Intermittent fasting increases the risk of death from cardiovascular causes? Study sparks debate

The findings, presented at the AHA’s Epidemiology, Prevention, Lifestyle, and Cardiometabolic Health Scientific Sessions in Chicago, IL, do not support the long-term use of 16:8 time-restricted eating for preventing cardiovascular death.

The analysis from the National Health and Nutrition Examination Survey (NHANES) showed that eating during an 8-hour or smaller window throughout the day was tied to a 91% higher risk of death from cardiovascular causes; greater risks were observed in those with cancer or cardiovascular disease (CVD).

Time-restricted eating has gained popularity as a dietary intervention that limits daily food intake to a 4- to 12-hour window. Most short-term randomized controlled trials (RCTs) reported that TRE improved cardiometabolic risk profiles. However, there is no knowledge of whether TRE is associated with long-term hard endpoints.

Against the above background, Meng Chen, Sch of Public Health, Shanghai Jiao Tong Univ Sch of Med, Shanghai, China, and colleagues assessed the hypothesis that TRE is linked with a reduced risk of cause-specific and all-cause mortality.

For this purpose, the researchers included participants aged at least 20 years who completed two valid 24-hour dietary recalls and reported usual intake in both recalls from the NHANES in 2003-2018. Mortality status as of December 2019 was obtained through linkage to the National Death Index.

An eating occasion needs consumption of more than 5 kcal of beverages or foods. For each day, the eating duration between the last and first eating occasion was calculated. The average duration of two recall days defined typical eating duration which was then divided as <8, 8-<10, 10-<12, 12-16 (reference group; mean duration in US adults), and >16 hours.

Multivariable Cox proportional hazard models were employed to estimate the association of eating duration with cause-specific and all-cause mortality in the overall sample and among adults with cancer or CVD.

Among 20,078 adults included, the weighted mean age was 48.5 years, 50.0% were men, and 73.3% were non-Hispanic White.

The study led to the following findings:

• During a median follow-up of 8.0 years, 2797 all-cause deaths occurred, including 840 cardiovascular deaths and 643 cancer deaths.
• Compared with eating 12-16 hours, eating duration <8 hours was significantly associated with an increased risk of cardiovascular mortality (HR, 1.96); this association was also observed in adults with cardiovascular disease (HR, 2.06) and adults with cancer (HR, 2.72).
• Other eating durations were not associated with cardiovascular mortality, except for eating duration of 8-<10 hours in people with cardiovascular disease (HR, 1.64).
• No significant associations were found between eating duration and all-cause or cancer mortality in the overall sample and diseased subsamples, except that eating duration >16 hours was associated with a lower risk of cancer mortality in people with cancer (HR, 0.46).

In conclusion, among US adults, TRE with eating duration <8 hours was significantly associated with a higher risk of cardiovascular mortality in the general population and people with cancer or CVD. These findings do not support the long-term use of 16:8 TRE for preventing cardiovascular death.

However, the authors acknowledged that the study findings need replication and warned that no specific dietary advice around restricted eating/intermittent fasting should be given based on their study alone.

Reference:

Chen M, Zhong VW. Association between time-restricted eating and all-cause and cause-specific mortality. Presented at: Epidemiology, Prevention, Lifestyle, and Cardiometabolic Health Scientific Sessions. Chicago, IL. March 18, 2024.