The relationship between low-fat diets and telomere length among USA adults: nationwide cross-sectional study

Previous studies have shown that low-fat diet (LFD) is associated with various health benefits, and that lipid and fatty acid metabolism is linked to telomere shortening. However, no epidemiological studies have examined the association between LFD and telomere length (TL). Dietary information was collected using 24-h recalls among 6981 adults from a nationwide cross-sectional study. Diet quality was assessed using overall LFD, healthful LFD (hLFD) and unhealthful LFD (uLFD). TL was measured using quantitative PCR. Linear regression was employed to evaluate the association between LFD and log-transformed TL, and ordinal logistic regression was performed to assess the association of LFD with ordinal quintiles of TL in descending order. In both fully adjusted linear and ordinal regression models, higher overall LFD (Tertile 3 v. Tertile 1: percentage change = 2·48 %, 95 % CI: 0·60 %, 4·40 %, P_trend = 0·003; OR = 0·79, 95 % CI: 0·68, 0·93; P_trend = 0·001) and hLFD (Tertile 3 v. Tertile 1: percentage change = 2·71 %, 95 % CI: 0·87 %, 4·58 %; P_trend = 0·002; OR = 0·84, 95 % CI: 0·72, 0·97; P_trend = 0·003) scores were significantly associated with longer TL. The positive association between hLFD and TL was observed in other racial/ethnic groups, but not in non-Hispanic whites (P_interaction < 0·005). There was no significant association between uLFD and TL in all the models. Our results suggest that LFD rich in high-quality carbohydrates, unsaturated fat and plant protein is associated with longer TL and underscore the need to consider the quality and dietary sources of the macronutrients.