What you carry at this position in your DNA and what research says about it.
Fatty Acid Metabolism: 9/10 evidence, 24 publications.
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Sample genotype (not yours): C/C
Typical Cholesterol and Efficient Omega Conversion
Efficient conversion of plant-based omega fatty acids into active forms characterizes this genetic profile. It also correlates with typical baseline levels of LDL cholesterol and blood glucose.
What this genotype means: Highly efficient conversion of plant-based omega-3s; Typical baseline LDL and total cholesterol levels; Standard blood glucose and HbA1c levels.
Sample genotype (not yours): C/T
Typical Cholesterol and Moderate Omega Conversion
Balanced desaturase activity provides moderate conversion of plant-based omega fatty acids. Circulating cholesterol and blood sugar levels generally remain at typical baseline values.
What this genotype means: Moderate conversion of plant-based omega-3s; Typical baseline LDL and total cholesterol levels; Standard blood glucose and HbA1c levels.
Sample genotype (not yours): T/T
Lower Cholesterol but Inefficient Omega Conversion
Reduced desaturase activity lowers LDL cholesterol and blood glucose but limits the conversion of plant-based omega fats. Direct dietary sources of active omega-3s are highly beneficial.
What this genotype means: Inefficient conversion of plant-based omega-3s; Lower circulating LDL and total cholesterol; Higher circulating triglycerides.
Gene function and biological role
Gene Function: The FADS2 gene encodes fatty acid desaturase 2, a critical enzyme that regulates the synthesis of polyunsaturated fatty acids [1]. This enzyme catalyzes the rate-limiting step in converting short-chain plant-derived fatty acids into long-chain active forms like arachidonic acid and docosahexaenoic acid [1] [2]. These long-chain fats are vital components of cell membranes and serve as precursors for inflammatory and anti-inflammatory signaling molecules [2]. Genetic variations in this gene cluster significantly influence circulating lipid levels and metabolic health [2] [3]. Consequently, FADS2 activity plays a central role in how the body processes dietary fats and maintains cardiovascular homeostasis [2].
Variant Impact: The rs174570 variant is located within an intron of the FADS2 gene and acts as a major genetic modifier of desaturase enzyme activity [1]. The common C allele is associated with high desaturase efficiency, leading to rapid conversion of plant-based omega-3 and omega-6 fats [1] [2]. Conversely, the minor T allele reduces enzyme activity, resulting in lower levels of converted long-chain fatty acids in blood cell membranes [1] [2]. This reduction in desaturase activity alters systemic lipid profiles, lowering total and LDL cholesterol while raising triglycerides [3]. This genetic trade-off highlights how a single nucleotide change can shift the balance between fatty acid synthesis and circulating cholesterol levels [1] [3].
Key Insight: A single genetic letter determines whether your body is optimized to process plant-based omega-3s or if you require direct marine sources like fish oil to maintain cellular health.
Location: FADS2. Chromosome 11 · 11q12.2 · 61.8 Mb
Origin Story: During the ancestral history of the Greenlandic Inuit, strong positive selection favored genetic variants in the FADS gene cluster that reduced desaturase activity. Because their traditional Arctic diet was exceptionally rich in marine mammals and fish, they consumed high amounts of pre-formed long-chain omega-3 fatty acids, making endogenous synthesis unnecessary. This genetic adaptation helped them manage the physiological demands of a high-fat diet and cold climate, though it also resulted in a significantly shorter average stature.
Estimated prevalence by population
Global 73.1%; European 74.8%; African 92.5%; East Asian 20.5%; South Asian 79.9%; Americas 38.0%; Ashkenazi 74.4%; Finnish 58.1%; Middle Eastern 79.4%; Amish 92.4%.
Estimated CC genotype frequency.
Global 23.0%; European 23.4%; African 7.3%; East Asian 49.6%; South Asian 19.0%; Americas 47.3%; Ashkenazi 23.7%; Finnish 36.3%; Middle Eastern 19.4%; Amish 7.4%.
Estimated CT genotype frequency.
Global 3.9%; European 1.8%; African 0.1%; East Asian 29.9%; South Asian 1.1%; Americas 14.7%; Ashkenazi 1.9%; Finnish 5.7%; Middle Eastern 1.2%; Amish 0.1%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Nutrition & Metabolism
Macronutrient Metabolism
Omega-3 Conversion. Evidence: 3/10. Source: PMID 20565855. Highly Efficient.
Cardiovascular & Metabolic
Lipids & Cholesterol
LDL Cholesterol. Evidence: 9/10. Source: PMID 19060911. Typical LDL.
Total Cholesterol. Evidence: 9/10. Source: PMID 19060911. Typical Cholesterol.
Triglycerides. Evidence: 8/10. Source: PMID 33462484. Typical Triglycerides.
Diabetes & Glycemic Traits
Blood Glucose. Evidence: 8/10. Source: PMID 33462484. Typical Glucose.
Lifestyle, Fitness & Aging
Height & Body Size
Height. Evidence: 8/10. Source: PMID 36224396. Typical Height.
Showing effects for C/T genotype
Omega-3 Conversion. Evidence: 3/10. Source: PMID 20565855. Moderate.
Showing effects for T/T genotype
Omega-3 Conversion. Evidence: 3/10. Source: PMID 20565855. Inefficient.
LDL Cholesterol. Evidence: 9/10. Source: PMID 19060911. Lower LDL.
Total Cholesterol. Evidence: 9/10. Source: PMID 19060911. Lower Cholesterol.
Triglycerides. Evidence: 8/10. Source: PMID 33462484. Higher Triglycerides.
Blood Glucose. Evidence: 8/10. Source: PMID 33462484. Lower Glucose.
Height. Evidence: 8/10. Source: PMID 36224396. Slightly Shorter.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Highly active desaturase enzymes allow for the rapid conversion of short-chain dietary fats into essential long-chain polyunsaturated fatty acids [1]. This efficient pathway ensures adequate levels of arachidonic acid and DHA even on a purely plant-based diet [1] [2]. However, this high metabolic throughput is accompanied by typical, slightly higher levels of total and LDL cholesterol compared to other genotypes [3]. Blood glucose and HbA1c levels also tend to remain at standard baseline values [4]. Because the body is highly capable of synthesizing its own long-chain fats, direct supplementation with fish oil may be less critical for maintaining membrane lipid balance [1]. Nonetheless, maintaining a balanced intake of dietary omega-3 and omega-6 fats remains important for overall cardiovascular health [5].
Highly efficient conversion of plant-based omega-3s; Typical baseline LDL and total cholesterol levels; Standard blood glucose and HbA1c levels.
Sample genotype: CT (Heterozygous)
Moderate desaturase enzyme activity provides a balanced rate of converting plant-derived fatty acids into active long-chain forms [1]. This intermediate metabolic rate typically maintains adequate levels of essential membrane lipids under normal dietary conditions [1] [2]. Circulating levels of total cholesterol, LDL cholesterol, and triglycerides generally remain at standard baseline values [3]. Similarly, blood glucose and HbA1c levels show typical patterns without significant genetic elevation [4]. While the body retains a reasonable capacity to synthesize active omega-3 and omega-6 fats, dietary intake of both plant and marine fats helps optimize lipid profiles [5]. This balanced genetic profile represents the most common metabolic state in many global populations, offering a stable baseline for cardiovascular health [3].
Moderate conversion of plant-based omega-3s; Typical baseline LDL and total cholesterol levels; Standard blood glucose and HbA1c levels.
Sample genotype: TT (Homozygous)
Significantly reduced desaturase enzyme activity limits the body's ability to convert plant-based omega-3 and omega-6 fats into active long-chain forms [1]. This metabolic bottleneck often results in lower levels of arachidonic acid and DHA in cell membranes [1] [2]. To compensate, obtaining pre-formed long-chain omega-3s directly from marine sources or supplements is highly beneficial [1]. On the positive side, this reduced metabolic throughput strongly correlates with lower circulating levels of total and LDL cholesterol [3]. Blood glucose and HbA1c levels also tend to be lower, which may offer some metabolic advantages [4]. However, these benefits are accompanied by a tendency toward higher circulating triglycerides [3]. This unique lipid profile was heavily selected for in Arctic populations adapting to marine-rich diets [5].
Inefficient conversion of plant-based omega-3s; Lower circulating LDL and total cholesterol; Higher circulating triglycerides.
Variants with shared genetic architecture
rs174574 · FADS2 Gene · Chr 11 · Fatty Acid Metabolism
rs99780 · FADS2 Gene · Chr 11 · Omega-3 Metabolism
rs1535 · FADS2 Gene · Chr 11 · Fatty Acid Metabolism
Genetic variation in lipid desaturases and its impact on the development of human disease.
Loci influencing lipid levels and coronary heart disease risk in 16 European population cohorts.
Content updated August 2026.
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