*Omega-3 fatty acids in bariatric gastric bypass surgery: effects on liver volume, immune response and erythrocyte function*

Gastric bypass surgery is the gold standard in bariatric surgery and is a
successful method to reduce weight in morbidly obese subjects. Patients
qualified for gastric bypass surgery are routinely pre-treated with a low
calorie diet in order to reduce liver volume and to facilitate the approach of
the gastro-oesophageal junction. Pre-treatment with omega-3 fatty acids has
similar effects on liver volume, but a prospective comparison of both
treatments has not been performed yet. Morbidly obese patients respond
differently to surgical stress, due to a number of factors. First, obesity is
associated with a low-grade inflammatory state induced by an increased amount
of macrophages in adipose tissue. This state is associated with higher levels
of pro-inflammatory cytokines in serum and with a less adequate immune response
to infections. Second, obesity is associated with an altered cortisol
metabolism possibly related to adrenal insufficiency. This could play an
important role in the altered response to surgical stress and postoperative
complications in obese subjects. Third, obesity is associated with altered
erythrocyte function, including decreased erythrocyte deformability and
increased aggregation, factors contributing to an impaired microcirculation.
This study has a number of different aims. First, we will compare pre-treatment
with the standard low calorie diet with omega-3 fatty acids on liver volume in
patients qualified for gastric bypass surgery because of morbid obesity.
Second, we will investigate the effect of omega-3 fatty acids on immune
function before and after bariatric surgery. Third, we will investigate the
effect of omega-3 fatty acids on the low-inflammatory state of adipose tissue.
Fourth, we will assess the effect of omega-3 fatty acids on the stress response
of obese subjects before and after the and after bariatric surgery. Fifth, we
will investigate the effect of omega-3 fatty acids on erythrocyte function
before and after the and bariatric surgery.

Our primary objective is to compare pre-treatment with the standard low calorie
diet with pre-treatment with supplemental omega-3 fatty acids on liver volume.
Secondary objectives are patient satisfaction about different dietary
pre-treatments, the effect of omega-3 fatty acids before and after bariatric
surgery on immune function, level of inflammatory state in adipose tissue and
function of involved leucocytes, cortisol response, erythrocyte function, and
the long term effect of bariatric surgery on immune function and erythrocyte
function six months after surgery.
Study design: This study is set up as a randomised controlled open label trial.

This study is set up as a randomised controlled open label trial.

Omega-3 fatty acids capsules, twice a day one capsule, during 2 weeks prior to
gastric bypass surgery.

The burden and risks associated with participation are associated with the
possible side effects of omega-3 fatty acids and two MRI measurements of liver
volume, small risk of additional peroperative blood loss because of abdominal
tissue biopsies and collection of venous blood samples at every time point of
the study.