Nutrition and the biology of human ageing: bone health and osteoporosis / sarcopenia / immune deficiency

Association of serum prealbumin with risk of osteoporosis in older adults with type 2 diabetes mellitus: a cross-sectional study

Background:

Poor nutritional status is associated with osteoporosis. Prealbumin is a more sensitive marker than albumin to assess nutritional status. Therefore, the relationship between serum levels of prealbumin and osteoporosis in older adults with type 2 diabetes mellitus (T2DM) was investigated.

Methods:

A total of 370 older adults with T2DM were divided into two groups: older adults with osteoporosis (n = 249) and older adults without osteoporosis (n = 121). Bone mineral density (BMD) and appendicular skeletal muscle (ASM) were measured by dual-energy X-ray absorptiometry (DEXA). Serum levels of prealbumin, highly sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), 25-hydroxyvitamin D₃ [25(OH) D₃] were also tested. Logistic regression analysis was performed to assess the association between prealbumin and osteoporosis.

Results:

The adults with osteoporosis had lower prealbumin levels than those without osteoporosis (235.40 ± 60.66 versus 261.34 ± 55.28 mg/l, p < 0.001). The proportion of adults with prealbumin levels below the normal range was significantly higher in individuals with osteoporosis compared with those without osteoporosis (16.53% versus 4.42%, respectively). After adjusting for age, sex, body mass index (BMI), anemia, handgrip strength and skeletal muscle index (SMI), logistic regression showed that participants with lower levels of prealbumin had a higher risk of osteoporosis [odds ratio (OR): 3.85; 95% confidence interval (CI): 1.54–6.34; p = 0.004].

Conclusion:

Our findings suggested that low levels of prealbumin were associated with an increased risk of osteoporosis in older adults with T2DM. Further longitudinal studies should be conducted to determine if there is a causative association between prealbumin and osteoporosis.

Yogurt supplemented with probiotics can protect the healthy elderly from respiratory infections: A randomized controlled open-label trial

PURPOSE

To evaluate whether yogurt supplemented with a probiotic strain could protect middle-aged and elderly people from acute upper respiratory tract infections (URTI) using a randomized, blank-controlled, parallel-group design.

PATIENTS AND METHODS

Two hundred and five volunteers aged ≥45 years were randomly divided into two groups. The subjects in the intervention group were orally administered 300 mL/d of yogurt supplemented with a probiotic strain, Lactobacillus paracasei N1115 (N1115), 3.6×107 CFU/mL for 12 weeks, while those in the control group retained their normal diet without any probiotic supplementation. The primary outcome was the incidence of URTI, and changes in serum protein, immunoglobulins, and the profiles of the T-lymphocyte subsets (total T-cells [CD3+], T-helper cells [CD4+], and T-cytotoxic-suppressor cells [CD8+]) during the intervention were the secondary outcomes.

RESULTS

Compared to the control group, the number of persons diagnosed with an acute URTI and the number of URTI events significantly decreased in the intervention group (P=0.038, P=0.030, respectively). The risk of URTI in the intervention group was evaluated as 55% of that in the control group (relative risk =0.55, 95% CI: 0.307-0.969). The change in the percentage of CD3+ cells in the intervention group was significantly higher than in the control group (P=0.038). However, no significant differences were observed in the total protein, albumin, globulin, and prealbumin levels in both groups (P>0.05).

CONCLUSION

The study suggested that yogurt with selected probiotic strains such as N1115 may reduce the risk of acute upper tract infections in the elderly. The enhancement of the T-cell-mediated natural immune defense might be one of the important underlying mechanisms for probiotics to express their anti-infective effects.

Quality of diet and level of physical performance related to inflammatory markers in community-dwelling frail, elderly people

OBJECTIVE

The aim of this study was to assess whether diet quality and functional status were associated with serum levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in frail, elderly, community-dwelling individuals.

METHODS

Seventy-eight frail, elderly individuals (age ≥65 y, usual gait speed <0.6 m/s and Mini Nutritional Assessment <24) participated in this cross-sectional study from the National Home Healthcare Services in Gangbuk-gu, Seoul, South Korea. Diet quality was assessed using mean adequacy ratio (MAR) of the diet, which was calculated by averaging the sum of the nutrient adequacy ratios (NAR) for the intakes of energy, protein, and 11 micronutrients. Grip strength was measured as an indicator of muscle strength, and short physical performance battery (SPPB) was measured as an indicator of physical performance. The levels of the inflammatory markers IL-6 and TNF-α were obtained from serum samples.

RESULTS

MAR and NAR scores for phosphorus; vitamins A, B₁, and B₆; and niacin were negatively associated with IL-6 (β = -0.006, -0.004, -0.004, -0.007, -0.004, and -0.005, respectively; P < 0.05). SPPB score, as well as NAR scores for vitamin B₆, niacin, and vitamin C, were negatively associated with TNF-α (β = -0.098, -0.006, -0.006, and -0.004, respectively; P < 0.05).

CONCLUSION

MAR of the diet was inversely associated with IL-6 concentration in frail elderly individuals, and higher SPPB score was associated with lower levels of TNF-α. Results from the present study suggest that improving diet quality and physical performance might lower levels of inflammation in this frail, elderly population.

Animal-Derived Protein Consumption Is Associated with Muscle Mass and Strength in Community-Dwellers: Results from the Milan EXPO Survey

OBJECTIVES

Behavioral factors, including protein intake, influence the quantity and quality of skeletal muscle. The aim of this study was to explore the relationship between animal-derived protein intake and muscle mass and function in a large sample of unselected community-dwellers.

MATERIAL AND METHODS

The VIP (Very Important Protein) study, conducted during Expo 2015 in Milan, was a population survey aimed at assessing major health metrics in a population outside of the research setting, with a special focus on the relation between animal-derived protein intake and muscle mass and function. A brief questionnaire exploring lifestyle habits, dietary preferences and the consumption of selected foods was administered. Muscle mass was estimated by calf circumference (CC) and mid-arm muscle circumference (MAMC) of the dominant side. Muscle strength of upper and lower extremities was assessed through handgrip strength testing and repeated chair stand test, respectively.

RESULTS

The mean age of the 1,853 participants was 50.3 years (standard deviation: 15.7; range: 18-98 years), of whom 959 (51.7%) were women. Participants in the highest tertile of protein consumption showed better performance at both the handgrip strength (p <0.001) and chair stand tests than those in the lowest tertile (p <0.01). The same results were found for CC (p <0.001) and MAMC (p <0.001). Participants with high protein intake and engaged in regular physical activity showed the higher scores in all the assessed domains.

CONCLUSIONS

The results of the VIP survey suggest an association between animal-derived protein intake and muscle mass and strength across ages. Our findings also indicate a synergistic effect of animal-derived protein intake and physical activity on muscle-related parameters.

Reduced prealbumin is associated with bone mineral density in women with osteoporosis

OBJECTIVES

Poor nutritional status is associated with osteoporosis (OP) in postmenopausal women. Moreover, recent studies documented that prealbumin is the best and most widely used parameter to monitor nutrition intervention and is a sensitive predictor of short-term outcome compared with albumin. Therefore, the aim of this study was to examine the association of prealbumin levels with bone mineral density (BMD) in patients with OP.

METHODS

This cross-sectional study recruited 664 women. Prealbumin levels and BMD at femoral neck and lumbar spine were measured. Multiple linear regression analysis was performed to assess the correlation between prealbumin and BMD.

RESULTS

Results of this study found that prealbumin levels dropped gradually as BMD decreased. Furthermore, partial correlation analysis revealed that prealbumin was correlated with BMD after adjusting for confounders. Multiple linear regression analysis showed that prealbumin is a significant factor for reduced BMD in women (for BMD at spine L2-4, β = 0.186, P < 0.001; for BMD at femoral neck, β = 0.180, P < 0.001).

CONCLUSION

Prealbumin was significantly correlated with BMD after adjusting for traditional cardiovascular risk factors. Further prospective research is warranted to further enhance our understanding of the important role of prealbumin in OP.