Comprehensive Approach to Medical Nutrition Therapy in Patients with Type 2 Diabetes Mellitus: From Diet to Bioactive Compounds.

In the pathogenesis of type 2 diabetes mellitus (T2DM), diet plays a key role. Individualized medical nutritional therapy, as part of lifestyle optimization, is one of the cornerstones for the management of T2DM and has been shown to improve metabolic outcomes. This paper discusses major aspects of the nutritional intervention (including macro- and micronutrients, nutraceuticals, and supplements), with key practical advice. Various eating patterns, such as the Mediterranean-style, low-carbohydrate, vegetarian or plant-based diets, as well as healthy eating plans with caloric deficits have been proven to have beneficial effects for patients with T2DM. So far, the evidence does not support a specific macronutrient distribution and meal plans should be individualized. Reducing the overall carbohydrate intake and replacing high glycemic index (GI) foods with low GI foods have been shown as valid options for patients with T2DM to improve glycemic control. Additionally, evidence supports the current recommendation to reduce the intake of free sugars to less than 10% of total energy intake, since their excessive intake promotes weight gain. The quality of fats seems to be rather important and the substitution of saturated and trans fatty acids with foods rich in monounsaturated and polyunsaturated fats lowers cardiovascular risk and improves glucose metabolism. There is no benefit of supplementation with antioxidants, such as carotene, vitamins E and C, or other micronutrients, due to the lack of consistent evidence showing efficacy and long-term safety. Some studies suggest possible beneficial metabolic effects of nutraceuticals in patients with T2DM, but more evidence about their efficacy and safety is still needed.

Obesity and infectious diseases: pathophysiology and epidemiology of a double pandemic condition.

The current pandemic due to widespread SARS-CoV-19 infection has again highlighted the role of obesity, whose global prevalence increased up to 13%, as a risk factor for both susceptibility to infections and the occurrence of a more severe disease course. To date, this association has not been sufficiently explored. Obesity-related susceptibility to infectious diseases is mostly thought to be due to an impairment of both innate and adaptive immune responses and vitamin D deficiency. Several cofactors can indirectly favour the onset and/or worsening of infectious diseases, such as impairment of respiratory mechanics, skin and subcutaneous tissue homoeostasis, obesity-related comorbidities and inappropriate antimicrobial therapy. Subjects with obesity have a higher incidence of cutaneous infections, probably due to changes in skin barrier functions and wound healing. Excess weight is also associated with an increased risk of urinary tract infection and its recurrence, as well as with a higher prevalence of both lower and higher respiratory tract infections. Moreover, patients with obesity appear to have an increased risk of surgical site infections when undergoing general, orthopaedic, gynaecological, and bariatric surgery. Data concerning the different infectious diseases related to obesity are rather limited since anthropometric parameters are usually poorly recorded. Furthermore, specific therapeutic protocols in subjects with obesity are lacking, especially regarding antibiotic therapy and further supplements. This review summarizes etiopathogenetic and epidemiological evidence and highlights areas of uncertainty in the field of infectious diseases and obesity, which require further research. It is important to raise public awareness of this additional risk related to obesity and to raise awareness among the scientific community to develop specific clinical protocols for subjects with obesity.

The role of melatonin in the molecular mechanisms underlying metaflammation and infections in obesity: A narrative review.

Obesity is a chronic condition whose management is a critical challenge for physicians. The scientific community has increased its focus on the molecular mechanisms involved in obesity etiopathogenesis to better manage patients with obesity and its associated complications. The tight connection between adipose tissue and the immune system has been demonstrated to play a crucial role in inflammation, and melatonin is important for circadian rhythm regulation and metabolic homeostasis, in which it orchestrates several molecular mechanisms involved in obesity and associated inflammation. Melatonin also regulates innate and adaptive immunity; its antioxidant properties are linked to reduced predisposition to infection and weight gain in patients with obesity through the modulation of the immune response, which has a significant beneficial effect on inflammation and, consequently, on the metabolic state. Low melatonin levels have been linked to obesity, and melatonin supplementation can reduce body weight, improve metabolic profile, and ameliorate immune responses and pro-inflammatory stimuli. The role of melatonin in obesity is mainly related to improved oxidative stress signaling, modulation of adipokine secretion, and a switching from white-to-brown adipose tissue phenotype and activity. Moreover, the role of melatonin in obesity modulation by controlling circadian rhythm has recently emerged as a pivotal mechanism for lipid and glucose metabolism dysfunction in adipose, muscle, and liver tissues. Melatonin may also regulate the immune system by acting directly on thymus morphology and activity as well as by modulating oxidative stress and inflammatory states during infections. The tight association between melatonin and immune response regulation is coordinated by Toll-like receptors, which are rhythmically expressed during the day. Their expression may be strongly modulated by melatonin as their signaling is highly inhibited by melatonin. The current review summarizes studies of melatonin-induced mechanisms involved in infection regulation, particularly the modulation of obesity-associated inflammation and systemic complications.