Sarcopenia is characterized by the age-related loss of muscle mass and strength. One of the mechanisms of sarcopenia is the loss in the function and number of muscle satellite cells. Royal jelly (RJ) is a health food used worldwide. To obtain better digestion and absorption than RJ, protease-treated RJ (pRJ) has been developed. RJ and pRJ have been suggested to have potential pharmacological benefits such as prolonging the life span and reducing fatigue. Because these effects may improve sarcopenia and the functions of satellite cells, we examined the effects of RJ or pRJ treatment on the skeletal muscles in an animal model using aged mice. In vivo, RJ/pRJ treatment attenuated the decrease in the muscle weight and grip strength and increased the regenerating capacity of injured muscles and the serum insulin-like growth factor-1 levels compared with controls. In vitro, using isolated satellite cells from aged mice, pRJ treatment increased the cell proliferation rate, promoted cell differentiation, and activated Akt intracellular signaling pathway compared with controls. These findings suggest that RJ/pRJ treatment had a beneficial effect on age-related sarcopenia.

Irritable bowel syndrome is a common gastrointestinal disorder that may affect dietary pattern, food digestion, and nutrient absorption. The nutrition-related factors are closely related to metabolic syndrome, implying that irritable bowel syndrome may be a potential risk factor for metabolic syndrome. However, few epidemiological studies are available which are related to this potential link. The purpose of this study is to determine whether irritable bowel syndrome is related to metabolic syndrome among middle-aged people. We designed a cross-sectional study of 1,096 subjects to evaluate the relationship between irritable bowel syndrome and metabolic syndrome and its components. Diagnosis of irritable bowel syndrome was based on the Japanese version of the Rome III Questionnaire. Metabolic syndrome was defined according to the criteria of the American Heart Association scientific statements of 2009. Dietary consumption was assessed via a validated food frequency questionnaire. Principal-components analysis was used to derive 3 major dietary patterns: “Japanese”, “sweets-fruits”, and “Izakaya (Japanese Pub) “from 39 food groups. The prevalence of irritable bowel syndrome and metabolic syndrome were 19.4% and 14.6%, respectively. No significant relationship was found between the dietary pattern factor score tertiles and irritable bowel syndrome. After adjustment for potential confounders (including dietary pattern), the odds ratio (95% confidence interval) of having metabolic syndrome and elevated triglycerides for subjects with irritable bowel syndrome as compared with non-irritable bowel syndrome are 2.01(1.13–3.55) and 1.50(1.03–2.18), respectively. Irritable bowel syndrome is significantly related to metabolic syndrome and it components. This study is the first to show that irritable bowel syndrome was significantly related to a higher prevalence of metabolic syndrome and elevated triglycerides among an adult population. The findings suggest that the treatment of irritable bowel syndrome may be a potentially beneficial factor for the prevention of metabolic syndrome. Further study is needed to clarify this association.

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Persistent low-grade systemic inflammation has been increasingly recognized as a common pathological process, and an important contributing factor to cardiovascular diseases and its risk factor, metabolic syndrome. Immunoglobulin M is reactive to multiple autoantigens and is inferred to be important for autoimmunity, implying that immunoglobulin M may be a potential risk factor for metabolic syndrome. However, few epidemiological studies are available which are related to this potential link. Therefore, we designed a cross-sectional study of 9,379 subjects to evaluate the relationship between immunoglobulin M and metabolic syndrome in an adult population. Subjects who received health examinations were recruited from the Tianjin Medical University General Hospital-Health Management Center in Tianjin, China. Immunoglobulin M was determined with an immunonephelometric technique. Metabolic syndrome was defined according to the criteria of the American Heart Association scientific statements of 2009. Multiple logistic regression analysis was used to examine the relationships between the quartiles of immunoglobulin M and the prevalence of metabolic syndrome. After adjustment for covariates, the odds ratio of having metabolic syndrome in the fourth quartile compared with the first quartile of immunoglobulin M was 1.19 times for males (95% confidence interval, 1.002–1.41) and 1.39 times for females (95% confidence interval, 1.07–1.80). Immunoglobulin M levels also showed positive relationships with the ratio of elevated triglycerides and reduced high-density lipoprotein cholesterol in males. The study is the first to show that immunoglobulin M is independently related to metabolic syndrome and its individual components (elevated triglycerides and reduced high-density lipoprotein cholesterol) in males, whereas immunoglobulin M is independently related to metabolic syndrome in females but not to its individual components. Further studies are needed to explore the causality and the exact role of immunoglobulin M in metabolic syndrome.