Association between Mediterranean diet and hand grip strength in older adult women

Summary

Background & aims

Mediterranean Diet (MD) is an eating pattern associated with multiple healthy benefits, including the conservation of skeletal muscle. Frailty is a major geriatric syndrome characterized by low muscle strength. The Hand Grip Strength (HGS) is the most frequently used indicator of muscle functional capacity for clinical purposes. The association between the adherence to the MD and HGS in elderly has not yet fully investigated. The goal of this study was to examine the association between the adherence to the MD and HGS in a not hospitalized elderly who participated in the project PERsonalised ict Supported Services for Independent Living and Active Ageing (PERSSILAA).

Methods

Eighty-four elderly women were consecutively enrolled (aged 60–85 years) in this cross-sectional observational study. Anthropometric measures were evaluated. A validated 14-item questionnaire PREDIMED (PREvención con DIeta MEDiterránea) was used for the assessment of adherence to the MD. Dietary data were collected by a 7-day food records. Muscle strength was measured by HGS using a grip strength dynamometer (KERN & SOHN GmbH).

Results

The majority of participants were overweight (46.4%). An average adherence to the MD was found in 52.4% of participants, while the minority of them showed a low adherence (21.4%). HGS > cut-point of 20 kg were found in 43 subjects (51.2%). According to the adherence to MD, 39% participants with HGS values higher than cut-point presented a high adherence score compared with 14% of those with lower values of HGS (p = 0.018). The participants with HGS > cut-point presented significantly higher PREDIMED score than those with HGS < cut-point (p < 0.001). Based on ROC curves, the most sensitive and specific cut-point for the PREDIMED score to predict HGS categories was ≥8. No evident correlations were observed between HGS and age, while HGS was negatively correlated with hip circumference (r = −0.233, p = 0.033) and BMI (r = −0.219, p = 0.045), and positively correlated with PREDIMED score (r = 0.598, p < 0.001). At binomial logistic regression analysis almost all 14-items of PREDIMED questionnaire were significantly associated with HGS adjusted for BMI. At multinomial logistic regression analysis to assess the association of the three classes of adherence to the MD with the HGS, after adjusting for BMI the lowest adherence to MD was associated with the lowest Odds Ratio of HGS (p < 0.001).

Conclusions

This study evidenced a positive association between the adherence to the MD and muscle strength in a sample of active elderly women, stratified according to the HGS > cut-point of 20 kg. Our study highlights the usefulness of the developing health services to detect and prevent age-associated decline in physical performance in elderly subjects by addressing nutritional and physical intervention.

Introduction

Nutrition is one of the major modifiable environmental risk factors for several non-communicable diseases and represents a mainstay for their prevention and also their initial treatment [1]. In particular, in the elderly population nutrition is an important element of health and there is increasing scientific and clinical evidence showing the link between nutrition and health as part of aging [2], [3].

The Mediterranean diet (MD) is a plant-based, antioxidant-rich diet known for its several health benefits. This dietary pattern is considered a nutritionally adequate, complete and easy to follow, as it is based on the traditional foods that people used to eat in their countries [4]. In particular, the MD features a high intake of whole grains, fruits, vegetables, tree nuts, legumes, and olive oil on a daily basis; a moderate intake of fish and poultry, low consumption of dairy products, red meat, processed meat and sweets, and moderate consumption of wine with meals [5], [6]. Large observational prospective epidemiological studies support that the Mediterranean dietary pattern increases life expectancy, reduce the risk of major chronic diseases, and improve quality of life and well-being [7], [8]. However, it should be considered that the Mediterranean dietary patterns may vary according to age, gender, ethnicity, culture and other lifestyle factors [9]. Indeed, previous studies have identified gender as a key determinant of food choices [10] with females having more motivation towards healthy eating and are more aware of healthy eating compared with males [11], [12]. In elderly subjects numerous studies have reported that higher adherence to the MD is associated with lowest mortality [13], [14], [15], [16], although most of these studies were not conducted specifically to determine the MD effects in elderly subjects. Higher adherence to the MD has been also proven to be effective in preserving the skeletal muscle mass in healthy women likely due to the potential anti-inflammatory and anti-oxidant properties of micronutrients (e.g. carotenoids and vitamins C and E) or through their direct role in muscle metabolism and physiology, such as with magnesium and potassium [17].

Nutrition plays a decisive role in the development of frailty [18], [19]. Frailty or “the frailty syndrome” are commonly used terms to denote a clinical entity in elderly subjects. Frailty has been reported to be associated with increased risk for adverse outcomes, such as onset of disability, morbidity, institutionalization or mortality [20]. In particular, the presence of frailty has been associated with increased all-cause mortality [21], [22], [23], [24] and increased incident cardiovascular disease [25], as well as poor survival after cardiac and surgical procedures. The effectiveness of the adherence to a Mediterranean dietary pattern on the risk of development of frailty in elderly adults has been demonstrated in different clinical settings. In particular, using the MD score, a high adherence to a MD was associated with a slower decline of mobility and to the development of frailty over time in community-dwelling elderly persons of both gender participating to the InCHIANTI Study [26], [27].

The Hand Grip Strength (HGS) is an objective component of the frailty syndrome in the elderly subjects, thereby representing the most frequently used indicator of muscle functional capacity for clinical purposes [28]. HGS is a non-invasive and reliable method for assessment of muscle power and nutritional status and portable HGS devices are quick and easy to use [29]. The association between nutrition status and HGS is well documented [30] and HGS is currently considered as a marker of the nutrition status [30], [31]. In particular, HGS reflects early nutrition deprivation and nutrition repletion also before changes in body composition parameters can be detected [30]. The Academy of Nutrition and Dietetics and the American Society for Parenteral and Enteral Nutrition has recently recommended reduced HGS values as a criterion for the identification and documentation of undernutrition in clinical practice [31]. Besides nutrition, other parameters, such as sex and age, have also been identified to be associated with HGS in elderly subjects [32], [33], [34], [35], [36]. HGS is associated with increased all-cause mortality [37], disability and increased length of hospital stay [38]. Thus, it is essential for public health to implement screenings and multidisciplinary treatments of frailty, especially through indirect but reliable measures, such as HGS.

This cross-sectional observational study was designed to capture the association between a Mediterranean dietary pattern with HGS in elderly women participants in the PERsonalised ict Supported Services for Independent Living and Active Ageing (PERSSILAA), an European project developing health services to detect and prevent frailty in elderly subjects by addressing cognitive, physical and nutritional domains in Campania Region, Italy and Enschede, the Netherlands [39].