Prolonged nightly fasting may do more harm than good in older adults

Habitual prolonged nightly fasting does not lead to improvements in certain cardiovascular, renal, inflammation, and nutritional status biomarkers among community-dwelling older adults, a study has found. Instead, it shows modest negative associations suggesting the potential harm of extended periods of time between meals.

A team of investigators examined the association of habitual prolonged nightly fasting with a wide array of biomarkers among older adults. They performed a cross-sectional analysis of data from 1,047 adults aged ≥65 years from the Seniors Study on Nutrition and Cardiovascular Risk in Spain 2 cohort and assessed habitual diet using a validated diet history.

Fasting time was classified as follows: <10, 10 to <12, and 12 h/d, the latter being considered prolonged nightly fasting. Linear regression models were used to estimate adjusted geometric means of biomarker concentrations in blood and serum by categories of fasting time. The main confounders were body mass index (BMI) and overall diet quality, defined as adherence to a Mediterranean diet score.

Longer fasting time significantly correlated with lower concentration of high-density lipoprotein cholesterol (difference between longest and shortest fasting category: ‒2.94 mg/dL, 95 percent confidence interval [CI], ‒4.80 to ‒1.09; p_trend=0.01), higher potassium concentration (0.11 mEq/L, 95 percent CI, 0.03‒0.19; p_trend=0.01), and lower concentration of chloride (‒0.50 mEq/L, 95 percent CI, ‒0.91 to ‒0.09; p_trend=0.03).

“These results were slightly attenuated after additional adjustment for BMI,” the investigators said.