For those who have been diagnosed with diabetes, fasting for a blood glucose test is essential for the ongoing treatment and management of the condition. Not only does the test give an accurate measure of blood sugar levels during a time outside of eating and drinking, but it can also help doctors diagnose any abnormal tendencies that arise from the result.
A common question among those fasting for a blood glucose test is whether caffeine consumption, whether in the form of coffee, tea or soft drinks, is still allowed during the fasting period. Despite the prevalence of the question, the answer is not as straightforward as you might expect.
According to Brian Cody, MD, endocrinologist at the University of Michigan, some studies have found a modest effect of caffeine consumption on elevating blood glucose levels. A study published in Diabetes Care (Cougle et. al., 2003) suggested that this effect could be as much as 8% of overall blood glucose levels.
Therefore, Dr. Cody recommends that those who are fasting should avoid coffee and other caffeinated beverages, or at least reduce their consumption, as far as possible. But because the effect of caffeine can vary from individual to individual, it is not guaranteed to raise blood sugar levels.
The American Diabetes Association further advises to all those with diabetes who plan to take a fasting blood glucose test to stop consuming any form of caffeine at least 8 hours before their blood draw. Such advice can help reduce any possible influence of caffeine on the blood sugar levels and improve the accuracy of the test.
In conclusion, due to the effects caffeine can have on blood sugar levels, consuming coffee before a fasting blood glucose test is not generally recommended. However, as the impact can vary from person to person, it is ultimately up to the individual and their medical team to decide.
Calculation of Glucose Levels
When a person undergoes a fasting blood glucose test, their blood sugar level is measured and calculated. The actual calculation corresponds to the amount of glucose present in a deciliter of blood and is expressed in milligrams of glucose per deciliter of blood (mg/dL).
For those who have been diagnosed with diabetes, the American Diabetes Association recommends that fasting blood sugar measurements should typically be below 100 mg/dL. Non-diabetics typically have readings of 70-99 mg/dL. Any measurements higher than these could be indicative of diabetes or other conditions which affect blood sugar levels.
In certain circumstances, a healthcare professional may request an Oral Glucose Tolerance Test (OGTT). This is done by measuring the person’s blood glucose levels both before and after drinking a glucose-containing solution.
Types of Blood Glucose Tests
Depending on the type of blood glucose test the individual is due to take, the guidelines around consuming coffee beforehand may differ. For instance, in the case of a glycated hemoglobin (A1C) test, which is used to assess long-term blood sugar levels, no fasting is typically required. Therefore, consuming coffee is generally not an issue.
However, for those undergoing a glucose tolerance test – the preferred method for women who have gestational diabetes – then the healthcare practitioner will likely request that the individual avoids consuming caffeine for at least 8 hours prior to the test.
The Link Between Caffeine and Blood Glucose Levels
Though research is currently inconclusive, some studies suggest that caffeine consumption can increase blood glucose levels, albeit slightly. This effect is thought to be down to the two main ingredients found in coffee, which are caffeine and chlorogenic acid.
Chlorogenic acid is known to reduce the absorption of glucose in the intestine. The presence of caffeine can be thought to reduce this effect and, as such, can lead to a slight raise in blood sugar levels.
However, according to a study published in the Diabetes Care journal, the effect of caffeine on blood sugar levels is small in most cases. Many researchers believe that more research is needed to identify why some people seem to experience more of an effect from caffeine than others.
The Effect of Coffee in Non-Fasting Blood Glucose Tests
For blood glucose tests which are not taken in a fasting state, does the same advice about avoiding coffee apply? Generally, the answer is no.
In this instance, because the person is eating and drinking normally, the intake of caffeine is likely to be less of a factor. As such, an individual is usually free to drink coffee or other caffeinated drinks at the same rate they usually would.
Methods of Preventing Blood Sugar Spikes
Aside from avoiding coffee, tea, and soft drinks, as well as other caffeinated beverages, there are some other steps people can take to limit the effect on their blood sugar levels.
A good first step is to maintain a healthy and balanced diet, with whole foods and an appropriate amount of protein and carbohydrates, to help stabilize the levels of insulin in the body. Additionally, ensuring you keep hydrated and exercising regularly can help maintain healthy and balanced blood sugar levels.
Diagnosis and Treatment for Diabetes
The results of a fasting blood glucose test can be essential in confirming or ruling out a diagnosis of diabetes. If diagnosis is made, then it is important to follow the advice of the doctor and make any necessary dietary and lifestyle changes accordingly.
In most cases, this means working closely with a dietician or nutritionist to ensure that the diet you follow is beneficial in terms of controlling your blood sugar levels. Besides, seeking advice on how to increase physical activity to assist in the management of diabetes is also essential.
Monitoring Blood Glucose at Home
For those living with diabetes, tracking their blood glucose levels on a regular basis can be important. Making use of a home glucose monitor can help to do this in a straightforward and convenient manner.
In most cases, a home glucose monitor consists of a single-use disposable strip to take a sample of a drop of blood, which is then put into a machine for measuring. The readings given by the machine are used to track blood sugar levels at home and assess the effectiveness of any dietary and lifestyle changes.
Medicinal Options to Treat Diabetes
In some cases, a doctor may prescribe medication to help treat diabetes, in addition to any dietary and lifestyle advice. Typical medications suggested as part of diabetes management include insulin, GLP-1 receptor agonists, and metformin.
All medications come with possible side effects and it is important to consult a healthcare practitioner before taking any new drugs for the treatment of diabetes.
