Fruit
Grapefruit
Nutrition facts
Serving: 1/2 grapefruit (125 g)
| Nutrient | Per serving | % DV |
|---|---|---|
| Calories | 53 kcal | |
| Protein | 1 g | |
| Carbs | 13.4 g | |
| Fibre | 2 g | 7 % |
| Sugars | 8.6 g | 9 % |
| Fat | 0.1 g | 0 % |
| Saturated fat | 0 g | 0 % |
| Sodium | 0 mg | 0 % |
| Vitamin C | 39 mg | 43 % |
Values per serving, calculated from the USDA FoodData Central (SR Legacy).
What the label does not say
- Grapefruit inhibits an intestinal enzyme (CYP3A4) that breaks down many medications, so their blood levels can rise. Half a grapefruit or one glass of juice is enough and, because the inhibition is irreversible, the effect lasts more than 24 hours: taking the medication at a different time does not solve it (Bailey et al., 2013).
- Furanocoumarins, not the vitamin C or the bitterness, cause the interaction; Seville oranges, limes and pomelos contain them too, sweet oranges do not.
Preparation
The fruit is eaten raw, so its vitamin C stays intact. Commercial pasteurized juice causes the same drug interaction as the fresh fruit: the compounds involved withstand heat.
To mention to a professional
- If you take medication (statins, some blood pressure drugs and immunosuppressants, among others), ask a healthcare professional whether it is on the list of drugs that interact with grapefruit; published lists include more than 85 medications.
Sources
- Grapefruit, raw, pink and red, all areas
- USDA FoodData Central, SR Legacy
- Bailey, Dresser and Arnold, 2013, CMAJ, Grapefruit-medication interactions
- Health Canada, Your Health and You, Effects of grapefruit and its juice on certain medications
- NIH Office of Dietary Supplements, Iron fact sheet
Educational information: it does not replace the advice of a health professional, especially if you take medication, are pregnant or are breastfeeding.