CYP1A1 is a gene that codes for an enzyme that breaks down (metabolizes) a few different toxins as well as naturally produced hormones. It is also involved in immune response in the intestines.
Contents:
CYP1A1 and Metabolism of Estrogen, Cigarette Smoke, and More
Genetic variants in the CYP1A1 gene are linked to a number of different health conditions, including an increased risk for estrogen-related cancers and an increased risk for lung cancer in smokers.
A quick overview of phase I detoxification :
Everything you eat or take (like a medication) is absorbed in the intestines and taken to the liver.
- This allows the liver to detoxify anything harmful that you’ve eaten and it also transforms nutrients into forms that you need.
- Fat-soluble toxins are made water-soluble.
- Then the toxin can be transformed and eliminated (mainly through the kidneys).
CYP1A1 gene:
The CYP450 (cytochrome P450) family of enzymes metabolize or break down thousands of different compounds. CYP1A1 is one member of the CYP family. (Learn more about other detoxification genes.)
- The CYP1A1 enzyme involved in the metabolism of poly-aromatic hydrocarbons (PAH) in the intestines, thus playing a role in smoking-related cancers from the activation of the aromatic hydrocarbons. Aromatic hydrocarbons are also found in wood smoke, vehicle exhausts, asphalt, and charred meats.
- In addition to toxins we may breathe in or eat, CYP1A1 is also involved in the metabolism of estrogen – specifically 17β-estradiol – as well as arachidonic acid and DHA (fatty acids).
- New research points to a role in immune homeostasis in the intestines.[ref]
CYP1A1 is an NADPH-dependent enzyme. Breaks down caffeine, theobromine,
Fast and slow CYP1A1 metabolism:
There are several genetic variants of CYP1A1 that can change the speed at which your body will metabolize substances.
- Increased CYP1A1 metabolism can cause the buildup of the intermediate metabolites if your body can’t get rid of them fast enough through phase II metabolism.
- Increased CYP1A1 activity can also increase the degradation of the aryl hydrocarbon receptor, which is an important mechanism for binding poly-aromatic hydrocarbons.[ref]
CYP1A1 Genetic Variants:
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CYP1A1*2: increased enzyme activity
Check your genetic data for rs1048943 A2455G (23andMe v.4 only)
- T/T: typical
- C/T: carrier of one CYP1A1*2 allele; smokers have a higher risk of lung cancers; higher activity in estrogen metabolism
- C/C: CYP1A1*2; higher risk of oral cancer & lung cancers in smokers; higher activity in estrogen metabolism[ref][ref][ref]
Members: Your genotype for rs1048943 is —.
Studies on CYP1A1*2 show a link to estrogen-related cancers, but the results vary according to population and possibly diet:
- A study in China showed that the CYP1A1*2 polymorphism had a lower risk of breast cancer.[ref]
- Another study showed that those with CYP1A1*2 had more inhibition with natural polyphenols (high fruit and vegetable diet) than those without the polymorphism.[ref]
- A study showed that CYP1A1*2 has a significantly higher activity level of estrogen metabolism which “may either increase or reduce the susceptibility to cancer depending on its combination with other genetic and environmental risk factors…“[ref]
CYP1A1*4 allele:
The CYP1A1*4 variant has a somewhat increased enzyme activity.
Check your genetic data for rs1799814 A2452C (23andMe v.4, v.5; AncestryDNA):
- G/G: typical
- G/T: one CYP1A1*4 allele
- T/T: increased enzyme activity, CYP1A1*4[ref]
Members: Your genotype for rs1799814 is —.
Studies on CYP1A1*4 show it to be protective against certain cancers, and others show it to slightly increase risk depending on the population and diet.[ref][ref][ref] Some studies show that the CYP1A1*4 allele is protective against lung cancer.[ref] A meta-analysis found it to be a risk factor for thyroid cancer.[ref]
Other CYP1A1 alleles:
While the two variants above seem to have the most impact, there are a few other CYP1A1 variants that have been studied for various health effects.
Check your genetic data for rs2606345 (23andMe v4, v5; AncestryDNA):
- C/C typical
- A/C: decreased risk of testicular cancer, decreased risk of pneumonia
- A/A: decreased risk of testicular cancer[ref] decreased risk of pneumonia[ref]
Members: Your genotype for rs2606345 is —.
Check your genetic data for rs2472297 (23andMe v4, v5; AncestryDNA):
- C/C: typical
- C/T: associated with slightly increased coffee consumption
- T/T: associated with increased coffee consumption[ref]
Members: Your genotype for rs2472297 is —.
Lifehacks:
Stop smoking:
People with the CYP1A1*2 allele are at a higher risk for lung cancer and definitely, should avoid cigarette smoke. So if you need yet another reason to stop smoking, this would be a big one.
Eat your veggies:
One study found that people who carry the CYP1A1*2 variant had a greater reduction in colon cancer risk with a diet high in polyphenols (found in veggies and fruit) than those without the variant.[ref]
Grapefruit juice also inhibits CYP1A1.[ref]
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