What you carry at this position in your DNA and what research says about it.
Omega Fatty Acid Processing: 4/10 evidence, 17 publications.
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Sample genotype (not yours): C/C
Efficient Fatty Acid Conversion and Higher Triglycerides
Highly efficient conversion of plant-based fats into active omega fatty acids characterizes this profile. However, it is also associated with slightly higher circulating triglyceride levels.
What this genotype means: Highly efficient synthesis of long-chain omega fatty acids; Slightly elevated circulating triglyceride levels; Stronger historical link to breastfeeding-related cognitive benefits.
Sample genotype (not yours): C/G
Typical Fatty Acid Conversion and Average Triglycerides
A balanced, intermediate metabolic profile characterizes this combination, keeping fatty acid conversion efficiency and triglyceride levels near the population average. Most people carry this balanced genetic setup.
What this genotype means: Standard rate of plant-based omega fatty acid conversion; Typical circulating triglyceride levels; Moderate genetic influence on lipid profiles.
Sample genotype (not yours): G/G
Slower Fatty Acid Conversion and Lower Triglycerides
Slower conversion of plant-based fats into active omega fatty acids is characteristic of this profile. However, it offers a beneficial link to lower circulating triglyceride levels.
What this genotype means: Reduced conversion of plant-based omega precursors; Lower circulating triglyceride levels; Greater dietary reliance on preformed DHA and EPA.
Gene function and biological role
Gene Function: The FADS2 gene encodes fatty acid desaturase 2, a key enzyme responsible for converting short-chain dietary fatty acids into long-chain polyunsaturated fatty acids (LC-PUFAs) [1]. These LC-PUFAs, including arachidonic acid and docosahexaenoic acid (DHA), are critical components of cell membranes and are highly concentrated in the brain [2]. FADS2 regulates the rate-limiting steps in both the omega-3 and omega-6 metabolic pathways [1]. Variations in this gene can significantly alter how efficiently a person synthesizes these essential fats from plant-based precursors [2].
Variant Impact: The rs174575 variant is located within an intron of the FADS2 gene and acts as a major genetic determinant of fatty acid desaturase activity [1]. Carrying the major C allele is associated with highly efficient conversion of precursor fatty acids into long-chain active forms like arachidonic acid [2]. Conversely, the minor G allele is linked to reduced enzyme activity, leading to a slower conversion rate and a distinct profile of circulating lipids [2]. This genetic difference has also been widely studied for its potential role in modulating how infant diet, particularly breastfeeding, influences early cognitive development [3].
Key Insight: Your ability to process plant-based omega-3s into brain-essential fats is highly dependent on this single genetic letter, making direct dietary intake of fish oil or algae oil much more important for some genotypes than others.
Location: FADS2. Chromosome 11 · 11q12.2 · 61.8 Mb
Origin Story: A dramatic increase in the frequency of the high-efficiency C allele occurred in early European populations as they transitioned from hunter-gatherer diets to agriculture, allowing them to survive on plant-based diets low in preformed marine omega fatty acids.
Estimated prevalence by population
Global 57.4%; European 55.1%; African 60.3%; East Asian 72.1%; South Asian 76.5%; Americas 47.0%; Ashkenazi 59.2%; Finnish 60.4%; Middle Eastern 46.3%; Amish 56.7%.
Estimated CC genotype frequency.
Global 36.5%; European 38.3%; African 34.7%; East Asian 25.6%; South Asian 21.9%; Americas 43.1%; Ashkenazi 35.5%; Finnish 34.6%; Middle Eastern 43.5%; Amish 37.2%.
Estimated CG genotype frequency.
Global 6.1%; European 6.7%; African 5.0%; East Asian 2.3%; South Asian 1.6%; Americas 9.9%; Ashkenazi 5.3%; Finnish 5.0%; Middle Eastern 10.2%; Amish 6.1%.
Estimated GG genotype frequency.
Showing effects for C/C genotype
Nutrition & Metabolism
Macronutrient Metabolism
Fatty Acid Conversion. Evidence: 3/10. Source: PMID 18936223. Efficient Conversion.
Cardiovascular & Metabolic
Lipids & Cholesterol
Triglycerides. Evidence: 4/10. Source: PMID 35393526. Higher Levels.
Neurology & Mental Health
Neurodevelopmental Traits
Breastfeeding and Cognition. Evidence: 3/10. Source: PMID 23737301. Associated.
Showing effects for C/G genotype
Fatty Acid Conversion. Evidence: 3/10. Source: PMID 18936223. Moderate Conversion.
Triglycerides. Evidence: 4/10. Source: PMID 35393526. Typical Levels.
Showing effects for G/G genotype
Fatty Acid Conversion. Evidence: 3/10. Source: PMID 18936223. Slower Conversion.
Triglycerides. Evidence: 4/10. Source: PMID 35393526. Lower Levels.
Breastfeeding and Cognition. Evidence: 3/10. Source: PMID 23737301. No Association.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
High efficiency of the FADS2 enzyme is typical for those with two copies of the C allele [1]. This allows the body to readily convert plant-derived alpha-linolenic acid (ALA) and linoleic acid into active, long-chain polyunsaturated fatty acids like arachidonic acid [1]. While this efficient synthesis is beneficial, particularly if the diet is low in seafood, it comes with a trade-off. Large-scale genetic studies show that the C allele is associated with higher circulating levels of triglycerides [2]. Additionally, historical research suggested that infants with this genotype might experience a more pronounced cognitive benefit from breastfeeding, though subsequent replication studies have yielded highly conflicting results [3].
Highly efficient synthesis of long-chain omega fatty acids; Slightly elevated circulating triglyceride levels; Stronger historical link to breastfeeding-related cognitive benefits.
Sample genotype: CG (Heterozygous)
A balanced, intermediate level of FADS2 desaturase activity is maintained by this heterozygous combination [1]. Precursor fatty acids from plant sources are converted into active long-chain forms at a typical rate, maintaining standard levels of arachidonic acid and other key lipids [1]. Predisposition for circulating triglycerides is also near the population average [2]. In terms of early development, children with this genotype were grouped with C/C carriers in early studies showing a cognitive boost from breastfeeding, but the scientific consensus remains unresolved due to mixed replication efforts [3].
Standard rate of plant-based omega fatty acid conversion; Typical circulating triglyceride levels; Moderate genetic influence on lipid profiles.
Sample genotype: GG (Homozygous)
Reduced activity of the FADS2 enzyme is associated with this homozygous G profile [1]. This slower desaturation rate means the body is less efficient at converting plant-based omega-3 and omega-6 precursors into active long-chain fatty acids like arachidonic acid [1]. Consequently, there may be a greater reliance on obtaining preformed long-chain fats, such as DHA and EPA, directly from dietary sources like cold-water fish or algae supplements [2]. On the positive side, this genotype is consistently linked to lower circulating triglyceride levels, which is favorable for cardiovascular health [3]. Early pediatric studies suggested that G/G infants did not show the same cognitive sensitivity to breastfeeding as C-carriers, but overall evidence for this interaction remains mixed [4].
Reduced conversion of plant-based omega precursors; Lower circulating triglyceride levels; Greater dietary reliance on preformed DHA and EPA.
Variants with shared genetic architecture
rs174570 · FADS2 Gene · Chr 11 · Fatty Acid Metabolism
rs174574 · FADS2 Gene · Chr 11 · Fatty Acid Metabolism
rs99780 · FADS2 Gene · Chr 11 · Omega-3 Metabolism
Genetic variation in lipid desaturases and its impact on the development of human disease.
An Amish founder population reveals rare-population genetic determinants of the human lipidome.
Content updated August 2026.
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