What are the safety and efficacy of fatty 15 (fatty acid) supplements?

Safety and Efficacy of Fatty 15 Supplements

There is insufficient evidence supporting the use of fatty 15 supplements for improving health outcomes, and current guidelines do not recommend fatty acid supplements for the general population or for cardiovascular risk reduction.

What is Fatty 15?

Fatty 15 (pentadecanoic acid, C15:0) is a type of odd-chain saturated fatty acid supplement that has been marketed as beneficial for health. However, it falls into the broader category of fatty acid supplements, which have been extensively studied in clinical research.

Evidence on Fatty Acid Supplements

Safety Considerations

• Dietary supplements, including fatty acid supplements, are not regulated to the same degree as prescription medications 1
• The content and quality of supplements can vary significantly 1
• Some supplements may contain impurities, including saturated fat, oxidized lipids, contaminants, or other potentially harmful ingredients 1
• While most supplements appear safe when consumed at typical doses, adverse effects can occur with large intakes 2
• Common side effects of fatty acid supplements include:
  • Gastrointestinal issues (burping, fishy taste, dyspepsia) 1
  • Potential increased risk of atrial fibrillation with high-dose omega-3 supplements 1, 3

Efficacy Evidence

• The American Diabetes Association and American Heart Association do not recommend omega-3 supplements for prevention or treatment of cardiovascular events in people without specific medical indications 4
• Systematic reviews have concluded that omega-3 dietary supplements did not improve glycemic management in individuals with type 2 diabetes 1
• In the ASCEND trial, supplementation with omega-3 fatty acids at 1 g/day did not lead to cardiovascular benefit in people with diabetes without evidence of CVD 1
• Only high-dose prescription EPA (4g/day) has shown cardiovascular benefit, and only in specific populations with established atherosclerotic CVD and hypertriglyceridemia 1, 3

Clinical Recommendations

When Fatty Acid Supplements May Be Considered

1. Severe hypertriglyceridemia:

   • Prescription-grade omega-3 fatty acids (not over-the-counter supplements) may be used as an adjunct to diet for triglyceride levels ≥500 mg/dL 1
   • Icosapent ethyl (prescription EPA) may be considered for patients with established cardiovascular disease or diabetes with multiple risk factors who have triglycerides ≥150 mg/dL despite maximally tolerated statin therapy 1

2. Food sources preferred over supplements:

   • Guidelines recommend obtaining fatty acids from food sources rather than supplements 4
   • The American Diabetes Association recommends consuming fatty fish at least twice weekly instead of taking supplements 4

Important Cautions

• Non-prescription fish oil products are classified as dietary supplements and are not FDA-approved to treat elevated triglyceride levels 1
• Supplements are necessary only in cases of nutrient deficiency and should be recommended and monitored by a physician 5
• Consumption of trans fats should be minimized due to association with increased cardiovascular risk 1
• The type of fats consumed is more important than total amount when considering metabolic goals and cardiovascular risk 1

Conclusion

For the general population, there is insufficient evidence supporting the use of fatty 15 or other fatty acid supplements for improving health outcomes. Current medical guidelines recommend obtaining fatty acids through food sources rather than supplements. If fatty acid supplementation is being considered for specific medical conditions like severe hypertriglyceridemia, prescription-grade products supervised by a healthcare provider are preferred over over-the-counter supplements.