Grapefruit and Diabetes

Grapefruit and Diabetes
Glycemic index:


Calories per 100 g:

36 kcal

Grapefruit has become a dietary favorite over the years and it's easy to see why with all the health benefits packed inside but if you're diabetic, you know how cautious you have to be with everything you eat. 

Diabetes is one issue that constantly makes us wary of what might affect our blood sugar level, cause weight gain or can even go as far as altering how our medication works.

As to if this fruit and diabetes are a safe combination is another question inspired by this anxiety. 

In this article, we will be giving all the details about grapefruit and diabetes and how they react to certain medications. 

Nutritional value

  • Protein 0.63 g
  • Carbohydrate 8.08 g
  • Fat 0.1 g
  • Fiber 1.1 g
  • Sugar 6.98 g
  • Cholesterol 0 g

What is a Grapefruit 

A subtropical citrus fruit grown first on the island of Barbados as well as in other parts of the Caribbeans and later in many states in the United States including Texas, Florida, and California. 

There are little over 20 varieties of grapefruit grown in the United State ranging from different sizes to colors of yellow, pink, and red. 

Described by the Jamaicans as the "forbidden fruit", this sweet and slightly bitter fruit is the result of the union between the sweet orange and Pomelo. 

It offers a lot of nutritional benefits including vitamins C with close to 50% of the daily recommended amount in it as well as vitamins A which supports healthy skin and hair and at 92%, its high water content is among many reasons why it has remained a food of choice, any time of the day.

It is rich in potassium and fiber, as well as protective antioxidants which may help manage blood pressure and both cholesterol and blood sugar levels. Human studies have demonstrated the beneficial role this fruit, and specifically, red grapefruit may play in helping people battling diabetes to improve cholesterol levels, particularly in those suffering from atherosclerosis.

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Diabetes and Insulin Resistance 

The primary purpose of insulin is to move sugar into the cell of the body to be used for energy as well as to protect it from too much sugar (glucose). When this doesn't happen in the body, then one is said to be insulin resistant and possibly have diabetes.

An elevated insulin levels come with a higher risk of developing chronic diseases including certain types of cancer and type 2 diabetes. 

Health benefits of Grapefruit

Beyond the fact that it does not have a significant effect on your blood sugar and weight gain, it comes with essential health benefits according to research and as long as you are eating the fruit or just drinking grapefruit juice, you are sure to feel a positive difference in your health.  

Boosts Immune System

Like many of its relatives, grapefruit is vitamin C heavy which contains loads of antioxidant properties used to protect you from harmful bacteria and viruses and even the common cold according to this study. 

It's also a rich source of vitamins A which aids to protect you from inflammation and several diseases. Many smaller chunks of vitamins and antioxidants including zinc, iron, copper, flavanones, lycopene, and Beta-carotene all combine to help keep you healthy. 

A source of Nutrient

If you're ever in demand for fruit rich in nutrients, then look no further than grapefruit. As evidence, a study found that women who ate grapefruit had a more robust volume of Vitamin C, Magnesium, dietary fiber, and diet quality. Although this is something to shout about, the only question to this study is that participants were not asked to eat just grapefruit so it's a bit unclear as to how much of an impact was made by its intake. 

Better Digestion

A ball of fresh grapefruit is well hydrated as it contains majorly water which is helpful for anyone that wants to prevent constipation. A grapefruit weighing little over 200 g is said to contain 182 g of water and 2.2 g of fiber. A diet rich in water and fiber will surely help with one's digestive tract.

Weight Loss benefits

It might not be the ultimate solution to battle weight gain but evidence reveals that eating this fruit might surely play a noticeable role in any weight loss diet. A 12-week Japanese study observed the effect of grapefruit against a placebo group which resulted in reduced weight in participants who ate half a grapefruit before a meal. 

Good for the heart

Any diet that is rich in flavonoids, the typical compounds found in many citrus fruits like grapefruit can lower a woman’s risk of stroke This is according to a 2012 report published by American Heart Association 

It is rich in potassium and fiber, as well as protective antioxidants which may help manage blood pressure and cholesterol levels. Human studies have demonstrated the beneficial role grapefruit, and specifically, the red variety may play in helping to improve cholesterol levels, particularly in those suffering from atherosclerosis.

Lower Sugar Level

Anything that helps to keep glucose levels down is seen as a diabetic delight and though it contains sugar, results suggest that eating grapefruit plays a major role in lowering blood glucose.

Closely related to the Japanese study, another study in 2014 was conducted and for this, researchers gave sweetened grapefruit juice to mice that were on either a low-fat diet or a high-fat diet and it showed that grapefruit juice aided the significant reduction of blood glucose levels, improved insulin resistance and helped to fight weight gain which are all major risk indicators of developing type 2 diabetes.   Although it must be noted that this research remains in doubt as it was funded by the California Grapefruit Growers.

Boosts Brain Function 

We said grapefruit comes with a good amount of flavonoids and another effect of this compound is that it has been suggested that when you add it to your diet, it can improve your memory and cognition and this is according to this promising research


Reduces the Risk of Kidney Stones

It has been quite powerful in the prevention of kidney stones. Owing to its rich constituent of citric acid, it can help to flush out calcium buildup and other waste materials found in the kidney. 

Helps Bones to Stay Strong

Grapefruit is packed with a decent amount of calcium and phosphorus which are the most essential for strong bones and teeth. 

Grapefruit juice or whole fruit?

Wellness professionals have long given varying opinions as to which is better between taking whole fruit or drinking its juice. Although, in the last few decades, experts in Diet and Nutritionist have gone on to favor whole fruit as a better option for low blood sugar levels.

It is quite refreshing when you drink grapefruit juice but the major challenge of drinking grapefruit juice is the absence of fiber which slows down digestion and the absorption of sugar.

In Order to make the grapefruit juice, one must press and squeeze the juice out of the whole fruit yet, it doesn't give you the same amount of nutrients as the whole fruit. It has been said to decrease the quality of nutrients especially fiber and water soluble nutrients.

Grapefruit and Medications 

There is no question as to the many health benefits this fruit offers but there is an apparent downside to its consumption as it appears it interacts with many medications

NHS has warned that whether eating or drinking grapefruit juice, you should avoid taking certain medications with it. This caution is due to the ability of this fruit to reduce their breakdown and elimination and consequently increase blood levels.

Grapefruit is said to interact with over 85 drugs and according to this study, 45 of them can lead to serious health issues when taken with grapefruit this applies to all forms of grapefruit including if you prefer drinking grapefruit in its freshly squeezed form. 

Drugs to watch out for include but not limited to statins such as simvastatin (Zocor) and atorvastatin (Lipitor), calcium channel blockers, a few cancer medications, and Entocort, which treats Crohn's disease, Pacerone, anti-anxiety drugs like buspirone, Antihistamines (used to treat allergies), drugs that treat abnormal heart rhythms. 

It must be pointed out that we are not generally saying that there is an effect when you eat grapefruit or drink grapefruit along with taking these drugs. This is because grapefruit juice is only drug-specific and not drug category-specific. 

Still, as we always like to inform you, It is best to contact your doctor If you are taking any prescription medication before feeding on grapefruit juice, the whole fruit or any other fruit for that matter. 

Metformin and Grapefruit 

Metformin or Metformin hydrochloride, is a diabetes drug prescribed by doctors to specifically treat type 2 diabetes. Typically, when the body is unable to process insulin resulting in high blood sugar levels or hyperglycemia.

Metformin, which has both immediate-release tablets (IR) and extended release metformin tablets (ER) form works to decrease the amount of glucose your body takes while eating. In many ways, taking metformin helps to control or bolsters the body's reaction to insulin.

Grapefruit just like other citrus do have chemicals that can disrupt the body's ability to metabolize metformin causing the side effect called lactic acidosis although there seems not to be any case study in humans that gives evidence that taking metformin with grapefruit juice can cause lactic acidosis

Although research information appears limited as regards the effect of grapefruit and Metformin in people that have type 2 diabetes, a few have given insight into it. 

One such study is the one conducted on nondiabetic rats who were either given Metformin and grapefruit juice while the others were given just Metformin. Findings revealed that it spiked the volume of lactic acid in the rats that took the grapefruit juice with Metformin. 

However, this effect has not been confirmed with humans so it's safe to say it's very likely that taking Metformin can still cause no harm with the fruit. 

Why does Grapefruit interact with Metformin 

Researchers have put forth two reasons as to why taking Metformin does this. For starters, they believe drug metabolism gives us more than a hint. furanocoumarins, a compound found in

Grapefruit or grapefruit juice can stop the function of CYP3A4, a digestive enzyme that tells the body to metabolize up to  50 percent of drugs. 

When this enzyme is blocked, certain drugs are forced to stay in the body longer than normal and build up in the bloodstream. This has been found to cause harmful effects and in some extreme cases, it can be fatal. 

This effect furanocoumarin has on the CYP3A4 is said to be irreversible and it will take about 3 days for it to produce a new CYP3A4. A 200 ml of grapefruit juice which is small in volume is potent enough to cause this interaction. 

Another reason explained given is said to be flavonoid, naringin, and hesperidin: all found when drinking grapefruit. 

Research reveals that Flavonoids can block organic anion transporter polypeptide (OATP), a protein that helps the body to move drugs into cells. 

The consequence is that the consumption of grapefruit or the drinking of grapefruit juice can decrease the absorption of certain drugs in the body thereby making it less effective even if it's only for about 4 hours. 

This means that if one relies purely on OATP for absorption then you can still go ahead to eating or drinking grapefruit as long as there is a 4 hours period between when you take the drug and when eating grapefruit. 

Final Take

There seems to be no doubt as to how powerful grapefruit products is to one's health and more closely, to people with diabetes . Its low-carbs, high-fiber, and lower glycemic index are just about perfect for diabetics. The whole fruit as well as grapefruit juice has been shown to improve blood pressure, manage blood sugar and some swear to it improving gut health and even some cancers.

However, for diabetics, caution is a virtue that saves life. Diet is not an easy road to travel when you're diabetic and that's why seeking professional help with all things diet and nutrition is a matter of survival.

With Klinio, a healthcare provider with many years in the field of all things diet and diabetes, you are rest assured of getting the necessary support needed to always win against diabetes and general health conditions

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