The effect of camelina oil on vascular function in essential hypertensive patients with metabolic syndrome: a randomized, placebo-controlled, double-blind study

Abstract

Background The effects of a dietary supplementation with the vegetable omega-3 α-linolenic acid (ALA) on cardiovascular homeostasis are unclear. In this context, it would be interesting to assess the effects of camelina oil. Objective This study aimed to assess the cardiovascular and metabolic effects of camelina oil in hypertensive patients with metabolic syndrome. Methods In a double-blind placebo-controlled randomized study, treated essential hypertensive patients with metabolic syndrome received during 6 months either cyclodextrin-complexed camelina oil containing ≈ 1.5 g ALA/day (n = 40), or an isocaloric placebo (n = 41), consisting in the same quantity of cyclodextrins and wheat starch. Anthropometric data, plasma lipids, glycemia, insulinemia, creatininemia, thiobarbituric acid reactive substances, high-sensitivity C-reactive protein, and n-3, n-6 and n-9 fatty acids in erythrocyte membranes were measured. Peripheral and central blood pressures, arterial stiffness, carotid intima-media thickness and brachial artery endothelium-dependent flow-mediated dilatation and endothelium-independent dilatation were assessed. Results Compared to placebo, camelina oil increased ALA (mean ± SD: 0 ± 0.04 vs. 0.08 ± 0.06%, P < 0.001), its elongation product eicosapentaenoic acid (EPA; 0 ± 0.5 vs. 0.16 ± 0.65%, P < 0.05), and the n-9 gondoic acid (0 ± 0.04 vs. 0.08 ± 0.04%, P < 0.001). No between-group difference was observed for cardiovascular parameters. However, changes in flow-mediated dilatation were associated with the magnitude of changes in EPA (r = 0.26, P = 0.03). Compared to placebo, camelina oil increased fasting glycemia (–0.2 ± 0.6 vs. 0.3 ± 0.5 mmol/L, P < 0.001) and homeostatic model assessment for insulin resistance (HOMA-IR; –0.8 ± 2.5 vs. 0.5 ± 0.9, P < 0.01) index, without affecting plasma lipids, or inflammatory and oxidative stress markers. Changes in HOMA-IR index were correlated with the magnitude of changes in gondoic acid (r = 0.32, P < 0.01). Nutritional intake remained similar between groups. Conclusion ALA supplementation with camelina oil did not improve vascular function but adversely affected glucose metabolism in hypertensive patients with metabolic syndrome Whether this adverse effect on insulin sensitivity is related to gondoic acid enrichment, remains to be elucidated.

Effects of camelina oil supplementation on lipid profile and glycemic control: a systematic review and dose‒response meta-analysis of randomized clinical trials

“…The dose of COS used ranged from 50 ml/d to 30 g/d, while the length of the interventions ranged from 6 to 24 weeks. The types of interventions used for the control groups included canola oil [ 9 , 10 ], sunflower oil [ 6 , 7 , 11 ], a diet with limited intake of fish and sources of ALA [ 12 ], and a mixture of cyclodextrin [ 8 ].…”

“…The incomplete outcome data domain of bias was low risk for six studies [ 6 – 9 , 11 , 12 ], and the Karvonen et al study [ 10 ] was ranked as having an unclear risk of bias. Four studies were ranked low risk [ 6 , 8 , 11 , 12 ], and three were categorized as having an unclear risk for the selective reporting bias domain [ 7 , 9 , 10 ]. All studies were ranked as low risk for other bias domains [ 6 – 12 ].…”

“…These investigations have yielded contradictory results. For instance, Musazadeh 2021 et al [ 7 ] and Bellien et al [ 8 ] revealed that COS might attenuate glycemic parameters in nonalcoholic fatty liver disease (NAFLD) and hypertensive patients, respectively. However, Schwab et al [ 12 ] showed that COS did not affect glycemic parameters among participants with impaired fasting glucose.…”

“…Furthermore, it has also been proposed to inhibit lipogenic gene expression, such as sterol regulatory element binding proteins (SREBPs), carbohydrate-responsive element-binding protein and PPARγ [ 6 ]. However, some studies did not show any significant effects of COS on the lipid profile as a CVD-related marker [ 8 , 12 ]. Thus, research on this topic has shown mixed findings, leading to a lack of consensus on the impact of COS on lipid profiles and glycemic control.…”

“… Musazadeh et al 2022 [ 6 ] Iran 130 (63/67) Male and female NAFLD patients 44.30 ± 4.38/ 43.86 ± 6.07 34.19 ± 3.55/ 33.90 ± 2.65 Parallel (Triple) 12 Weeks Camelina oil 20 g/d Sunflower oil 20 g/d Camelina oil intake led to a significant decrease in FI, and HOMA-IR in compared with the placebo group. Bellien et al 2022 [ 8 ] France 81 (40/41) Male and female Hypertensive patients with metabolic syndrome 57.7 ± 8.4/ 55.0 ± 7.5 30.0 ± 4.0/ 30.3 ± 4.2 Parallel (Double) 24 Weeks Camelina oil 5.2 g/d A mixture of cyclodextrin Compared with placebo, camelina oil increased fasting glycemia and HOMA-IR index, without affecting plasma lipids NR Not reported, HDL High-density lipoprotein, FBS Fasting blood sugar, NAFLD Nonalcoholic fatty liver disease, FI Fating insulin, HOMA-IR Homeostasis model assessment of insulin resistance …”