Blueberry for Type 2 Diabetes!

Although the proper treatment of diabetes includes insulin injection continuously to maintain blood glucose levels, nowadays, there is an increasing interest in the use of alternative approaches for treating insulin resistance and T2D. Due to the side effects and temporary use of chemical drugs, herbal and natural medicines, and chemical drugs are recommended for people with diabetes.

 Blueberry and diabetes

Blueberry leaves help lower blood and urine sugar levels and increase metabolism. Studies reported that foods rich in anthocyanins, and blueberries, cause to lower risk of T2DM and peripheral insulin resistance index. Anthocyanin’s polyphenols in blueberries belong to the flavonoid as strong natural dark antioxidants.

Some researchers concluded no effect of blueberries on insulin resistance and glucose tolerance in obese mice and rats. Although researchers did not observe any significant changes in HOMA-IR using blueberry, they found significant changes in the glucose metabolism markers such as hemoglobin A1c, retinol-binding protein 4, and resistin concentrations. Another study applied a single oral capsule of 0.47 g bilberry extract (36% w/w anthocyanins) to T2DM cases.

Blueberry-leaf extract is rich in phenols that regulate glucose homeostasis, pancreatic β-cell function, and insulin sensitivity in induced diabetic mice fed a high-fat diet. Blueberry-leaf extract (BLE) contains chlorogenic acid and flavanol glycosides rich in phenolic-enriched BLE to improve glucose homeostasis and insulin sensitivity. Administration of 1% blueberry-leaf extract decreases blood glucose and improves the pancreatic function induced diabetes mice-fed high-fat. Using 1% blueberry-leaf extract reduced glucose tolerance, body weight, plasma glucoseglycated hemoglobin, insulin, insulin resistancetriglyceride (TG), and non-esterified fatty acids. BLE reduced the pancreatic islet size and insulin content, increased the mRNA of pancreatic β-cell proliferation-related genes and pancreatic insulin signaling-related genes, and GLUT-2, and decreased the transcriptional expression of the β-cell apoptosis-related gene. BLE enhances insulin sensitivity by inhibiting TG synthesis and increasing lipid utilization in the liver and white adipose tissue. Chlorogenic acid of BLE increased β-cell proliferation and promoted insulin signaling. Phenolic compounds of BLE inhibit induced glucose tolerance and hyperglycemia by improving pancreatic β-cell function.

T2DM case that consumed capsules containing 80 mg anthocyanins obtained from the bilberry and blackcurrant; twice daily for 24 weeks, they significantly improved HOMA-IR. Another study reached the same result by applying a single oral capsule of 0.47 g standardized bilberry extract (36% w/w anthocyanins) to the subjects with T2DM.

The milk contained in the blueberry smoothie did not mask the beneficial effects of the blueberries on insulin sensitivity and endothelial function. Using blueberries in the diet of obese rodents showed decreased body weight gain and lipid accumulation in tissues with increased insulin sensitivity.

Anthocyanins of blueberries protected obese mice against obesity. In addition, its reported that blueberries in the diet reduced abdominal fat and increased insulin sensitivity in obese Zucker rats. Despite no changes in body weight and fat composition, still observed an increase in insulin sensitivity after 6 weeks of blueberry consumption without changing body weight and fat composition.

Mechanism of the anti-diabetic effects of Blueberry

There is an increasing interest in using alternative approaches for treating insulin resistance and T2D. It is confirmed that blueberries, blueberry leaves, and cinnamon improve insulin sensitivity or insulin action. Obesity is linked with macrophage infiltration into adipose tissue and the activation of the inflammatory pathway, leading to insulin resistance.

The accumulation of macrophages in the adipocytes leads to secret proinflammatory cytokines. These changes in gene expression of inflammatory cytokines may cause to increase in insulin sensitivity. Increased insulin sensitivity, but no significant effect was not observed on plasma inflammatory markers in obese Zucker rats. Reported that using blueberry-anthocyanins did not increase glucose uptake in skeletal muscle cells. It’s concluded that rats had an increase in glucose uptake and metabolism in the skeletal muscle and retroperitoneal fat after consuming blueberries for 12 weeks.

This activation-induced upregulation of GLUT 4 and glucose uptake and utilization in these tissues without insulin. blueberries increased glucose uptake into the skeletal muscle cells and adipocytes via an insulin-independent mechanism blueberry.

Blueberry Tea is a blend of dried blueberries (37% wt/wt), blueberry leaves, raspberry leaves, spearmint leaves, and cinnamon. Improving glycemic control is important for regulating insulin resistance and T2D and hypertension, and cardiovascular disease (stroke, heart attack, and heart failure). Unique blueberry tea blend fully recovers insulin sensitivity in the muscle of insulin-resistant rats fed high-fat and is linked with improvements in muscle glucose uptake and insulin sensitivity of the body. Improvement in Glucose Tolerance after 4 weeks of drinking blueberry tea. Drinking blueberry tea after 4 weeks improved Hemoglobin A1c (HbA1c), fasting serum lipid (cholesterol, HDL, LDL, triglycerides), fasting serum pro-inflammatory cytokine (IL-6, IL-1b, CRP, TNFa), resting blood pressure (central and brachial blood pressure).

Due to the side effects and temporary use of chemical drugs, herbal drugs like blueberry along with chemical drugs are recommended for diabetes. However, more scientific studies are needed to confirm the effectiveness of blueberry supplements on diabetes cases.

5 Benefits of Blueberries


Stull AJ. Blueberries’ Impact on Insulin Resistance and Glucose Intolerance. Antioxidants (Basel). 2016;5(4):44. Published 2016 Nov 29. doi:10.3390/antiox5040044

Elks, C.M.; Terrebonne, J.D.; Ingram, D.K.; Stephens, J.M. Blueberries improve glucose tolerance without altering body composition in obese postmenopausal mice. Obesity 2015, 23, 573–580.

Stull, A.J.; Cash, K.C.; Johnson, W.D.; Champagne, C.M.; Cefalu, W.T. Bioactives in blueberries improve insulin sensitivity in obese, insulin-resistant men and women. J. Nutr. 2010, 140, 1764–1768.

Stull, A.J.; Cash, K.C.; Champagne, C.M.; Gupta, A.K.; Boston, R.; Beyl, R.A.; Johnson, W.D.; Cefalu, W.T. Blueberries improve endothelial function, but not blood pressure, in adults with metabolic syndrome: A randomized, double-blind, placebo-controlled clinical trial. Nutrients 2015, 7, 4107–4123.

Vuong, T.; Martineau, L.C.; Ramassamy, C.; Matar, C.; Haddad, P.S. Fermented canadian lowbush blueberry juice stimulates glucose uptake and amp-activated protein kinase in insulin-sensitive cultured muscle cells and adipocytes. Can. J. Physiol. Pharmacol. 2007, 85, 956–965.

Li H.,  Park Hye-Mi  Ji Hyeon  Han Jisu  S-K Kim et al. 2020.Phenolic-enriched blueberry-leaf extract attenuates glucose homeostasis, pancreatic β-cell function, and insulin sensitivity in high-fat diet–induced diabetic mice. Nutrition Research 73, 83-96

Are blueberries healthy?

Absolutely. In fact, blueberries are one of the healthiest fruits for you, Zumpano says. “Studies show that they help protect against aging, cancer and damage to your DNA.” A standard serving of 100 grams (3/4 of a cup) provides 65 calories and 15 grams of carbohydrates.

Here are a few reasons why blueberries are such a healthy option.

Rich in antioxidants

Stress isn’t good for your body — especially oxidative stress. This kind of stress occurs due to the presence of molecules called free radicals. Produced naturally as a result of metabolism or because of exposure to pollution, cigarette smoke and alcohol, free radicals don’t get along with your body. In fact, they damage cells.

Antioxidants are key to reducing the impact of oxidative stress. “Antioxidants create a barrier or a shield around the cell to help protect it from being damaged,” Zumpano explains. As it happens, blueberries are very high in antioxidants — specifically anthocyanins, which are also found in chokeberries and elderberries.

According to a 2004 study, a cup of cultivated blueberries (berries grown to eat) has 9,019 antioxidants. Lowbush (or wild) blueberries have 13,427 total antioxidants per cup.

Full of vitamins and minerals

In addition to being low in calories, blueberries are nutrient-dense. They’re good sources of vitamin C and vitamin K, as well as manganese.

A cup of blueberries provides the following recommended daily intake of vitamins and minerals:

  • Vitamin C: 24%.
  • Vitamin K: 36%.
  • Manganese: 25%.
  • Dietary fiber: 14%.

Vitamin C is known for boosting your immune system and fortifying other body functions, while vitamin K helps your blood clot properly. Manganese, meanwhile, can also help with blood clotting, while promoting bone and muscle strength.

Help manage cholesterol

Blueberries are high in soluble fiber. “Soluble fiber binds around the bile in our guts and helps remove that bile,” Zumpano says. Bile is waste that’s made of several things — including cholesterol, bile acids, salts, metals, and bilirubin (a substance produced after breaking down red blood cells) — which is why removing it is so important.

“When soluble fiber binds around the bile, it helps to remove that bile, composed of cholesterol with the body’s waste, therefore can lead to a reduction in cholesterol, which therefore leads to it preventing or reverse reducing your risk of heart disease,” she continues.

Potentially help manage blood sugar

Because blueberries are high in fiber and lower in sugar when compared to other fruits, they don’t cause your blood sugar to spike. For people with certain health conditions, scientists suspect this positive effect could aid with blood sugar management. A 2016 review of animal and human studies concluded that more human studies were warranted, though, on the effect of blueberries on insulin resistance, which can lead to diabetes. A later 2020 study of men living with Type 2 diabetes found that eating blueberries daily lowered certain cardiometabolic health parameters, such as triglycerides.

Potentially reduces blood pressure

2019 study of people living with metabolic syndrome found that eating blueberries daily had a positive impact. Although insulin resistance was unchanged, people saw a reduction in other areas. “Eating blueberries helps reduce blood pressure in people who have metabolic syndrome because it helps the body produce more nitric oxide, which relaxes your blood vessels,” Zumpano notes.

How to get the most benefits from blueberries

There’s no downside to eating blueberries every day because they’re so healthy. But Zumpano says you’ll get the most benefits from fresh, uncooked organic berries. While delicious, blueberry pancakes or muffins aren’t quite as healthy.

“Antioxidants can be harmed by heat,” Zumpano explains. “You don’t kill the fiber, and you still have the vitamins and minerals. But heat can affect the antioxidant content. So raw, fresh and organic blueberries are the best way to go.”

If you do buy non-organic blueberries, Zumpano also recommends washing them before eating. “I usually soak all my berries that are non-organic in lemon juice, or filtered water with baking powder,” she says. “I let them soak for a couple of minutes, and then drain and rinse them.”

The lemon juice tends to make them taste better, she adds. “Some of the berries get mushy after the baking soda. If it’s a rougher vegetable or something with a skin, like an apple or a cucumber or carrots, I’ll be more likely to use baking soda. However, berries tend to hold their share and texture better when cleaning with a filtered water with a small amount of lemon juice.”

Blueberries are also a versatile fruit suitable for meals at any time. You can enjoy them in cereal, oatmeal, smoothies or salads. “Organic frozen berries can be a little less expensive,” Zumpano says. “You can put them in hot oatmeal and let them defrost allowing their juices to release natural sweetness and flavor. Throw them in a smoothie, or just snack on them frozen for a refreshing snack for great ways to enjoy them.”

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