Table 1 Classification and nutritional importance of dietary lipids in T2DM
From: The roles of dietary lipids and lipidomics in gut-brain axis in type 2 diabetes mellitus
Type of fat | Description | Dietary sources | Role of mechanism |
|---|---|---|---|
Saturated fatty acids | Single-bond fatty acids, such as lauric acid, palmitic acid, stearic acid | Meat and sausages, butter, milk and dairy products, palm oil, coconut oil | In the pancreas, liver, adipose tissue Increase inflammation, endoplasmic reticulum stress, lipid oxidation, reactive oxygen species, and lipotoxicity Decrease β-cell function and mass, insulin production, insulin receptor expression and activity, mitochondrial function, adiponectin secretion, and insulin-induced glycogen synthesis In muscle Induce mitochondrial dysfunction, SFA-induced insulin resistance, and impaire glucose metabolism Reduce insulin signaling In gut Increase in local and systemic LPS concentrations, systemic inflammation, and metabolic endotoxemia |
Trans fatty acids | Polyunsaturated fatty acids whose double bonds are in the "trans" position Industrially (hydrogenation), excessive heating of oil with a high level of unsaturated fatty acids naturally produce by ruminants | Margarine, butter, milk and dairy products, meat | In the pancreas, liver, adipose tissue Increase in oxidative stress, inflammation, and insulin resistance Decrease in insulin secretion Impare β-cell and ER function, glucose uptake In muscle Increase oxidative stress Impare glucose uptake and insulin-stimulated glucose metabolism In gut Increased inflammation and metabolic endotoxemia Cause lipotoxicity |
Monounsaturated fatty acids | Fatty acids with one double bond in the fatty acid chain (cis-position) such as oleic acid and palmitoleic acid | Plant-based food: olive oil, safflower oil, hazelnuts, almonds, pistachios, olives, avocados Animal-based foods: eggs, butter, dairy products, meat and meat products | In the pancreas, liver, adipose tissue Improve fasting glucose, insulin resistance, fasting glucose, and β cell function, increase GLP-1, adiponectin levels, FA oxidation, activate PPARγ receptors Decrease inflammation In muscle Increase membrane translocation of GLUT 4 and glucose uptake In gut Improve gut homeostasis and decreases gut dysbiosis |
Polyunsaturated fatty acids | Fatty acids with more than one double bond in the fatty acid chain (cis-position) such as omega 6 fatty acids and omega 3 fatty acids | Dietary sources of omega 6 and omega 3 fatty acids | Â |
Omega 3 fatty acids | Polyunsaturated fatty acids with the last double bond in the omega 3 position (the third position counting from the methyl end) such as ALA, EPA, DHA *EPA and DHA can be synthesized in the body from ALA | ALA is an important molecule found mostly in plant-based foods such as rapeseed oil, linseed oil, soybean oil, and walnut EPA and DHA are mostly found in foods derived from animals such as salmon, tuna, and microalgae | In the pancreas, liver, adipose tissue Increase insulin secretion, FA oxidation, PPARγ activity, glucose uptake via GLUT-4 translocation, and mitochondrial biogenesis Improve insulin resistance and insulin secretion Decrease ER stress, inflammation, and lipogenesis In muscle Increase in FA oxidation, insulin action on glucose usage, and protein synthesis Decrease inflammation In gut Increase in insulin sensitivity through GPR120 Decrease in metabolic endotoxemia, insulin resistance |
Omega 6 fatty acids | Polyunsaturated fatty acids with the last double bond in the omega 6 position (the sixth position counting from the methyl end) such as LA, AA *Omega 6 fatty acids can be synthesized in the body from AA | Sunflower oil, corn oil, meat, butter, milk and dairy products, egg yolk | In the pancreas, liver, adipose tissue Improve insulin sensitivity, inflammatory cytokines Stimulate FA oxidation Inhibit lipogenesis In muscle Enhance affinity for the FA transporters In gut Increase inflammation |