Transcript: Tell Your Doctor If You Eat Grapefruit
If you have people eat half a grapefruit three times a day before each meal for a couple months, they may lose about two pounds, but that's no more than if they ate 3 apples or pears a day. In this study the grapefruit eaters not only saw their weight go down, but their waist got slimmer, and their body fat melted away. If, however, you repeat the experiment and instead ask people to drink a half cup of water before each meal, you get the same result. So this belief that grapefruit has some special fat-burning quality appears to be just a long-held myth.
Here's the latest, showing grapefruit consumers had a drop in weight, significant drop in cholesterol, and significant drop in blood pressure. Conclusion:This study suggests that consumption of grapefruit daily for 6 weeks does not significantly decrease body weight, cholesterol, or blood pressure. What?! That made me do a little double take, but again, it's because the grapefruit didn't do any better than placebo.
Other studies have found a legitimate cholesterol-lowering benefit, especially eating red as opposed to white grapefruits, and even a little dip in triglycerides. This was one grapefruit a day for 30 days, but as you can see though, they went from one life-threatening cholesterol level to another life-threatening cholesterol level. To prevent heart disease, you really have to get down to a total cholesterol of around 150, the average cholesterol of those eating diets composed exclusively of plant foods, not just grapefruits.
Even though grapefruits alone don't do much, the researchers suggest that people might be more likely to stick with them than cholesterol lowering drugs, noting that most people with heart disease stop taking their statin drugs within a couple years because of the adverse side effects. Grapefruit alone don't have any side effects, but, ironically, combine grapefruits and drugs together and you can make drug side effects even worse.
Now hopefully if you eat lots of fruits and vegetables you won't need a lot of drugs, but certain phytochemicals in plants can affect the metabolism of drugs in the body, and grapefruit is the poster child, described as a pharmacologist's nightmare. Natural phytochemicals in grapefruit suppress the enzymes that help clear more than half of commonly prescribed drugs, and less drug clearance means higher drug levels in the body. Now this may be good if you want a better caffeine buzz from your morning coffee, or your doctor wants to help you save thousands of dollars boosting the effects of expensive drugs, instead of just peeing them down the toilet.
But higher drug levels may mean higher risk of side effects. Women taking the pill are at a higher risk of blood clots, particularly, perhaps, if they have been consuming grapefruit. Taking the pill with grapefruit juice may increase blood concentrations by 137%.
If suppressing our drug clearance enzymes with grapefruit juice elevates levels of ingested estrogen, what might it be doing to our own estrogen levels? This study, associating grapefruit consumption with breast cancer freaked out the medical community, but subsequent studies on even larger groups of women found no evidence of a link. In fact if anything the Harvard Nurses’ Study found a decreased risk of the scariest breast cancer type, so it doesn't look like one has to worry about grapefruit affecting our natural chemistry. For those prescribed unnatural chemistries, it may be a good idea to discontinue grapefruit consumption for 72 hours before use of a drug that may interact with it. If you don't want to give up your grapefruit, you can ask your doctor about switching from one of the grapefruit-affected drugs like Lipitor to one of the citrus-proof alternatives.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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