Br J Nutr., 2019., Jul 16:1-8. doi: 10.1017/S0007114519001132.

Long-term vitamin D and high-dose n-3 fatty acids’ supplementation improve markers of cardiometabolic risk in type 2 diabetic patients with CHD.

Talari HR Najafi V Raygan F et al.

Abstract

This study was performed to evaluate the effects of vitamin D and n-3 fatty acids’ co-supplementation on markers of cardiometabolic risk in diabetic patients with CHD. This randomised, double-blinded, placebo-controlled trial was conducted among sixty-one vitamin D-deficient diabetic patients with CHD. At baseline, the range of serum 25-hydroxyvitamin D levels in study participants was 6·3-19·9 ng/ml. Subjects were randomly assigned into two groups either taking 50 000 IU vitamin D supplements every 2 weeks plus 2× 1000 mg/d n-3 fatty acids from flaxseed oil (n 30) or placebo (n 31) for 6 months. Vitamin D and n-3 fatty acids’ co-supplementation significantly reduced mean (P = 0·01) and maximum levels of left carotid intima-media thickness (CIMT) (P = 0·004), and mean (P = 0·02) and maximum levels of right CIMT (P = 0·003) compared with the placebo. In addition, co-supplementation led to a significant reduction in fasting plasma glucose (β -0·40 mmol/l; 95 % CI -0·77, -0·03; P = 0·03), insulin (β -1·66 μIU/ml; 95 % CI -2·43, -0·89; P < 0·001), insulin resistance (β -0·49; 95 % CI -0·72, -0·25; P < 0·001) and LDL-cholesterol (β -0·21 mmol/l; 95 % CI -0·41, -0·01; P = 0·04), and a significant increase in insulin sensitivity (β +0·008; 95 % CI 0·004, 0·01; P = 0·001) and HDL-cholesterol (β +0·09 mmol/l; 95 % CI 0·01, 0·17; P = 0·02) compared with the placebo. Additionally, high-sensitivity C-reactive protein (β -1·56 mg/l; 95 % CI -2·65, -0·48; P = 0·005) was reduced in the supplemented group compared with the placebo group. Overall, vitamin D and n-3 fatty acids’ co-supplementation had beneficial effects on markers of cardiometabolic risk.

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Key Points

There is evidence that vitamin D and n-3 fatty acids’ intake may have glucose-lowering and anti-inflammatory effects, and co-supplementation might benefit diabetic patients with CHD. The present study was, therefore, performed to evaluate the effects of long-term vitamin D and n-3 fatty acids’ co-supplementation on CIMT, glucose homeostasis parameters, lipid concentrations and inflammatory markers in diabetic patients with CHD for  6-month supplementation. Beneficial effects were noted on mean and maximum levels of left and right CIMT, glycaemic control, LDL-, HDL-, total-/HDL-cholesterol and hs-CRP levels among diabetic patients with CHD. In summary, vitamin D and n-3 fatty acids’ co-supplementation for 6 months had beneficial effects on the markers of cardiometabolic risk among diabetic patients with CHD.