Grapefruit a no-no with ER/PR positive Ca?
 

I knew about soy and topical lavender having hormonal influence and that it is to be avoided with ER/PR positive cancer. Lately I came across two articles on breast cancer that said grapefruit is also to be avoided. If it truely has significant impact I want to skip grapefruit but if it's a meaningless drop in the bucket I'll keep eating our beautiful Florida grapefruit.

Is there a list floating around here on foods/products that ***truely are meaningful to avoid when fighting breast cancer?****

I have heard many times that sugar feeds cancer but I haven't heard it in conventional medicine circles and it's sure on the menu at the hospital. I know someone fighting cancer who restricts their fruit intake to low sugar fruit like lemons, etc. I eat a LOTof low glycemic fruit with plenty of fructose in my diet but avoid processed sugar for health reasons and weight control. I wonder if it matters or not in the sceme of things. I dont want to be paranoid or unneccessary restrict my diet but do want to be wise. What do you guys think? What kinds of changes have you made in diet since learning you have cancer?


Paula

Re: Grapefruit a no-no with ER/PR positive Ca?
 

Grapefruit needs to be avoided only while on an AI or tamoxifen because it changes the way the drugs are metabolised. Grapefruit does this to many medications and it does so for the antihormonal drugs.

Secondly, grapefruit also affects the way estrogen is metabolized in the body - it affects the enzyme that makes it break down so it lasts longer in the body. I suppose there are implications on this - perhaps a small bc risk?

Re: Grapefruit a no-no with ER/PR positive Ca?
 

I didn't know about avoiding grapefruit if taking AI! Darn.

Re: Grapefruit a no-no with ER/PR positive Ca?
 

Med Pregl. 2010 Nov-Dec;63(11-12):805-10.
[Drug interactions with grapefruit].

[Article in Serbian]
Bojanić ZZ, Bojanić NZ, Bojanić VV.
Source

Institut za farmakologiju i toksikologiju, Medicinski fakultet, Nis. bojaniczoran@gmail.com

Abstract

INTRODUCTION: The concentration of many orally given medications may be affected by grapefruit or grapefruit juice consumption. It may result in numerous harmful effects. INTERACTION OF GRAPEFRUIT WITH DRUGS: Taking only one cup of juice may induce interactions with different drugs even during the period of a few days. The effect is induced by suppression of cytochrome P450 isoenzyme CYP3A4 in the intestinal wall. The Latin name of grapefruit, Citrus paradisi, is quite opposite to the effects which could be induced by taking grapefruit and some medications at the same time. It is necessary to avoid taking grapefruit with the drugs whose pharmacokinetics could be altered by the active principles found in that fruit.

DISCUSSION: The coloured grapefruit contains less furanocoumarins, but there is no difference in induction and intensity of pharmacokinetic interaction with drugs related to its colour. Other citrus fruits (orange, lemon) do not have such effects, but some other fruits (pomegranate, stella fruit, banpeiyu, hassaku, takaoka-buntan and kinkan) exert inhibitory effects on the activity of cytochrome P450 isoenzyme.

Re: Grapefruit a no-no with ER/PR positive Ca?
 

Cancer Causes Control. 2009 Aug;20(6):803-9. Epub 2009 Feb 18.
Prospective study of the association between grapefruit intake and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC).

Spencer EA, Key TJ, Appleby PN, van Gils CH, Olsen A, Tjønneland A, Clavel-Chapelon F, Boutron-Ruault MC, Touillaud M, Sánchez MJ, Bingham S, Khaw KT, Slimani N, Kaaks R, Riboli E.
Source

Cancer Epidemiology Unit, University of Oxford, Oxford, UK. elizabeth.spencer@ceu.ox.ac.uk

Abstract

Grapefruit inhibits cytochrome P450 3A4 and may affect estrogen metabolism. In the European Prospective Investigation into Cancer and Nutrition (EPIC), we examined the relationships of grapefruit intake with risk of breast cancer and with serum sex hormone levels. 114,504 women with information on dietary intake of grapefruit and on reproductive and lifestyle risk factors were followed for a median 9.5 years and 3,747 incident breast cancers were identified.

Fifty-nine percent of women reported eating grapefruit, 4% ate > or = 60 g/day. Cox proportional hazard models were used to estimate the hazard ratio (HR) for breast cancer according to grapefruit intake, adjusting for study centre, reproductive factors, body mass index, energy intake, and alcohol intake.

Grapefruit intake was not related to the risk of breast cancer: compared with women who ate no grapefruit, women with the highest intake of > or =60 g/day had a HR of 0.93 (95% CI 0.77-1.13), p for linear trend = 0.5. There was no relationship between grapefruit intake and breast cancer risk among premenopausal women, all postmenopausal women, or postmenopausal women categorized by hormone replacement therapy use (all p>0.05).

There was no association between grapefruit intake and estradiol or estrone among postmenopausal women. In this study, we found no evidence of an association between grapefruit intake and risk of breast cancer.

Re: Grapefruit a no-no with ER/PR positive Ca?
 

Thanks Jackie. Good articles.
I don't know about grapefruit and ER/PR, but I do know that grapefruit interacts negatively with some medications. Be sure to ask for literature every time you get a new medication. You can also check for drug to food interactions, drug to drug interactions or drug to supplement interactions on www.drugs.com or other reliable sites devoted to that kind of activity.
I do that every time I get a new prescription from a medical professional.

Re: Grapefruit a no-no with ER/PR positive Ca?
 

I use drugs.com too, but it's not comprehensive (although it is better than most other interaction checkers I've tried.) I also use the Natural Standard interaction checker, but the site requires a subscription, and again, it's not comprehensive.

Many ordinary foods, drugs and supplements affect both estrogen and tamoxifen (not to mention AIs and chemo drugs). For example, I recently wrote to the manufacturer of Ester-C to ask if tangeretin* (a citrus bioflavonoid that inhibits tamoxifen) is used in its product. I haven't heard back yet, but I'm pretty sure I know the answer, which means I have 3/4ths of the large-size bottle to discard.

It would be nice to have a definitive list.

(*It's okay to eat oranges as long as you don't eat the peels. See here for good info: http://foodforbreastcancer.com/foods/oranges)

Re: Grapefruit a no-no with ER/PR positive Ca?
 

There is no solid evidence that reasonable amounts of "estrogenic" fruits and vegetables raise the risk of breast cancer. Grapefruit, however, does interfere with many drugs.

Re: Grapefruit a no-no with ER/PR positive Ca?
 

I also did not know that grapefruit interferes with my Femara. I've been eating it a few times/month since taking it starting Jan. 2010. Only another few months (July 2012) until I am off Femara, I'll avoid grapefruit now until then.

all the best
caya

Re: Grapefruit a no-no with ER/PR positive Ca?
 

Heh..so true.

But...

http://her2support.org/vbulletin/showthread.php?t=39588

Re: Grapefruit a no-no with ER/PR positive Ca?
 

Hubby is not supposed to eat grapefruit as he's on heart/blood pressure medicine. Guess there are plenty of other fruit out there for us to eat...