Written by Lina Pena. Reviewed by Diana Licalzi, MS, RD, CDE.
Bananas generate a lot of controversy in the health and diabetes world. People often associate them as a high carbohydrate food but did you know a medium banana has nearly the same carb content as a medium apple? And that a banana has less natural sugar (fructose) than a whole range of fruit? More on this later! From vitamins, minerals, instant energy, enhanced mood, and heart health benefits, bananas provide a lot of health benefits for only 100 calories. In this blog, we’ll take a deeper dive and find out while this fruit might not be as bad as you think.
High in Carbs? Think again.
Bananas are often villainized for their high carbohydrate and natural sugar content, but they contain very similar quantities as many other fruit. For example, as seen below, one cup of blueberries contains almost as many carbs as a medium banana and even has one more gram of sugar! So, next time someone tells you bananas are a high-carb fruit, surprise them with your new nutrition knowledge. What’s more, by choosing slightly under-ripe (green-yellow) bananas you can significantly decrease their impact on your blood sugars.
According to the International Glycemic Index Database, green-yellow bananas have a low glycemic index (GI) of 51. The glycemic index (GI) measures the extent to which blood sugar levels rise after eating a specific food. A GI score of 55 or less is considered low, meaning these foods will not raise blood sugar significantly. On the other hand, a GI score of 70 or more is considered high, meaning foods digest much faster and cause a spike in blood sugar.
Banana's Secret Nutrient
Slightly under-ripe bananas also contain ample resistant starch -- an indigestible type of carbohydrate. As its name implies, this type of starch resists digestion and absorption in the small intestine. Similar to fiber, resistant starch acts like a barrier slowing down glucose from entering the bloodstream. Studies show that approximately 15-30 grams of resistant starch a day can improve insulin sensitivity by as much as 33-50%! A slightly green banana contains roughly 4.7 grams of resistant starch. Other foods rich in the nutrient include beans, lentils, peas, and whole grains like oats and barley.
When put to the test in humans, how do bananas affect blood sugar? In this study, participants with type 2 diabetes received 250 or 500g of bananas for breakfast (about two to four medium-sized bananas!) for 14 weeks. At the end of the study, the results showed that daily intake of bananas significantly lowered participant’s blood sugar. So remember, while bananas may contain 27g of carbohydrates, over a third of those carbs are from fiber and resistant starch -- carbohydrates that your body can’t even digest and absorb!
A Way to Control Blood Pressure
People with type 2 diabetes face a greater risk of developing hypertension, also known as high blood pressure. One effective method of controlling blood pressure is by consuming a potassium-rich diet. Potassium is a vital mineral and electrolyte essential for heart health and controlling blood pressure. How can you get a healthy dose of potassium? Bananas! One medium banana has approximately 422mg of potassium, which contributes about 20% of your daily recommended potassium levels. In addition to potassium, bananas have zero saturated fat or sodium and contain an array of other nutrients including vitamin B6, manganese, magnesium, and vitamin C. If you suffer from high blood pressure, consider adding high potassium foods like bananas to your diet.
Tips for Eating Bananas with Type 2 Diabetes
- Choose slightly under-ripe bananas for their beneficial resistant starches, which help control post-meal blood sugar levels.
- Pair bananas with high fiber non-starchy vegetables and/or fruit, like a spinach, blueberry and banana smoothie.
- If you tend to experience very high glucose levels after meals (aka you are very insulin resistant), start with half an under-ripe banana. As you transition to a plant-based lifestyle, you will notice your insulin sensitivity improve and your post-meal glucose levels will stabilize after meals.
Now let's take our bananas to the kitchen! Who doesn't like a little after-dinner dessert? This chilled and refreshing dessert is especially perfect for the summer months.
- 1 banana, frozen, chopped
- 1 tbsp cocoa powder (high in magnesium)
- ¼ cup nut milk, or any type of alternative milk
- sprinkle of cinnamon
- 1 tbsp hemp seeds, optional (provides an extra boost of healthy fats, protein, helps to control blood sugar)
Blend all ingredients in food processor. Sprinkle with hemp seeds. Enjoy!
Potassium Intake and Risk Of Stroke in Women With Hypertension and Nonhypertension in the Women's Health Initiative. Seth A;Mossavar-Rahmani Y;Kamensky V;Silver B;Lakshminarayan K;Prentice R;Van Horn L;Wassertheil-Smoller S; - https://pubmed.ncbi.nlm.nih.gov/25190445/
WHFoods. 2020. Bananas. http://www.whfoods.org/genpage.php?tname=foodspice&dbid=7
NHS. 2015. High Blood Pressure: Does it lead to Diabetes? https://www.nhs.uk/news/diabetes/high- blood-pressure-does-it-lead-to-diabetes/#:~:text=People%20with%20high%20blood %20pressure,risk%20of%20more%20than%2070%25
Maki KC, Pelkman CL, Finocchiaro ET, et al. Resistant starch from high-amylose maize increases insulin sensitivity in overweight and obese men. J Nutr. 2012;142(4):717‐723. doi:10.3945/jn.111.152975
Resistant Starch Improves Insulin Sensitivity in Metabolic Syndrome. Johnston, Thomas, Bell, Frost, & Robertson. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1464-5491.2009.02923.x
What is Resistant Starch?http://hopkinsdiabetesinfo.org/what-is-resistant-starch/