Health (Commonwealth Union) – Preliminary research presented at the American Heart Association’s Epidemiology and Prevention Lifestyle and Cardiometabolic Scientific Sessions 2024, held from March 18 to 21 in Chicago, reveals intriguing insights from an analysis of over 20,000 U.S. adults. The study suggests that individuals who adhere to time-restricted eating plans, consuming their meals within less than an 8-hour window per day, may face a heightened risk of cardiovascular disease mortality compared to those who spread their eating over a 12 to 16-hour period.
Time-restricted eating, a form of intermittent fasting, entails restricting daily eating to a specific timeframe, typically ranging from 4 to 12 hours within a 24-hour cycle. Among adherents of this dietary approach, the 16:8 regimen is popular, involving the consumption of all meals within an 8-hour window and fasting for the remaining 16 hours daily, as outlined by the researchers. Despite previous research indicating improvements in various cardiometabolic health markers such as blood pressure, blood glucose, and cholesterol levels associated with time-restricted eating, this latest study raises questions about its potential impact on cardiovascular health outcomes.
Dr. Victor Wenze Zhong, a professor and chair of the department of epidemiology and biostatistics at the Shanghai Jiao Tong University School of Medicine in Shanghai, China, highlighted the growing trend of limiting daily eating to a short timeframe, such as 8 hours per day, for weight management and heart health improvement. Yet, he emphasized the lack of clarity regarding the enduring impacts of this practice on overall health, including mortality risk and cardiovascular disease.
The study had scientists delve into the potential lasting health effects of adhering to an 8-hour time-restricted eating regimen. They scrutinized dietary habits among individuals participating in the annual 2003-2018 National Health and Nutrition Examination Surveys (NHANES), juxtaposing this data with information on individuals who passed away in the United States from 2003 through December 2019, sourced from the Centers for Disease Control and Prevention’s National Death Index database.
Prior studies have demonstrated that intermittent fasting has the potential to result in substantial weight loss and enhance metabolic health among individuals struggling with obesity.
The analysis revealed significant correlations: individuals consuming all their food within less than 8 hours per day faced a staggering 91% higher risk of death from cardiovascular disease. This heightened risk extended to those already grappling with heart disease or cancer. Even among those with pre-existing cardiovascular issues, an eating window of 8 to less than 10 hours daily was linked to a 66% increased risk of death from heart disease or stroke. However, contrary to expectations, time-restricted eating didn’t mitigate the overall risk of mortality from any cause. Intriguingly, those who extended their eating duration beyond 16 hours per day exhibited a reduced risk of cancer mortality among cancer patients.
“It’s crucial for patients, particularly those with existing heart conditions or cancer, to be aware of the association between an 8-hour eating window and increased risk of cardiovascular death. Our study’s findings encourage a more cautious, personalized approach to dietary recommendations, ensuring that they are aligned with an individual’s health status and the latest scientific evidence,” said Zhong and continued. “Although the study identified an association between an 8-hour eating window and cardiovascular death, this does not mean that time-restricted eating caused cardiovascular death.”
The study encompassed around 20,000 adults residing in the United States, with an average age of 49 years, monitored over a median period of 8 years, with some followed up to 17 years. These individuals were drawn from NHANES participants aged 20 or above at enrollment spanning from 2003 to 2018, who had completed two 24-hour dietary recall questionnaires within the first year of enrollment. Gender distribution was balanced, with approximately half identifying as men and half as women. In terms of racial demographics, 73.3% identified as non-Hispanic white adults, 11% as Hispanic adults, 8% as non-Hispanic Black adults, and 6.9% as belonging to other racial categories, including mixed-race adults and those from other non-Hispanic racial backgrounds.
The study was constrained by its dependence on self-reported dietary data, susceptible to memory biases and potentially inaccurate portrayal of regular eating habits. Additionally, the analysis did not incorporate other health-influencing factors beyond daily eating duration and cause of death.
The authors suggested future investigations delve into the biological underpinnings of the connections between time-restricted eating schedules and negative cardiovascular outcomes. They also highlighted the need to explore whether these findings hold true for diverse global populations.
