Every time you pick up a magazine, you see warnings about the dangers of sugar and for good reason! Consumption of sugar is linked with weight gain, poor blood sugar control, and even mental health issues such as anxiety and depression. Plus, when you consume a diet rich in sugar, it triggers rapid swings in your blood glucose level. Your blood sugar and your mood are up one minute but this rise is quickly followed by an energy crash that leaves you feeling tired and hungry. Sound familiar? With so much emphasis on avoiding sugar, some people have taken sugar avoidance to the next level. They’ve chosen to avoid all sugar, including sugar you find naturally in fruit. Is that a smart idea?
Yes, fruit does contain varying quantities of natural sugar, some of which is fructose and the rest glucose. We’ve heard a lot about the potential dangers of fructose, particularly high fructose corn syrup, as you find in many packaged foods. Studies suggest that your body processes fructose differently than it does glucose. In fact, when fructose reaches your liver, your liver uses it to synthesize fat through a process called lipogenesis. Some studies link the consumption of fructose with a higher risk of nonalcoholic fatty liver disease, a growing epidemic in this country. Wouldn’t fruit that’s high in fructose carry the same risks?
Is the Natural Sugar in Fruit Unhealthy?
Don’t be too quick to dismiss fruit for its high fructose content, as many low-carbers are doing. In fact, based on some studies, eating fruit may actually improve blood sugar control. An example is a study published in the Journal of Nutrition. In the study, researchers asked 32 obese men and women, without diabetes, to drink one of two smoothies twice daily for six weeks. One group drank a smoothie that contained 22.5 grams of blueberry bio-actives. The second group drank smoothies that were equivalent nutritionally but didn’t contain blueberry bio-actives.
After the smoothie meals, researchers measured insulin sensitivity and inflammatory markers for both groups. The results? The group that drank the blueberry smoothie experienced greater improvements in insulin sensitivity – and that bodes well for metabolic health. If you only looked at the natural sugar content of blueberries, around 15 grams per serving, you might be tempted to avoid blueberries but, as this study shows, blueberries may actually boost insulin sensitivity and blood sugar regulation. Berries are generally lower in natural sugar than other fruits, although, among the berries, blueberries rank high in sugar content. In contrast, raspberries only have 5 grams of sugar per serving.
Do Even High-Sugar Fruits Help with Blood Sugar Control?
Although blueberries contain more natural sugar than other berries, they contain less sugar than another tasty, tropical fruit, the mango. In fact, a serving of mango clocks in at 23 grams of natural sugar. Most low carbers avoid relatively high-sugar fruits, like mango, entirely due to concerns about their impact on blood sugar. Yet, even the relatively sugary mango doesn’t seem to negatively impact blood sugar and may even improve blood sugar control.
How do we know this? In a small study, 20 obese, young and middle-aged adults, consumed 10 grams of freeze-dried mango daily for 12 weeks. At the end of 12 weeks, the participants experienced significant improvements in fasting blood sugar levels. Plus, the mango was freeze-dried, making it a more concentrated source of sugar. Yet, it was still linked with better glucose control.
Mangos have other health benefits that make them an appealing fruit to munch on. For one, mangoes are a rich source of an antioxidant called zeaxanthin that blocks the negative effects of blue light on the back of the eye. Eating zeaxanthin-rich foods may also lower the risk of eye problems, like macular degeneration, one of the most common causes of visual loss in older people.
Why Natural Sugar Doesn’t Negatively Impact Blood Sugar
If you look at fruit only in terms of its sugar content, you’re not giving it enough credit. Fruit is a complex blend of vitamins, minerals, phytonutrients, and fiber. One reason eating a bowl of fruit doesn’t cause a rapid rise in blood sugar like a pastry does is the fiber content of fruit. When a food contains fiber, it slows the absorption of sugars from the fruit, leading to a less pronounced rise in blood glucose and insulin.
Plus, a class of phytonutrients in fruit, called polyphenols, may slow the rise in blood sugar. Some research suggests that polyphenols, a type of antioxidant, may moderate the blood sugar response and lower the risk of metabolic syndrome and type 2 diabetes. In addition, research suggests that polyphenols may also protect against some of the complications of diabetes in people who already have it. Fruit has a combination of polyphenols and fiber, which is favorable for blood sugar control. Plus, some studies show that fruit protects against another common complication of diabetes, stroke.
The Bottom Line
Cut back or eliminate sugar from packaged foods, soft drinks, desserts, and other sources of added sugar. Also, avoid carbohydrates such as products made with white flour – but don’t eliminate fruit from your diet. A piece of fruit is chock full of fiber and phytonutrients that are beneficial for your health and these components change how your body responds to the natural sugar in fruit. If you prefer fruit lower in sugar, stick to berries. They’re the most nutrient-dense fruit and lowest in sugar as well. Whatever you do, don’t give up fruit based only on their sugar content – you’ll miss out on too many other benefits.
Harvard Health Letter. “Abundance of fructose not good for the liver, heart”
J Nutr. 2010 Oct; 140(10): 1764–1768.Published online 2010 Aug 19. doi: 10.3945/jn.110.125336.
Nutrition and Metabolic Insights 2014:7 77-84. August 28, 2014.
Berkeley Wellness. “Don’t Be Afraid of Fruit”
Nutrients. 2016 Jan; 8(1): 17. Published online 2016 Jan 5. doi: 10.3390/nu8010017
Diabetes Daily. “The Health Benefits of Polyphenols for Diabetics”
Neurology. 2005 Oct 25;65(8):1193-7.
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