Personalized dietary programs outperform general advice for better heart health

In a recent Nature Medicine study, researchers compare the effectiveness of personalized dietary programs (PDP) and general advice on cardiometabolic health.

Study: Effects of a personalized nutrition program on cardiometabolic health: A randomized controlled trial. Image Credit: Inside Creative House / Shutterstock.com 

The role of diet in disease risk

Diet and lifestyle-related interventions are effective non-pharmaceutical approaches that can reduce the risks of many chronic diseases. Although many studies have emphasized the importance of an adequate diet, a significant increase in diet-related diseases has been observed and attributed to poor adherence to dietary guidelines.

In fact, one recent study revealed that less than 1% of the United Kingdom population adheres to all dietary recommendations, with similarly poor adherence reported in the United States. Multiple factors influence the variability in health responses to food; therefore, effective personalized nutrition programs based on lifestyle and phenotypic biological factors could increase compliance rates with dietary guidelines.

Previously conducted randomized controlled trials (RCTs) designed to evaluate the efficacy of personalized nutrition programs indicated an overall positive result. Some benefits associated with this approach include improved blood parameters, glycemic index, dietary habits, gut health, physical activity, and anthropometric measurements. Nevertheless, additional studies are needed to determine the efficacy of PDP concerning adherence to recommendations and health outcomes.

About the study

The ZOE Measuring Efficacy Through Outcomes of Diet (METHOD) study hypothesized that dietary customization encompassing multiple factors contributing to inter- and intraindividual variability to nutritional responses to diet will increase adherence to recommendations and improve health outcomes. The ZOE METHOD study, which involved a parallel-design eighteen-week RCT, compared the efficacy of PDP with standard care dietary advice in the U.S. adult population.

Standard care dietary advice was obtained from the United States Dietary Guidelines for Americans 2020-2025, whereas PDP dietary guidelines were based on the ZOE 2022 algorithm. PDP recommendations were based on an individual’s health history, gut microbiome composition, and glucose and postprandial triglycerides (TG) levels. The dietary and lifestyle recommendations for PDP were delivered remotely through a phone application called ZOE.

The current study recruited male and female participants between 40 and 70 years of age. All participants resided in the U.S., reported fruit and vegetable intake below 450 grams daily, and had waist circumference measurements greater than ethnicity- and sex-specific 25^th percentile values. The selected participants were randomly assigned to one of the two treatment groups.

Study findings 

A total of 177 and 170 participants were assigned to PDP and control groups, respectively. The PDP intervention provided more significant health improvements than adherence to U.S. standard care dietary advice, as demonstrated by greater reductions in weight, TG levels, waist circumference, and hemoglobin A1c (HbA1c) in the PDP group. However, no change in low-density lipoprotein cholesterol (LDL-C) levels was observed in the PDP group. 

A greater variation in nutritional intake and individual food was associated with PDP compared to the control group. An improved and sustained gut microbial composition was observed in the PDP group compared to the control, with these microbiome changes more predictive of weight loss and reduction in hip circumference than the control diet.

Study participants in the PDP group also exhibited favorable feelings of hunger, mood, and energy. Compared to standard dietary advice, customized dietary advice was more effective in reducing central adiposity and TG levels in healthy populations.

Although overall LDL-C levels were similar in both groups after eighteen weeks of dietary intervention, a notable reduction was observed in healthy participants who adhered to PDP guidelines. When participants were further stratified in accordance with unhealthy levels at baseline, reduced LDL-C levels were observed across all adherence groups.

Consistent with previous studies, the current study observed that TG levels were sensitive to nutritional interventions. Significantly, LDL-C levels do not change with weight loss induced by dietary modification.

Moreover, the current study reported a greater improvement in body weight and waist circumference in participants of the PDP group than in those who followed generalized guidance.

Conclusions

The potential benefit of a PDP supersedes standard dietary advice, as individuals with the poorest diets were found to experience the greatest benefits from a personalized nutrition intervention. Interestingly, the current study did not observe any significant health benefits in participants who usually follow a healthy lifestyle from baseline.

The study findings demonstrate that a personalized nutrition program is highly beneficial for improving cardiometabolic health.