When we decided to offer dried berries, we looked hard for ones that did not have any added sugar.
Most dried berry makers apply a bit of sugar to get an appealing sweet-tart balance … and a very thin oil coating to keep the berries from sticking together.
Our organic berries are very lightly coated with organic hi-oleic sunflower oil, which is extremely low in the omega-6 fatty acids that most Americans consume to unhealthful excess.
But we've had no luck finding dried berries that meet our criteria – certified organic, with great taste and texture – that don't have a very small amount of added organic sugar.
What is the
For years, foods have been ranked according to their glycemic index or GI, which is a measure of the blood sugar response they elicit over a two hour period.
Last year, Swedish scientists developed the glycemic profile (GP) measuring system to provide a more accurate picture of the blood glucose response to a given food.
The new GP system is more accurate because it considers the change in blood sugar levels over a period of three hours, shown as a curve on a graph.
The flatter the resulting blood sugar curve, the better. Foods that produce an even, reasonably low curve score as having the healthiest (highest) GP score.
A food with a high GP indicates that the energy lasts longer, and the ideal is for a food to have a low glycemic index (GI) and a high GP.
For example, white pasta has a high glycemic index. However, the GP of white pasta is just as good (high) as the GP of whole-wheat pasta.
(Of course, there are other reasons to choose whole grain products over white flour ones, such as more fiber and antioxidants.)
One example is boiled rye kernels, which have a GI of 73 (100 is the GI of white wheat bread) and a high GP of 94.
In contrast, boiled wheat kernels have a slightly lower GI of 68 but a lower GP of 51, which suggests that rye kernels have a healthier blood sugar profile.
Some carb-conscious customers have expressed concern about the added sugar, but clinical research suggests that those misgivings are misplaced, for two reasons.
First, dried fruits are inherently high in sugar, because removal of their water concentrates all other constituents, including their naturally occurring sugars (mostly sucrose).
Thus, the small amount of sugar added to their exterior doesn't raise their sugar content a great deal.
Second, new research from Scandinavia shows that the polyphenol-type antioxidants in berries can blunt and even neutralize the effects of dietary sugar on our blood sugar and insulin levels.
Twin Finnish studies find berries suppress blood sugar spikes
We came across two recent clinical trials, from separate academic centers in Finland.
Study #1: Sweetened berries yield no sugar spike
This small clinical trial involved 10 healthy men and was conducted by researchers from Finland's University of Turku (Linderborg KM, Jarvinen R, Lehtonen H-M et al. 2012).
At separate times the subjects were given a fat-free yogurt meal with one of four variations:
Added sugar (50 grams / 1.7 oz of glucose) with lingonberry powder (40 grams / 1.4 oz).
Added sugar (50 grams / 1.7 oz of glucose) without added lingonberry powder.
Added fat (35 grams / 1.25 oz of triglycerides) with added lingonberry powder (60 grams / 2.1 oz).
Added fat (35 grams / 1.25 oz of triglycerides) without added lingonberry powder.
To ensure greater accuracy, the researchers used a “crossover” study design, in which the men switched places to consume the other test meals, and had their blood analyzed after each meal.
The results showed that the berry powder prevented any spike in blood sugar or insulin when the participants ate the sugared yogurt.
This was true even though the sweetened yogurt with added lingonberry powder had more sugars than the control (unsweetened) yogurt (64.7 grams versus 50 grams, respectively).
Unsurprisingly, adding berries to the added-fat yogurt did not prevent a rise in blood fat levels.
Study #2: Berries blunt the effects of dietary sugar
Another clinical trial comes from the University of Eastern Finland (Törrönen R et al. 2012).
The scientists recruited 12 healthy people into a randomized, single-blind, placebo-controlled crossover study
They wanted to measure what happened to the volunteers' blood sugar and insulin levels after eating sugar alone, versus eating sugar plus a blend of berries.
The subjects consumed two different test meals on separate days:
Berry Meal – Pureed berries (150 grams / 5.3 oz of bilberries, blackcurrants, cranberries, and strawberries) plus white sugar (35 grams / 1.25 oz of sucrose).
Control Meal – White sugar (35 grams / 1.25 oz of sucrose) in water.
Blood samples were taken before the meals and at 15, 30, 45, 60, 90, and 120 minutes after starting to eat the meal.
Compared to the Control Meal, the Berry Meal resulted in lower blood glucose and insulin levels after 15 minutes.
Although the Berry Meal produces slightly higher blood sugar levels after 90 minutes, it reduced the maximum increases in blood glucose and insulin levels and improved the participants' “glycemic profiles” ... which is more important (see our sidebar, “What is the “glycemic profile”?).
As the authors wrote, “These results suggest that the glycemic control after ingestion of sucrose can be improved by simultaneous consumption of berries.” (Törrönen R et al. 2012)
Linderborg KM, Jarvinen R, Lehtonen H-M, Viitanen M, Kallio HPT. The fiber and/or polyphenols present in lingonberries null the glycemic effect of the sugars present in the berries when consumed together with added glucose in healthy human volunteers. Nutrition Research doi: 10.1016/j.nutres.2012.06.004
Linderborg KM, Lehtonen HM, Järvinen R, Viitanen M, Kallio H. The fibres and polyphenols in sea buckthorn (Hippophaë rhamnoides) extraction residues delay postprandial lipemia. Int J Food Sci Nutr. 2012 Jun;63(4):483-90. Epub 2011 Nov 18.
Törrönen R, Sarkkinen E, Niskanen T, Tapola N, Kilpi K, Niskanen L. Postprandial glucose, insulin and glucagon-like peptide 1 responses to sucrose ingested with berries in healthy subjects. Br J Nutr. 2012 May;107(10):1445-51. Epub 2011 Sep 20.