Why Should Providers Evaluate 2OH/4OH and 2OH/16OH Ratios to Understand Estrogen Detox? 

How one metabolizes estrogen can influence their signs and symptoms of estrogen excess, severity of estrogen-related conditions, and cancer risk. Thus, assessing a person’s estrogen metabolism patterns can be helpful in improving their hormone-related health. Estrogen detox includes phase I, phase II, and phase III metabolism. The DUTCH Test measures five phase I metabolites (2-OH-E1, 2-OH-E2, 4-OH-E1, 4-OH-E2, and 16-OH-E2) and one phase II metabolite (2-Methoxy-E1) and calculates two very important ratios: the 2OH/4OH ratio and 2OH/16OH ratio. This blog covers the importance of assessing the 2OH/4OH and 2OH/16OH ratios and provides potential support considerations for suboptimal ratios from a functional medicine perspective.  

What are the 2-OH, 4-OH, and 16-OH-E1 metabolites? 

During phase I, estrone (E1) and estradiol (E2) are hydroxylated into 2-OH, 4-OH, and 16-OH metabolites.  

All these phase I metabolites have oxidative, or damaging, potential; however, some are more damaging than others. When evaluating phase I metabolism, it is important to look at the ratios of 2OH/4OH and 2OH/16OH to see which pathways are metabolically preferred. 

2-OH Metabolites 

• CYP1a1 is the enzyme responsible for the metabolism of E1 to 2-OH-E1 and E2 to 2-OH-E2.  
• This is the preferred pathway because 2-OH-E1 is the most stable of the three phase 1 estrogen metabolites measured on the DUTCH Test.  

4-OH Metabolites 

• CYP1b1 is the enzyme responsible for the metabolism of E1 to 4-OH-E1 and E2 to 4-OH-E2.  
• This pathway is considered the most genotoxic as the 4-OH estrogen metabolites can become reactive quinones that have the potential to bind to DNA and form damaging (unstable) depurating adducts, that may increase risk for cancer, such as breast and prostate cancer. 

16-OH-E1 Metabolites 

• CYP3a4 is the enzyme responsible for the metabolism of E1 to 16-OH-E1, and E2 to 16-OH-E2 (i.e., estriol).
• 16-OH-E1 is a proliferative estrogen, although less biologically active than estradiol.
• Elevations in 16-OH-E1 may exacerbate estrogen excess symptoms and can contribute to estrogen sensitive tissue proliferation (breast, endometrial, prostate, etc.).
• 16-OH-E2 (also known as E3, or estriol) is a safer estrogen metabolite, as it is a very weak estrogen and may have protective properties.
• Both 16-OH-E1 and 16-OH-E2 are important for bone health.

What are the 2OH/4OH and 2OH/16OH ratios? 

The 2OH/4OH and 2OH/16OH ratios allow a provider to assess whether their patient has a 2-OH (preferred), 4-OH (potentially damaging and carcinogenic), and/or 16-OH-E1 (proliferative) preference.

As a person’s preference can influence their signs and symptoms of estrogen excess, severity of estrogen-related conditions, and cancer risk, it is important to look at these ratios when assessing phase 1 estrogen detox.

The 2OH/4OH Ratio 

A low 2OH/4OH ratio, as seen in the slider below, indicates a preference for the more damaging 4-OH pathway. 

Recall that the 4-OH metabolites can increase risk for certain cancers, such as breast and prostate cancer, through their DNA-damaging effect. In fact, CYP1B1 activity can be high in the breast tissue - not great for breast cancer risk! 

In their 2019 study, Miao, et al state, “Among many alterations of sex hormone metabolisms, 4-hydroxy estrogen (4-OH-E) metabolite was found to be significantly increased in the urine samples of patients with breast cancer compared with the normal healthy controls. This was the most important risk factor for breast cancer.” 

Moreover, the 2010 Cavalieri EL, et al. study below showed that the level of depurinating estrogen DNA-adducts in the urine of women with breast cancer and women at high risk of breast cancer were significantly elevated compared to that of healthy women.  

2OH/16OH Ratio 

A low 2OH/16OH ratio, as seen in the slider below, indicates a preference for the more proliferative 16-OH-E1 pathway. 

Recall that the 16-OH-E1 estrogen metabolites are proliferative (cause tissue growth), thus, anecdotally we see elevated 16-OH-E1 levels associated with proliferative conditions such as heavy bleeding, breast tenderness, endometriosis, and fibroids. Moreover, due to its proliferative nature, a 16 preference may not be ideal for women with a history of estrogen-sensitive breast cancer, as a 16 preference may increase the rate of cancer recurrence. A 16-OH-E1 preference is not always a bad thing, however; because it is proliferative, a 16 preference may be beneficial for bone health.

The importance of assessing both the 2-OH, 4-OH, and 16-OH-E1 values and 2OH/4OH and 2OH/16OH ratios 

It is important to assess both the values of 2-OH, 4-OH and 16-OH-E1 (by looking at the dials), and the 2OH/4OH and 2OH/16OH ratios. For example, in a postmenopausal woman with low estrogen - if the 2OH/4OH ratio is low (indicating a preference for the more damaging 4-OH pathway), however, the 4-OH value is at the low end of the postmenopausal range, then the low ratio may not be as concerning.

On the other hand, in a woman with estrogen excess – despite having an optimal 2OH/4OH ratio – if the 4-OH value is above range because of high levels of estrogen in the body, there is still concern for potential DNA damage from elevated 4-OH metabolites.

Potential support considerations if the 2OH/4OH and/or 2OH/16OH ratios are low 

Sulforaphane 

Sulforaphane helps to prevent DNA damage by estrogen quinones and semi-quinones. It does this by improving the detox of phase I estrogens through supporting phase II reactions like sulfation, glucuronidation, and methylation. Sulforaphane also activates antioxidant pathways, such as Nrf2/ARE pathways which regulate glutathione. Glutathione can help “quench” the reactive quinones and clear them out before they are able to cause DNA damage.

Lastly, sulforaphane activates quinone reductase. Quinone reductase is an enzyme that “reduces” the reactive quinones back into their 4-OH estrogen catechol form. Once back into the catechol form, they will hopefully be readily methylation instead of becoming a reactive free radical again.

Broccoli sprouts are one of the best sources of sulforaphane. They have high concentrations of glucoraphanin that is converted to sulforaphane by the myrosinase enzyme once the sprouts are crushed.

NAC and Resveratrol 

N-acetylcysteine (NAC) and resveratrol are both antioxidants that can decrease DNA damage in the breast tissue and reduce the malignant transformation of cultured breast epithelial cells. Resveratrol, in particular, has been shown to inhibit CYP1b1 (decreases 4-OH production and improves the 2OH/4OH ratio), inhibit CYP3a4 (decreases 16-OH-E1 production and improves the 2OH/16OH ratio), induce oxidative pathways such as Nrf2, and induce quinone reductase which may help reduce estrogen semi-quinones back into catechol estrogens.

Consider avoiding things that increase (i.e., induce) CYP1b1 and CYP3a4 enzymatic activity 

Recall that CYP1b1 is the enzyme that converts estrogen to the 4-OH metabolites and CYP3a4 is the enzyme that converts estrone (E1) to the 16-OH-E1 metabolite, and estradiol (E2) to estriol (E3). CYP1b1 inducers include inflammation, polycyclic aromatic hydrocarbons (PAHs), xenoestrogens, alcohol, and smoking. CYP3a4 inducers include St. John’s wort, pesticides, caffeine, excess omega-6 fatty acid consumption, inflammatory cytokines (especially in the gut), smoking, polycyclic aromatic hydrocarbons (PAHs), alcohol, obesity, and hypothyroidism. Note that as CYP3a4 is a major detox enzyme,and helps to metabolize and clear out other waste products and pharmaceuticals from the body,  induce or inhibit CYP3A4 activity with caution.

Consider supporting CYP1a1 activity and the preferred 2-OH pathway 

Consider adding in things that increase CYP1a1 enzymatic activity such as cruciferous vegetables, carrot (apiaceae) family vegetables, rosemary, ground flaxseeds, organic non-GMO soy, fish oil, and diindolylmethane/indole-3-carbinol (DIM/I3C). Note that, clinically, we tend to see DIM and I3C lower E1 and E2 which may not be appropriate for every person. When using DIM and/or I3C, it is important that phase II detoxification is well supported so that the phase I metabolites do not build up in the body and cause oxidative damage. If on Tamoxifen, note that DIM and I3C may render Tamoxifen less effective.

Ways to support phase II estrogen detoxification 

The phase II estrogen detoxification pathways are important for converting reactive phase I metabolites into water-soluble, inactive phase II estrogen metabolites that can no longer damage DNA. 

Supporting phase II detox of the 2-OH and 4-OH metabolites 

• The 2-OH and 4-OH estrogen metabolites are cleared out in phase II primarily through methylation, which is carried out by the catechol-o-methyltransferase (COMT) enzyme.  
• Sluggish methylation can be due to genetics (COMT, MTHFR, etc.), epigenetics (environmental or lifestyle factors that affect gene expression), and/or decreased precursors.  
• Methylation support may include active B vitamins, magnesium, choline, trimethylglycine (TMG), methionine, zinc, and SAMe. 
   

Supporting phase II detox of the 16-OH-E1 metabolites 

• The 16-OH-E1 estrogen metabolites are cleared out in phase II primarily through glucuronidation and sulfation.  
• Sulfation support includes supplementing with the cofactor molybdenum and sulfur donors such as methionine, NAC, methylsulfonylmethane (MSM), taurine, sulforaphane, glutathione, and/or sulfurous vegetables such as onions, garlic, eggs, brassicas, asparagus, arugula, etc.  
• In addition, consider assessing inflammation and thyroid function, as inflammation and hypothyroidism may be associated with poor sulfation.  
• Glucuronidation support may include sulforaphane, citrus fruits, quercetin, curcumin, and calcium-d-glucurate. 

Also consider supporting phase III elimination through the stool 

Phase III of estrogen detox via the bile/stool is required for the continued detoxification of estrogens. Poor phase III detox can cause estrogens and metabolites to recirculate back into the body, increasing the opportunity for DNA damage.

Conclusion 

In conclusion, because estrogen detoxification preferences can influence estrogen’s activity in the body, the severity of estrogen-related conditions, and cancer risk, assessing a person’s estrogen metabolism patterns with a DUTCH Test may be helpful in improving their hormone-related health. The DUTCH panels that measure the phase I and phase II metabolites and display the 2OH/4OH and 2OH/16OH ratios include the DUTCH Complete, DUTCH Plus, and DUTCH Sex Hormone panels.

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