Grapes And Diabetes: Nutrition, Benefits & Side Effects In 2024

You might have heard that grapes are too high in sugar for those with diabetes. But what does the science say? Can grapes and diabetes go together? 

Grapes may have surprising benefits for those with diabetes. Over 1,600 health-promoting substances^[1] have been found in grapes, including antioxidants like resveratrol, lycopene, quercetin, and melatonin. Red and black grapes^[2] usually contain more antioxidants than green grapes.

But what about the sugar content? Are grapes good for diabetes if you consume grapes regularly? Let’s take a look at what the research says.

Nutritional Value Of Grapes

The nutritional content of grapes might vary depending on the variety. Red and black grapes have higher antioxidant levels^[2] than green grapes. But the basic nutritional content of common green and red grapes is similar. 

Here are the main nutrients in a 100-gram serving of seedless red grapes:^[3]

• Calories: 86 calories.
• Carbohydrates: 20.2 grams.
  • Sugars: 17.3 grams.
  • Dietary fiber: 0.9 grams.
• Protein: 0.91 grams.
• Fat: 0.16 grams.
• Vitamin C: 3.3 milligrams.
• Calcium: 10 milligrams.
• Iron: 0.16 milligrams.
• Magnesium: 8.6 milligrams.
• Phosphorus: 25 milligrams.
• Potassium: 229 milligrams.
• Sodium: 7 milligrams.
• Zinc: 0.04  milligrams.
• Copper: 0.081 milligrams.
• Manganese: 0.098 milligrams.

Grapes And Blood Sugar Levels

Grapes have a low to moderate glycemic index^[4] — a measure of how quickly a food spikes blood sugar levels. This means they have a mild impact on blood sugar levels compared to high glycemic index foods. 

Yes, grapes contain natural sugars, but alongside healthy fiber and antioxidants that reduce their glycemic index.^[5] This means grapes are healthy for those with diabetes if consumed in moderation. Any fruit can potentially increase blood glucose levels, particularly when consumed in excess. But, one serving of grapes will not likely make a detrimental difference. 

What about consuming grapes and type 2 diabetes? Recent research suggests that eating grapes may improve insulin resistance.^[6] However, eating grapes didn’t affect other markers of diabetes, such as fasting insulin levels. Also, grapes worsened fasting blood glucose levels compared to the control group. This means that the control group had lower blood glucose levels after a period of fasting than those who had eaten grapes. More research is needed to confirm these findings.

Health Benefits Of Grapes For Diabetics

Several health benefits attributed to fruit consumption include grapes which may benefit those with type 2 diabetes.

Potent Antioxidant Effects

Grapes are a good source of antioxidants like resveratrol — a potent antioxidant in some plant-based foods. The main sources^[7] of resveratrol are grapes, peanut skins, and grape products such as wine. 

Resveratrol is known for^[8] its antioxidant, anti-inflammatory, and immune-supporting properties.  It may help manage diabetes by balancing blood sugar and protecting the body from oxidative damage.^[2] It may also help reduce the risk of heart disease, cancer, liver disease, obesity, Alzheimer’s disease, and Parkinson’s disease.

Improves Cardiovascular Health

Cardiovascular disease, or CVD is the main cause of death^[9] in those with type 2 diabetes. Adults with diabetes have a 1.7 times higher chance of dying from CVD than those without diabetes. Why? Common symptoms of type 2 diabetes are risk factors for CVD, including obesity, high blood pressure, and high ‘bad’ cholesterol levels. 

Anthocyanins are natural antioxidant pigments in grapes, particularly in red and black varieties. Research suggests anthocyanins may reduce cholesterol levels^[10] and chronic inflammation, protecting against CVD. 

Supports Weight Management

Being overweight increases your risk^[11] of developing type 2 diabetes. Grapes are rich in dietary fiber, which helps promote a feeling of fullness and may aid weight management. 

A high-fiber diet is associated with a lower risk^[12] of type 2 diabetes and may improve the health^[13] of adults with diabetes. Diets high in fiber can improve blood sugar control, cholesterol levels, body weight, and inflammation while reducing the risk of early death. 

Improves Insulin Sensitivity

Research suggests that the polyphenols found in grapes may help improve insulin sensitivity,^[14] potentially benefiting people with type 2 diabetes. Grapes do not spike blood sugar levels as some fruits may.

Insulin^[15] is a hormone that promotes glucose absorption from the blood to the muscle, liver, and fat tissues. Insulin resistance occurs when the body loses insulin sensitivity and stops responding. This leads to high blood sugar levels, poor blood glucose control, and eventually type 2 diabetes. 

Polyphenols can improve insulin resistance by lowering blood sugar after meals, regulating glucose transport, affecting insulin signaling, and protecting insulin-producing cells from damage. 

Improves Eye Health

Diabetic retinopathy^[16] is a common complication of diabetes and is one of the leading causes of blindness worldwide. 

Grapes contain lutein and zeaxanthin, two important nutrients for maintaining eye health.^[17] Consuming foods rich in these nutrients may help support eye health in those with type 1 and type 2 diabetes.

Supports Immune Function

Grapes are a good source of vitamin C, which can help support a healthy immune system.^[18] This is essential for people with diabetes, who may have a higher risk of infections.^[19]

Reduces Inflammation

Some compounds in grapes, such as resveratrol and other polyphenols, have anti-inflammatory properties.^[20] These may help reduce chronic inflammation, a common factor of diabetes that can lead to the development of chronic diseases such as cancer and heart disease.

Improves Brain Function

Poorly managed diabetes is associated with cognitive impairment.^[21] Grapes contain antioxidants and nutrients that may help support brain health,^[22] potentially reducing the risk of cognitive decline.

Are There Any Side Effects?

Grapes are considered a healthy fruit, but there can be some potential side effects — particularly for individuals with diabetes or specific health conditions. Some of these side effects include:

• High sugar content: Red or green grapes contain natural sugar, primarily in the form of fructose. Consuming large quantities of grapes may lead to elevated blood sugar. 
• Weight gain: Although grapes are nutritious, they can contribute to your daily caloric intake. Eating too many calories may lead to weight gain – which is not ideal for individuals with diabetes who need to maintain a healthy weight.
• Allergies: Some people may be allergic to grapes^[23] or grape products, such as wine. This can cause symptoms ranging from mild to severe, including itching, hives, swelling, or difficulty breathing.
• Gastrointestinal issues: Consuming too many grapes may lead to gastrointestinal discomfort, such as bloating, gas, or diarrhea.
• Pesticide exposure: Non-organic grapes may have pesticide residues^[24] on their skin, although these residues are likely within safe levels.^[25] Opt for organic grapes or thoroughly wash them before consumption to minimize exposure.

Other Fruits For Diabetes

While people with diabetes need to moderate sugar, that does not mean they can’t have fruit as part of a balanced diet. Some fruits are better for diabetics than others, and it may help to consume them with a protein source such as protein powder. Consuming sugar with protein can help slow the absorption of sugar into your bloodstream and prevent blood sugar spikes.

1. Berries: Berries are considered a superfood rich in nutrients and healthy compounds. Recent evidence suggests they can help reduce the risk of chronic diseases^[26] like type 2 diabetes. Cranberries, blueberries, raspberries, and strawberries can all help lower high blood sugar and insulin levels in adults with insulin resistance or metabolic syndrome.
2. Cherries: Eating cherries helps improve blood vessel function and manage liver-related issues, reducing the risk of diabetes-related health problems.^[27] These findings show a diet rich in antioxidants, like those found in cherries, could prevent blood vessel and liver complications associated with type 2 diabetes.
3. Apples: A recent study found that eating apples before a meal might improve blood sugar and insulin levels.^[28] 
4. Oranges and other citrus fruits: Studies have found that citrus flavonoids can help with diabetes.^[29] These flavonoids can improve blood sugar control, cholesterol levels, kidney function, and pathways related to glucose uptake and insulin sensitivity. 

The Takeaway

Grapes are healthy for people with diabetes when eaten as a whole fruit. Consume grapes regularly as part of a balanced diet for diabetics and other fruits and supplements for diabetics. 

How many grapes can a diabetic eat? Aim for half a cup to promote blood sugar balance and avoid a spike in blood sugar levels. You can add a few grapes to a paste salad or incorporate grapes into your breakfast. Some people freeze grapes to add to drinks instead of ice cubes.

Overall, it’s essential for people with diabetes to carefully monitor their diet — especially their vitamin intake and blood sugar levels. Discuss your diabetic diet and other dietary options with a healthcare professional.

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