A national analysis suggests that diets that support a healthier gut microbiome may help identify patients with coronary heart disease who are at lower risk of death.
Study: Association of dietary indicators of gut microbiota with all-cause mortality in coronary heart disease: A retrospective cohort analysis of NHANES (2005-2018). Image credit: Maslova Valentina / Shutterstock
In a recent study published in the journal medicineA group of researchers used data from the National Health and Nutrition Examination Survey (NHANES) (2005-2018) to assess the association between dietary indicators of intestinal microbiota (DI-GM) and all-cause mortality in adults with coronary heart disease.
background
Millions of people die each year from coronary heart disease, making it one of the leading causes of death worldwide. While age and genetics contribute to disease risk, lifestyle factors such as diet offer opportunities to improve long-term health. Recent research shows that the gut microbiome can influence heart health. These microorganisms help regulate inflammation, fat metabolism, and vascular function. Diet determines the type of gut microbes, which can influence the course of the disease. However, evidence regarding diet quality and coronary heart disease mortality focusing on the gut microbiota remains limited. Further research is needed to clarify this relationship.
About research
The study used data from NHANES, a nationally representative survey of the U.S. population conducted between 2005 and 2018. Initially, 70,190 participants were identified. Individuals lacking information on mortality, DI-GM score, coronary heart disease, or relevant demographic and clinical variables were excluded. The final analysis included 1,537 participants with coronary heart disease, representing an estimated 8,124,166 U.S. adults.
The DI-GM score was calculated based on 14 dietary components through a 24-hour dietary recall. This includes harmful ingredients such as avocado, broccoli, chickpeas, cranberries, fermented dairy products, dietary fiber, green tea, soy, whole grains, coffee, and refined grains, red and processed meats, and high-fat foods. Participants were divided into four groups based on their scores: 0–3, 4, 5, and ≥6.
Information on demographics, BMI, smoking and drinking habits, hypertension, diabetes, laboratory results, and socio-economic status including poverty-to-income ratio was obtained. Follow-up was calculated from the baseline interview until death or December 31, 2019, whichever came first. Cox proportional hazards models were used to analyze the association between DI-GM scores and all-cause mortality, and restricted cubic spline analyzes were used to assess nonlinear relationships between DI-GM scores and study variables. Additionally, subgroup and interaction analyzes were conducted to determine whether associations differed between participant characteristics.
Research results
A total of 1,537 participants had coronary heart disease, representing an estimated 8,124,166 U.S. adults. The median age was 68 years, with an interquartile range of 61 to 77 years. The study group consisted of 66.34% men and 33.66% women, and the overall mortality rate was 37.41%. In general, participants with higher DI-GM scores differed in age, race, poverty-to-income ratio, and body mass index, but there were no significant differences in gender, education level, marital status, smoking, alcohol intake, monocyte count, neutrophil count, hypertension, lymphocyte count, hemoglobin, platelet count, albumin, or creatinine across dietary score groups. The median DI-GM score was 5.00, with an interquartile range of 4.00 to 7.00.
The association between DI-GM and all-cause mortality was examined through a weighted Cox proportional hazards model. When DI-GM was analyzed as a continuous score, each 1-point increase was associated with a lower estimated risk of death in age- and sex-adjusted analyses. However, after the researchers took into account additional demographic, socioeconomic, lifestyle, clinical, and laboratory factors, the association weakened and became no longer statistically significant. Although this suggests that the overall trend indicates a possible benefit, there was insufficient evidence to confirm a clear independent relationship when DI-GM was analyzed as a continuous measure.
When participants were grouped by score, higher DI-GM scores were associated with lower mortality. Compared with the lowest scoring group, participants with a DI-GM score of 5 and those with a score of 6 or higher had a significantly lower risk of death during follow-up. Score 4 showed a similar trend toward lower mortality, but the results did not reach statistical significance.
Additional analyzes suggest that this relationship is not linear, meaning that each increase in DI-GM score does not reduce mortality risk by the same amount. Subgroup analyzes showed no significant differences in this pattern across categories of age, sex, BMI, smoking, alcohol intake, hypertension, or poverty-to-income ratio, although diabetes status appeared to influence the association.
conclusion
This study suggested that people with coronary heart disease and high DI-GM scores may have a lower risk of all-cause mortality, and that the relationship showed a nonlinear pattern. When participants were compared by dietary score group, and diabetes status altered this relationship, the association remained clear even after extensive adjustment for potential confounders. These findings suggest that dietary patterns that support gut microbiota health may be relevant to dietary risk stratification and nutritional management in patients with coronary heart disease, although a causal relationship has not yet been proven.
Improving overall diet and promoting a healthier gut microbiome may be associated with lower all-cause mortality in this high-risk population. However, the authors noted limitations including the retrospective design, reliance on a single 24-hour dietary recall, self-reported disease information, US study population, and potential for residual confounding.
Reference magazines:
- Cao, F., Zhang, G., Liu, J., Tian, Y., Zhang, W., Zhang, S., Hou, F., Bao, Z., Liu, Z., Xiao, P., Jiang, J., Zhu, Y., and Wu, K. (2026). Association between dietary indicators of gut microbiota and all-cause mortality in coronary heart disease: A retrospective cohort analysis of NHANES (2005-2018). medicine. 105(27). Doi: 10.1097/MD.0000000000049532, https://www.ovid.com/jnls/md-journal/fulltext/10.1097/md.0000000000049532~association-between-the-dietary-index-for-gut-microbiota-and
