Table 1 Studies assessing the lipid lowering effects of n-3 PUFA by dietary intervention

Lara (2007) [31]

16 males, 32 females

125 g of salmon (5.4 g of n-3 PUFA)

Intervention (no placebo)

4 week intervention; 4 week washout without fish

TG reduced 15 % (sig)

Blood pressure reduced 4 % (sig)

Scottish

LDL-c reduced 7 %

20–55 yrs old

Adiponectin reduced

(TG – 83, Total-C - 167, LDL-C - 92)

HDL-c elevated 5 % (sig)

Hallund (2010) [32]

68 males

150 g of trout fed marine diet (3.4 g n-3 PUFA)

Randomized, parallel arm trial

8 weeks

TG reduced 14 % and 6 % in participants consuming trout fed marine-based diet and trout fed a vegetable-based diet, respectively

Trout fed marine-based diet resulted in a reduction of blood pressure and CRP, compared to trout on vegetable diet

Danish

40–70 yrs old

(TG – 102, Total-C - 189, LDL-C - 117)

Vs.

150 g of trout fed vegetable diet (0.8 g n-3 PUFA)

Ambring (2004) [33]

12 males, 10 females

Mediterranean diet (4.1 g n-3 PUFA)

Randomized, cross-over trial

4 week on one diet, 4 week washout, 4 week on opposite diet

TG reduced 9 % in the group receiving Mediterranean diet

Consumed fewer calories on Mediterranean vs. Swedish diet (1869 vs. 2090, respectively)

Swedish

Vs.

30–51 yrs old

Swedish diet (2.3 g n-3 PUFA)

Switching from a Swedish diet to a Mediterranean diet reduced serum TG, Total-c and LDL-c by 17 %, 17 % and 23 %, respectively (sig)

(TG – 97, Total-C - 217, LDL-C - 139)

Source of n-3 PUFA in both diets was oily fish

Navas-Carretero (2009) [34]

25 iron deficient females

Oily fish diet (2.8 g n-3 PUFA)

Randomized, cross-over trial

8 weeks per diet

TG reduced 3.1 % while on fish diet

TG and HDL-c increased by 7.9 % and HDL-c by 1.2 % while on red meat diet

18–30 yrs old

(TG – 60, Total-C - 173, LDL-C - 97)

Vs.

Total-c and LDL-c reduced 2.3 % and 7.5 %, respectively, while HDL-c increased by 7.2 %, while on fish diet (sig)

Red meat diet (1.3 g n-3 PUFA)

Baro (2003) [35]

15 males, 15 females (low background daily fish intake)

500 ml of n-3 PUFA enriched semi-skimmed milk (0.33 g EPA + DHA)

Intervention (no placebo, initial values vs. final)

4 week run in on low fish diet, 8 weeks consuming enriched milk

Total-c and LDL-c decreased 6 and 16 % (sig)

Homocysteine and VCAM-1 decreased by 13 % and 16 %, respectively

Spanish

20–45 yrs old

(TG – 108, Total-C - 176, LDL-C - 91)

Dyerberg (2006) and Dyerberg (2004) [27, 29]

79 males

Bakery products supplemented with 33 g of experimental fats: (a) 33 g control fat;

Randomized, double blind parallel arm trial

8 weeks

TG reduced 26 % from baseline in the n-3 PUFA group. Change was significantly greater than the TG reduction observed in the control group.

The n-3 PUFA diet resulted in a 3 beat/min reduction in heart rate of subject with a normal heart rate variability

Danish

20–60 yrs old

Vs.

HDL-c reduced in the group receiving soy oil compared to the control

(TG – 102, Total-C - 185, LDL-C - 116)

(b) 12 g fish oil (4 g n-3 PUFA);

Vs.

(c) 33 g soy oil (20 g trans FA)

Garcia-Alonso (2012) [36]

18 females

2 glasses of 250 ml n-3 PUFA-enriched tomato juice (500 mg EPA + DHA total)

Randomized, single blind, parallel arm trial

2 weeks

No effect on lipid profile

Enriched juice reduced serum homocysteine, VCAM-1 and ICAM-1 levels (sig)

Spanish

35–55 yrs old

Vs.

(TG – 59, Total-C - 197, LDL-C - 113)

Placebo

Hamazaki (2003) [37]

16 females, 25 males

1 glass of 250 ml Soybean milk enriched with:

Randomized, double blind placebo controlled trial

12 weeks

TG levels reduced 17 % (sig) in the group receiving the n-3 PUFA enriched soybean milk (no changes observed in the olive oil enriched milk)

Japanese

43–59 yrs old

Fish oil (0.6 g EPA + 0.26 g DHA)

(TG – 154, Total-C - 211, LDL-C - 127)

Vs.

LDL-c levels did not change, while total-c elevated in both groups by 2 %

Olive oil

Coates (2009) [38]

29 males

200 g portion of pork from pigs fed a diet fortified with n-3 (0.185 g n-3 PUFA)

Randomized, double-blind, parallel arm, placebo controlled trial

12 weeks

TG levels reduced 27 % in the group consuming the n-3 PUFA fortified pork compared to controls

The n-3 PUFA fortified pork diet resulted in an elevation of serum thromboxane production (sig compared to the control)

25–65 yrs old

(TG – 84)

Stuglin (2005) [39]

15 males

3 flaxseed-enriched muffins (6.67 g ALA total)

Intervention (no placebo, compared initial and final values)

4 weeks

TG elevated 41 % (sig)

Canadian

22–47 yrs old

(TG – 124, Total-C - 172, LDL-C - 108)

Dodin (2008) and Dodin (2005) [28, 30]

179 post-menopausal females

2 slices of flaxseed bread (8.42 g ALA)

Randomized, double blind, placebo controlled, parallel arm trial

12 months

Flaxseed-enriched bread raised the participants’ serum TG 3 %

Flaxseed bread reduced BMI from baseline values (sig)

French Canadian

49–65 yrs old

Vs.

LDL-c reduced in the group receiving flaxseed bread compared to the placebo

(TG – 101, Total-C - 221, LDL-C - 134)

2 slices of ground grain bread

Patenaude (2009) [40]

Group 1–10 females, 10 males

1 muffin, enriched with either:

Randomized, double blind, parallel arm trial

4 weeks

Diet (A) decreased total-c, LDL-c and TG by 7 %, 12 % and 11 % respectively, in Group 1. In group 2, Diet A decreased total-c and LDL-c 2 % while elevating TG by 13 %

Group 2 receiving diet B) had reduction in platelet aggregation (sig.)

18–29 yrs old

(TG – 91, Total-C - 165, LDL-C - 78)

A) Ground flaxseed (6.5 g ALA)

Group 2–10 females, 10 males

Vs.

45–69 yrs old

(TG – 81, Total-C - 181, LDL-C - 99)

B) Flaxseed oil (5.74 g of ALA)

Diet (B) decreased TG 20 % in Group 1, while elevating TG by 3.5 % in Group 2

Minihane (2005) [41]

19 males

n-3 PUFA-enriched cooking oil and margarine (2 g n-3 PUFA) with either:

Randomized, double blind, parallel arm trial

6 weeks

A diet containing a moderate ratio of n-6:n-3 PUFA resulted in 3 % and 8 % reductions in total-c and LDL-c, respectively, while increasing HDL-c by 8 % (0.05 < p < 0.1)

Diet providing a moderate ratio of n-6:n-3 PUFA increased total n-3 PUFA within RBC

Indian Asian (in the UK)

35–70 yrs old

Diet providing a high ratio of n-6:n-3 PUFA increased plasma insulin levels and the participant’s HOMA-IR index (sig)

Moderate n-6:n-3 (15 g n-6 PUFA)

(TG – 140, Total-C - 192, LDL-C - 120)

Vs.

High n-6:n-3 (26 g n-6 PUFA)

Sofi (2013) [42]

12 males, 8 females

Gilthead sea bream fillets (2.3 g n-3 PUFA) fed either: Plant protein (2 g n-6 PUFA) Vs.

Randomized, single blind, cross-over trial

15 day run in with no fish consumption, 10 weeks on fishmeal fed fish followed by 10 weeks on plant protein fed fish (or vice versa)

TG, total-c and LDL-c decreased 11.7 %, 29.3 % and 21.6 %, respectively, in group first receiving fishmeal fed fish (sig). Values rebounded to normal following second dietary intervention

Group first receiving fishmeal fed fish experienced reductions in IL-6 and IL-8, and improvements in RBC filtrate rate

Finish

23–67 yrs old

Group A: fish fed fishmeal followed by fish fed plant protein each for 10 weeks

(TG – 117, Total-C - 233, LDL-C - 152)

Fishmeal (1 g n-6 PUFA)

The group initially receiving plant protein fed fish experienced reductions in cholesterol occurring 10 weeks after subsequently fed fish fed fishmeal

Group B: fish fed plant protein followed by fish fed fishmeal each for 10 weeks

(TG – 94, Total-C - 216, LDL-C - 139)