by James Channing Shaw, MD
There is something you should know about grapefruit. It could change your life.
One week after Mr. Andersen (patient’s name changed) started drinking grapefruit juice every morning, his wife noticed a difference. He had very little interest in sex. At first he passed it off as aging variation, but it persisted into a second week. He had no libido whatsoever. Never before had he experienced problems with low libido or erectile dysfunction. He eventually clued into the grapefruit juice, stopped drinking it, and after two weeks, was ‘back’, just like the ads in the subway.
I knew about grapefruit’s role in altering drug metabolism in the body, but couldn’t find any studies suggesting a direct hit on testosterone, the main determinant of sex drive. Something in that grapefruit juice must have interfered with Mr. Andersen's testosterone for him to have such a rapid response and recovery.
Serendipitously, one month later, I read an article in the British Journal of Cancer(BJC) of a study showing that women who consumed as little as ¼ of a grapefruit per day had a 30 per cent higher risk of developing breast cancer than those who didn’t. This risk was as high as from taking HRT (hormone replacement therapy). The culprit in HRT is estrogen, well known to increase breast cancer risk. Perhaps estrogen was the link to Mr. Andersen's grapefruit scare. It made sense. I probed more.
It turns out there are strong links between grapefruit and estrogen. First, grapefruit contains estrogen-like compounds called flavanoids, also found in green tea and soy products. Flavanoid effects are identical to those of synthetic estrogen, and if you give a man estrogen, his libido drops to near zero.
The other link is the drug metabolism effect. Grapefruit juice is known to inhibit the breakdown of estrogen as well as many drugs, the most notable being cholesterol-lowering drugs called statins. A single six-ounce glass of grapefruit juice is enough to raise blood concentrations of statins.
There is more. In 2007, a study in Nutrition and Cancer found that daily intake of ¼ of a grapefruit increased natural levels of estrogens by about 30 per cent in post-menopausal women. When researchers looked for a link between grapefruit and breast cancer, the 2007 BJC study showed a 30 per cent increase, but a subsequent letter to the editor and a 2009 study in Cancer Causes & Control showed no increased estrogen or cancer risk with grapefruit consumption.
More research is needed to prove the cancer link, but grapefruit’s potential effect on estrogen seems probable.
One thing is certain: testosterone drives libido, and estrogen turns it off. It is highly plausible that a widespread estrogen-like phenomenon from grapefruit juice has been overlooked.
The relationship between grapefruit, estrogen, breast cancer and libido needs further characterization. In the meantime, readers be forewarned.
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ReplyDeleteAfter reading this article and several other articles on Grapefruit/Drug interactions & estrogen levels, I quit eating my normal whole grapefruit with breakfast. In January 2008, I was 46 yrs old, 6'4", weighed 277 Lbs. I was getting exhausted going up stairs, was started to feel chest pains with exertion, tired, sluggish, etc. I knew I was headed towards a heart attack if I didn't lose weight & get more exercise. I started dieting (including a whole Grapefruit, Yogurt & Green Tea for breakfast every morning), walking/hiking 1-3 hours everyday and lost 36 Lbs in ~ 5 months. I felt a lot better and could hike 10,000 ft peaks in the area without much problem by the end of that summer. Although, the dieting faded & I gained a little weight back, I've kept pretty active since, & I've ate a grapefruit, yogurt & green tea almost every morning for 3+ years.
ReplyDeleteThe weird thing was, by fall of 2008, my sexual performance was slowly degrading. It usually worked OK when I was fatter/lazier? In my head, I was blaming my wife for not having enough sex with me (use it or lose it?) By the spring of 2009, it was difficult to get/maintain an erection in the evening, somewhat better, but not great in the early mornings? It was causing me marriage problems. My wife thought I didn't find her attractive anymore and wondered if I had a girlfriend? I finally went to the doctor in Apr 2009, and was diagnosed with an enlarged prostrate (BPH), ED, & low testosterone. I figured the enlarged prostrate was the culprit to everything? I started on Hytrin for the BPH, eventually adding Levitra & Androgel for the ED/low testosterone. The combo worked quite well initially, but over the last 2 years, performance degraded a lot, occasionally "things" worked great, usually erections were degraded but sufficient, occasionally I had complete failures with Levitra. I tried different things & found separating taking the Levitra from my other drugs by a few hours, and not eating a large fatty meal seemed to help sometimes.
I started dieting again in January this year, to get what I had put back on off, +more. I was at 259 Lbs after the holidays, and I was down to 236 Lbs at the end of February. But no improvement in the sex department. At the end of Feb, my wife went with me on a 9 day business trip back East, in which I didn't bring/eat grapefruit. By the end of that week "things" worked quite well with Levitra, and not bad without. I thought it just must have been the lower altitude and relaxation. Upon returning home & eating Grapefruit for a week again, I had a night-time complete failure with Levitra. Frustrated I started searching the web for Levitra interactions and found some articles on grapefruit's interactions with both Levitra & Hytrin, & then the estrogen/grapefruit connection.
Wow, I was never warned by my Pharmacist or Doctor about this? I had my last grapefruit 3+ weeks ago. I've since switched to berries with my yogurt for breakfast. I didn’t notice a real Levitra difference in the 1st week, but after a 2 week grapefruit absence, it’s worked quite well a few times. I never realized a fruit that's acclaimed so highly for dieting, could cause this problem? I'm not totally knocking Grapefruit, I do believe it really helped me diet & lose weight. I’ve only dropped 1 Lb since stopping. But I do believe it may be the biggest culprit to my prostate enlargement & ED problems. I really wished the doctor would have ran estrogen tests with the testosterone tests, but now I’ll never know?
Grape fruit is very tasty to me but I was generally too lazy to eat fresh ones, but then I
ReplyDeletesaw gruitfruit in jars in the store and started buying them. I didn't know but for 3 years I would
go off and on (erection wise) and didn't know what was up, generally I am very healthy. Then I purchased (3) 32 oz containers of grapefruit for a vacation. Nobody seemed to eat it so I ate most of the 90 oz's plus the juice. It shut me down like a LA traffic jam. Luckily, the man here had this article, it real, believe me. I will never eat grapefruit again, LOL. I'm single, and it wasn't helping me find a GF.
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