March 18


When Should People with High Blood Glucose Avoid Grapefruit?

By Gabriela

March 18, 2022

Grapefruit is a great source of one of the most important vitamins – vitamin C. However, being diagnosed with diabetes means avoiding it since it can interact with a lot of medications for managing the disease.

To know if these people can or can’t consume grapefruit, they should consult with a doctor or a pharmacist.

We recommend asking for advice before implementing this fruit in one’s diet. However, if they are not taking any medications, grapefruit can be great for their health. Therefore, have in mind that this fruit can drastically increase blood sugar levels. So, eat it with care.

Here is everything we need to know about grapefruit and this chronic illness.

Carbohydrate Content

The amount of carbohydrates that this fruit contains in a small part is similar to the number of carbohydrates in two kiwis, one pear, or an apple. Therefore, grapefruit contains a lot of carbohydrates which can increase blood sugar levels.

If we plan to add grapefruit to our diet, we better combine it with about 15g of carbohydrates in one serving. Moreover, we should monitor the blood sugar levels at all times, so that we keep them under control.

Lastly, we may want to try to avoid consuming grapefruit juice. In one cup, there are about 24g of carbohydrates. So, it contains no fiber but a lot of carbohydrates.

Glycemic Index

The glycemic index of grapefruit is 25. That being said, this fruit is a safer option compared to bread, white rice, and potatoes. In other words, a low glycemic index that is under 55 is best for people affected by chronic illness.

Grapefruit Interacts with Medications

The biggest problem with grapefruit is that it interacts with the medications. Since a lot of people with poor blood glucose control have to use drugs to manage their blood cholesterol, blood pressure, and depression, this fruit may cause a serious issue.

The unique compound in grapefruit can affect the enzyme in the gastrointestinal tract and boost the absorption of some medications which might cause problems in the blood. The most common medications that can be affected by this fruit are:

  • Anti-depressant drugs;
  • Statins;
  • Medications for keeping the blood cholesterol in check;
  • Calcium channel;
  • Anti-hypertensive medications.

Grapefruit and Metformin

Metformin is NOT broken down by enzymes as the other drugs are. Therefore, it leaves the body unprocessed through the urine. But, there is only a little information about how grapefruit can affect people who are taking metformin.

A paper issued in 2009, focused on the effects of grapefruit while taking metformin in rats.

Some rats took metformin with grapefruit juice, while others took only metformin. As a result, the rats who took metformin with grapefruit juice had increased levels of lactic acid production in the body.

In addition, the researchers assumed that grapefruit juice increased the accumulation of metformin in the liver.

In the end, it probably caused lactic acid production to increase. As a result, the researchers suggest that people who take metformin shouldn’t drink grapefruit juice since it can increase the risk of lactic acidosis.

However, have in mind that this research has not been replicated in humans.

Therefore, the results proved effective only on non-diabetic rats, not on humans. So far, there hasn’t been a human study that would indicate that metformin and grapefruit juice is dangerous for overall health.

Grapefruit Nutrition Facts

If we want to consume grapefruit, we should make sure to pair it with some nuts, protein, fat, yogurt, or even cottage cheese. Eating healthy fats and protein can help reduce the release of glucose in the bloodstream.

Here is everything we need to know about the nutritional facts of this fruit.

  • Grapefruit is quite low in calories. In fact, half a grapefruit can contain from 30 to up 40 calories.
  • Half a grapefruit contains from one to 1.5g of fiber.
  • 1/2 a grapefruit has around 59% of the recommended daily amount of vitamin C, potassium, copper, vitamin A, and biotin.
  • Its glycemic index is low, only 25.


  • Gabriela

    Co-Founder & Editor-in-Chief of Diabetes Health Page, Fitness trainer and instructor has dedicated her career to educating and informing people for over 10 years. As one of the most passionate diabetes advocates, Gabi has worked tirelessly to ensure that those people receive the education and support they need to properly manage their diabetes and achieve their health, fitness and weight loss goals.

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