Candida, diet, and gut fungi: a 2013 study

In a cross-sectional study of 96 analyzed stool samples, relative Candida abundance was positively associated with recent carbohydrate intake and negatively associated with total saturated fatty acids. The same direction for usual diet was not statistically significant. The study did not test Candida disease or diet as treatment.

This is a human observational study of diet and fungi detected in stool. Its finding is an association, not evidence that carbohydrates cause pathogenic Candida to grow. The broad Candida claims evidence map places it alongside the full evidence set.

The analysis used one stool sample per participant from healthy United States volunteers. Ninety-eight samples were collected; sequences from 96 passed quality filtering and were analyzed. The volunteers were screened to exclude chronic gastrointestinal disease, cardiac disease, diabetes, and immunodeficiency.

Researchers compared fungal marker-gene sequences from stool with self-reported usual and recent diet. Usual diet came from a food-frequency questionnaire. Recent diet came from three trained-nutritionist interviews recalling food eaten on three days in the week before stool collection. No diet was assigned, and each participant provided one stool sample.

The study detected genus-level Candida in 57% of the analyzed samples. Relative Candida abundance correlated positively with carbohydrate intake and negatively with total saturated fatty acids in the recent-diet inventory. The same direction appeared for usual long-term diet but did not reach statistical significance. The article reports no correlation coefficient or confidence interval in its text; Figure 5 is a heatmap rather than an extractable effect-size table. No symptoms, candidiasis diagnosis, or clinical outcome were measured.

These findings describe diet associations with relative fungal sequence abundance in stool from a selected group of healthy volunteers. They do not show that carbohydrate feeds pathogenic Candida, that restriction changes Candida, that stool detection means infection, or that a diet treats symptoms.

The cross-sectional design cannot establish which factor came first or whether the association was causal. Diet was self-reported, each participant contributed one stool sample, and sequencing measured relative proportions rather than absolute fungal burden. The diet analyses included multiple exploratory comparisons with an FDR threshold as high as 25%. The article gives no textual effect size, and it reports no disease, symptom, treatment, or clinical follow-up outcome.

Contextual. The study records a recent-diet association in stool samples, while the same direction for usual diet was not statistically significant. It does not establish infection, a causal dietary effect, or a treatment benefit.

No practical change. This association does not support carbohydrate restriction or another diet as Candida treatment, and it should not guide an individual's care.

Funders included Project UH2/3 DK083981, the Penn Genome Frontiers Institute, the NIH, Penn Digestive Disease Center, the Joint Penn–CHOP Center for Digestive, Liver, and Pancreatic Medicine, and other listed research awards. The authors reported that funders had no role in the study or publication and declared no competing interests.

Read the original PLOS ONE article (published June 17, 2013; DOI: 10.1371/journal.pone.0066019). The full text is also available from PubMed Central.