Therapeutic potential of marine n-3 fatty acids in CABG patients

The relation of saturated fatty acids with low-grade inflammation and cardiovascular disease

The mantra that dietary (saturated) fat must be minimized to reduce cardiovascular disease (CVD) risk has dominated nutritional guidelines for decades. Parallel to decreasing intakes of fat and saturated fatty acids (SFA), there have been increases in carbohydrate and sugar intakes, overweight, obesity and type 2 diabetes mellitus. The "lipid hypothesis" coined the concept that fat, especially SFA, raises blood low-density lipoprotein-cholesterol and thereby CVD risk. In view of current controversies regarding their adequate intakes and effects, this review aims to summarize research regarding this heterogenic group of fatty acids and the mechanisms relating them to (chronic) systemic low-grade inflammation, insulin resistance, metabolic syndrome and notably CVD. The intimate relationship between inflammation and metabolism, including glucose, fat and cholesterol metabolism, revealed that the dyslipidemia in Western societies, notably increased triglycerides, "small dense" low-density lipoprotein and "dysfunctional" high-density lipoprotein, is influenced by many unfavorable lifestyle factors. Dietary SFA is only one of these, not necessarily the most important, in healthy, insulin-sensitive people. The environment provides us not only with many other proinflammatory stimuli than SFA but also with many antiinflammatory counterparts. Resolution of the conflict between our self-designed environment and ancient genome may rather rely on returning to the proinflammatory/antiinflammatory balance of the Paleolithic era in consonance with the 21st century culture. Accordingly, dietary guidelines might reconsider recommendations for SFA replacement and investigate diet in a broader context, together with nondietary lifestyle factors. This should be a clear priority, opposed to the reductionist approach of studying the effects of single nutrients, such as SFA.

Patients undergoing elective coronary artery bypass grafting exhibit poor pre-operative intakes of fruit, vegetables, dietary fibre, fish and vitamin D

CHD may ensue from chronic systemic low-grade inflammation. Diet is a modifiable risk factor for both, and its optimisation may reduce post-operative mortality, atrial fibrillation and cognitive decline. In the present study, we investigated the usual dietary intakes of patients undergoing elective coronary artery bypass grafting (CABG), emphasising on food groups and nutrients with putative roles in the inflammatory/anti-inflammatory balance. From November 2012 to April 2013, we approached ninety-three consecutive patients (80% men) undergoing elective CABG. Of these, fifty-five were finally included (84% men, median age 69 years; range 46-84 years). The median BMI was 27 (range 18-36) kg/m(2). The dietary intake items were fruits (median 181 g/d; range 0-433 g/d), vegetables (median 115 g/d; range 0-303 g/d), dietary fibre (median 22 g/d; range 9-45 g/d), EPA+DHA (median 0.14 g/d; range 0.01-1.06 g/d), vitamin D (median 4.9 μg/d; range 1.9-11.2 μg/d), saturated fat (median 13.1% of energy (E%); range 9-23 E%) and linoleic acid (LA; median 6.3 E%; range 1.9-11.3 E%). The percentages of patients with dietary intakes below recommendations were 62% (fruits; recommendation 200 g/d), 87 % (vegetables; recommendation 150-200 g/d), 73% (dietary fibre; recommendation 30-45 g/d), 91% (EPA+DHA; recommendation 0.45 g/d), 98% (vitamin D; recommendation 10-20 μg/d) and 13% (LA; recommendation 5-10 E%). The percentages of patients with dietary intakes above recommendations were 95% (saturated fat; recommendation < 10 E%) and 7% (LA). The dietary intakes of patients proved comparable with the average nutritional intake of the age- and sex-matched healthy Dutch population. These unbalanced pre-operative diets may put them at risk of unfavourable surgical outcomes, since they promote a pro-inflammatory state. We conclude that there is an urgent need for intervention trials aiming at rapid improvement of their diets to reduce peri-operative risks.

Prevention of postoperative atrial fibrillation in open heart surgery patients by preoperative supplementation of n-3 polyunsaturated fatty acids: an updated meta-analysis

BACKGROUND

Several randomized clinical trials evaluated whether preoperative supplementation of omega-3 (n-3) polyunsaturated fatty acids protects against postoperative atrial fibrillation after cardiac surgery, a condition associated with increased cardiac and cerebral mortality. However, their efficacy remains still controversial. An updated meta-analysis was performed to clarify if preoperative n-3 polyunsaturated fatty acid supplementation prevents postoperative atrial fibrillation in patients undergoing cardiac surgery.

METHODS

Articles were retrieved until November 2012 by screening electronic databases (PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials) and cross references. Two of us independently reviewed articles and agreed to select 8 randomized clinical trials. For each study, the incidence of atrial fibrillation in both the intervention and placebo groups was extracted to calculate odd ratio and 95% confidence intervals (CIs). Weighted study-specific estimates were combined using fixed (Mantel-Haenszel method) and random-effects (DerSimonian-Laird method) models.

RESULTS

This meta-analysis includes 2687 patients (1337 in the intervention group) who underwent cardiac surgery. Pooled analysis using fixed-effects models showed a significant reduction (average, 16%; 95% CI, 1%-29%) in postoperative atrial fibrillation by preoperative n-3 polyunsaturated fatty acids. There was a low heterogeneity among studies (P = .07 and I(2) = 46%). By using a random-effects model, the reduction averaged 25% (odds ratio, 0.75; 95% CI, 0.57-1.00; P = .05). When isolated coronary artery bypass graft surgery was only considered (7 studies), a significant protection averaging 34% was observed in a fixed model (odds ratio, 0.66; 95% CI, 0.50-0.87; P = .003; I(2) = 26%, P = .23).

CONCLUSIONS

A preoperative supplementation of n-3 polyunsaturated fatty acids significantly prevents the occurrence of postoperative atrial fibrillation in patients undergoing cardiac surgery, in particular coronary artery bypass surgery.