FADS2 rs174570: PUFA Metabolism and Lipid Balance
The rs174570 variant is a single-nucleotide polymorphism located in an intronic region of the fatty acid desaturase 2 (FADS2) gene on chromosome 11. It is statistically associated with modest variations in endogenous desaturase enzyme activity and the resulting balance of circulating polyunsaturated fatty acids (PUFAs). Scientific evidence evaluating rs174570 is currently classified as limited, showing complex gene-diet interactions across diverse populations rather than direct clinical diagnostic outcomes.
What each genotype means
Higher desaturase enzyme activity
This genotype is associated with higher expression levels of the FADS1 and FADS2 enzymes, which play a key role in converting dietary fats into long-chain polyunsaturated fatty acids. Research suggests this may influence your plasma fatty acid profile, though the clinical significance of these variations remains a subject of ongoing study.
This is the major genotype in most global populations, carried by the majority of individuals.
Intermediate desaturase enzyme activity
Carrying one copy of the minor allele is associated with intermediate levels of FADS1 and FADS2 enzyme expression compared to those with two copies of the major allele. This variation may influence how your body processes specific dietary fats, but individual responses can vary significantly based on diet and other genetic factors.
This heterozygous genotype is common, appearing in roughly 30-40% of many populations.
Lower desaturase enzyme activity
This genotype is associated with decreased expression levels of the FADS1 and FADS2 enzymes, which may impact the efficiency of your body's conversion of certain fatty acids. Some studies have linked this variant to differences in systemic inflammatory markers or metabolic traits, though these associations are complex and not diagnostic of any specific health condition.
The minor allele (T) has a frequency of approximately 20-35% globally, making this homozygous genotype less common than the others.
Genetic Location and Variant Overview
The single-nucleotide polymorphism rs174570 sits in intron 1 of the FADS2 gene on human chromosome 11. At this specific genomic locus, the DNA sequence commonly features either a cytosine (C) or a thymine (T) nucleotide. Because rs174570 resides in a non-coding region, it does not alter the primary amino acid sequence of the resulting protein. Instead, functional and genomic studies suggest that this variant operates as a regulatory marker. Expression quantitative trait locus (eQTL) and methylation quantitative trait locus (mQTL) investigations have linked the minor T allele with altered DNA methylation patterns across the FADS gene cluster, which in turn correlates with reduced transcript expression of both FADS1 and FADS2. Rather than disabling the gene, rs174570 appears to act in concert with surrounding regulatory loci to subtly fine-tune transcriptional activity.
The Role of FADS2 in Lipid Metabolism
The FADS2 gene encodes the delta-6 desaturase (D6D) enzyme, an essential, rate-limiting catalyst in the long-chain polyunsaturated fatty acid biosynthesis pathway. Delta-6 desaturase introduces a double bond into short-chain plant-derived dietary fats, initiating the conversion of alpha-linolenic acid (an omega-3 PUFA) into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as linoleic acid (an omega-6 PUFA) into arachidonic acid (AA). Together with its sister enzyme delta-5 desaturase (encoded by FADS1), FADS2 regulates the rate at which cells synthesize the building blocks for lipid membranes and inflammatory signaling molecules known as eicosanoids. When enzyme activity decreases, the conversion of precursor fatty acids to downstream active forms slows, reshaping the relative proportions of circulating lipids.
Published Scientific Evidence and Associations
Genome-wide and candidate gene association studies have linked rs174570 to subtle shifts in plasma and erythrocyte fatty acid levels. In particular, carrying the minor T allele has been associated with reduced conversion efficiency along desaturation cascades, which frequently manifests as lower levels of arachidonic acid and higher ratios of dietary precursor fats. Some cohorts also report that the variant modifies how serum lipid panels or fasting glucose respond to dietary intake of polyunsaturated fats. However, the overall strength of evidence for rs174570 directly impacting distinct clinical endpoints remains limited. Many reported associations are modest, depend on background dietary habits, and are complicated by high linkage disequilibrium across the entire FADS1-FADS2-FADS3 gene cluster, making it difficult to isolate the exact independent causal variant.
Population Frequency and Evolutionary Context
The minor T allele of rs174570 exhibits a minor allele frequency typically ranging between 0.20 and 0.35 across most global populations. Genomic studies have revealed significant ancestral divergence across the broader FADS locus, which has been subject to natural selection driven by historical dietary shifts. Ancestral hunter-gatherer populations adapted to diets rich in marine fats often developed lower endogenous conversion capacities, while agricultural populations that relied on plant seeds typically favored alleles promoting higher baseline desaturase activity. Consequently, the distribution of FADS genotypes varies considerably among European, East Asian, indigenous Arctic, and African-descent groups, highlighting how ancestral dietary pressures shaped human polyunsaturated fatty acid processing.
Interpreting Your Results Responsibly
Understanding your rs174570 genotype provides educational context regarding baseline tendencies in polyunsaturated fatty acid conversion, but it cannot diagnose any disease or predict personal health outcomes. Because human lipid profiles and inflammatory responses reflect the combined effects of overall diet, physical activity, and dozens of genetic loci, no single intronic variant dictates nutritional status. Knowing your genotype does not mean you must take targeted supplements or restrict particular foods. Individuals interested in how their nutritional intake affects blood lipids or overall health should discuss comprehensive lipid testing and dietary habits with a physician or registered dietitian rather than making medical choices based on a single SNP.
How common is this variant?
The minor T allele of rs174570 maintains a minor allele frequency of approximately 0.20 to 0.35 across global populations, with heterozygous and minor homozygous genotypes showing varying prevalence depending on ancestral background.
Frequently asked questions
What is the primary function of the FADS2 gene?
The FADS2 gene provides instructions for making delta-6 desaturase, an enzyme that introduces double bonds into polyunsaturated fatty acids. This enzymatic step is essential for converting plant-based fatty acids into active long-chain forms such as arachidonic acid and docosahexaenoic acid (DHA).
Does having the rs174570 T allele cause a fatty acid deficiency?
No, having the T allele does not cause a clinical fatty acid deficiency. Studies show that it is only associated with modest statistical variations in enzyme expression and lipid conversion rates, with actual fatty acid levels remaining predominantly shaped by diet.
Can rs174570 tell me if I need to take omega-3 supplements?
No, this genetic variant cannot determine whether you need fish oil or omega-3 dietary supplements. Decisions regarding nutritional supplementation should be based on your overall dietary intake, direct lipid panel measurements, and consultation with a healthcare professional.
Why is the scientific evidence for rs174570 rated as limited?
The evidence is considered limited because rs174570 sits in a dense cluster of highly linked variants, making it challenging to isolate its specific biological effect. Additionally, observed associations between this variant and health traits vary widely across different dietary patterns and ancestral populations.
Sources & further reading
Educational information only, last refreshed 9/5/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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