Effects of krill oil containing n-3 polyunsaturated fatty acids in phospholipid form on human brain function: a randomized controlled trial in healthy elderly volunteers

Figures & data

Table 1 Composition of each supplement (per daily dose)

Nutrients	MCTs	KO	SO
Components
Water (g)	<0.02	Trace	0
Total lipids (g)	1.98	1.98	1.98
Tocopherol (mg)	0	14	20
Lipid class
Phospholipids in total lipids (g)	0	0.90	0
Fatty acid composition of total lipids
8:0 (mg)	1,497	13	0
10:0 (mg)	287	7	0
12:0 (mg)	5	5	0
14:0 (mg)	0	155	84
14:1 (mg)	0	4	0
15:0 (mg)	0	7	3
16:0 (mg)	0	280	106
16:1 (mg)	0	87	148
16:2 (mg)	0	9	27
16:3 (mg)	0	3	44
16:4 (mg)	0	11	77
17:0 (mg)	0	35	5
17:1 (mg)	0	4	0
18:0 (mg)	0	19	9
18:1 (mg)	13	249	154
18:2n-6 (mg)	4	25	22
18:3n-3 (mg)	0	13	14
18:4n-3 (mg)	0	34	82
20:1 (mg)	0	11	3
20:2n-6 (mg)	0	0	2
20:3n-6 (mg)	0	0	3
20:4n-6 (mg)	0	3	20
20:4n-3 (mg)	0	4	17
20:5n-3 (EPA) (mg)	0	193	491
21:5n-3 (mg)	0	5	19
22:0 (mg)	0	0	3
22:1 (mg)	0	12	0
22:5n-6 (mg)	0	0	5
22:5n-3 (mg)	0	5	46
22:6n-3 (DHA) (mg)	0	92	251
Unidentifiable (mg)	0	70	54

Note: Subjects took four capsules (0.25 g oil/capsule) twice a day after breakfast and dinner.

Abbreviations: MCTs, medium-chain triglycerides; KO, krill oil; SO, sardine oil; EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid.

Figure 1 Channel positions for near-infrared spectroscopy. Changes in oxyhemoglobin concentration were measured at 24 sites in the bilateral frontal areas of the brain. Filled (black) circles and open (white) circles show the emitter and detector probes, respectively. The numbers show the location of the measured channels.

Table 2 Baseline characteristics of the participants

	MCT (n = 15)	KO (n = 15)	SO (n = 15)	P-value
Age (years)	67.3 ± 3.4	67.1 ± 3.7	67.0 ± 3.3	0.962
Height (cm)	167.0 ± 3.9	163.5 ± 5.8	168.6 ± 4.5	0.019
Body weight (kg)	66.2 ± 10.7	64.9 ± 8.3	63.0 ± 5.9	0.604
BMI (kg/m^2)	23.7 ± 3.5	22.8 ± 2.6	23.6 ± 2.2	0.666
Current smoker	1 (7)	2 (13)	4 (27)	0.306
Alcohol consumer	11 (73)	13 (87)	12 (80)	0.659

Notes: Mean ± standard deviation or n (%). P-values derived by one-way analysis of variance or chi-square test.

Abbreviations: MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil; BMI, body mass index.

Figure 2 Flow chart of participation throughout the study.

Abbreviations: MCTs, medium-chain triglycerides; KO, krill oil; SO, sardine oil.

Table 3 Polyunsaturated fatty acids in plasma

	Week 0			Week 6			Week 12			P-value
	MCT	KO	SO	MCT	KO	SO	MCT	KO	SO
DGLA (μg/mL)	25.3 ± 2.5	21.1 ± 2.6	27.3 ± 2.1	25.4 ± 2.1	19.5 ± 1.8	23.4 ± 1.8	25.8 ± 2.4	19.9 ± 2.1	20.0 ± 2.0	0.011
AA (μg/mL)	156 ± 8	130 ± 5	143 ± 8	158 ± 8	136 ± 6	152 ± 7	159 ± 10	128 ± 7	141 ± 7	0.700
EPA (μg/mL)	110 ± 10	122 ± 20	99 ± 10	113 ± 12	155 ± 21	155 ± 14	108 ± 12^a	125 ± 18^a,b	157 ± 12^b	0.001
DHA (μg/mL)	192 ± 14	191 ± 19	191 ± 16	196 ± 14	196 ± 17	205 ± 15	177 ± 13	179 ± 19	187 ± 15	0.944

Notes: Mean ± standard error. MCT, n = 15; KO, n = 13; SO, n = 14. P-values show significant probability of interaction between treatments and ingestion periods derived by two-way repeated-measures analysis of variance. Numerical values within the same period given different superscript letters (^a and ^b) show significant differences between treatments (P < 0.05 by Bonferroni post hoc test).

Abbreviations: DGLA, dihomo-gamma-linolenic acid (20:3n-6); AA, arachidonic acid (20:4n-6); EPA, eicosapentaenoic acid (20:5n-3); DHA, docosahexaenoic acid (22:6n-3); MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil.

Figure 3 Topographic maps of changes in oxyhemoglobin concentration at 225.0 seconds during working memory task.

Note: MCT, n = 15; KO, n = 13; SO, n = 14.

Abbreviations: MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil.

Figure 4 Comparison of changes in oxyhemoglobin (oxy-Hb) concentrations at channel 10 during working memory task.

Notes: Values are expressed as the group mean ± standard error. MCT, n = 15; KO, n = 13; SO, n = 14. Values were significantly different from the MCT group. *P < 0.05, **P < 0.01 by Bonferroni post hoc test.
Abbreviations: MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil.

Figure 5 Comparison of differential values in P300 latencies and amplitudes during the working memory task. (A) Latency at Cz, (B) latency at Pz, (C) amplitude at Cz, and (D) amplitude at Pz.

Notes: Values are expressed as the group mean ± standard error. MCT, n = 15; KO, n = 13; SO, n = 14. Values were significantly different from the MCT group: *P < 0.05 by Mann-Whitney U-test with Bonferroni correction. No significant difference in P300 amplitude was observed between the treatments at week 6 or week 12.
Abbreviations: MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil.

Figure 6 Topographic maps of changes in oxyhemoglobin concentration at 150.0 seconds during the calculation task.

Note: MCT, n = 15; KO, n = 13; SO, n = 14.

Abbreviations: MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil.

Figure 7 Comparison of changes in oxyhemoglobin (oxy-hb) concentration at channel 15 during the calculation task.

Notes: Values are expressed as the group mean ± standard error. MCT, n = 15; KO, n = 13; SO, n = 14. Values were significantly different from the MCT group: **P < 0.01 by Bonferroni post hoc tests.
Abbreviations: MCT, medium-chain triglyceride; KO, krill oil; SO, sardine oil.