Gut-friendly diet linked to lower risk of coronary heart disease mortality

A national analysis shows that diets that support a healthier gut microbiota may help identify coronary heart disease patients with a lower risk of death.

Study: Association between the Dietary Gut Microbiota Index and 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 evaluated the association between the Dietary Index for Gut Microbiota (DI-GM) and all-cause mortality among adults with coronary artery disease using data from the National Health and Nutrition Examination Survey (NHANES) (2005-2018).

Background

Every year, millions of people die from coronary artery 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 outcomes. Recent studies show that gut microbiota can affect heart health. These microbes help regulate inflammation, fat metabolism and blood vessel function. Diet can shape the types of gut microbes, which are likely to influence the course of the disease. However, evidence on diet quality and mortality in coronary heart disease focusing on the gut microbiota remains limited. Further research is needed to clarify this relationship.

About the Study

The study used data from NHANES, a nationally representative survey of the United States population conducted between 2005 and 2018. Initially, 70,190 participants were identified. Subjects with incomplete information on mortality, DI-GM scores, coronary artery disease, or relevant demographic and clinical variables were excluded. The final analysis included 1,537 participants with coronary heart disease, representing approximately 8,124,166 adults in the United States.

DI-GM scores were calculated based on 14 dietary components through a 24-hour food recall, which included avocados, broccoli, chickpeas, cranberries, fermented dairy products, dietary fiber, green tea, soybeans, whole grains and coffee, and unfavorable components such as high-fat and refined meats. grains. Participants were divided into four groups: 0–3, 4, 5, and ≥6 based on the score.

Information was obtained on demographics, body mass index, smoking and drinking habits, hypertension, diabetes, laboratory results, and socioeconomic conditions, including poverty-to-income ratio. Follow-up was calculated from the baseline interview until death or December 31, 2019, whichever occurred first. Cox proportional hazards models were used to analyze the relationship between DI-GM scores and all-cause mortality, while restricted cubic spline analysis was used to assess non-linear relationships between DI-GM scores and the investigated variables. Additionally, subgroup analyzes and interaction analyzes were performed to test whether associations differed across participant characteristics.

Study Results

A total of 1,537 participants with coronary artery disease, representing approximately 8,124,166 adults in the United States, were included in the analysis. The median age was 68 years, with an interquartile range of 61–77 years. The study group consisted of 66.34% males and 33.66% females and the overall mortality rate was 37.41%. Participants with higher DI-GM scores generally differed in age, race, poverty-to-income ratio, and body mass index, while sex, education level, marital status, smoking, alcohol consumption, monocyte count, neutrophil count, hypertension, lymphocyte count, hemoglobin, diet, hemoglobin, diet, and platelet count. rating 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 using weighted Cox proportional hazards models. When the DI-GM was analyzed as a continuous score, each one-point increase was associated with a lower estimated risk of death in age- and sex-adjusted analysis. However, after the researchers accounted for additional demographic, socioeconomic, lifestyle, clinical and laboratory factors, the association weakened and was no longer statistically significant. This suggests that the overall trend indicated a potential benefit, but the evidence was not strong enough to confirm a clear independent relationship when DI-GM was analyzed as a continuous measure.

Higher DI-GM scores were associated with lower mortality rates when participants were grouped by score. Compared with the lowest-scoring group, participants with a DI-GM score of 5 and those with a score of 6 or higher had significantly lower risks of death during follow-up. A score of 4 showed a similar trend toward lower mortality, but the effect did not reach statistical significance.

Additional analysis suggested that the relationship was not linear, meaning that mortality risk did not decrease by the same amount with each increase in DI-GM score. Subgroup analyzes found no significant differences in this pattern across categories of age, sex, body mass index, smoking, alcohol consumption, hypertension, and poverty-to-income ratio, although diabetes status appeared to influence the association.

Conclusion

The study showed that people who have coronary heart disease and high DI-GM scores may have a lower risk of all-cause mortality, with the relationship showing a non-linear pattern. The association remained evident after extensive adjustment for potential confounders when participants were compared by diet score group, and diabetes status modified this relationship. These findings suggest that dietary patterns that support gut microbiota health may be related to dietary risk stratification and nutritional management in people with coronary artery disease, although causal effects remain unproven.

Improving overall nutrition and promoting healthier gut microbiota 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, the study population in the United States, and potential residual confounding.