A1C tests measure long-term regulation of blood glucose levels.
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What is an A1C test?
An A1C test measures how well the body is maintaining blood glucose levels. To do this, an A1C test averages the percentage of sugar-bound hemoglobin in a blood sample.
When glucose enters the blood, it binds to a red blood cell protein called hemoglobin. The higher blood glucose levels are, the more hemoglobin is bound.
Red blood cells live for around 4 months, so A1C results reflect long-term blood glucose levels. A1C tests are done using blood obtained by a finger prick or blood draw.
Physicians will usually repeat A1C tests before diagnosing diabetes. Initial A1C tests help physicians work out an individual's baseline A1C level for later comparison.
How often A1C tests are required after diagnosis varies depending on the type of diabetes and management factors.
Lowering A1C levels
Many studies have shown that lowering A1C levels can help reduce the risk or intensity of diabetes complications.
With type 1 diabetes, more controlled blood glucose levels are associated with reduced rates of disease progression. With type 2 diabetes, more controlled A1C levels have also been shown to reduce symptoms affecting the small arteries and nerves in the body. This influences eyesight and pain while decreasing complications.
Long-term studies have also shown that early and intensive blood glucose control can reduce cardiovascular complications in people with type 1 or 2 diabetes.
Even small changes in A1C levels can have big effects. The ADA recommend that maintaining fair control over blood glucose levels lowers the chance of diabetes complications significantly. They suggest that most people with diabetes should maintain A1C levels below 7 percent. A diagnosis of diabetes occurs with an A1C of 6.5 percent or higher on two separate occasions.
There are many ways to help reduce or control A1C levels using a combination of physical activity and diet.
Physical activity tips to help lower A1C levels include:
- Getting a minimum of 150 minutes of moderate physical exercise is recommended weekly. That equates to 30 minutes at least 5 days per week.
- Increasing activities of daily life (ADLs). These are defined as routine activities that people tend to do daily. Workout schedules are helpful, but all activity can help in lowering A1C levels.
- Monitoring blood glucose to ensure targets are being met and changes addressed.
- Sticking to treatment or medication plans.
- Setting and achieving weight loss goals.
- Tracking progress for self-motivation and physician reference.
- Getting others involved. Lifestyle changes are often easier to adopt if other people can encourage and monitor progress.
Nearly all foods aside from lean proteins contain some sugar. Managing sugar intake and maintaining a healthful diet is key to lowering A1C levels healthfully.
General diet tips to lower A1C levels include:
- controlling portion sizes
- keeping a strict meal schedule, eating every 3-5 hours
- eating similar sized portions at meals and snacks
- planning meals ahead of time
- keeping a journal of food, medication, and exercise
- spreading out carbohydrate-rich foods throughout the day
- choosing less processed or whole foods like whole grains, fruits, vegetables, legumes, and nuts
- eating a balanced diet complete with healthy proteins, fats, and carbohydrates
- seeking out the help of a registered dietitian
Another diet tip is carbohydrate counting. The ADA define one serving of carbohydrates as 15 grams and recommend adults consume 45 to 60 grams with each meal. Increasing or decreasing intake may be necessary depending on individual needs, exercise routines, and treatment plans.
Foods that lower A1C
The longer food takes to digest, the slower and lesser the impact it has on blood sugar levels. Foods with simple sugars are digested much quicker and can spike blood glucose levels.
Most blood glucose management plans focus on controlling carbohydrates, the main dietary source of glucose (sugar).
While managing carbohydrates is important, people do not need to avoid them altogether. Carbohydrates are the body and brain's main fuel source and contain important nutrients.
People with diabetes can enjoy carbohydrates while maintaining healthy A1C levels as long as consumption is balanced and spread out evenly throughout the day.
Carbohydrates are broken into sugars, starches, and fibers. Sugars contain molecules that are quickly absorbed, causing blood glucose level to spike. Starches contain sugar molecules that take longer to be broken down and absorbed, affecting blood glucose levels more evenly over time.
Fiber is complex, and takes longer to break down, which provides more sustainable energy and decreases the spike in blood sugar. Fiber also helps flush the digestive tract.
Less processed, natural sugars like those found in fruits, vegetables, and low-fat dairy products are recommended over added, refined sugars. Whole fruits, vegetables, and dairy products all contain far higher levels of vital nutrients than most processed foods and less sugar.
For most fruits and vegetables, one serving of carbohydrates is about ½ cup or 4 ounces.
Although all whole fruits and vegetables have natural sugars and nutrients, some have more than others. Many vegetables contain high levels of fiber.
Low-sugar fruit and vegetable options include:
Many berries are considered to be relatively low in sugar.
- cranberries, raspberries, blackberries, and strawberries
- tangerines, nectarines, and plums
- broccoli and cauliflower
- kale, cabbage, bok choy, and Brussels sprouts
- spinaches, collard greens, and Swiss chard
- cucumbers and zucchini
Fruits and vegetables that are high in sugar should not be avoided but controlled. Many contain vital nutrients that are difficult to obtain elsewhere.
Lactose is the sugar found in dairy products. There is typically not a huge difference in sugar amounts between full fat, reduced fat, or non-fat milk.
Low or no-sugar dairy options include:
- plain yogurts
- cottage cheese
- unsweetened creamers
Low-sugar, dairy-free options include:
- unflavored, fortified soy, rice, almond, flax, and coconut milk or products
Starches or complex carbohydrates include grains, starchy vegetables, and legumes and should make up most of carbohydrate consumption. For most grains and starches, half a cup contains one 15 gram serving of carbohydrates.
While starches are better carbohydrate choices than simple sugars, not all starches are created equally.
Whole-grain breads, cereals, pastas, and rices contain B and E vitamins, minerals, essential fatty acids, and fiber. Bleached or processed grains and cereals generally contain fewer nutrients and higher levels of sugar than whole-grain products.
People with diabetes should be wary of products that claim to be made with or contain whole wheat. Many still have high levels of refined grains and even more added sugar.
The best whole-grain options include:
- whole-wheat flour
- buckwheat or buckwheat flour
- cracked wheat
- whole-grain barley
- whole rye
- whole oats
- brown rice
- wild rice
- whole faro
- whole-grain corn or corn meal
Starchy vegetables and legumes
Plenty of starchy vegetables and legumes also contain high levels of nutrients and fiber in their skins or pods. Some vegetables, such as root vegetables like potatoes, have much higher concentrations of starch than others. For these, consumption need be monitored more closely.
Parsnips, sweet potatoes, and pumpkins are all good starchy options for lowering A1C levels.
Healthful, starchy vegetable and legume options include:
- green peas
- black, lima, and pinto beans
- butternut, acorn, and spring squash
- dried black-eyed or split peas
- low-fat refried beans or baked beans
- yams or sweet potatoes
- palm hearts
Understanding A1C levels
A1C test results are expressed as a percentage. The greater the A1C level, the greater the risk of diabetes complications.
Physicians may also describe A1C test results in terms of average glucose, or eAG. The eAG is determined by correlating A1C values with whole numbers.
In the United States, eAG results are reported in milligrams per deciliter (mg/dL). Based on A1C results, eAG represents average 3-month blood glucose levels.
|A1C value||eAG value||ADA diagnosis|
|5.6 percent or less||117 mg/dl or less||Normal|
|5.7-6.4 percent||117-137 mg/dl||Prediabetes|
|6.5 percent or more||137 mg/dl||Diabetes|
A1C level recommendations vary between individuals. People with more advanced diabetes will have higher A1C targets than healthy adults without diabetes. Factors like life expectancy, treatment response, and medical history also have an impact.
|A1C value||eAG value||ADA recommended goal for|
|5.6 percent or below||117 mg/dl or below||Healthy, adults without diabetes|
|6.5 percent||140 mg/dl||People with short-term diabetes, managed type 2 diabetes, no cardiovascular disease, long life expectancy|
|7 percent or less||154 mg/dl or less||Most non-pregnant adults with diabetes|
|8 percent or less||183 mg/dl or less||People with long-standing or severe diabetes, limited life expectancy, extensive additional health complications, or poor treatment response|