FADS1 (Fatty Acid Desaturase 1)

Overview

The FADS1 gene encodes delta-5 desaturase (D5D), a key enzyme for converting short-chain to long-chain polyunsaturated fatty acids (LC-PUFAs). These are essential for brain function, inflammatory responses, and cardiovascular health.

📍 Position
11q12.2 (Chromosome 11)

🏷️ Category
Metabolism

⚡ Enzyme
Delta-5 Desaturase (D5D)

📊 Frequency
C-allele ~50-70%

Function & Significance

FADS1 catalyzes delta-5 desaturation—the introduction of an additional double bond into fatty acids:

Important Conversions by FADS1:

Omega-6 Series

Dihomo-γ-linolenic acid (DGLA)
↓ FADS1
Arachidonic Acid (ARA, C20:4)

ARA is a precursor for eicosanoids (inflammatory mediators)

Omega-3 Series

Eicosatetraenoic acid
↓ FADS1
Eicosapentaenoic Acid (EPA, C20:5)

EPA is anti-inflammatory and important for cardiovascular health

💡 Why is this important? Most people can only convert alpha-linolenic acid (ALA) to EPA/DHA to a limited extent (often <5%). FADS1 genetics significantly influences this efficiency!

🧬 Genetic Variant

rs174550
11:61597230

Lower Activity

A

/

Higher Activity

C

A>C Variant: The C-allele is associated with higher desaturase activity (more efficient production of ARA and EPA). The A-allele shows reduced activity.

A/A or A/C
Reduced D5D activity. Poorer conversion of Omega-3 precursors. Increased requirement for direct EPA/DHA from fish/algae.

C/C (Common)
Higher D5D activity. Better endogenous synthesis of ARA and EPA. However, also higher ARA levels (more pro-inflammatory).

🐟 Dietary Recommendations

A-Allele Carriers (30-50%)

Regular fish consumption: Fatty fish 2-3x per week
EPA/DHA supplementation: Consider 1-2g/day
Algae oil over flaxseed oil: Direct DHA source
Test Omega-3 Index: Target: >8%

C/C Genotype

Better conversion, but higher ARA risk
Reduce Omega-6 intake (limit sunflower oil)
Monitor Omega-3:Omega-6 ratio (target 1:1 to 1:4)
Promote anti-inflammatory diet

✅ Omega Sources:

Direct EPA/DHA: Salmon, mackerel, sardines, algae oil (vegan)
Precursor ALA: Flaxseeds, chia, walnuts (poor conversion!)
Precursor LA: Vegetable oils converted into ARA

🔗 Health Associations

Cardiovascular: Higher FADS1 activity associated with better triglyceride levels
Allergies: ARA is a precursor to prostaglandins and leukotrienes—A/C carriers may experience allergies more frequently
ADHD: Low Omega-3 levels are common; FADS1 variants influence availability
Mental Health: EPA has mood-stabilizing effects; DHA is essential for the brain

⚠️ A/A Genotype: Carriers are “poor converters” and often have Omega-3 indices <4% despite flaxseed/ALA consumption. Direct EPA/DHA intake is often necessary.

📚 Data Sources

OMIM: #606148 (FADS1 Gene)
dbSNP: rs174550
PubMed: Glaser et al. (2011) – Genetic variants in FADS and lipid metabolism
AJCN: Ameur et al. (2012) – Genetic adaptation of fatty acid metabolism
Nature Genetics: FADS cluster and human evolution

Last Update: February 2026

FADS1