Nutrition in Patients with Type 2 Diabetes: Present Knowledge and Remaining Challenges

Abstract

Unhealthy behaviours, including diet and physical activity, coupled with genetic predisposition, drive type 2 diabetes (T2D) occurrence and severity; the present review aims to summarise the most recent nutritional approaches in T2D, outlining unmet needs. Guidelines consistently suggest reducing energy intake to counteract the obesity epidemic, frequently resulting in sarcopenic obesity, a condition associated with poorer metabolic control and cardiovascular disease. Various dietary approaches have been proposed with largely similar results, with a preference for the Mediterranean diet and the best practice being the diet that patients feel confident of maintaining in the long term based on individual preferences. Patient adherence is indeed the pivotal factor for weight loss and long-term maintenance, requiring intensive lifestyle intervention. The consumption of nutritional supplements continues to increase even if international societies do not support their systematic use. Inositols and vitamin D supplementation, as well as micronutrients (zinc, chromium, magnesium) and pre/probiotics, result in modest improvement in insulin sensitivity, but their use is not systematically suggested. To reach the desired goals, patients should be actively involved in the collaborative development of a personalised meal plan associated with habitual physical activity, aiming at normal body weight and metabolic control.

Keywords: behaviour; diet; lifestyle; nutrition supplements; sarcopenia; type 2 diabetes.

Figure 1

Interorgan amino acid exchange in the postabsorptive state and after meals in diabetes. Note the importance of BCAAs (valine, isoleucine and leucine) as nitrogen carriers to the muscle tissue (lean mass) in the post-prandial period (blue arrows) and the reverse importance of alanine and glutamine as nitrogen carriers to central organs in the post-absorptive state (liver, kidney, intestine) (green arrows). In this context, the regulatory role of the pancreas (altered secretion of insulin and glucagon) and the adipose tissue (lipolysis, release of free fatty acids and inflammatory adipokines in the general circulation, particularly in the post-absorptive state) is pivotal for the regulation of hepatic and whole-body homeostasis (red arrows).