Introduction
Obesity-induced inflammation
Modulation of inflammation by dietary fatty acids: mechanistic insights
Saturated fatty acids
Polyunsaturated fatty acids
Clinical evidence
Acute dietary intake
Amount of dietary fats on postprandial inflammatory response
Subjects: n (F/M) | Postprandial duration | Test meal | Inflammatory response in overweight/obese individuals | Remarks | References |
---|---|---|---|---|---|
Lean: 10 (-/10) Obese: 10 (-/10) T2DM: 10 (-/10) | 0, 1, 2, 3, 4, 5, 6 h | HFM: 57.5 g fat (29 g SFA)
A bacon and egg muffin, 2 hash browns, caramel flavored milk drink (250 ml of 4% fat milk, 4 teaspoons skim milk powder and 1 teaspoon caramel flavor)
| IL-6, hsCRP: HFM ↑ over time; NS TNF-α: =; NS Total adiponectin: HFM ↑ over time; NS HMW adiponectin: =; NS | Sample size was calculated based on the changes of adiponectin, but not other markers | [62] |
Water (control) | Small sample size | ||||
Lean: 14 (14/-); obese: 15 (15/-) | 0, 1, 4, 6 h | SFA: 71 g fat (18 g palmitate)
Instant potato with 16 g cream/kg body weight, 100 ml hot water
| IL-6: ↓ at 1 h, ↑ at 6 h; NS IL-8, TNF-α: =; NS | Timing of menstrual cycle and oral contraceptive usage were not taken into account | [16] |
MUFA: 72 g fat (9 g palmitate )
Instant potato with 0.6 g/kg body weight of olive oil, 160 ml hot water
| Subjects with hypertension and dyslipidemia were included | ||||
n-6 PUFA:72 g fat (5 g palmitate)
Instant potato with 0.6 g/kg body weight of canola oil, 160 ml hot water
| Test meals were not iso-caloric Small sample size. | ||||
LFM–potato: 12 g fat (3 g palmitate)
Instant potato, 160 ml hot water.
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LFM – bran: 13 g fat (3 g palmitate)
All-Bran, 40 ml trim milk, and 2 cooked eggs
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*test meals for obese subjects only
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Obese: 38 (-/38) | 0, 4, 8 h | 60 g fat/m2 body surface
Eggs, cheese, toast, peanut 7, whipped cream, peaches and milk
| IL-6: ↑ at 6 h TNF-α: ↓ at 4 h | Control not included | [63] |
Overweight: 15 (2/13) | 0, 0.5, 1, 2, 4, 6, 8 h | 82 g fat (36.9 g SFA)
Fried potatoes, fried eggs, Emmenthal cheese, Italian rose-shaped dinner rolls, with 500 ml of low sugar content beverage
| IL-6, TNF-α: ↑ over time | Small sample size Control not included Short postprandial period | [64] |
Lean: 10 (5/5); Obese: 8 (5/3) | 0, 1, 2, 3 h | HFM, 60 g fat
Big Mac, large French fries, a large Coke, and apple pie
| ROS generation and NF-κB binding : ↑ over time | Small sample size Short postprandial period Control not included | [15] |
Type of dietary fats on postprandial inflammatory response
Subjects: n (F/M) | Postprandial duration | Test meal | Inflammatory response in overweight/obese individuals | Remarks | References |
---|---|---|---|---|---|
Overweight: 13 (-/13) | 0, 15, 30, 45, 60, 90 min, 2, 3, 4, 5, 6, 7, 8 h | SFA: 56.6 g fat (33.9 g SFA)
2 muffins with butter and 250 ml water
| IL-6, TNF-α, sVCAM-1: SFA ↑, PUFA ↓ MCP-1: ↓ over time; NS sICAM-1: = ; NS | Small sample size | [67] |
n-6 PUFA: 60.5 g fat (12.9 g SFA, 21.8 g PUFA)
2 muffins with 40 g butter and 10 g margarine, and 250 ml water
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A low fat lunch was served after 3 h
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Lean: 14 (14/-) Obese: 15 (15/-) | 0, 1, 4, 6 h | SFA: 71 g fat (18 g palmitate)
Instant potato with 16 g cream/kg body weight, 100 ml hot water
| IL-6: ↓ at 1 h, ↑ at 6 h; NS IL-8, TNF-α: =; NS | Timing of menstrual cycle and oral contraceptive usage were not taken into account | [16] |
MUFA: 72 g fat (9 g palmitate)
Instant potato with 0.6 g/kg body weight of olive oil, 160 ml hot water
| Subjects with hypertension and dyslipidemia were included | ||||
n-6 PUFA:72 g fat (5 g palmitate ) Instant potato with 0.6 g/kg body weight of canola oil, 160 ml hot water
| Test meals were not iso-caloric Small sample size | ||||
LFM–potato: 12 g fat (3 g palmitate)
Instant potato, 160 ml hot water.
| |||||
LFM – bran: 13 g fat (3 g palmitate)
All-Bran, 40 ml trim milk, and 2 cooked eggs
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*test meals for obese subjects only
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Lean: 18 (-/18) Obese: 18 (-/18) | 0, 2, 4 h | SFA: 95 g fat (51 g SFA)
Shakes containing low fat yogurt, low fat milk, strawberry flavor, sugar and 95 g palm oil
| IL-8: ↑ over time; NS IL-6: ↓ over time; NS CRP: =; NS | Short postprandial period Small sample size | [61] |
MUFA: 95 g fat (8 g SFA)
Shakes containing low fat yogurt, low fat milk, strawberry flavor, sugar and 95 g high oleic sunflower oil
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n-3 PUFA: 95 g fat (32 g SFA)
Shakes containing low fat yogurt, low fat milk, strawberry flavor, sugar and 40 g palm oil + 55 g Marinol D40 (40% DHA).
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Lean: 18 (-/18) Obese: 18 (-/18) Obese diabetic: 6 (-/6) | 0, 2, 4 h | SFA: 95 g fat (51 g SFA)
Shakes containing low fat yogurt, low fat milk, strawberry flavor, sugar and 95 g palm oil
| IL-1β and TNF-α: =; NS PBMC MCP-1 and IL-8: MUFA and n-3 PUFA ↑↑, SFA ↑ at 4 h | Short postprandial period Small sample size | [70] |
MUFA: 95 g fat (8 g SFA)
Shakes containing low fat yogurt, low fat milk, strawberry flavor, sugar and 95 g high oleic sunflower oil
| |||||
n-3 PUFA: 95 g fat (32 g SFA)
Shakes containing low fat yogurt, low fat milk, strawberry flavor, sugar and 40 g palm oil + 55 g Marinol D40 (40% DHA)
| |||||
Obese/overweight: 10 (6/4) | 0, 1, 2, 4, 6 h | SFA: 83 g fat
Refined palm oil blended with 1% milk, strawberry flavored syrup, low fat frozen, and non-fat dry milk powder.
| CRP: ↑; over time NS TNF-α: ↓ over time; NS NF-κB AUC (4 h): PUFA ↑↑, SFA↑ VCAM-1: =; NS ICAM-1: =; MUFA ↓↓ vs. SFA, n-3 PUFA | Small sample size Test meals were not iso-caloric | [71] |
MUFA: 83 g fat
Refined olive oil blended with 1% milk, strawberry flavored syrup, low fat frozen, and non-fat dry milk powder.
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n-3 PUFA: 85 g fat
Refined olive oil + 4 g n-3FA from 8 g fish oil supplement pills (300 mg EPA, 200 mg DHA/g), blended with 1% milk, strawberry flavored syrup, low fat frozen, and non-fat dry milk powder.
|
Chronic dietary intervention
Effects of the type of dietary fats on inflammation
Subjects: n (F/M) | Design | Dietary intervention | Inflammatory response | Remarks | References |
---|---|---|---|---|---|
Overweight/obese: 14 (14/-) | Crossover; 3-week, 1 week wash-out | PUFA 40% en total fat (25% en PUFA, 8.5% en SFA)
Fat from vegetable sources
| CRP: PUFA↓ vs baseline
IL-18: NS vs baseline | Small sample size Dyslipidemic and postmenopausal women were recruited | [74] |
SFA 42% en total fat (29% en SFA, 3% en PUFA)
Dairy and animal fats
|
*No comparison was made between diets
| Short dietary intervention | |||
Iso-caloric diet (2738 kcal) with ~21% en exchange between PUFA and SFA
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Abdominally overweight: 61 (gender not specified) n-6 PUFA:32 SFA: 29 | Parallel; 10-week | n-6 PUFA 40% en total fat (10% en SFA, 13.5% en LA)
Scones (baked using sunflower oil), margarine, sunflower oil and sunflower seeds
| IL-1RA, TNF-R2: n-6 PUFA↓ vs SFA CRP, IL-6, IL-1β and IL-10: NS | Subjects used antihypertensive and lipid lowering drugs. | [75] |
SFA 40% en total fat (20% en SFA, 4% en LA)
Scones (baked using butter), butter and butter
| Low compliance: n-6 PUFA diet (n = 27); SFA diet (n = 19) | ||||
Iso-caloric diet (2000 kcal) consisted with 10% en exchange between n-6 PUFA and SFA. Key fat sources were provided
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Overweight and obese: 76 (63/13) Krill: 25 (22/3) Menhaden: 26 (21/5) Control:25 (20/5) | Parallel; 4-week | Krill oil: 90 mg DHA + 216 mg EPA Menhaden oil: 178 mg DHA + 212 mg EPA Control: 2 g olive oil
4 x 500 mg capsules/day for each supplementation
| hsCRP: NS | Habitual diet was not controlled | [78] |
Sedentary overweight: 138 (93/45) | Parallel: 4-month | n-3 PUFA: 2.5 g/day
Fish oil (6 x 500 mg capsules/d);EPA:DHA ratio is 7:1
| TNF-α, IL-6: both doses ↓ vs placebo; NS | Calorie and fatty acid composition of habitual diets were not standardized | [79] |
n-3 PUFA 2.5 g/day: 46 (29/17) n-3 PUFA: 1.25 g/day: 46 (28/18) Placebo: 46 (36/10) | n-3 PUFA: 1.25 g/day Placebo: 3 g
Mixture of palm, olive, soy, canola and cocoa butter oils; (SFA:MUFA:PUFA ratio = 37:42:21)
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Severely obese:55 (46/9) n-3 PUFA: 27 (23/4) Control: 28 (23/5) | Parallel: 8-week | n-3 PUFA: 4 x 1 g capsules/day (3.36 g EPA + DHA) Control: 5 g butterfat | IL-6: n-3 PUFA ↓ hsCRP: NS | 30 subjects used supplementary medication such as antihypertension and proton pump inhibitors Incomplete dietary records | [82] |
Iso-caloric diet consisted of 30% en fat, 15% protein and 55% en carbohydrate
| SAT gene expression of CCL2, CCL3, H1F1A and TGFB1: n-3 PUFA ↓ | ||||
EPA- and DHA-derived eicosanoids synthesis in SAT and VAT: n-3 PUFA ↑ | |||||
Abdominally overweight/ obese: 51 (40/11) | Parallel: 8-week | ALA: 11 g/day flaxseed oil Control: habitual diet | IL-6, TNF-α, CRP: NS | [83] | |
ALA: 27 (21/6) Control: 24 (19/5) |
Iso-caloric diet (~2000 kcal) with a balance of SFA and MUFA intake
|
Restricted calorie diets with varying amount of dietary fats on inflammation
Subjects: n (F/M) | Design | Dietary intervention | Inflammatory response | Remarks | References |
---|---|---|---|---|---|
Overweight: 15 (-/15) | Crossover: 6-week | VLCKD 60% en total fat, 10% en CHO, 30% en protein Unlimited type of fat or cholesterol amount from sources such as beef, poultry, fish, oils, various nuts/seeds, moderate amount of vegetables, salads with low-carbohydrate dressings, moderate amount of cheese, eggs, protein powder, water/ low-carbohydrate diet drinks, low-carbohydrate bars and shakes *Customied diabetic exchange lists were used.
| TNF-α, IL-6, hsCRP, sICAM-1: both VLCKD & LFD ↓ vs baseline: NS sP-sel: NS
Body weight: VLCKD ↓ 6.5 kg, LFD ↓3.7 kg
| Protein intake not standardised across diets | [84] |
LFD 25% en fat, 55% en CHO, 20% en protein (< 10% SFA, < 300 mg cholesterol) | |||||
Overweight: 20 | Parallel: 12-week | VLCKD 60% en fat 10% en CHO 30% en protein Unlimited amount of beef, poultry, fish, eggs, oils and heavy creams; moderate amount of hard cheeses, low-carbohydrate vegetables and salad dressings; small amount of nuts, nut butters and seeds.
| TNF-α, IL-8, MCP-1, E-selectin, sICAM-1 PAI-1: both VLCKD & LFD ↓ vs baseline; VLKCD ↓↓ IL-6, CRP, VEGF, P-sel, EGF and sVCAM-1: both VLCKD & LFD ↓ vs baseline; NS | Protein intake not standardised across diets Dyslipidemic subjects were included | [85] |
LFD 25% en fat, 55% en CHO, 20% en protein (< 10% SFA, < 300 mg cholesterol) Whole grains (bread, cereals and pastas), fruit/fruit juices, vegetables, vegetables oils, low at dairy, and lean meat products
*Standard diabetic exchange lists were used.
|
Body weight: VLCKD ↓ 5.6 kg, LFD ↓3.7 kg
|
Restricted calorie diets with varying type of dietary fats on inflammation
Subjects: n (F/M) | Design | Dietary intervention | Inflammatory response | Remarks | References |
---|---|---|---|---|---|
Overweight: 33 (22/11) | Parallel: 12-week | n-3 PUFA: 6 capsules of 1 g fish oil daily (0.42 g EPA + 1.62 g DHA/d)
| Body weight: n-3 PUFA ↓4.2 kg, placebo ↓ 3.17 kg; NS | [86] | |
n-3 PUFA:15 (10/5) Placebo:18 (12/6) | Placebo (MUFA): 6 capsules of 1 gunola oil daily
| Leptin, adiponectin, hsCRP, IL-6: NS | |||
Daily intake were 5000 kJ for female and 6000 kJ for males with ~30% en total fat intake
| TNF-α: n-3 PUFA ↓ vs baseline; NS | ||||
Overweight: 26 (16/10) | Parallel: 14-week |
Phase 1 (lead-in):
34.3% en fat (4.8% en n-6, 0.5% en n-3 PUFA) | Body weight after Phase 3: Both diets ↓ (~3.5% body weight); NS | [87] | |
n-3 PUFA: 13 (8/5) control: 13 (8/5) |
Phase 1: 2-week
Phase 2: 2-week
Phase 3:12-week
|
Both n-3 PUFA and control groups consumed the same diet
Phase 2 (iso-caloric, 1800 kcal)):
n-3 PUFA: 12 capsules of 725 mg fish oil (2.88 g n-3 PUFA) 34.7% en fat (n-6 PUFA, 4.9% en, n-3 PUFA, 3.6% en)
Main source of n-3 PUFAs: canola and flaxseed oils, and margarines rich in ALA
| Adiponectin: both diets ↑ vs baseline; NS HMW adiponectin: NS | ||
Control: high oleic sunflower oil capsules 34.3% en total fat (4.8% en n-6, 0.5% en n-3 PUFA)
Main source of oils: high oleic safflower and sunflower oils, and margarines based on these oils
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Phase 3 (ad libitum):
115% of the amount of food provided in phase 1 and 2 | |||||
Obese: 11 (-/11) Phase 1:11(-/11) Phase 2:8 (-/8) | Cross-over Phase 1: 6-week Phase 2: 8-week
(very low calorie diet, 4-week; restricted energy diet, 2-week; weight sustained diet, 2-week)
|
Phase 1 (fish oil study):
n-3 PUFA: 0.6 g EPA + 0.5 g DHA Control: 6 capsules 500 mg of high oleic sunflower oil with ad-libitum Dutch diet
No fish consumption is allowed
| Postprandial IL-6, CRP, sTNF-R55, sTNF-R75, PAI-1 antigen: weight loss ↓: NS TNF-α: NS | Small sample size | [5] |
Phase 2 (weight loss period):
Very low calorie diet: 480 kcal/day with shakes + 250 g vegetables and fruits except banana
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Postprandial challenges at the end of each intervention: 0, 2, 4 h
| Restricted energy diet: 1000 kcal/day with mixed solid energy-restricted diet with a recommended composition
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Weight sustained diet: Diet at commensurate calories to maintain the newly achieved weights
Postprandial meals: 50.1 g fat, milkshake | |||||
Obese: 11 (-/11) | Cross-over |
Phase 1 (fish oil study):
n-3 PUFA: 0.6 g EPA + 0.5 g DHA | Fasting sICAM-1, hsCRP: weight loss ↓; NS sE-sel, MCP-1: NS | Small sample size | [6] |
Phase 1:11(-/11) Phase 2:8 (-/8) | Phase 1: 6-week Phase 2: 8-week (very low calorie diet, 4-week; restricted energy diet, 2-week; weight sustained diet, 2-week)
| Control: 6 capsules 500 mg of high oleic sunflower oil
with ad-libitum Dutch diet
No fish consumption is allowed
| Postprandial sICAM, hsCRP: weight loss ↓ MCP1: PUFA & weight loss ↓ sel: NS | ||
Phase 2 (weight loss period):
Very low calorie diet: 480 kcal/day with shakes + 250 g vegetables and fruits except banana
| |||||
Postprandial challenges at the end of each intervention: 0, 2, 4 h
| Restricted energy diet: 1000 kcal/day with mixed solid energy-restricted diet with a recommended composition
Weight sustained diet: Diet at commensurate calories to maintain the newly achieved weights
| ||||
Postprandial meals: 50.1g fat, milkshake |