The aim of this cross-sectional study was to examine the association between the geriatric nutritional risk index (GNRI) and the prevalence of sarcopenia in people with type 2 diabetes (T2DM). Having both low handgrip strength (<28 kg for men and <18 kg for women) and low skeletal muscle mass index (<7.0 kg/m² for men and <5.7 kg/m² for women) was diagnosed as sarcopenia. GNRI was estimated by the formula as below: GNRI = (1.489 × serum albumin level [g/L]) + (41.7 × [current body weight (kg)/ideal body weight (kg)]). Participants were dichotomized on the basis of their GNRI scores (GNRI < 98, low; or GNRI ≥ 98, high). Among 526 people (301 men and 225 women) with T2DM, the proportions of participants with sarcopenia and low GNRI were 12.7% (n = 67/526) and 5.1% (n = 27/526), respectively. The proportion of sarcopenia in participants with low-GNRI was higher than that with high GNRI (44.4% [n = 12/27] vs. 11.0% [n = 55/499], p < 0.001). The GNRI showed positive correlations with handgrip strength (r = 0.232, p < 0.001) and skeletal muscle mass index (r = 0.514, p < 0.001). Moreover, low GNRI was related to the prevalence of sarcopenia (adjusted odds ratio, 4.88 [95% confidence interval: 1.88–12.7], p = 0.001). The GNRI, as a continuous variable, was also related to the prevalence of sarcopenia (adjusted odds ratio, 0.89 [95% confidence interval: 0.86–0.93], p < 0.001). The present study revealed that low GNRI was related to the prevalence of sarcopenia.

Insulin resistance is a risk of sarcopenia, and the presence of sarcopenia is high in patients with type 2 diabetes (T2DM). It has been reported that habitual miso soup consumption was associated with lower insulin resistance. However, the association between habitual miso consumption and the presence of sarcopenia in patients with T2DM, especially sex difference, was unclear. In this cross-sectional study, 192 men and 159 women with T2DM were included. Habitual miso consumption was defined as consuming miso soup regularly. Having both low skeletal muscle mass index (<28.64% for men, <24.12% for women) and low adjusted hand grip strength (<51.26% for men, <35.38% for women) was defined as sarcopenia. The proportions of sarcopenia were 8.7% in men and 22.6% in women. The proportions of habitual miso consumption were 88.0% in men and 83.6% in women. Among women, the presence of sarcopenia was lower in the group with habitual miso consumption (18.8% versus 42.3%, p = 0.018); however, there was no association between habitual miso consumption and the presence of sarcopenia in men. Habitual miso consumption was negatively associated with the presence of sarcopenia in women (adjusted odds ratio (OR), 0.20 (95% confidence interval (CI): 0.06–0.62), p = 0.005) but not in men. This study indicated that habitual miso consumption was associated with the presence of sarcopenia in women but not in men.

The aim of this prospective cohort study was to examine the relationships between the intakes of various vitamins and the loss of muscle mass in older people with type 2 diabetes (T2DM). The change in skeletal muscle mass index (SMI, kg/m²) (kg/m²/year) was defined as follows: (SMI at baseline (kg/m²) − SMI at follow-up (kg/m²))/follow-up period (year). The rate of SMI reduction (%) was calculated as follows (the change in SMI (kg/m²/year)/SMI at baseline (kg/m²)) × 100. The rate of SMI reduction ≥ 1.2% was considered as the loss of muscle mass. Among 197 people with T2DM, 47.2% of them experienced the loss of muscle mass at the 13.7 ± 5.2 month follow-up. Vitamin B1 (0.8 ± 0.3 vs. 0.8 ± 0.3 mg/day, p = 0.031), vitamin B12 (11.2 ± 8.3 vs. 13.4 ± 7.5 μg/day, p = 0.049), and vitamin D (16.5 ± 12.2 vs. 21.6 ± 13.0 μg/day, p = 0.004) intakes in people with the loss of muscle mass were significantly lower than those without. Vitamin D intake was related to the loss of muscle mass after adjusting for sex, age, exercise, alcohol, smoking, body mass index, SMI, glucagon-like peptide-1 agonist, sodium glucose cotransporter-2 inhibitor, insulin, HbA1c, creatinine, energy intake, and protein intake (adjusted odds ratio 0.93, 95% confidence interval: 0.88–0.97, p = 0.003). This study showed that vitamin D intake was related to the loss of muscle mass in older people with T2DM. Vitamin B12 intake tended to be related to the loss of muscle mass, although vitamin A, vitamin B2, vitamin B6, vitamin C, and vitamin E intake were not related.

Exercise has been reported to be effective in maintaining and recovering muscle; however, the effect of exercise combined with adequate or inadequate protein intake on muscle mass is not clear. Therefore, this study investigates the effect of exercise habit on changes in muscle mass, with adequate or inadequate protein intake. This retrospective cohort study included 214 elderly patients with type 2 diabetes. The rate of skeletal muscle mass index (SMI) change (%) was defined as ((SMI at follow-up minus SMI at baseline)/(follow-up years [kg/m²/year] × SMI at baseline [kg/m²])) × 100. Adequate protein intake was defined as protein intake ≥1.2 g/kg ideal body weight/day. During a mean follow-up duration of 18.0 (7.1) months, the rate of SMI change was −1.14 (4.10)% in the whole sample. The rate of SMI change of non-habitual exercisers with inadequate protein intake, habitual exercisers with inadequate protein intake, non-habitual exercisers with adequate protein intake, and habitual exercisers with adequate protein intake was −1.22 (3.71), −2.31 (3.30), −1.88 (4.62), and 0.36 (4.29)%, respectively. Compared with patients with exercise habit and adequate protein intake, the odds ratio for decreasing SMI was 2.50 (0.90–6.90, p = 0.078) in patients with no exercise habit and inadequate protein intake, 3.58 (1.24–10.4, p = 0.019) in those with exercise habit and inadequate protein intake, and 3.03 (1.27–7.22, p = 0.012) in those with no exercise habit and adequate protein intake, after adjusting for covariates. Therefore, exercise habit without adequate protein intake was associated with an increased risk of decreasing SMI compared with exercise habit with adequate protein intake.

This study aimed to identify the serum metabolites associated with sarcopenic risk in Japanese patients with type 2 diabetes, determine the effect of dietary protein intake on the serum metabolic profile, and examine its association with sarcopenia. Ninety-nine Japanese patients with type 2 diabetes were included, and sarcopenic risk was defined as low muscle mass or strength. Seventeen serum metabolites were quantified after gas chromatography–mass spectrometry analysis. The relationship between dietary protein intake and the metabolites concerning sarcopenia was analyzed, and the factors affecting sarcopenic risk were clarified. Twenty-seven patients were classified as being at risk of sarcopenia, the same as the general risk, which was associated with older age, a longer duration of the disease, and a lower body mass index. Low levels of leucine and glutamic acid were significantly associated with low muscle strength (p = 0.002 and p < 0.001, respectively), and leucine was also associated with muscle mass (p = 0.001). Lower levels of glutamic acid had higher odds of sarcopenic risk after being adjusted for age and HbA1c (adjusted OR 4.27, 95% CI 1.07–17.11, p = 0.041), but not for leucine. Leucine and glutamic acid can serve as useful biomarkers for sarcopenia, highlighting potential targets for its prevention.

Non-alcoholic fatty liver disease (NAFLD), often complicated by type 2 diabetes mellitus (T2DM), is reported to be associated with diet habits, including eating speed, in the general population. However, the association between eating speed and NAFLD in patients with T2DM, especially sex difference, has not been reported so far. This cross-sectional study included 149 men and 159 women with T2DM. Eating speed was evaluated by a self-reported questionnaire and divided into three groups: fast, moderate, and slow eating. Nutrition status was evaluated by a brief-type self-administered diet history questionnaire. NAFLD was defined as the hepatic steatosis index ≥36 points. Body mass index and carbohydrate/fiber intake in the fast-eating group were higher than those in the slow-eating group in men, whereas this difference was absent in women. In men, compared with eating slowly, eating fast had an elevated risk of the presence of NAFLD after adjusting for covariates (odds ratio (OR) 4.48, 95% confidence interval (CI) 1.09–18.5, p = 0.038). In women, this risk was not found, but fiber intake was found to be negatively associated with the presence of NAFLD (OR 0.85, 95% Cl 0.76–0.96, p = 0.010). This study indicates that eating speed is associated with the presence of NAFLD in men but not in women.