Fresh blueberries are one of my favorite fruits. I have to limit how many I eat, though, since blueberries have more fructose than other berries. In fact, fresh blueberries are the only popular berry that isn’t low fructose at normal serving sizes.
Blueberries are high fructose. Half a cup of commercially grown blueberries has 3.7 grams of fructose. Wild blueberries have less fructose, but blueberries typically exceed the low fructose guideline of 3 grams fructose per serving or less.
In this post we’ll look at at the fructose content of different kinds of blueberries. Though wild blueberries are widely grown in North America, most blueberries sold in grocery stores are a commercial variety. We’ll discuss the differences between the two. But let’s start by reviewing the various ways researchers define low and high fructose.
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What is High Fructose?
There aren’t commonly agreed upon definitions of “low fructose” and “high fructose.” Low FODMAP researchers use one standard to define low fructose. Other researchers and nutritionists use different standards.
Low FODMAP researchers use the excess fructose rule to classify foods as low or high fructose. They do this by comparing the amount of glucose and fructose in foods to find the amount of excess fructose.
If a food has more glucose than fructose, it has no excess fructose. If a food has more fructose than glucose, it has excess fructose. Foods that have less than .15 to .40 grams of excess fructose per serving are considered low FODMAP and, thus, low fructose.1
The excess fructose guideline isn’t really used outside of low FODMAP studies. Other researchers use either percent fructose or fructose per serving, instead.
The percent fructose rule is really simple. If fructose makes up 50% or more of the total sugar content, then a food is considered high fructose. Any food in which fructose makes up less than 50% of total sugar content is considered low fructose.2
The fructose content per serving rule considers only the amount of fructose in a food. Typically, if a food has 3 or more grams of fructose per serving, it’s considered high fructose. This is true regardless of how much glucose is in the food or how much fructose contributes to total sugar content.3
In this post, I’ve included data on fructose, percent fructose and excess fructose for different types of blueberries.
Types of Blueberries
Blueberries are produced from a flowering plant that can range in height from 4 inches to 13 feet. Blueberries that grow on smaller plants are called lowbush blueberries, while those that grow on taller plants are called highbush blueberries.4
Lowbush blueberries are also known as wild blueberries. Wild blueberries are typically much smaller than highbush blueberries. But, don’t be confused by the term “wild.” These days, both highbush and lowbush (wild) blueberries are mostly farm or field grown.4 Lowbush blueberries are harvested in many areas, including eastern Canada, Alaska and Maine, which produces the majority of wild blueberries grown in the United States.5
All types of blueberries are high in vitamins C and K and are also a good source of fiber.6 Blueberries are also thought to reduce the risk of cardiovascular disease and type 2 diabetes.7 Wild blueberries in particular have high levels of polyphenols, which have been shown to protect against neurodegenerative disorders by reducing brain inflammation.8
Blueberries have been called a “superfood” and are certainly deserving of the label. However, they are a bit high in fructose. Those who must watch their fructose intake closely need to be mindful of their blueberry consumption. This is especially true for dried blueberries, which have much more fructose than their fresh counterparts.
Blueberry Fructose Content
The easiest way to measure fructose in blueberries is simply by looking at the fructose content. The table below shows the amount of fructose in blueberries at normal serving sizes.
|Type||Serving Size||Fructose (grams)|
|Wild (Alaska)||1/2 cup||2.48|
|Dried, sweetened||1/4 cup||11.10|
As shown, a half cup of commercial blueberries, the kind most commonly sold in grocery stores, has about 3.7 grams of fructose. This exceeds the recommended 3 grams of fructose or less per serving for those following a low fructose diet.
If you much watch your fructose intake carefully, wild blueberries are a better option. They are more difficult to find in stores, however. And, as evident in the table, you should avoid dried blueberries completely.
Excess Fructose in Blueberries
The excess fructose rule is the one typically used by low FODMAP researchers. This compares the amount of fructose to the amount of glucose in a food.
If fructose is the only FODMAP present in a food, as is the case with blueberries, then the amount of excess fructose should be .40 grams or less. The following table shows excess fructose calculations for different types of blueberries at normal serving sizes.
|Wild (Alaska)||1/2 cup||2.29||2.48||.19|
|Dried, sweetened||1/4 cup||11.70||11.10||N/A|
As shown, applying the excess fructose rule gives drastically different results. While commercial blueberries are considered high fructose when only taking into account fructose content, they are considered low FODMAP and, thus low fructose, based on FODMAP standards.
Wild blueberries actually have more excess fructose than commercial blueberries. They’re still considered low FODMAP, but rate high on the FODMAP scale, despite the fact that they’re considered low fructose when compared to commercial blueberries.
And dried blueberries are also considered low FODMAP, because the added sugars change the glucose-to-fructose ratio so that they have no excess fructose. Which may lead some people to think they’re healthy, even though they’re loaded with sugar.
Comparing fructose content to excess fructose really highlights the significance of how fructose is measured. Someone who must follow a low fructose diet should probably not use the low FODMAP excess fructose rule when deciding which fruits to put on their safe list.
And, don’t forget, there’s another way to measure fructose, just to add more confusion.
Percent Fructose in Blueberries
The percent fructose rule simply states that if fructose makes up more than 50% of total sugar in a food, then the food is high fructose. Below 50%, the food is considered low fructose.
In order for this rule to be helpful, you have to know the total sugar content, plus the amounts of each type of sugar in a food. So, it’s a bit more involved than the other two rules, which look only at fructose and glucose.
I’ve included a breakdown of the sugar content in blueberries in the table below. As shown, fructose contributes between 47% to 50% to the total sugar in blueberries. Blueberries also contain lots of glucose, but only small amounts of sucrose.
Blueberry Sugar Content
|Wild (Alaska)||1/2 cup||.00||2.29||2.48||4.77||52.00%|
|Dried, sweetened||1/4 cup||.54||11.70||11.10||23.34||47.56%|
Using the 50% rule, we can see that wild blueberries are classified high fructose at normal serving sizes. Commercial blueberries fall just below the 50% threshold, while dried sweetened blueberries have the lowest percentage of fructose.
Blueberries provide a good example of how the different ways of measure fructose content can lead to different, and confusing, results. But, this situation isn’t unique to blueberries. For example, I’ve written before about why bananas are considered high fructose, even though they’re classified as low FODMAP.
Conclusion: Blueberries are High Fructose
Based on most measures, commercial blueberries, the kind typically sold in grocery stores, are high fructose. That said, the fructose content of blueberries barely exceeds the 3 grams of fructose per serving rule. This is why, in my post on low fructose fruits, I listed blueberries as moderate fructose rather than high fructose.
As discussed here, how you measure fructose matters a lot. Most low fructose diets use the fructose content rule, rather than the excess fructose or percent fructose rules. Research on low fructose diets suggest keeping total daily fructose intake to between 10 and 15 grams.9
Obviously, if your doctor has told you to restrict fructose intake, you should follow their recommendation. But, if you think fructose may be causing you digestive issues, you may try limiting intake to less than 15 grams a day as a start.
Personally, I’m finding that the fructose content of a food is a bigger factor for me than excess fructose, so have stopped following low FODMAP guidelines when it comes to fructose intake. Fortunately, I can still enjoy blueberries, but reduce my serving size to a fourth of a cup.
Posts Related to “Are Blueberries High in Fructose?”
I mentioned that I’d written a post on low fructose fruits. This post lists more than 15 fruits that fall within the 3 gram rule. It also contains a list of moderate fructose fruits, those with 3 to 5 grams of fructose per serving.
And, on the flip side, I also created a list of high fructose fruits that you should avoid. Truthfully, most fresh fruits are low to moderate fructose; only a handful are truly high fructose, containing more than 5 grams of fructose per serving. But, that post has a full discussion of dried fruit, which really is something low fructose eaters should avoid.
About the Author
Amanda Coleman, PhD, studies food culture and teaches a popular Food and Society course. Years of digestive problems led her to live low FODMAP. Now she uses her research and analysis skills to help others understand FODMAP essentials, so they can lead better, healthier lives.
Disclaimer: the author is not a certified medical professional. Opinions expressed and content contained on this website are for informational purposes only and should not be interpreted as medical advice. Exercise caution and due diligence when using this site and the information contained herein and understand your experiences may vary.