Raspberries at Christmas
Beautiful berries this Christmas:
Berries are abundant at Christmas time in Australia. Not only are they lusciously cooling and delicious but they are powerful health giving additions to our diets. One of the most interesting new areas of research involves the potential for raspberries to improve management of obesity.
Quick facts on Raspberries
- Raspberries are low in calories and fats yet they are a rich source of dietary fibre and antioxidants.
- Scientific studies show that the antioxidant compounds in these berries play a potential role against cancer, aging, inflammation and neuro-degenerative diseases.
- Xylitol can be extracted from raspberries! A teaspoonful of xylitol carries just 9.6 calories as compared to 15 calories of sugar. Xylitol absorbed into the blood more slowly in the intestines than simple sugar and does not contribute to high glycemic index, so can be helpful in diabetics to regulate wide fluctuations of blood sugar levels.
- Fresh raspberries are an excellent sources of vitamin-C, contain anti-oxidant vitamins like vitamin A, and vitamin E. They contain a good amount of minerals like potassium, manganese, copper, iron and magnesium and are rich in B-complex group of vitamins and vitamin K.
Although this research is in its early stages, scientists now know that metabolism in our fat cells can be increased by phytonutrients found in raspberries, especially rheosmin (also called raspberry ketone). By increasing enzyme activity, oxygen consumption and heat production in certain types of fat cells, raspberry phytonutrients like rheosmin may be able to decrease risk of obesity as well as risk of fatty liver.
Perhaps the most interesting new area of research on raspberries involves management of obesity and type 2 diabetes. In the case of obesity, two compounds found in raspberries have received special attention: raspberry ketone (also called rheosmin) and a type of flavonoid called tiliroside.
Raspberry ketone is a compound that occurs naturally in raspberries, but unlike its name suggests Raspberry ketone is found in a wide variety of plants, although not usually in the sizable amounts that are found in raspberries. Turkish rhubarb, larch, yew, maple and pine are plants that contain amounts of raspberry ketone and in some studies, pine needles have been used as a source of this compound for research.
The rheosmin found in raspberries can boost metabolism in our fat cells by increasing enzyme activity, oxygen consumption and heat production in certain types of fat cells. By boosting fat metabolism in this way, we may be less likely to store fat in our fat cells and we may be able to use up some of the fat already stored there.
Raspberries and type 2 diabetes:
In obese persons with type 2 diabetes, a substance called adiponectin is not made in sufficient amounts or, if enough is made, it remains too inactive. This lack of adiponectin in obese persons with type 2 diabetes is a major problem for regulation of their blood sugar and blood fats. By activating adiponectin, the tiliroside in raspberries can help improve insulin balance, blood sugar levels, and blood fat balance in obese persons with type 2 diabetes. In studies, there is no indication that raspberry tiliroside will stop weight gain or prevent fat accumulation. However it may be able to help prevent the unwanted consequences of too much body fat and compromised regulation of blood sugar, blood insulin and blood fats.
Within the field of obesity and blood sugar regulation, another aspect of raspberry phytonutrients has captured the attention of researchers involving the ability of raspberry extracts to block activity of an enzyme called alpha-glucosidase. Alpha-glucosidase is a starch-digesting enzyme and when it becomes active in the digestive tract, it boosts the breakdown of starches into sugars. These sugars get taken up into the bloodstream and can cause excessively high levels of blood sugar following a meal. (This process is called postprandial hyperglycemia.) By restricting activity of alpha-glucosidase, raspberry extracts may make it possible for persons with type 2 diabetes (or obese persons experiencing problems with blood sugar regulation) to better manage their blood sugar levels.
What is the GI of Raspberries?
It’s been estimated that berries fall into the 40-50 GI range and for most researchers, that would place them in the low GI category. Since one cup of fresh raspberries provides about 15 grams of total carbohydrates and only 5-6 grams of sugar (compared with 8 grams of dietary fibre), a modest serving of fresh raspberries (for example, 1/2 cup) is likely to be a very good addition in most diets, even diets focused on stabilization of blood sugar.