Manipulation of host diet to reduce gastrointestinal colonization by the opportunistic pathogen Candida albicans

Authors: GUNSALUS, KEARNEY - Tufts University; TORNBERG-BELANGER, STEPHANIE - Tufts University; MATTHAN, NIRUPA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; LICHTENSTEIN, ALICE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; KUMAMOTO, CAROL - Tufts University

Submitted to: mSphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2015
Publication Date: 11/18/2015
Citation: Gunsalus, K.T., Tornberg-Belanger, S.N., Matthan, N., Lichtenstein, A.H., Kumamoto, C.A. 2015. Manipulation of host diet to reduce gastrointestinal colonization by the opportunistic pathogen Candida albicans. mSphere. 1(1). pii:e00020-15. doi:10.1128/mSphere.00020-15.

Interpretive Summary: Candida albicans (C. albicans) is the most common cause of fungal infections. Fungal infections arise from an overgrowth of C. albicans in the gastrointestinal tract where it is a normal constituent of the microflora. One approach to prevent C. albicans overgrowth is to modify the diet in a way that will minimize colonization. To determine the feasibility of dietary modification to reduce C. albicans gastrointestinal colonization we investigated the impact of dietary fat. Coconut oil and its constituent fatty acids have antifungal activity in vitro; we hypothesized that dietary coconut oil, compared to another saturated fat, beef tallow or a polyunsaturated fat, soybean oil, would reduce C. albicans colonization. Colonization was significantly lower in mice fed a coconut oil-rich diet than in mice fed the beef tallow or soybean oil rich diets. Switching beef tallow-fed mice to a coconut oil diet reduced preexisting colonization. The concomitant presence of dietary beef tallow with coconut oil did not mitigate the effects of the latter fat. Polyunsaturated fat fatty acids were less abundant in the cecal contents of coconut oil-fed mice than beef tallow-fed mice. In addition, the expression of genes involved in fatty acid utilization was lower in the mice fed the coconut oil. Extrapolating to humans, these findings suggest that coconut oil could become an acute dietary intervention to reduce C. albicans gastrointestinal tract colonization during high risk periods such as hospitalization.

Technical Abstract: Candida albicans, the most common human fungal pathogen, can cause systemic infections with a mortality rate of ~40%. Infections arise from colonization of the gastrointestinal (GI) tract, where C. albicans is part of the normal microflora. Reducing colonization in at-risk patients using antifungal drugs prevents C. albicans-associated mortalities. C. albicans provides a clinically relevant system for studying the relationship between diet and the microbiota as it relates to commensalism and pathogenicity. As a first step toward dietary intervention to reduce C. albicans GI colonization, we investigated the role of dietary lipids on murine colonization by C. albicans. Coconut oil and its constituent fatty acids have antifungal activity in vitro; we hypothesized that dietary coconut oil would reduce GI colonization by C. albicans. Colonization was lower in mice fed a coconut oil-rich diet than in mice fed diets rich in beef tallow or soybean oil. Switching beef tallow-fed mice to a coconut oil diet reduced preexisting colonization. Coconut oil reduced colonization even when the diet also contained beef tallow. Dietary coconut oil also altered the metabolic program of colonizing C. albicans cells. Long-chain fatty acids were less abundant in the cecal contents of coconut oil-fed mice than in the cecal contents of beef tallow-fed mice. Extrapolating to humans, these findings suggest that coconut oil could become the first dietary intervention to reduce C. albicans GI colonization.