Bioavailability and safety of a high dose of docosahexaenoic acid triacylglycerol of algal origin in cystic fibrosis patients: a randomized, controlled study

Nutrition. 2006 Jan;22(1):36-46. doi: 10.1016/j.nut.2005.05.006. Epub 2005 Oct 12.


Objective: Several studies have reported omega-3 and omega-6 fatty acid imbalances in patients with cystic fibrosis (CF). Whether these imbalances contribute to or are manifestations of the pathophysiology of CF is unknown. The study objective was to determine bioavailability, tissue accretion, and safety of a large dose of an algal source of docosahexaenoic acid (DHA) triacylglycerol and to observe effects on lung function in patients with CF.

Methods: Twenty subjects with CF (8 to 20 y of age) were randomly assigned to receive algal oil providing 50 mg of DHA per kilogram per day (1 to 4.2 g of DHA per subject per day) or placebo for 6 mo. Fatty acids, liver enzymes, and lipid soluble antioxidants were measured in blood at baseline and at 1, 3, and 6 mo. Rectal biopsy specimens were collected at baseline and at 3 mo for fatty acid analysis. Lung function, anthropometrics, and adverse experiences were monitored throughout the study.

Results: Compared with placebo, DHA supplementation increased plasma, erythrocyte, and rectal DHA levels four- to five-fold (P < 0.001) with concomitant decreases in blood arachidonic acid levels and the ratio of arachidonic acid to DHA. Supplementation was well tolerated, with no treatment-related changes in liver enzymes, growth, or antioxidant status. DHA supplementation had no detectable effect on lung function during the course of this study.

Conclusions: Algal DHA triacylglycerol oil is readily absorbed, well tolerated, and increases blood and tissue DHA levels in patients with CF. No adverse developments were associated with this large dose of DHA oil. Larger studies of longer duration are needed to determine whether DHA supplementation results in any clinically significant benefits in patients with CF.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Arachidonic Acid / blood
  • Biological Availability
  • Child
  • Cystic Fibrosis / metabolism*
  • Dietary Fats, Unsaturated / adverse effects
  • Dietary Fats, Unsaturated / blood
  • Dietary Fats, Unsaturated / pharmacokinetics
  • Dietary Supplements
  • Docosahexaenoic Acids / adverse effects
  • Docosahexaenoic Acids / blood
  • Docosahexaenoic Acids / pharmacokinetics*
  • Dose-Response Relationship, Drug
  • Eukaryota*
  • Female
  • Humans
  • Intestinal Absorption
  • Liver / enzymology
  • Lung / drug effects*
  • Lung / metabolism
  • Lung / physiology
  • Male
  • Respiratory Function Tests
  • Safety
  • Triglycerides / adverse effects
  • Triglycerides / blood
  • Triglycerides / pharmacokinetics*


  • Dietary Fats, Unsaturated
  • Triglycerides
  • Docosahexaenoic Acids
  • Arachidonic Acid