Low-fat, high-carbohydrate diets improve wound healing and increase protein levels in surgically stressed rats.

The specific effects of omega 3 and omega 6 polyunsaturated fatty acids on wound healing, nutrition status, or immune function are controversial. Therefore, we investigated the effects of fatty acid supplementation on wound healing and nitrogen retention in a surgically stressed rat model. Male Sprague-Dawley rats (weighing 250 g) were placed into three isocaloric, isonitrogenous feeding groups (controls [standard Vivonex]; 30% safflower oil [omega 6]; or 30% fish oil [omega 3]) for 8 days prior to receiving subcutaneous vascular graft wound cylinders in their dorsal midline. Nitrogen balance was monitored daily. Wounds healed for 10 days, animals were then euthanized, serum was drawn, and wound cylinders were harvested for analyses. The low-fat, high-carbohydrate control group had higher serum albumin levels at 10 days than either fatty acid-supplemented group (3.5 +/- 0.4 g/dL v 2.9 +/- 0.3 g/dL and 2.7 +/- 0.2 g/dL, omega 3 and omega 6, respectively; both P less than .05) and had better nitrogen balance (8.6 +/- 0.8 mg N/d v -2.6 +/- 0.9 mg N/d and 0.8 +/- 1.2 mg N/d, omega 3 and omega 6, respectively; both P less than .05). They also had better healed wounds at 10 days (450 +/- 290 micrograms 5-hydroxyproline [OHP]/cm of wound cylinder v 150 +/- 40 micrograms OHP/cm and 145 +/- 90 micrograms OHP/cm, omega 3 and omega 6, respectively). Surgically stressed rats had higher protein levels, better nitrogen balance, and improved wound healing when fed a diet high in carbohydrates and low in fat.