Diet Quality Scores Are Positively Associated with Whole Blood-Derived Mitochondrial DNA Copy Number in the Framingham Heart Study

BACKGROUND

The association between diet quality and mitochondrial DNA copy number (mtDNA-CN) remains to be examined.

OBJECTIVES

We aimed to study the relation between diet quality and mtDNA-CN.

METHODS

We analyzed data from 2931 Framingham Heart Study (FHS) participants (mean age of 57 y, 55% females). Whole-genome sequencing was used to calculate mtDNA-CN from whole-blood samples. We examined the cross-sectional associations between 3 diet quality scores, the Dietary Approaches to Stop Hypertension (DASH) score, the Alternative Healthy Eating Index (AHEI), and the Mediterranean diet score (MDS), and mtDNA-CN. Linear mixed models were used to account for maternal lineage.

RESULTS

We observed that a higher DASH score was positively associated with mtDNA-CN after adjusting for sex, age, energy intake, smoking status, alcohol intake, and physical activity level. A 1-SD increase in the DASH score was associated with a 0.042-SD greater mtDNA-CN (95% CI: 0.007, 0.077; P = 0.02). Similarly, for each SD increase in AHEI and MDS, the mtDNA-CN SD increased by 0.056 (95% CI: 0.019, 0.092; P = 0.003) and 0.047 (95% CI: 0.01, 0.083; P = 0.01), respectively. Diet quality scores were associated with neutrophil and lymphocyte counts but not platelet counts, e.g., for a 1-SD increase in the DASH, neutrophils decreased by 0.8% (95% CI: 0.5%, 1.1%; P = 4.1 × 10-6), lymphocytes increased by 0.7% (95% CI: 0.4%, 1%, P = 1.2 × 10-5), and there was no significant change in platelet number (0.1 × 1000/μL; 95% CI: -1.6, 1.9; P = 0.89). Further adjustment for neutrophil, lymphocyte, and platelet counts and the associations between diet quality scores and mtDNA-CN were completely attenuated to nonsignificant (P = 0.95, 0.54, and 0.91, respectively).

CONCLUSIONS

We observed that higher diet quality is associated with a greater whole-blood derived mtDNA-CN in middle-aged to older adult FHS participants, and that blood cell composition, particularly neutrophil counts, attenuated the association between diet quality and mtDNA-CN.

Parent Diet Quality and Energy Intake Are Related to Child Diet Quality and Energy Intake

BACKGROUND

Parents' diets are believed to influence their children's diets. Previous studies have not adequately and simultaneously assessed the relationship between parent and child total diet quality and energy intakes.

OBJECTIVE

Our aim was to investigate whether parent and child diet quality and energy intakes are related.

DESIGN

We conducted a cross-sectional analysis using baseline dietary intake data from the Neighborhood Impact on Kids study collected in 2007 to 2009.

PARTICIPANTS/SETTING

Participants were parents and 6- to 12-year-old children from households in King County (Seattle area), WA, and San Diego County, CA, targeted by Neighborhood Impact on Kids were recruited. Eligible parent-child dyads (n=698) with two or three 24-hour dietary recalls were included in this secondary analysis.

MAIN OUTCOME MEASURES

Child diet quality (Healthy Eating Index-2010, Dietary Approaches to Stop Hypertension score, and energy density [for food only]) and energy intake were derived from the dietary recalls using Nutrition Data Systems for Research.

STATISTICAL ANALYSES PERFORMED

Multiple linear regression models examined the relationship between parent diet quality and child diet quality, and the relationship between parent energy intake and child energy intake. In both analyses, we controlled for parent characteristics, child characteristics, household education, and neighborhood type.

RESULTS

Parent diet quality measures were significantly related to corresponding child diet quality measures: Healthy Eating Index-2010 (standardized β=.39; P<0.001); Dietary Approaches to Stop Hypertension score (β=.33; P<0.001); and energy density (β=.32; P<0.001). Parent daily mean energy intake (1,763±524 kcal) was also significantly related (β=.30; P<0.001) to child daily mean energy intake (1,751±431 kcal).

CONCLUSIONS

Parent and child intakes were closely related across various metrics of diet quality and for energy intake. Mechanisms of influence are likely to be shared food environments, shared meals, and parent modeling.

Diet quality as assessed by the Healthy Eating Index, the Alternate Healthy Eating Index, the Dietary Approaches to Stop Hypertension score, and health outcomes: a systematic review and meta-analysis of cohort studies

Dietary patterns consider synergistic effects compared with isolated foods or nutrients on health outcomes. The aim of this systematic review and meta-analysis was to examine the associations of diet quality as assessed by the Healthy Eating Index (HEI), the Alternate Healthy Eating Index (AHEI), and the Dietary Approaches to Stop Hypertension (DASH) score and the risk of all-cause mortality, cardiovascular mortality or incidence, cancer mortality or incidence, type 2 diabetes mellitus, and neurodegenerative diseases. A literature search was performed using the electronic databases MEDLINE, SCOPUS, and EMBASE with an end date of May 10, 2014. Study-specific risk ratios were pooled using a random effect model by the Cochrane software package Review Manager 5.2. Fifteen cohort studies (34 reports), including 1,020,642 subjects, met the criteria and were included in the meta-analysis. Diets of the highest quality, as assessed by the HEI, AHEI, and DASH score, resulted in a significant risk reduction (RR) for all-cause mortality (RR 0.78, 95% CI 0.76 to 0.80; P<0.00001; I²=61%, 95% CI 20% to 81%), cardiovascular disease (incidence or mortality) (RR 0.78, 95% CI 0.75 to 0.81; P<0.00001; I²=45%, 95% CI 13% to 66%), cancer (incidence or mortality) (RR 0.85, 95% CI 0.82 to 0.88; P<0.00001; I²=77%, 95% CI 68% to 84%), and type 2 diabetes mellitus (RR 0.78, 95% CI 0.72 to 0.85; P<0.00001; I²=74%, 95% CI 52% to 86%). Differences observed for neurodegenerative diseases were not significant. Egger regression tests provided no evidence of publication bias. Diets that score highly on the HEI, AHEI, and DASH are associated with a significant reduction in the risk of all-cause mortality, cardiovascular disease, cancer, and type 2 diabetes mellitus by 22%, 22%, 15%, and 22%, respectively, and therefore is of high public health relevance.