Functional foods-based diet as a novel dietary approach for management of type 2 diabetes and its complications: A review

Table 1 Bioactive compounds and functional properties of some of favorable fruits and vegetables

Ref.	Possible functional properties in diabetes	Main bioactive components and phytochemicals	Fruits and vegetables
[58-62]	↓ Systolic and diastolic blood pressure ↑ apolipoprotein a1 and HDL-C ↓ LDL oxidation, improve diabetes-induced lipid disorders ↓ cardiovascular risk factors ↓ aldose reductase activity and cataract ↑ antioxidative enzymes activity	Lycopene, β-carotene, flavonoids, anthocyanins, phytoan, phyto flava, quercetin, kampferol	Tomato and its by products
[63-65]	↓ Triglyceride levels, enhance endogenous antioxidant defense system, regulation of appetite	Lycopene, pectin, naringin, hesperidin	Grapefruit
[66-69]	↑ Nitric oxide biosynthesis, improve endothelial function ↓ blood pressure ↑ plasma arginine levels and consequently ↓ insulin resistance and adipocyte size	Lycopene, carotenoids, cytrolin	Watermelon
[70-73]	↓ Absorption of dietary carbohydrate ↓ postprandial glycemia, improve pancreatic β-cell function ↓ free radical generation ↓ lipid peroxidation ↑ plasma total antioxidant capacity, prevent vascular damage, improve dyslipidemia	Soluble fiber, quercetin, catechins, epicatechin, P-cumaric acid, chlorogenic acid, gallic acid, phlordizin, procyanidins	Red apple, apple peel, apple and its by products
[74-81]	Glycemic control, inhibit α-glucosidase and α-amylase activity ↓ digestion and absorption of dietary carbohydrates ↓ insulin resistance, improve dyslipidemia ↓ postprandial oxidative stress ↓ lipid peroxidation ↑ plasma total antioxidant capacity ↓ systolic blood pressure ↑ antioxidative enzymes activity ↑ adipocytes lipolysis ↓ inflammatory processes, modulation of peroxisome proliferator-activated receptors	Anthocyanins, tannins, ellagitanins, α-carotene, β-carotene, lutein, delphinidins, pelargonidins, ciyanidins, catechins, hydroxy-cinnamic acid	Berries; cranberry, blackberry, black raspberry, blueberry, red raspberry, strawberries
[82-86]	Protective effects on vascular system ↓ platelet hyperactivity and aggregation ↓ cardiovascular diseases ↓ oxidative damage ↓ rennin-angiotensin activity ↑ production of nitric oxide ↓ blood pressure ↑ bone-marrow-derived endothelial progenitor cells	Anthocyanins, resveratrol	Grapes, grape by products
[87-91]	↓ Hyperglycemia ↓ HbA1c, improve lipid disorders, anti-inflammatory properties (inhibit cyclooxygenase) ↓ abdominal fat ↓ microalbuminuria, improve metabolic syndrome and fatty liver features ↓ oxidative stress ↓ production of cytokines, induction of PPARγ↓ diabetic neuropathy	Anthocyanins, quercetin, hydroxy-cinnamic acid, carotenoids, melatonin, phenolic acids, gallic acid, lutein, xanthine, β-carotene	Cherries
[92-95]	↓ Hyperglycemia, attenuate hyperglycemia-induced metabolic disorders ↓ lipid peroxidation, induction of gluthathione reductase, glutathione peroxidase, superoxide dismutase, delay progression of nephropathy ↓ inflammatory processes, improve dyslipidemia	Isothiocyanates, anthocyanins (red cabbage), carotenoids, lutein, β-carotene	Cabbage, Cauliflower
[96-100]	↓ Hyperglycemia ↑ endothelial nitric oxide synthase activity, inhibit angiotensin converting enzyme ↓ blood pressure, improve vascular function ↓ cholesterol and atherogenic lipids ↓ lipid peroxidation ↓ progression of atherosclerosis ↑ plasma total antioxidant capacity, modulate activation of PPARγ and nuclear factor κB ↑ activity of paraxonase 1 and HDL-C levels ↓ serum resistin levels and ameliorate obesity-induced insulin resistance	Anthocyanins, tannins, catechins, gallocatechins, punicalagin acid, ellagic acid, gallic acid, oleanolic acid, ursolic acid, uallic acid	Pomegranate and its by products, pomegranate peel and seeds
[101-105]	↓ Hyperglycemia, induce insulin secretion from β-cell ↓ blood pressure, inhibit enzyme involved in cholesterol biosynthesis, improve dyslipidemia, prevent atherosclerosis ↓ lipid peroxidation ↓ platelet hyperactivity and aggregation, regulate glycolysis, gluconeogenesis and carbohydrate metabolism pathways ↑ insulin sensitivity	Allyl sulfors, flavonoids, quercetin, dihydroflavonols, anthocyanins (red onion)	Garlic, onions
[106-111]	↓ Endothelial macrophage activation ↓ hyperactivity and aggregation of platelet, improve vascular function ↓ oxidative stress and inhibit stress-sensitive signaling pathways ↓ digestion of dietary lipids, improve dyslipidemia ↓ pro-inflammatory cytokines ↓ lipid peroxidation	Lutein, xanthine, α-cryptoxanthin, β-cryptoxanthin, naringenin, hesperidin, β-carotene, phytosterols	Citrus fruits
[112-113]	↓ Free radical generation and lipid peroxidation, binding to bile acids ↑ cholesterol excretion, improve lipid profile ↑ plasma total antioxidant capacity	Lutein, betaine, violaxanthine, opioid peptides (rubisculins), P-cumaric acid, ferulic acid	Spinach
[114-115]	Improve glycemic and insulinemic response ↓ systemic inflammation ↓ cardiovascular disease risk factors	Carotenoids, pectin, oleic and linolenic acids	Pumpkin
[116]	Improve hyperglycemia and dyslipidemia ↑ adiponectin, antioxidant and anti-inflammatory effect	Fiber, polyphenols, chlorogenic acid, flavonoids, anthocyanins	Plums
[117-119]	Improve dyslipidemia, anti-inflammatory properties ↓ lipid peroxidation ↑ plasma total antioxidant capacity	Soluble fiber (pectin), α-carotene, β-carotene lutein, phenolic acids, stilbenes	Carrots
[120-122]	Inhibit α-amylase ↓ postprandial glycemia ↑ glycogen synthesis, improve dyslipidemia ↓ lipid peroxidation, protective effect against diabetic nephropathy	Carotenoids, quercetin, kampferol, gallic acid, caffeic acid, catechins, tannins, mangiferin	Mango
[123-127]	Regulate carbohydrate metabolism (↑ glucokinase and glucose-6-phosphate dehydrogenase activity ↓ glucose-6-phosphatase activity) ↓ lipid peroxidation ↓ protein carbonylation ↑ antioxidant enzyme activity, improve metabolic syndrome features ↑ insulin sensitivity ↓carbohydrate absorption ↓ plasma free fatty acid	Anthocyanins, alkaloid compounds (berberine, oxycontin)	Barberry
[128-131]	Protective effects against diabetic neuropathy ↓ lipid peroxidation, induce antioxidant enzymes, protect liver and kidney against oxidative damage	Dietary fiber, polyphenols, acid cinnamic, melatonin	Date fruit
[132-133]	Improve lipid and lipoprotein metabolism ↑ insulin sensitivity ↓ blood pressure	Dietary fiber, pectin, flavonoids, gallic acid, chlorogenic acid, catechins, anthocyanins	Figs

PPARγ: Peroxisome proliferator-activated receptor γ.

Table 2 Bioactive compounds and functional properties of some of favorable functional foods

Ref.	Possible functional properties in diabetes	Main bioactive components and nutraceuticals	Functional foods
[168-179]	Improve the features of metabolic syndrome, modulate gut microbiota, regulate satiety and food intake ↑ adiponectin, modulate adipocytokines, induce thermogenesis, lipolysis and β-oxidation ↑ dietary fat excretion ↓ adiposity and body weight ↓ oxidative stress and inflammatory markers, hypo-lipidemic and anti-thrombotic effects ↑ insulin sensitivity, modulate immune responses in diabetic patients ↑ total antioxidant capacity ↓ lipid peroxidation ↓ HbA1c	Calcium, vitamin B, bioactive proteins such as casein and whey, immunoglobulines, bioactive peptides (α- and β-lactorphines, lactoferrin, lactoferricin, α-lactalbumin, β-lactoglobulin, growth factors), conjugated linoleic acids, lactic acid bacteria and bifidobacteria	Dairy products and probiotics
[180-185]	Improve hypertriglyceridemia and hypertension ↓ cardiovascular disease ↓ insulin resistance and inflammation, improve glycemic management ↓ proteinuria ↓ oxidative stress, inhibit lipogenesis and induce lipolysis, induce PPARα and PPARβ↓ adiposity and weight management ↑ thermogenesis and energy expenditure, inhibit angiotensin converting enzyme and modulate blood pressure	Bioactive peptides, antioxidant compounds, ω3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid), selenium, taurine	Fish and seafood
[186-189]	Regulate cholesterol metabolism ↓ LDL oxidation, protect vascular endothelium against atherogenesis, inhibit platelet aggregation ↓ atherosclerosis development ↓ pro-inflammatory cytokines, activate PPARγ, improve sub-clinical inflammation	Oleic acid, ω3 fatty acids, Flavonoids, cinnamic acid, benzoic acid, lignans, cumaric acid, ferulic acid, tocopherols, carotenoids, oleuropein, oleocanthal	Olive oil
[190-193]	Promote endogenous antioxidant defense system, induce superoxide dismutase and catalase ↓ lipid peroxidation, improve glycemic control ↑ insulin sensitivity ↓ gluconeogenesis ↑ glycogen content ↓ glycation of collagen and fibrosis, protect cardiac muscle, regulate lipid metabolism as well as adipose tissue metabolism, inhibit lipogenic enzymes ↓ satiety ↑ thermogenesis ↓ proliferation and differentiation of adipocytes ↓ pro-inflammatory cytokines ↓ monocyte chemotactic protein-1	Polyphenols, phenolic acids, catechins, epigallocatechin-3-gallat, chlorophyll, carotenoids, pectin, plant sterols	Green tea
[194-196]	↑ Iinsulin sensitivity, improve peripheral uptake of glucose, increase glycolysis and gluconeogenesis, hypoglycemic and hypolipidemic effects, antioxidant and anti-inflammatory properties	Cinnamaldehyde, cinnamic acid, coumarin, catechins, epicatechin, procyanidins B-2	Cinnamon
[197-199]	Inhibit enzymes involved in inflammation including cyclooxygenase-2, lipoxygenase, and nuclear factor κB, inhibit α-glucosidase and α-amylase activity ↓ postprandial glycemic response ↓ proteinuria, activate PPARγ and regulate carbohydrate and lipid metabolism, prevent diabetic cataract	Curcuminoids, stigmasterol, β-sitosterol, 2-hydroxy methyl anthraquinone, bioactive peptide turmerin	Turmeric
[200-203]	Attenuate oxidative stress, protective effects against oxidative damage ↓ serum creatinine and urea, improve dyslipidemia ↓ atherogenic lipoprotein levels ↓ lipid peroxidation in renal tissue, inhibit α-glucosidase activity ↓ carbohydrate digestion and absorption, protect liver against diabetes-induced oxidative damage	Tannins, flavonoids, anthocyanins, phenolic acid, gallic acid	Sumac

PPAR: Peroxisome proliferator-activated receptor.