What you carry at this position in your DNA and what research says about it.
Omega Fatty Acid Processing: 9/10 evidence, 22 publications.
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Sample genotype (not yours): T/T
Efficient Omega Processing but Higher Blood Sugar
Enhanced enzyme activity enables highly efficient conversion of plant-based fats into active omega-3 and omega-6 fatty acids. However, this efficient metabolism is also linked to slightly higher fasting blood sugar and cholesterol levels.
What this genotype means: Highly efficient conversion of plant-based omega fats; Slightly elevated fasting blood sugar; Slightly higher total and LDL cholesterol.
Sample genotype (not yours): C/C
Impaired Omega Fatty Acid Conversion
Reduced desaturase enzyme activity limits the internal synthesis of active omega-3 and omega-6 fatty acids from plant sources. However, this slower processing is accompanied by naturally lower fasting blood sugar and cholesterol levels.
What this genotype means: Impaired conversion of plant-based omega fats; Naturally lower fasting blood sugar; Naturally lower total and LDL cholesterol.
Sample genotype (not yours): T/C
Typical Omega and Lipid Balance
Moderate desaturase enzyme activity provides a balanced rate of converting plant-based fats into active omega fatty acids. Metabolic markers like blood sugar and cholesterol levels typically remain at baseline levels.
What this genotype means: Moderate conversion of plant-based omega fats; Typical baseline fasting blood sugar; Typical baseline cholesterol levels.
Gene function and biological role
Gene Function: The FADS1 gene encodes the delta-5 desaturase enzyme, a critical player in lipid metabolism. This enzyme catalyzes the conversion of short-chain plant-derived fatty acids into long-chain polyunsaturated fatty acids. Specifically, it converts alpha-linolenic acid into eicosapentaenoic acid and linoleic acid into arachidonic acid. These long-chain fats are essential components of cell membranes and serve as precursors for signaling molecules that regulate inflammation. Variations in this gene directly influence circulating lipid levels and metabolic health.
Variant Impact: The rs174550 variant is an intron variant located within the FADS1 gene that modulates its expression level. The T allele is associated with increased expression of the desaturase enzyme, leading to highly efficient conversion of plant-based fats. Conversely, the C allele reduces enzyme expression, which limits the body's ability to synthesize long-chain omega-3 and omega-6 fatty acids internally. This genetic difference also impacts broader metabolic markers, including blood sugar and cholesterol levels.
Read on the Omega-3 Conversion page
Key Insight: Your ability to convert plant-based omega fats into active forms depends heavily on this variant, which simultaneously influences your natural cholesterol and blood sugar baselines.
Location: FADS1. Chromosome 11 · 11q12.2 · 61.8 Mb
Origin Story: The high-activity variant was strongly selected for in early European agriculturalists as they transitioned from marine diets to plant-based farming diets.
Estimated prevalence by population
Global 52.9%; European 44.1%; African 85.0%; East Asian 19.9%; South Asian 67.3%; Americas 26.3%; Ashkenazi 50.9%; Finnish 33.5%; Middle Eastern 42.7%; Amish 58.7%.
Estimated TT genotype frequency.
Global 36.7%; European 44.6%; African 14.4%; East Asian 49.4%; South Asian 29.5%; Americas 50.0%; Ashkenazi 40.9%; Finnish 48.7%; Middle Eastern 45.3%; Amish 35.9%.
Estimated TC genotype frequency.
Global 10.4%; European 11.3%; African 0.6%; East Asian 30.7%; South Asian 3.2%; Americas 23.8%; Ashkenazi 8.2%; Finnish 17.7%; Middle Eastern 12.0%; Amish 5.5%.
Estimated CC genotype frequency.
Showing effects for T/T genotype
Nutrition & Metabolism
Macronutrient Metabolism
Omega-3 Conversion. Evidence: 8/10. Source: PMID 25500335. Highly Efficient.
Cardiovascular & Metabolic
Diabetes & Glycemic Traits
Fasting Glucose. Evidence: 8/10. Source: PMID 22581228. Slightly Higher.
Lipids & Cholesterol
LDL Cholesterol. Evidence: 6/10. Source: PMID 29507422. Slightly Higher.
Total Cholesterol. Evidence: 9/10. Source: PMID 29507422. Slightly Higher.
Showing effects for C/C genotype
Omega-3 Conversion. Evidence: 8/10. Source: PMID 25500335. Impaired.
Fasting Glucose. Evidence: 8/10. Source: PMID 22581228. Slightly Lower.
LDL Cholesterol. Evidence: 6/10. Source: PMID 29507422. Slightly Lower.
Total Cholesterol. Evidence: 9/10. Source: PMID 29507422. Slightly Lower.
Showing effects for T/C genotype
Omega-3 Conversion. Evidence: 8/10. Source: PMID 25500335. Moderate.
Fasting Glucose. Evidence: 8/10. Source: PMID 22581228. Typical.
LDL Cholesterol. Evidence: 6/10. Source: PMID 29507422. Typical.
Total Cholesterol. Evidence: 9/10. Source: PMID 29507422. Typical.
What this genotype means for the people who carry it
Sample genotype: TT (Homozygous)
High desaturase activity in this genotype ensures robust internal synthesis of long-chain polyunsaturated fatty acids from plant precursors like flaxseed or canola oil. Research indicates that these individuals experience a significant increase in circulating eicosapentaenoic acid when consuming plant-based omega-3s. However, this metabolic efficiency comes with a trade-off in other cardiometabolic markers. Large-scale genetic studies associate this genotype with slightly elevated fasting glucose levels. It is also linked to higher total and LDL cholesterol levels compared to other genotypes. Balancing dietary fat intake and monitoring metabolic markers can help manage these overlapping genetic tendencies.
Highly efficient conversion of plant-based omega fats; Slightly elevated fasting blood sugar; Slightly higher total and LDL cholesterol.
Sample genotype: CC (Homozygous)
Low desaturase activity in this genotype significantly restricts the conversion of plant-based essential fats into active long-chain polyunsaturated fatty acids. Individuals with this profile often have lower circulating levels of eicosapentaenoic acid and arachidonic acid. Consequently, obtaining preformed omega-3 fatty acids directly from marine sources like fish or algae oil is particularly important. On the positive side, this slower metabolic pathway is associated with favorable metabolic profiles. Genetic analyses show these individuals have lower fasting blood sugar levels. They also exhibit lower total and LDL cholesterol levels, which may offer natural cardiovascular advantages.
Impaired conversion of plant-based omega fats; Naturally lower fasting blood sugar; Naturally lower total and LDL cholesterol.
Sample genotype: TC (Heterozygous)
An intermediate rate of fatty acid desaturation allows for moderate conversion of dietary plant-derived fats into long-chain polyunsaturated fatty acids. This balanced state means the body synthesizes some active omega-3 and omega-6 fats internally, though dietary sources remain highly beneficial. Metabolic studies show that fasting glucose levels in these individuals generally sit at the population average. Similarly, circulating total and LDL cholesterol levels tend to be typical and balanced. This genotype represents a common genetic baseline with no extreme metabolic trade-offs. Maintaining a diverse diet rich in both plant and marine fats supports optimal lipid homeostasis.
Moderate conversion of plant-based omega fats; Typical baseline fasting blood sugar; Typical baseline cholesterol levels.
Variants with shared genetic architecture
rs174546 · FADS1 Gene · Chr 11 · Fatty Acid Metabolism
rs174554 · FADS1 Gene · Chr 11 · Omega Fat Conversion
rs174545 · FADS1 Gene · Chr 11 · Fatty Acid Metabolism
Content updated August 2026.
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