Grapefruit benefits and Special Cautions

As you may already know, grapefruits are good to our health with high vitamin C content, fiber and potassium. This citrus fruit also has a lot of minerals and components which can protect our cells from damage and reduce the cholesterol. But is that all the information you need to know about grapefruit? As what I knew and read about grapefruit, there are many concerns and cautions and side effects when using grapefruit.

Grapefruit Nutrition

In the below figures are some key essential nutrition in grapefruit. Figures are based on a 1/2 serving of grapefruit as well as how much percent does it account for daily values (DV).

½ of grapefruit (123g)     % DV
Carbon hydrate
         13g       (4%)
        1 g
Vitamin A
1415 IU                                        (28%)
Vitamin C
38.4 mg                                       (64%)
Vitamin E
0.2 mg                                         (1%)
16.0 mcg                                      (4%)
Vitamin B6
0.1 mg                                          (3%)
Pantothenic Acid
0.3 mg                                         (3%)
27.1 mg                                        (3%)
0.1 mg                                          (1%)
11.1 mg                                         (3%)
22.1 mg                                        (2%)
166 mg                                         (5%)

What I can do with grapefruit?

  • Healthy food: Cut grapefruit horizontally and scooping out sections of the halves with a spoon. To reduce the bitter of grapefruit you can put some olive oil in a surface. Grapefruits can also be peeled like oranges with your hands or with a knife. 
  • Grapefruit Juice: Squeeze grapefruit to make a fresh fruit juice. You can put some sugar or salt to reduce the bitterness. But with me I prefer using salt than sugar. The salt can reduce the bitterness and bring a little sweet feeling to grapefruit juice. And more important, you can reduce the amount of sugar you consume in a day.
  • Grapefruit salad: Making tropical salad by combining grapefruit with cooked shrimp, avocado and lettuce. 

What are benefits of grapefruit?

1. Rich sources of Vitamin and mineral:

Grapefruit have rich sources of Vitamin C, Vitamin A and other minerals. A half of grapefruit can give you 64% of the Vitamin C and 28% of Vitamin A which your body needs in a day. Besides, grapefruit can give you rich sources of iron, calcium, magnesium.  

2. Grapefruit and weight loss

Grapefruit contained the largest proportion of lower molecular weight pectin. Naringenin (NRG), the aglycone flavonoid present in grapefruits. This pectin possesses anti-inflammatory, anti-carcinogenic, anti-lipid peroxidation and hepato-protective effects. But it is poorly soluble in water and exhibits slow dissolution after oral ingestion.

3. Reduce heart diseases

Vitamin E in grapefruit can be healthy and have been shown to lower the risk of heart disease. Besides grapefruit pectin supplementation may inhibit high cholesterol. There are promising evidences to support the use of grapefruit pectin in the prevention of heart disease. But more studies are needed in this area. 
4. Rich sources of Antioxidant ingredient.

5. Prevent cancers

Red and pink grapefruit contain rich sources of lyconpene. Lycopene has been considered as a potential agent to prevent some types of cancers, particularly prostate cancer. However, this area of research is still insufficient of evidence.

What are side effects of grapefruit?

Grapefruit has Generally Recognized as Safe (GRAS) status in the United States. There are rarely cases of adverse effects from grapefruit juice when using it without medicines. 
But if you eat too much grapefruit you might have tooth surface loss, development of kidney stones. Grapefruit overdose might increase the potassium clearance, lowered elevated hematocrits and Liddle’s syndrome.

  • Be careful when having grapefruit and drinking red wine at the same time. Red wine might combine with grapefruit and cause an additive inhibitory  on the way liver breaks down some agents. 
  • Patients who drink tonic water or smoke should also be careful with grapefruit too.
  • Ask doctor for advice before using grapefruit if you have history with liver cirrhosis, at risk for kidney stones and undergone gastric bypass surgery. 

Special Precautions and Warning when using grapefruit:

Normally grapefruit is safe when you use it as food with who are not on current drug therapy. But, in these special cases, people should be serious caution or stop using grapefruit. 

1. Pregnancy and breast-feeding

Grapefruit is not recommended for pregnant or breastfeeding women due to a lack of scientific evidences.  

2. Breast cancer 

Grapefruit juice might increase estrogen levels in the body and decrease the broken down of estrogen. Besides, grapefruit can interact with cancer drugs and leads to dead. Avoid grapefruit juice if you have breast cancer and at higher risk for developing breast cancer. 

3. Grapefruit and medication interaction

More than 20 years ago, doctors discovered that grapefruit makes some medicines dangerously strong. According to Dr. David Bailey, a researcher at the Lawson Health Research Institute in London said there are 85 medicines can interact with grapefruit and causes serious side effects. Dr. David Bailey also said, ‘One tablet with a glass of grapefruit juice can be like taking five or ten tablets with a glass of water’. 

One we take medicine along with grapefruit juice, the chemical called furanocoumarins in grapefruit will interfere with cytochrome P450 3A4 in our intestines. The Cytochrome P450 3A4 enzyme controls the amount of drugs that enters the bloodstream. Once furanocoumarins are present in the intestine, they stop cytochrome P450 3A4 from working. This is a reason why grapefruit juice might increase the drug’s concentration in the blood three-fold. As a result, more of the drug gets into the bloodstream and a patient is at risk of an overdose.

The effects of mixing medicine and grapefruit can be dramatic and some can be deadly. This side-effect can happen even if patients consume grapefruit hours before taking medicine. People who eat lots of the fruit over a long period of time appear to be at even higher risk. Here are some main groups of medicines can interact with grapefruit:

  • Group of lower cholesterol medicine statins: simvastatin, lovastatin and atorvastatin.  Overdose of statin drug can lead to muscle pain, swelling, vomiting, diarrhea and breakdown of muscle tissues.
  • The antibiotic erythromycin used to treat skin and urinary infections. Drinking these drugs with grapefruit might cause nasty symptoms including stomach upsets. 
  • The blood-thinning drugs lopidogrel used after heart attacks, strokes or angina. Unusually it doesn’t become more potent with grapefruit, but can stop working completely. Overdose of blood-thinning drugs such as apixaban and rivaroxaban can cause stomach bleeding. 
  • Anti-cancer drugs:  Overdosing anti-cancer drugs can weaken immune systems, irregular heart rhythms and even sudden death.
  • Estrogens pills such as Premarin, ethinyl estradiol, estradiol (Climara, Vivelle, Estring), and others. Grapefruit juice might decrease the body breaks down estrogen and increase absorbing estrogen. High level of estrogen can lead to serious sickness such as breast cancer.
  • Anti-infective drug: Including treatment for HIV, malaria and antibiotic medicines.
  • Central nervous systems drugs: anxiety, depression, bipolar disorder and schizophrenia, pain killer.

You can read more detail about medicines which interacts with grapefruit in Webmd and CBC news.

4. Interactions with Herbs 

The herbs, processed by liver’s cytochrome P450 enzyme system, might interact with grapefruit. Grapefruit can increase the levels of other herbs or supplements in the blood too high than usual. Here are some cases of herbs can interact with grapefruit:

  • A mixing of grapefruit and green tea can increase caffeine levels in the body. High level of caffeine can gain risks of cardiovascular, central nervous system stimulative effects.
  • Grapefruit juice may increase the concentration of digitalis (foxglove) and vitamin C levels.
  • Risks of bleeding might increase when using herbs and supplements with grapefruit juice. There are some reported cases of bleeding by mixing grapefruit with Ginkgo biloba, garlic and saw palmetto. 
  • If both licorice and grapefruit are taken together, you might have the risk of high blood pressure.
  • You should be caution when using xanthine-containing herbs with grapefruit. They may interact with each other.

Here are some main information about health benefits and side effects of grapefruit. I like grapefruit because of valuable health benefits but I also do concern about grapefruit’s side effect. Always consider about the grapefruit’s side effects. Ask your doctor for advice if you are in therapy and have sickness history before using it.



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