Mediterranean diet and telomere length in high cardiovascular risk subjects from the PREDIMED-NAVARRA study

Telomere length as a biomarker of accelerated aging: is it influenced by dietary intake?

PURPOSE OF REVIEW

There is increasing interest in exploring whether age-related diseases can be prevented by dietary means through nutrients or food bioactives, whole foods, or specific dietary patterns. Because of the slow nature of the aging process, biomarkers such as telomere length are helpful for this purpose. Here we update the developments in the area during the last 2 years.

RECENT FINDINGS

Most data stem from epidemiologic studies, often cross-sectional in design. Recent articles strengthened the link between consumption of sugar-sweetened beverages and telomere shortening, whereas a novel association between telomere length and drinking coffee has been uncovered. Controversy on meat consumption and telomere length persists, mostly because of the presumed different effects of total meat and processed meat. In general terms, increasing consumption of antioxidant-rich plant foods relates to maintained telomere length. Feeding intervention trials with outcomes on telomere length are few and thus far have contributed little to further knowledge on this topic.

SUMMARY

Epidemiologic studies provide support for the putative effects of diet components on telomere length and on the aging process in general. Dietary associations with telomere length should be confirmed with adequately powered randomized controlled trials.

Diet Quality Indices and Leukocyte Telomere Length Among Healthy US Adults: Data From the National Health and Nutrition Examination Survey, 1999-2002

Aging is the biggest risk factor for the development of chronic diseases. Telomere length may represent one important mechanism by which dietary intake influences risk of age-related diseases; however, it is unknown which diet pattern is most strongly related to telomere length. We compared the relationships between 4 evidence-based diet quality indices and leukocyte telomere length in a nationally representative sample of healthy adults, and the extent to which these associations differed between men and women. Data on 4,758 adults aged 20-65 years with no prior diagnosis of major chronic disease were obtained from the 1999-2002 cycles of the National Health and Nutrition Examination Survey. Diet was assessed using one 24-hour dietary recall. After adjustment for sociodemographic and health characteristics, comparison of the top and bottom quintiles showed that higher Healthy Eating Index 2010 scores (β = 0.065, 95% confidence interval (CI): 0.018, 0.112; P-trend = 0.007), Alternate Healthy Eating Index 2010 scores (β = 0.054, 95% CI: 0.010, 0.097; P-trend = 0.007), Mediterranean Diet scores (β = 0.058, 95% CI: 0.017, 0.098; P-trend = 0.008), and Dietary Approaches to Stop Hypertension (DASH) scores (β = 0.052, 95% CI: 0.014, 0.090; P-trend = 0.007) were each associated with longer telomere length in women. These results may provide insight into the complex associations between optimal nutrition and longevity. Further investigation is needed to understand why associations were not observed in men.

Telomeropathies: rare disease syndromes

Telomeres are located at the end of the chromosomes. They protect chromosomes from fusion and degradation. Every cell division causes a shortening of the telomeres. A special enzymatic complex called telomerase is responsible for maintaining telomere length in intensively dividing cells, such as epithelial cells and bone marrow cells. The enzymatic complex includes the TERT subunit, which has reverse transcriptase activity, and the TERC subunit, which acts as a template. Other important components of telomerase are the proteins that are responsible for structural stability. Telomerase remains active only in the dividing cells of the body. The rate of telomere shortening depends on many factors including age, sex, and comorbidities. Faster shortening of telomeres is caused by gene defects, which have an impact on telomerase action. Collectively, these are called telomeropathies. Common causes of telomeropathies are mutations in the TERT and TERC telomerase genes. Types of telemeropathies include dyskeratosis congenita, idiopathic pulmonary fibrosis, and aplastic anaemia, among others. Clinical manifestations and prognoses depend on the type and quantity of mutated genes. Diagnosis of telomeropathies is often problematic because they present with the same symptoms as other diseases. So far, no effective therapeutic methods have been developed for telomeropathies. A therapeutic method for patients with bone marrow failure may be the transplantation of hematopoietic stem cells. For patients with idiopathic pulmonary fibrosis, treatments include immunosuppressive therapy, lung transplantation, or palliative care. In the future, gene therapy may be an effective treatment strategy for telomeropathies. Lifestyle changes may also have a positive impact on the person. Physical activity combined with a healthy diet rich in antioxidants and unsaturated fatty acids can decrease the oxidative stress levels in cells and lead to a slower shortening of the telomeres.

Ageing at the level of telomeres in association to residential landscape and air pollution at home and work: a review of the current evidence

Studies suggest that leukocyte telomere length is an index of systemic ageing. Here, we discuss telomere length as a marker of biological ageing in relation to residential landscape (greenness), residential air pollution and work-related exposures. Telomere lengths are memories of cumulative oxidative and inflammatory stress, and show to have inverse associations with the risk of non-communicable diseases. For this reason, telomeres are considered as markers of biological ageing. Studies at birth, in children, young adulthood, and elderly show that residential green space, lower traffic exposure and long-term lower exposure to particulate air pollution are associated with longer telomeres. Work-related exposures including exposure to toxic metals, polycyclic aromatic hydrocarbons and particulate matter are associated with shorter telomeres for a given age. In contrast to chronic exposures, evidence is present of the observation that recent exposure is associated with longer telomeres. Our overview shows that the magnitude of residential and work-related environmental factors on telomere length are often as important as many classical lifestyle factors.

Beginning at the ends: telomeres and human disease

Studies of rare and common illnesses have led to remarkable progress in the understanding of the role of telomeres (nucleoprotein complexes at chromosome ends essential for chromosomal integrity) in human disease. Telomere biology disorders encompass a growing spectrum of conditions caused by rare pathogenic germline variants in genes encoding essential aspects of telomere function. Dyskeratosis congenita, a disorder at the severe end of this spectrum, typically presents in childhood with the classic triad of abnormal skin pigmentation, nail dystrophy, and oral leukoplakia, accompanied by a very high risk of bone marrow failure, cancer, pulmonary fibrosis, and other medical problems. In contrast, the less severe end of the telomere biology disorder spectrum consists of middle-age or older adults with just one feature typically seen in dyskeratosis congenita, such as pulmonary fibrosis or bone marrow failure. In the common disease realm, large-scale molecular epidemiology studies have discovered novel associations between illnesses, such as cancer, heart disease, and mental health, and both telomere length and common genetic variants in telomere biology genes. This review highlights recent findings of telomere biology in human disease from both the rare and common disease perspectives. Multi-disciplinary collaborations between clinicians, basic scientists, and epidemiologist are essential as we seek to incorporate new telomere biology discoveries to improve health outcomes.

Leukocyte telomere length and diet in the apparently healthy, middle-aged Asklepios population

Telomere length is a prognostic biomarker for aging diseases. As it is unknown whether diet plays a role in these associations, we aimed to assess the impact of diet on telomere length. Moreover, given that telomere length is modulated by oxidative stress and inflammation, an additional goal was to evaluate whether the latter may mediate possible telomere - diet associations. Southern blot measured leukocyte telomere length and food frequency questionnaire data were compared for 2509 apparently healthy men and women (~35 to 55 years) from the Asklepios population. No significant associations were found between telomere length and overall dietary characteristics, such as dietary diversity, quality, equilibrium, and the dietary inflammatory index. Exploratory analysis of individual dietary variables revealed that a higher daily intake of deep fried potato products was associated with shorter telomeres (P = 0.002, 151 bp per 100 g/day), also in both sexes separately. Deep fried potato product consumption was also significantly associated with C-reactive protein (P = 0.032) and uric acid (P = 0.042), but not other inflammation and oxidative stress markers. These results suggest an at most limited association between overall dietary patterns and telomere length in the general population. Nevertheless, the association between telomere length and deep fried potato product intake warrants additional research.

Aging and Adherence to the Mediterranean Diet: Relationship with Cardiometabolic Disorders and Polypharmacy

OBJECTIVES

To investigate the association between adherence to the Mediterranean Diet (Med-Diet), cardiometabolic disorders and polypharmacy.

DESIGN

Cross-sectional study.

SETTING

Geriatrics outpatient clinic, Policlinico Umberto I, Sapienza University of Rome.

PARTICIPANTS

508 patients (219 male, 289 female) aged 50 to 89 who were evaluated for cardiovascular and metabolic disorders.

METHODS AND MEASUREMENTS

Patients underwent a comprehensive medical assessment including medical history and the use of medications. Adherence to Med-Diet was assessed using the validated Med-Diet 14-item questionnaire; for the analysis, patients were divided in high (≥8) and medium-low (<8) adherence. Polypharmacy was defined as taking ≥5 medications.

RESULTS

476 patients completed the study. Mean age was 70.4 years; 58% female. Median Med-Diet score was 8 (interquartile range, 6-9). Patients with medium-low adherence had higher body mass index (p=0.029) and higher prevalence of arterial hypertension (p<0.001), previous coronary (p=0.002) and cerebrovascular events (p=0.011), diabetes, (p<0.001) and dyslipidemia (p=0.001) compared to those at high adherence. Med-Diet score decreased with the number of cardiometabolic disorders (p<0.001). The prevalence of polypharmacy was 39%. Consumption of olive oil (p=0.005), vegetables, (p<0.001), wine (p=0.017), legumes (p=0.028), fish (p=0.046) and nuts (p=0.045) were all inversely associated with the overall number of medications. In a multivariable regression model, medium-low adherence to Med-Diet was independently associated to polypharmacy (O.R.:1.859; 95% CI 1.142 to 3.025; p=0.013), after adjusting for possible confounding factors.

CONCLUSION

Med-Diet was inversely associated with cardiometabolic disorders and with polypharmacy, suggesting that improved Med-Diet adherence might potentially delay the onset of age-related health deterioration and reduce the need of multiple medications.

PUFA Status and Methylmercury Exposure Are Not Associated with Leukocyte Telomere Length in Mothers or Their Children in the Seychelles Child Development Study

Background: Leukocyte telomere length (TL) is associated with age-related diseases and early mortality, but there is a lack of data on the determinants of TL in early life. Evidence suggests that dietary intake of marine n-3 (ω-3) polyunsaturated fatty acids (PUFAs) is protective of telomere attrition, yet the effect of methylmercury exposure, also found in fish, on TL is unknown.Objective: The aim of this study was to investigate the associations between prenatal PUFA status, methylmercury exposure, and TL in mothers and children in the SCDS (Seychelles Child Development Study), for whom fish consumption is high.Methods: Blood samples collected from 229 mothers (at 28 wk gestation and delivery) and children (at 5 y of age) in the SCDS first nutrition cohort were analyzed for PUFA concentrations. Prenatal mercury was measured in maternal hair collected at delivery. Postnatal mercury was also measured in children's hair samples with the use of a cumulative metric derived from values obtained at 3-5 y of age. Relative TL was measured in blood obtained from mothers at delivery, in cord blood, and in children at 5 y of age by quantitative polymerase chain reaction. Linear regression models were used to investigate the associations between PUFA status, methylmercury exposure, and TL.Results: Neither prenatal PUFA status or methylmercury exposure was associated with TL of the mother or child or with TL attrition rate. However, a higher prenatal n-6:n-3 PUFA ratio was significantly associated with longer TLs in the mothers (β = 0.001, P = 0.048). Child PUFA status and methylmercury exposure were not associated with child TL. However, higher family Hollingshead socioeconomic status (SES) scores at 9 mo of age were significantly associated with longer TLs in cord blood (β = 0.005, P = 0.03).Conclusions: We found no evidence that PUFA status or methylmercury exposure are determinants of TL in either the mother or child. However, our results support the hypothesis that family SES may be associated with child TL.

Higher adherence to the 'vegetable-rich' dietary pattern is related to longer telomere length in women

BACKGROUND & AIMS

Increasing evidence suggests a role of nutrition in aging process measured by telomere length (TL). However, data from Chinese are scarce. Moreover, the potential mechanism underlying diet and aging is not clear. Although inflammation has been hypothesized as one of the main factors, direct evidence is lacking. We examined whether dietary patterns were associated with TL in Chinese adults, with particular attention paid to body fat (excessive accumulation of body fat is a state of high-systematic oxidative stress and inflammation) and C-reactive protein (CRP, a marker of inflammation).

METHODS

Principal components analysis was used to identify dietary patterns from a 66-item food frequency questionnaire. TL was measured by Southern blots-based assay (Telomere restriction fragments, TRF). Data on sociodemographic characteristics, lifestyle behaviors, anthropometry and metabolism were collected. Multivariate linear regressions were performed in 553 Chinese adults (50.8% men) aged 25-65 years.

RESULTS

Four main dietary patterns were identified. After adjustment for potential confounders, only the 'vegetable-rich' pattern characterized by higher intake of fruits, whole grains, various vegetable groups, dairy products, nuts, eggs and tea, was positively related to TL in women (β = 160.81, P for trend <0.05). The strength of this relation was almost identical with further adjustment for body fat (β = 160.50, P for trend <0.05), but was attenuated slightly with additional adjustment for CRP (β = 152.02, P for trend <0.05). No significant relations were observed in men between dietary patterns and TL.

CONCLUSIONS

Chinese women with higher adherence to 'vegetable-rich' dietary pattern have a longer TL. This relation was partially explained by CRP but not by body fat.

NutrimiRAging: Micromanaging Nutrient Sensing Pathways through Nutrition to Promote Healthy Aging

Current sociodemographic predictions point to a demographic shift in developed and developing countries that will result in an unprecedented increase of the elderly population. This will be accompanied by an increase in age-related conditions that will strongly impair human health and quality of life. For this reason, aging is a major concern worldwide. Healthy aging depends on a combination of individual genetic factors and external environmental factors. Diet has been proved to be a powerful tool to modulate aging and caloric restriction has emerged as a valuable intervention in this regard. However, many questions about how a controlled caloric restriction intervention affects aging-related processes are still unanswered. Nutrient sensing pathways become deregulated with age and lose effectiveness with age. These pathways are a link between diet and aging. Thus, fully understanding this link is a mandatory step before bringing caloric restriction into practice. MicroRNAs have emerged as important regulators of cellular functions and can be modified by diet. Some microRNAs target genes encoding proteins and enzymes belonging to the nutrient sensing pathways and, therefore, may play key roles in the modulation of the aging process. In this review, we aimed to show the relationship between diet, nutrient sensing pathways and microRNAs in the context of aging.

Association between the dietary inflammatory index (DII) and telomere length and C-reactive protein from the National Health and Nutrition Examination Survey-1999-2002

SCOPE

Leukocyte telomere length (LTL) is an important biomarker of aging. This study examined whether inflammatory potential of diet, as measured by the Dietary Inflammatory Index^TM (DII) has an impact on telomere shortening in the National Health and Nutrition Examination Survey (NHANES). We also carried out validation of the DII with C-reactive protein (CRP).

METHODS AND RESULTS

Data came from NHANES 1999-2002. LTL and CRP were assayed from leukocyte DNA and serum specimens, respectively. The DII was calculated from food intakes assessed using 24-h dietary recalls and expressed per 1000 calories consumed. Associations were examined using survey-based multivariable linear regression for log-transformed LTL. After multivariable adjustment, higher DII scores (i.e. relatively more pro inflammatory) were associated with shorter LTL both when used as continuous (b  =  -0.003; 95% confidence interval [CI]  =  -0.005, -0.0002) and as quartiles (b_{DIIquartile4vs1}   =  -0.013; 95% CI  =  -0.025, -0.001; P_trend   =  .03). In this same sample the DII also was associated with CRP ≥3 mg/L (OR_{DIIcontinuous} = 1.10; 95% CI = 1.06, 1.16).

CONCLUSION

In these NHANES data there was an association between DII and LTL. This study also provided a successful construct validation of the DII using CRP in a nationally representative sample. These results are consistent with the hypothesis that diet-associated inflammation determines LTL.

Diet quality and telomere length in older Australian men and women

PURPOSE

Telomere length is a biomarker of cellular ageing, with longer telomeres associated with longevity and reduced risk of chronic disease in older age. Consumption of a healthy diet may contribute to longevity via its impact on cellular ageing, but studies on diet and telomere length to date have been limited and their findings equivocal. The aim of this study was to examine associations between three indices of diet quality and telomere length in older men and women.

METHODS

Adults aged 57-68 years participating in the Wellbeing, Eating and Exercise for a Long Life (WELL) study in Victoria, Australia (n = 679), completed a postal survey including an 111-item food frequency questionnaire in 2012. Diet quality was assessed via three indices: the Dietary Guideline Index, the Recommended Food Score, and the Mediterranean Diet Score. Relative telomere length was measured by quantitative polymerase chain reaction. Associations between diet quality and telomere length were assessed using linear regression adjusted for covariates.

RESULTS

After adjustment for age, sex, education, smoking, physical activity, and body mass index (BMI), there were no significant associations between diet quality and relative telomere length.

CONCLUSIONS

In a sample of older adults residing in Victoria, Australia, men and women aged 57-68 years with better-quality diets did not have longer telomeres. Further investigation in longitudinal studies will determine whether diet can influence telomere length over time in an ageing population.