Postprandial glucose, insulin, and free fatty acid response to sucrose consumed with blackcurrants a
Berries and berry products are essential source of polyphenols, such as anthocyanins, ellagitannins and proanthocyanidins, in the Nordic diet. Berries contain only limited amount of available carbohydrates (mainly glucose and fructose), and they have a very low glycemic effect. However, berries are often consumed with added sugar. Sugar masks the acidic taste of many berries and increase their consumption, but on the other hand, may decrease the health benefits of the berries.
Sucrose is one of the principle sugars used in the diet. Sucrose is structured from glucose and fructose. Sucrose and glucose trigger increases in postprandial blood glucose and insulin concentrations, followed by hypoglycemia and increased free fatty acid concentration. Repeated postmeal fluctuation of the concentration of sugar, insulin and free fatty acid in blood may promote for example oxidative stress, inflammation, dyslipidemia, insulin resistance and repeated feelings of hunger.
The study investigated the effects of sugared blackcurrant- and lingonberry purées and nectars on the postmeal concentrations of glucose, insulin and free fatty acids in the blood.
An expectation was that polyphenolic-rich berries inhibit digestion and absorption of sugar and suppress postprandial glycemia.
The study design included 20 healthy women as subjects. The study meals were:
- Control meal: 300 mL water + 35 g sucrose
- Blackcurrant-purée: 150 g smashed berries + 150 mL water + 35 g sucrose
- Lingonberry-purée: 150 g smashed berries + 150 mL water + 35 g sucrose
- Blackcurrant-nectar: 300 mL (industrial juice concentrates, diluted with water 1:1, equal to 150 g fresh berries) + 35 g sucrose
- Lingonberry-nectar: 300 mL (industrial juice concentrates, diluted with water 1:1, equal to 150 g fresh berries) + 35 g sucrose
The blood samples for plasma glucose, insulin and free fatty acid were drawn before the test meal (0 min) and 15, 30, 45, 60, 90 and 120 after starting to eat the meal.
According to the most important results, the concentrations of glucose, insulin and free fatty acid in plasma were lower after sugared blackcurrant- and lingonberry purées than after sugared control meal. Similar, but weaker tendency in plasma glucose, insulin and free fatty acid concentrations were found after nectar-meals as purées.
In summary, the fluctuation of glucose concentration in blood caused by added sugar is milder when consumed with blackcurrants and lingonberries than without berries. This may be due to the slower digestion and absorption of carbohydrates when sugar is consumed with polyphenol-rich berries. This finding has practical implications because especially blackcurrants and lingonberries are usually sweetened with sugar before consumption.
Törrönen, R., Kolehmainen, M., Sarkkinen, E., Mykkänen, H. & Niskanen, L. (2012) Postprandial glucose, insulin, and free fatty acid response to sucrose consumed with blackcurrants and lingonberries in healthy women. Am J Clin Nutr. 96: 527-533.Avainsanat:
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