Can diabetics eat grapefruit? Diabetics that are not on any medication can eat grapefruit safely with their condition as long as they keep intake low enough so they don’t exceed their recommended daily intakes of carbohydrates and sugar, a crucial aspect of successfully managing the metabolic condition. However, if they are receiving any form of medication for their condition, then it’s likely not safe to eat the fruit or drink the fruit juice. The effects of grapefruit on diabetes are far more complex than those of bananas or cherries or even pineapple and watermelon because the fruit contains natural chemicals that either increase or decrease the concentrations of certain medication in the bloodstream and their effects.
Grapefruit and medication. The main reason why diabetics receiving medication can’t have grapefruit or drink grapefruit juice is because the fruit and its juice contain naturally occurring compounds called furanocoumarins and flavanones that influence how certain medicines are absorbed and how strong or weak their effects are as a result. Three such compounds are bergamottin, dihydroxybergamottin and naringenin which act on specific liver and digestive enzymes which activate or inactivate medicines, including diabetes, blood pressure, arrhythmia, cholesterol, anxiety, depression, blood clotting and immune system suppressing medication as well as antihistamines.
The primary enzyme affected by compounds in grapefruit is Cytochrome P450 3A4, but Cytochromes P450 proteins involved in enzymatic reactions are also affected. The enzyme mostly deactivates medication to facilitate its removal from the human body, but also holds the biological ability to activate some medicines, increasing their efficacy. When grapefruit compounds alter the activity of this enzyme and various enzymatic processes, they cause either stronger effects of some medication by increasing their concentration into the bloodstream and potential toxicity effects, or reduce the efficacy of some medication, prompting related side effects.
So it’s true that eating grapefruit affects diabetes medication metabolism. The more severe or poorly managed the condition is (requiring several different medicines – for managing blood sugar, blood pressure, statins for lowering cholesterol) and the higher the intake or the more frequent the consumption of the fruit or fruit juice, the more likely and serious the side effects for a diabetic patient. For example, eating one whole fruit or drinking even a 200 ml glass of its juice can be a source of serious side effects for some diabetics. The effects of the fruit on diabetes medication are collectively known as the grapefruit effect.
The compounds responsible for these effects are present in all varieties of the fruit and similar compounds can be found in other citrus fruits as well, which prompts medical professionals to advise their diabetic patients to caution when it comes to eating grapefruit or drinking grapefruit juice with diabetes, or other citrus. If there is a medication that requires you to absolutely avoid having grapefruit with, then the information should be listed on the label as a warning or contraindication. If you are receiving any pharmaceutical treatment for your condition, it is imperative that you ask your doctor if it’s safe for you to eat grapefruit with the medication your are currently receiving.
Here is a partial list of diabetes medicines and medicines for associated conditions affected by grapefruit consumption:
1) Metformin, glipizide, glyburide and other medication for lowering blood sugar levels (in type 2 diabetes).
2) Atorvastatin, lovastatin and other statins for lowering blood cholesterol levels.
3) Nifedipine for high blood pressure.
If in addition to diabetes there are other conditions such as anxiety, depression, arrhythmia, blood clots, then there may be interactions with medicines used for treating these conditions as well (example: warfarin).
Grapefruit and blood sugar levels. Despite its modest nutrition, grapefruit is actually good for diabetes because it contributes to better blood sugar levels. And it’s not only because of special compounds in grapefruit itself stabilize blood sugar levels. It’s also because the moderately low carbohydrate and sugar content as well as the low glycemic index of the fruit do not raise blood sugar levels to begin with, provided intake is limited to small amounts, the fruit not consumed every day and preferably no more than one serving a day. Even better is to have grapefruit after a light protein meal or combine it with a source of fat and protein such as a little cheese or walnuts, that is, if you can have it in the first place. Fat and protein slow down digestion and contribute to more stable blood sugar levels.
Carbohydrate content: 10.66 g of total carbohydrates/100 g of fruit (including fiber, sugar and other carbohydrates)
Sugar content: 6.89 g of sugar/100 g of fruit
Fiber: 1.6 g of dietary fiber/100 g of fruit
Energetic value: 33-42 kcal/100 g of fruit
Protein: 0.77 g of protein/100 g
Fat: 0.14 g of fat/100 g
Do grapefruits have a lot of sugar? Actually, grapefruits are moderately low in sugar for a fruit and don’t have excessive amounts of carbohydrates either (carbohydrates except for indigestible ones like fiber or cellulose are also broken down into simple forms following digestion and contribute to blood sugar levels). Eating small amounts can be beneficial for a diabetic patient who is not on any medication. Both white and pink or red varieties have about the same carbohydrate and sugar content.
Grapefruit glycemic index (GI): low, 25. The glycemic index is a scale that measures how fast the sugars from plant foods raise blood sugar levels. Bellow 55 is a low GI. Between 55-69 is a medium GI. Between 70-100 is a high GI. Diabetics benefit most from eating low GI foods like grapefruit which help stabilize blood sugar levels. Nutrients such as dietary fiber (1.6 g per 100 g of grapefruit) slow down digestion of the fruit and the absorption of sugar into the bloodstream, preventing unhealthy rises in blood sugar levels.
Grapefruit and type 2 diabetes. Complications from medicine interactions aside, grapefruit is good for diabetes type 2 and can be eaten safely in limited amounts if the diabetic patient is not on any medication. The advantages of eating grapefruit with diabetes type 2 include:
1) A moderate carbohydrate and sugar content which contribute to more stable blood sugar levels.
2) Good fiber content to slow down the absorption of sugar into the bloodstream and improve cholesterol levels.
3) Low fat content and low energetic value to encourage weight loss and support a healthy weight.
4) Good vitamin C content (33.3 mg/100 g of fruit) to help with wound healing, a big issue for diabetics. Vitamin C supports the production of collagen for skin repair and enhances the immune function with implications for wound healing.
5) Source of potent antioxidants such as naringenin, lycopene and vitamin C which hold therapeutic effects such as reducing oxidative stress with potential benefits for diabetes prevention and help regulate glucose metabolism in the liver which further contributes to better glucose tolerance.
Grapefruit and diabetes type 1. If you have type 1 diabetes, it is imperative you talk to your doctor to see if you can include grapefruit in your diet. If you are receiving medication such as statins for lowering blood cholesterol levels, high blood pressure medication or medication for controlling blood sugar, then you likely can’t have grapefruit because of the compounds in the fruit and its juice that interact with such medicines and cause potentially serious complications.
Conclusion. When it comes to grapefruit, it’s not just the sugar, total carbohydrate and glycemic index that matter like with most other fruits, but also the effects of special compounds present in the fruit and its juice that dictate how medication for diabetes and associated conditions (high blood pressure, high cholesterol) are absorbed and how strong or weak their effects will be. Ideally, all diabetic patients should consult their doctor and ask if their current condition allows them to consume the fruit or fruit juice as well as inquire how much of the fruit or fruit juice they can have safely. For the most part, diabetic patients with a great management of their condition, who are not on any medication, can eat grapefruit safely. But grapefruit is usually not one of the best fruits for diabetes if you are on any kind of medication and patients might be better off avoiding the fruit and its juice altogether in this case.