Vegetarian Diet + Letrozole
Letrozole brand name: Femara.
We found no known interaction between Vegetarian Diet and Letrozole in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.
Vegetarian Diet and Letrozole
We checked these two against our interaction database. Here is what we found.
No Known Interaction Found
We did not find a documented interaction between Letrozole and Vegetarian Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Vegetarian Diet alongside specific medications may be limited.
Worth understanding: our licensed dataset holds no drug-interaction record for Vegetarian Diet at all — not against Letrozole, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.
Vegetarian Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. Do not stop a prescribed medicine on your own.
Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.
Vegetarian Diet safety at a glance
Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Vegetarian Diet in Pregnancy & Breastfeeding
When used appropriately. A position statement from the Academy of Nutrition and Dietetics indicates that a nutritionally adequate vegetarian diet is appropriate during pregnancy and lactation. Following a vegetarian diet when pregnant or lactating should not pose a risk to the child as long as nutritional needs are met. Nutrients of concern may include omega-3 fatty acids, iron, zinc, calcium, vitamin D, and vitamin B12. Additionally, one small observational study has found that consuming a vegetarian diet during pregnancy is not associated with lower cognitive function, as measured by intelligence quotient (IQ), in the child at 6-7 years of age. Although some observational research has found an association between consuming a vegetarian diet during pregnancy and an increased risk for low birth weight or small for gestational age (SGA), most research has not accounted for diet variability or adherence or controlled for nutritional status or body mass index. When specific vegetarian diets are examined, only a vegan diet, not a lacto-ovo-vegetarian diet, has been associated with an increased risk of SGA or low birth weight.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center
What Letrozole Is Prescribed For, and What Vegetarian Diet Has Been Studied For
These two come up together because they touch the same health topic — not because they do the same job. Letrozole is a prescription medicine with approved uses on its FDA label. Vegetarian Diet is an eating pattern: what follows is what researchers have looked at it for, and how strong that evidence is.
Letrozole is prescribed for: Letrozole (brand name Femara) is used to treat breast cancer in postmenopausal women whose tumors are driven by estrogen. It is used in three settings: as adjuvant (after-surgery) treatment for hormone receptor positive early breast cancer; as extended adjuvant treatment for women who have already completed about five years of tamoxifen therapy; and as first- or second-line treatment for locally advanced or metastatic (spread) breast cancer. Femara is specifically indicated for first-line treatment of hormone receptor positive or receptor-unknown locally advanced or metastatic breast cancer, and for advanced breast cancer in women whose disease has progressed after antiestrogen therapy.
Vegetarian Diet has been studied for:
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Cancer studied, not established Vegetarian Diet has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows
Vegetarian Diet for cancer
It is unclear if following a vegetarian diet is beneficial for preventing various forms of cancer.
Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Letrozole on your own; if you are taking Vegetarian Diet for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.
Questions About Vegetarian Diet or Letrozole
These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Vegetarian Diet or Letrozole, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:
Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.
See Every Supplement That Interacts With Letrozole
This page covers Vegetarian Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Letrozole page lists 142 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), 7-methoxyflavone (moderate) and Acacia Rigidula (moderate).
By severity: 3 major · 99 moderate · 40 minor.
From our pharmacist’s overview on the Letrozole page
“Letrozole (Femara) is prescribed to keep hormone-driven breast cancer from returning, so a supplement that shifts its blood level can quietly undercut treatment. Give this list of 142 ingredients genuine respect, and learn the three major entries first.”
Reviewed by 2 · Jul 18, 2026
Where Vegetarian Diet and Letrozole Sit Against Everything Else
Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.
#1,011 of 1,452 supplements looked up here in the last 7 days
#48 of 2,830 medications looked up here in the last 7 days
Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.
Where does our data come from?
- Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
- Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Vegetarian Diet reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Vegetarian Diet and Letrozole records this page draws on were last updated July 10, 2026.
- What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
About Vegetarian Diet
What is Vegetarian Diet?
- Heart health
- Weight management
- Blood sugar control
- Lowering cholesterol
- Ethical or environmental reasons
- General wellness
A vegetarian diet emphasizes plant foods and avoids meat, and when well-planned it is linked with lower risks of heart disease, high blood pressure, and type 2 diabetes. It can be very healthy but needs attention to certain nutrients like vitamin B12, iron, and protein. Talk with a doctor or dietitian before making major dietary changes, especially if you are pregnant, nursing, or have a health condition.
Whole-food eating pattern (no specific product form)
An interaction check asks whether these two react with each other — it does not ask whether Vegetarian Diet is a good idea for someone in your situation. Here is what our Vegetarian Diet record says about it on its own.
Vegetarian Diet: dosing
There is no "dose" for a vegetarian diet. Instead, the goal is a balanced, varied eating pattern built around vegetables, fruits, whole grains, beans and lentils, nuts, seeds, and (if included) dairy and eggs.Many vegetarians, especially vegans, benefit from a vitamin B12 supplement or B12-fortified foods. Some also need iron, vitamin D, calcium, or omega-3 supplements depending on their individual needs and lab results.
From our Vegetarian Diet monograph — the full record covers uses, side effects and every documented interaction.
About Letrozole
What Is Letrozole Used For?
Brand name: Femara
Letrozole (brand name Femara) is used to treat breast cancer in postmenopausal women whose tumors are driven by estrogen. It is used in three settings: as adjuvant (after-surgery) treatment for hormone receptor positive early breast cancer; as extended adjuvant treatment for women who have already completed about five years of tamoxifen therapy; and as first- or second-line treatment for locally advanced or metastatic (spread) breast cancer.
Femara is specifically indicated for first-line treatment of hormone receptor positive or receptor-unknown locally advanced or metastatic breast cancer, and for advanced breast cancer in women whose disease has progressed after antiestrogen therapy.
Other Drugs & Vegetarian Diet
Browse every other medication we’ve checked against Vegetarian Diet — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
No interaction 2,829 drugs checked — show the list
We also checked Vegetarian Diet against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Acetaminophen ›
- Tadalafil ›
- Clopidogrel ›
- Atorvastatin ›
- Docusate ›
- Valacyclovir ›
- Hydroxyurea ›
- Abemaciclib ›
- Ibuprofen ›
- Methamphetamine ›
- Sumatriptan ›
- Semaglutide ›
- Warfarin Sodium ›
- Tirzepatide ›
- Prednisone ›
- Propranolol ›
- Bupropion ›
- Metformin ›
- Lisdexamfetamine ›
- Amoxicillin ›
- Acyclovir ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Methotrexate ›
- Fluoxetine ›
- Lamotrigine ›
- Amphetamine ›
- Gabapentin ›
- Pregabalin ›
- Acetaminophen, Codeine ›
- Azithromycin ›
- Dextroamphetamine ›
- Isotretinoin ›
- Clonazepam ›
- Omeprazole ›
- Quetiapine ›
- Methylene Blue ›
- Duloxetine ›
- Amlodipine Besylate ›
- Buspirone ›
- Citalopram ›
- Naproxen ›
- Ciprofloxacin ›
- Bisoprolol ›
Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Vegetarian Diet list.
Vegetarian Diet References
The 11 references that drive our Vegetarian Diet monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.
- Foster M, Herulah UN, Prasad A, Petocz P, Samman S. Zinc Status of Vegetarians during Pregnancy: A Systematic Review of Observational Studies and Meta-Analysis of Zinc Intake. Nutrients. 2015 Jun 5;7(6):4512-25. PubMed
- Ho-Pham LT, Nguyen ND, Nguyen TV. Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis. Am J Clin Nutr. 2009;90(4):943-50. PubMed
- Majchrzak D, Singer I, Männer M, et al. B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans. Ann Nutr Metab. 2006;50(6):485-91. PubMed
- Institute of Medicine (US) Panel on Micronutrients. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington (DC): National Academies Press (
- Crozier SR, Godfrey KM, Calder PC, et al. Vegetarian Diet during Pregnancy Is Not Associated with Poorer Cognitive Performance in Children at Age 6-7 Years. Nutrients. 2019;11(12):3029. PubMed
- Iguacel I, Miguel-Berges ML, Gómez-Bruton A, Moreno LA, Julián C. Veganism, vegetarianism, bone mineral density, and fracture risk: a systematic review and meta-analysis. Nutr Rev. 2019;77(1):1-18. PubMed
- Tan C, Zhao Y, Wang S. Is a vegetarian diet safe to follow during pregnancy? A systematic review and meta-analysis of observational studies. Crit Rev Food Sci Nutr. 2019;59(16):2586-2596. PubMed
- Yisahak SF, Hinkle SN, Mumford SL, et al. Vegetarian diets during pregnancy, and maternal and neonatal outcomes. Int J Epidemiol 2021;50(1):165-178. PubMed
- Avnon T, Paz Dubinsky E, Lavie I, Ben-Mayor Bashi T, Anbar R, Yogev Y. The impact of a vegan diet on pregnancy outcomes. J Perinatol 2021;41(5):1129-1133. PubMed
- Kesary Y, Avital K, Hiersch L. Maternal plant-based diet during gestation and pregnancy outcomes. Arch Gynecol Obstet 2020;302(4):887-898. PubMed
- Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016;116(12):1970-1980. PubMed
Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
Following Vegetarian Diet While Taking Letrozole: Common Questions
Is it safe to follow Vegetarian Diet while taking Letrozole?
Are Vegetarian Diet and Letrozole used for the same thing?
Does Letrozole interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.