Unsaturation index and type 2 diabetes: Unknown, unloved

Table 1 Unsaturation index of erythrocyte membrane fatty-acid composition of controls and type 2 diabetes patients without diabetic retinopathy

Fatty acids	Controls (n = 18)		T2D patients without diabetic retinopathy (n = 14)
	% of total fatty acids1		% of total fatty acids1
		× number of double bonds		× number of double bonds
C14:0	0.43	-	0.48	-
C15:0	0.17	-	0.22	-
C16:0	22.41	-	23.75	-
C17:0	0.38	-	0.44	-
C18:0	17.22	-	17.72	-
C20:0	0.15	-	0.18	-
C22:0	0.33	-	0.42	-
C24:0	0.74	-	0.78	-
C16:1	0.73	0.73	1.03	1.03
C18:1 (trans)	0.22	-	0.2	-
C18:1	17.16	17.16	19.15	19.15
C20:1 n-9	0.21	0.21	0.26	0.26
C20:3 n-9	0.19	0.57	0.2	0.6
C22:1 n-9	0.06	0.06	0.09	0.09
C24:1 n-9	0.69	0.69	1.15	1.15
C18:2 n-6	12.87	25.74	10.58	21.16
C18:3 n-6	0.09	0.27	0.12	0.36
C20:2 n-6	0.2	0.4	0.23	0.46
C20:3 n-6	1.3	3.9	1.5	4.5
C20:4 n-6	13.04	52.16	11.33	45.32
C22:4 n-6	2.0	8	2.01	8.04
C22:5 n-6	0.35	1.75	0.3	1.5
C18:3 n-3	0.22	0.66	0.21	0.63
C20:5 n-3	0.97	4.85	1.03	5.15
C22:5 n-3	2.23	11.15	1.56	7.8
C22:6 n-3	4.51	27.06	2.85	17.1
Unsaturation index2		155.36		134.3

¹Data published by Koehrer et al[5];

²The unsaturation index was calculated as the mean number of double bonds per fatty acid residue multiplied by 100.

Table 2 Calculated unsaturation indices based on erythrocyte fatty-acid compositions reported by several studies

Disease	Participants (n)		Erythrocyte membrane	Unsaturation index1		Decrease (%)	Ref.
	Controls	Disease		Controls	Diabetic subjects
T2D/T1D	18	13/1	Total phospholipid	155.4	134.3	13.5	[5]
T2D/T1D + mild DR	18	11/1	Total phospholipid	155.4	125.9	19.0	[5]
T2D/T1D + moderate DR	18	11/1	Total phospholipid	155.4	119.5	23.1	[5]
T2D/T1D + severe DR	18	19/3	Total phospholipid	155.4	124.7	19.7	[5]
T2D/T1D + proliferative DR	18	17/7	Total phospholipid	155.4	136.9	11.9	[5]
Gestational diabetes	61	53	PC + PE	162.8	137.1	16.3	[6]

¹The unsaturation index was calculated as the mean number of double bonds per fatty acid residue multiplied by 100[4]. DR: Diabetic retinopathy; PC: Phosphatidylcholine; PE: Phosphatidylethanolamine.