Authors: Mahima Viswanathan, MBBS; Rinky Agnes Botleroo, MBBS; Satya Harika Manda, MBBS
Mentor: Dr. Lubna Mirza, MD Norman Endocrinology Associates
The mango-diabetes ‘paradox’
Mangifera Indica (Mango), commonly referred to as the “king of fruits,” is one of the most coveted but forbidden fruits for people on a diabetic diet aiming to control their blood sugars. It is a common belief that mango contains lots of simple carbohydrates that rapidly spike blood sugar level, which is detrimental to achieving glycemic control and overall ‘bad for your health’ when you have diabetes- and so people are usually advised against eating them. However, this may not be completely true. In fact, mango is a highly nutritious fruit with several health benefits.
Yes, you read that correctly. Per data from the USDA National Nutrient Database for Standard Reference, 100 grams of fresh mango contains 14.98 g of carbohydrates, 0.82 g of protein, 0.38 g of fat, and 1.6 g of fiber, contributing approximately 60kcal of energy. Over 90% of these calories are shown to come from carbohydrates, the main reason why diabetic mango connoisseurs counseled on diet management often fear mangoes may increase their blood sugar levels uncontrollably and are to be avoided in their entirety. However…
Glycemic index- all foods are not created equal
Even if two foods have identical carbohydrate content, their effect on blood glucose levels varies. The glycemic index (GI) is a value calculated to measure this and helps predict the blood sugar responses to different foods. On a scale of 0–100, 0 means no effect on blood sugar level, and 100 represents the anticipated impact of spooning pure sugar into one’s mouth. Any food with GI under 55 is considered low, and the GI of mango ranges from 51-56. This number seems relatively low for a fruit supposedly full of sugar and terrible for one’s health, does it not? That is because the higher soluble dietary fiber (1.6 g), antinutrients (phytic acid) and organic acids (malic, citric, and tartaric acids) within the pulp slow down digestion and absorption of sugars and are thus responsible for mango’s lower GI compared to fruits such as banana (62) and watermelon (72).
Mango anatomy and blood sugar
Mangiferin, a phenolic compound found in mango pulp, peel, and seeds, is observed to have hypoglycemic properties, moderating and lowering blood sugar. It achieves this by inhibiting glucosidase enzymes responsible for carbohydrate digestion and decreases intestinal glucose absorption. What this means is that including the pulp and peel in one’s mango portion will make the blood sugar rise slower and to a lesser extent. This is also the reason why highly processed forms of mango without the fruit fiber, such as bottled mango juice, have a very high glycemic index and are frowned upon by your dietician.
The beauty of a mango
Yes, mangoes are appealing- both visually and gastronomically- but their charm does not end there. Mangoes contain significant amounts of nutrients we require on a regular basis- vitamins (A, C, E, Niacin), minerals (sodium, potassium, calcium, iron, zinc, etc.), and phytochemicals.
Mangoes have strong antioxidant properties- compounds that fight highly unstable, toxic oxygen radicals called reactive oxygen species or ROS produced by our bodies as a byproduct of normal physiological functioning. The ROS can accumulate in our body, leading to cellular dysfunction which can injure the cells and cause complications of diabetes like damage to the eyes, nerves, kidneys, or blood vessels. Mango antioxidants such as Vit C, carotenoids, mangiferin and gallic acid decrease the levels of these free radicals and have protective effects on the body. Further, studies on vitamin C have shown that the recommended daily intake (RDA) is about 75 mg in adult women and 90 mg in adult men (higher in pregnancy and smokers), and taking up to 1000 mg per day was found to reduce blood sugar levels, lipid levels, and overall inflammatory status in people with diabetes with or without high blood pressure. As ¾ cup of mango provides 50% of the RDA, a moderate amount of mango intake may thus contribute to one’s daily requirements.
Mango also possesses anti-inflammatory, anticarcinogenic, liver protective and antimicrobial properties. Apart from lowering blood sugar, the fruit fiber promotes healthy bacteria in the gut and a stronger immune system.
Mangoes in diabetes- clinical studies
Allopathic physicians provide dietary advice derived from evidence-based medicine. This means that they can only make recommendations that have been scientifically analyzed, measured and proven to be beneficial in a way that can be redemonstrated. This high level of precision and reliability of doctors’ advice is based on the hundreds of clinical trials that have been conducted by researchers. Here are some of the mango-related research studies conducted in humans:
Edo et al. studied the glycemic response of five fruits, namely banana, orange, pineapple, pawpaw, and mango, among ten people with Diabetes mellitus Type 2. Each subject received standardized portions of 50 grams of carbohydrate per serving. Mango showed the lowest rise in post-meal blood sugar levels, followed by orange and pawpaw. Studies such as this one determined mango’s comparatively lower GI.
A study conducted by Evan et al. revealed that eating freeze-dried mango decreases blood sugar levels in both men and women. Twenty obese individuals aged 20-50 years old were given 10g/day of ground freeze-dried mango pulp for three months to study weight loss and sugar control. Even though the participants did not lose weight- men experienced decreased hip circumference, while women observed no changes- this study revealed the sugar controlling effects of mango fiber, and was one among many to analyze different parts of the mango.
Ray et al. compared the postprandial glycemic response to mango to an equal amount of starchy product (white bread) among individuals with diabetes versus nondiabetic control subjects. Results showed 50g of mango produced a similar glycemic response as that of 14g of white bread, emphasizing that naturally occurring sugars from mango are highly preferable over starchy refined ones and do not cause postprandial hyperglycemia in normal or diabetic individuals. This study emphasized the importance of the type of carbohydrate consumed with respect to blood sugar and is a key principle of the diabetic diet.
Glycemic load- is this the caveat?
Mango as a food has been given a low-medium glycemic index, but that doesn’t mean it can become the mainstay of one’s diet. Monitoring the glycemic index of food helps better manage post-meal sugars, determine appropriate combinations of fiber, fat and protein with the carbs consumed and indicates which carbohydrate sources are of better quality than others.
However, one’s blood sugar levels are ultimately affected by the total carbohydrate load in the diet, irrespective of composition. The ‘glycemic load’ is considered a better measure to determine the complete impact of carbohydrates on blood sugar- taking into account the speed of digestion with glucose absorption and the amount of glucose present in a normal serving of the food. The medium range of glycemic load is from 11-19.
One serving of mango is ¾ cup, with a glycemic load of 18.9. When consumed along with fiber, protein or fat, the glycemic index of the whole meal is said to be lower. However, the glycemic load of the mango itself remains the same, and the total calories consumed actually increases. Regular overindulgence will lead to uncontrolled blood sugars that cause a whole host of complications. Nonetheless, in the spirit of maintaining a high quality of life in the face of a chronic disease like diabetes, mango is permissible- but moderation is key.
What’s the bottom line
Diabetes can seem to be all about the numbers, all of the time. The number on the GI scale, the sugar numbers before and after a meal, the number of grams of carbohydrates consumed. Taking these numbers into account is important, but it is not everything.
People with diabetes can still eat mangoes if they follow certain precautions. The most important ones are to ingest fruit pulp rather than juice and avoid overeating at a time. Consuming smaller portions of mangoes like half a cup (82.5g) and cutting down on other carbohydrates like rice minimizes the glycemic load and fluctuations in blood sugar levels. Having mango as a snack in between meals is a good option to lower total meal carbohydrate intake. Consumption along with high fiber food such as salads, beans or whole grains and good protein sources like boiled eggs, cheese and nuts can further lower the glycemic index.
Mango is a delicious fruit. By limiting portion sizes and regularly monitoring blood glucose levels, patients with diabetes can include it in their diet and enjoy its flavor.