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.
Genetic variants in the CYP1A1 gene are linked to a number of different health conditions, including an increased risk for estrogen-related cancers and increased risk for lung cancer in smokers.
Everything you eat or take (like a medication) is absorbed in the intestines and taken to the liver.
The CYP450 (cytochrome P450) family of enzymes metabolize or break down thousand of different compounds. CYP1A1 is one member of the CYP family.
CYP1A1 is an NADPH dependent enzyme. Breaks down caffeine, theobromine,
There are several genetic variants of CYP1A1 that can change the speed at which your body will metabolize substances.
CYP1A1*2: increased enzyme activity
Check your genetic data for rs1048943 A2455G (23andMe v.4 only):
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:
The CYP1A1*4 variant has a somewhat increased enzyme activity.
Check your genetic data for rs1799814 A2452C (23andMe v.4, v.5; AncestryDNA):
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):
Members: Your genotype for rs2606345 is —.
Check your genetic data for rs2472297 (23andMe v4, v5; AncestryDNA):
Members: Your genotype for rs2472297 is —.
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.
CYP1A1 is inhibited by several natural polyphenols including St. John’s Wort, I3C, and resveratrol.[ref] Foods containing I3C include broccoli and other cruciferous vegetables. Resveratrol is found in grapes and red wine as well as in supplement form.
Inhibiting CYP1A1 may help increase the aryl hydrocarbon receptors, which bind to PAHs and theoretically could decrease cancer risk. [ref]
Camel milk inhibits CYP1A1.
Interestingly, camel milk has traditionally been thought to be protective against cancer in the Middle East. Researchers found that smokers with CYP1A1*2 variants who drink camel milk reduce the high risk of lung cancer.[ref]
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]
Originally published 6/15. Updated 06/20.