a daily drink, is pulling its funding from the project, saying controversy about the sponsorship threatens to undermine the study’s credibility, the company announced Friday.

The company announced its decision in a letter to Maria C. Freire, president and executive director of the Foundation for the National Institutes of Health, a nongovernmental entity that is authorized to raise money from the private sector for N.I.H. initiatives and manages the institutes’ public-private partnerships.

The N.I.H. last month suspended enrollment in the 10-year clinical trial on the health benefits of moderate drinking after The New York Times reported that N.I.H. officials and scientists met directly with alcohol groups to solicit funds and strongly hinted that the study’s results would favor moderate drinking.

Anheuser-Busch InBev had committed $15.4 million to support the trial, representing nearly one-quarter of the $66 million in funds pledged by beer and liquor companies to date. The payments were being channeled through the Foundation for the N.I.H. in 10 annual installments, and payments started three years ago.