Pflanzliche Ernährung und ausreichende Proteinzufuhr für ein gesundes Altern

Da die zunehmend ungesunde Ernährungs- und Lebensweise westlicher Industrienationen zur steigenden Prävalenz ernährungsbedingter, chronischer Erkrankungen beitragen, rückt eine pflanzenbasierte Ernährung (PBE) immer mehr in den Fokus der Forschung. Insgesamt ist eine PBE mit vorteilhaften Effekten auf die kardiovaskuläre und metabole Gesundheit assoziiert. Dies wird auf die höhere Nährstoffdichte und reduzierte Proteinzufuhr zurückgeführt, die sich auch günstig auf das Mortalitätsrisiko auszuwirken scheint. Unklar ist allerdings, wie günstig sich eine PBE im höheren Lebensalter auswirkt, da longitudinale Daten speziell für die ältere Generation fehlen. Außerdem besteht im Alter (> 65 Jahre) ein Proteinmehrbedarf, sodass aufgrund der geringeren Proteindichte und Proteinqualität einer PBE Bedenken bez. einer adäquaten Proteinversorgung bestehen. Sehr restriktive Ernährungsweisen werden aufgrund des zu erwartenden Protein- und Nährstoffmangels insbesondere im höheren Lebensalter nicht empfohlen.

Effects of Exercise and Omega-3-Supplemented, High-Protein Diet on Inflammatory Markers in Serum, on Gene Expression Levels in PBMC, and after Ex Vivo Whole-Blood LPS Stimulation in Old Adults

Inflammaging is related to cell senescence and reflects an erratic immune system, which promotes age-associated diseases. Exercise and nutrition, particularly omega-3 fatty acids, are able to affect inflammation. Therefore, we examined the effects of an 8-week exercise and dietary intervention on the inflammatory response in community-dwelling old adults. All participants received weekly vibration and home-based resistance exercise. Furthermore, participants were randomized to either a control, high-protein (1.2-1.5 g/kg), or high-protein, omega-3-enriched (2.2 g/day) diet. Before and after treatment, inflammatory markers in fasting serum and after whole-blood ex vivo lipopolysaccharide (LPS) stimulation were assessed. Gene expression levels of inflammatory markers were quantified in peripheral blood mononuclear cells (PBMC). Sixty-one participants (age: 70.6 ± 4.7 years; 47% men) completed the study. According to generalized linear mixed models, a high-protein, omega-3-enriched diet decreased circulating anti-inflammatory interleukin (IL-) 10 and IL-1 receptor antagonist (IL-1RA). Sex-stratified analyses showed also significantly reduced pro-inflammatory markers in men with a high-protein, omega-3-enriched diet. Gene expression of IL-1RA was significantly reduced after both protein-enriched diets compared with controls. In comparison to a high-protein diet, exercise alone showed lower LPS-induced release of c-c motif chemokine ligand-2 (CCL-2), which tended to be more pronounced in men compared with women. Eight weeks of a high-protein, omega-3-enriched diet combined with exercise decreased circulating anti-inflammatory markers, and pro-inflammatory markers in men. A high-protein diet attenuated anti-inflammatory markers on gene expression level in PBMC. Exercise alone resulted in a lower pro-inflammatory response to LPS-exposure in whole-blood cultures.

Effects of an Omega-3 Supplemented, High-Protein Diet in Combination with Vibration and Resistance Exercise on Muscle Power and Inflammation in Old Adults: A Pilot Randomized Controlled Trial

Background: Inflammaging is considered to drive loss of muscle function. Omega-3 fatty acids exhibit anti-inflammatory properties. Therefore, we examined the effects of eight weeks of vibration and home-based resistance exercise combined with a whey-enriched, omega-3-supplemented diet on muscle power, inflammation and muscle biomarkers in community-dwelling old adults. Methods: Participants were randomized to either exercise (3x/week, n = 20), exercise + high-protein diet (1.2–1.5 g/kg, n = 20), or exercise + high-protein and omega-3-enriched diet (2.2 g/day, n = 21). Muscle power (watt/m²) and chair rise test (CRT) time (s) were assessed via CRT measured with mechanography. Furthermore, leg strength (kg/m²) and fasting concentrations of inflammatory (interleukin (IL-) 6, IL-10, high-mobility group box-1 (HMGB-1)) and muscle biomarkers (insulin-like growth factor (IGF-) 1, IGF-binding protein-3, myostatin) were assessed. Results: Sixty-one participants (70.6 ± 4.7 years; 47% men) completed the study. According to generalized linear mixed models, a high-protein diet improved leg strength and CRT time. Only IGF-1 increased with additional omega-3. Sex-specific analyses revealed that muscle power, IL-6, IL-6/IL-10 ratio, and HMGB-1 improved significantly in the male high-protein, omega-3-enriched group only. Conclusion: Vibration and home-based resistance exercise combined with a high-protein, omega-3-enriched diet increased muscle power and reduced inflammation in old men, but not in old women. While muscle biomarkers remained unchanged, a high-protein diet combined with exercise improved leg strength and CRT time.

Dietary Inflammatory Index and Cross-Sectional Associations with Inflammation, Muscle Mass and Function in Healthy Old Adults

IMPORTANCE

Inflammaging is considered a driver of age-related loss of muscle mass and function (sarcopenia). As nutrition might play a role in this process, the Dietary Inflammatory Index® (DII) has been developed to quantify the inflammatory potential of an individual diet.

OBJECTIVES

We aimed to examine associations between the DII, inflammation, oxidative stress and sarcopenia-related parameters in healthy old compared to young adults.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included data of 79 community-dwelling, healthy old adults (65-85 years) and 59 young adults (18-35 years) who participated in a randomized controlled trial from April to December 2019.

MEASUREMENTS

The DII was computed with dietary data collected from 24-h recall interviews. Associations between the DII, inflammatory and oxidative stress markers as well as bioimpedance-derived body composition, handgrip strength and gait speed were determined with multiple linear regression analyses adjusted for age, sex, physical activity and insulin resistance.

RESULTS

Regression analyses revealed significant relationships between a higher interleukin (IL) 6 and IL-6:IL-10-ratio and higher percentage fat mass (%FM), waist-to-height-ratio (WHtR) as well as lower percentage skeletal muscle mass (%SMM) and gait speed exclusively in old adults. Subsequent analyses showed that IL-6 was associated with a pro-inflammatory diet as indicated by a higher DII, again exclusively in old adults (beta coefficient (β)= 0.027, standard error (SE) 0.013, p=0.037). While the DII was not related with handgrip strength or oxidative stress in neither old nor young adults, linear models confirmed that a higher DII was inversely associated with gait speed in old participants (β= -0.022, SE 0.006, p<0.001). Finally, a pro-inflammatory diet was significantly associated with higher %FM, WHtR and lower %SMM in both age groups.

CONCLUSION AND RELEVANCE

A pro-inflammatory diet reflected by the DII is associated with higher systemic inflammation, slower gait speed as well as lower muscle mass in old adults. Intervention studies are needed to examine whether anti-inflammatory dietary approaches can help to improve muscle mass and function and thus minimize the risk for sarcopenia in the long-term.

Altered Adiponectin Response in Older Women Following Dextrose and High-Fat Dietary Challenges

SCOPE

Despite its beneficial properties, higher adiponectin concentrations are paradoxically associated with mortality in advanced age. Several mechanisms are being discussed. However, little is known about postprandial regulation of adiponectin in older adults. We assessed age-specific differences of the adiponectin response to different test meals considering potential determinants.

METHODS AND RESULTS

Older (n = 20) and younger (n = 22) women are randomized to a dextrose (DEX) or high-fat (HF) dietary challenge. Postprandial adiponectin and fibroblast growth factor 21 (FGF21) concentrations are measured before and 60, 120, 240 min after ingestion. We assessed postprandial changes and group differences using linear mixed models controlled for possible determinants. In younger women, postprandial adiponectin remains stable after both test meals. In contrast, adiponectin increases following DEX and decreases after HF in older women, irrespective of control variables. Postprandial adiponectin is positively associated with malondialdehyde and inversely associated with interleukin-6 following DEX and also negatively associated with metabolic parameters after both test meals. In older women, elevated postprandial FGF21 concentrations are associated with a higher adiponectin response (β = 30.7, 95% CI 10.6-50.8, p = 0.007).

CONCLUSIONS

Adiponectin response is associated with type of dietary challenge, age, and FGF21 response. Age-group differences are partly attributable to metabolic parameters and oxidative stress.

Postprandial dynamics and response of fibroblast growth factor 21 in older adults

BACKGROUND & AIMS

Fibroblast growth factor 21 (FGF21) plays a pivotal role in glucose and lipid metabolism and has been proposed as a longevity hormone. However, elevated plasma FGF21 concentrations are paradoxically associated with mortality in higher age and little is known about the postprandial regulation of FGF21 in older adults. In this parallel group study, we investigated postprandial FGF21 dynamics and response in older (65-85 years) compared to younger (18-35 years) adults following test meals with varying macronutrient composition.

METHODS

Participants (n = 60 older; n = 60 younger) were randomized to one of four test meals: dextrose, high carbohydrate (HC), high fat (HF) or high protein (HP). Blood was drawn before and 15, 30, 60, 120, 240 min after meal ingestion. Postprandial dynamics were evaluated using repeated measures ANCOVA. FGF21 response was assessed by incremental area under the curve.

RESULTS

Fasting FGF21 concentrations were significantly higher in older adults. FGF21 dynamics were affected by test meal (p < 0.001) and age (p = 0.013), when adjusted for BMI and fasting FGF21. Postprandial FGF21 concentrations steadily declined over 240 min in both age groups after HF and HP, but not after dextrose or HC ingestion. At 240 min, FGF21 concentrations were significantly higher in older than in younger adults following dextrose (133 pg/mL, 95%CI: 103, 172 versus 91.2 pg/mL, 95%CI: 70.4, 118; p = 0.044), HC (109 pg/mL, 95%CI: 85.1, 141 versus 70.3 pg/mL, 95%CI: 55.2, 89.6; p = 0.014) and HP ingestion (45.4 pg/mL, 95%CI: 34.4, 59.9 versus 27.9 pg/mL 95%CI: 20.9, 37.1; p = 0.018). FGF21 dynamics and response to HF were similar for both age groups.

CONCLUSIONS

The age-specific differences in postprandial FGF21 dynamics and response in healthy adults, potentially explain higher FGF21 concentrations in older age. Furthermore, there appears to be a significant impact of acute and recent protein intake on FGF21 secretion.