If you have diabetes (or someone you know does) it’s likely that you have to check your blood sugar levels regularly. In fact, you may be performing a “finger-prick” blood test a few times a day. Accurate readings are a must for maintaining good health. You might not be aware, however, that food particles on your fingers can push blood sugar readings higher than they really are.
According to a study performed at Juntendo University Graduate School of Medicine in Tokyo, Japan, sugars from fruit will stay on your fingers until you wash them with tap water. So, peeling fruit right before you use a blood sugar meter or eating some juicy fruit with your hands, for example, could lead to an inaccurate reading even if you rub your finger with alcohol first.
A blood sugar meter works by taking a drop of blood from the tip of your finger and testing the sample for how much sugar is in the blood drop. Many people with diabetes use these meters more than once a day to monitor their blood sugar levels. They can help a diabetic determine how much insulin to take.
For the study, 10 healthy volunteers were recruited. None of the volunteers had diabetes; they all had normal blood sugar levels. The researchers measured the blood sugar levels of the volunteers under a variety of conditions. First, participants swabbed a finger with alcohol and did the test before handling any fruit, to find their true blood sugar levels.
Next, the researchers had the volunteers peel oranges, grapes or kiwis and checked their blood sugar under three different states: without doing any washing up; after cleaning up with alcohol; and after washing with tap water.
The researchers found that blood sugar levels remained the same when fruit peeling was followed by hand-washing. But when volunteers peeled fruit and took a blood sugar reading right away, the levels shown by the blood sugar meter shot up. The biggest jump was recorded after handling grapes.
This is when the researchers discovered that if the peelers swabbed their finger with alcohol in between peeling and doing the blood test, the readings were still higher than normal. Even swabbing five times didn’t produce correct results.
The important message from the study seems to be to wash your hands before using a blood sugar meter and not to rely on just alcohol swabs (recommended in the directions of most blood test kits), especially if you’ve been handling any fruit.