Last modified on May 23rd, 2023
If you have been diagnosed with diabetes or prediabetes, your doctor has likely talked to you about your A1c levels.
Your A1c level can help show how well-controlled your diabetes is, with lower numbers meaning better blood sugar control than higher numbers.
For this reason, if you have diabetes or prediabetes, your doctor likely pays close attention to your A1c.
What is A1c?
An A1c level is a marker for blood sugar control. Typically, a doctor will order a blood draw that will test for several different labs, including A1c. The A1c lab result is known by several different names, including hemoglobin A1C and HbA1c.
It shows up as a percentage value on lab results and can help your doctor determine if your diabetes is well-controlled. A1c is used to measure blood sugar control in type 1 diabetes, an autoimmune disease in which the body destroys the cells in the pancreas that produce insulin.
A1c is also used in type 2 diabetes, a disease where the cells in the body become less responsive to insulin, and the pancreas can no longer produce enough insulin to keep up with the body’s increasing needs.
The A1c test reflects the fact that hemoglobin, the component of red blood cells that carries oxygen, attaches to sugar in your bloodstream. The amount of sugar that is attached to the hemoglobin shows a snapshot of your overall blood sugar control over the average 3-month lifespan of the red blood cells in your body.
How Accurate is the A1c Test?
The A1c test is accurate in most people. However, because the A1c test looks at hemoglobin in red blood cells, if you have a medical condition that impacts hemoglobin or red blood cells, your test may be less accurate. Medical conditions that can skew an A1c result include:
- Severe anemia: Iron-deficiency anemia, a condition where you have low blood iron, leads to low hemoglobin levels. In turn, A1c test results may be falsely low. This is especially true in people with anemia severe enough to need medications to stimulate erythropoietin.
- Sickle-cell trait and sickle-cell anemia: These conditions, more common among people of African-American descent, involve abnormal hemoglobin. Studies have shown that A1c test results may be falsely low in people with sickle-cell conditions.
- Pregnancy: Because of the increased turnover in red blood cells in the second and third trimesters of pregnancy, A1c can be falsely in women during pregnancy. Further, A1c levels can be immediately postpartum.
- Glucose-6-phosphate dehydrogenase deficiency: This blood disorder, most common in males, increases the breakdown of red blood cells and can make A1c appear falsely low.
- Dialysis: People with severe kidney disease who get hemodialysis, a process that filters impurities from the blood, may have falsely low A1c levels.
- Blood loss or transfusion: A recent major blood loss or blood transfusion can cause A1c levels to appear falsely low.
- Other blood disorders: Any blood disorder that impacts the hemoglobin levels may distort A1c results.
How Often Should my A1c Be Checked?
Red blood cells that carry hemoglobin are recycled in your body every 3 months. For this reason, the A1c test is done every 3 months in many people with diabetes. Doing the test more often does not give the new red blood cells a chance to bind to your blood sugar enough to make a large difference in your lab values.
Sometimes, your doctor will check your A1c every 6 months. This is particularly true if your blood sugar and A1c are already well-controlled.
If you do not have diabetes, your doctor may check your A1c every 12 months just to make sure that you are not developing the disease.
Why Does A1c Matter?
A1c is closely linked to the risk of cardiovascular complications in diabetes. Good A1c control is linked to a 57% decrease in cardiovascular problems like heart attack and stroke in people with type 1 diabetes. Further, A1c control is associated with a long-term reduction in cardiovascular problems in some studies of people with type 2 diabetes. Studies have also shown that having a well-controlled A1c can reduce the risk of diabetic eye, kidney and nerve problems by 50% to 76%.
What Should My A1c Be?
A normal A1c is below 5.7%. If you have been diagnosed with prediabetes, which is an A1c of between 5.7% and 6.4%, your doctor has likely encouraged you to get your A1c below 5.7% to avoid a diabetes diagnosis.
An A1c of 6.5% or above indicates diabetes. Having an A1c at this level can be used to make a type 2 diabetes diagnosis, even if you do not have other symptoms of the disease like increased hunger, thirst, or excessive need to empty your bladder.
If you have diabetes, your doctor can help you decide what your goal A1c should be. In general, you should have an A1c goal of under 7% if you are a healthy young adult. As you get older, or if you have serious medical problems, your doctor may recommend a higher A1c goal.
How do A1c Levels Relate to Blood Sugar Levels?
An A1c shows the average blood sugar over the past 3 months. The higher the A1c, the higher the average blood sugar levels have been:
A1c | Average blood sugar |
6% | 126 mg/dl |
6.5% | 140 mg/dl |
7% | 154 mg/dl |
7.5% | 169 mg/dl |
8% | 183 mg/dl |
8.5% | 197 mg/dl |
9% | 212 mg/dl |
9.5% | 226 mg/dl |
10% | 240 mg/dl |
10.5% | 255 mg/dl |
11% | 269 mg/dl |
11.5% | 283 mg/dl |
12% | 298 mg/dl |
Because an A1c level looks back in time, it may not reflect recent changes in blood sugar levels. For example, if your average blood sugar level has been 240 mg/dl for several months, and over the past week it has decreased to 140 mg/dl, your A1c is likely to be close to 10%, despite the recent change in blood sugar.
How Can I Lower My A1c?
Experts recommend several different strategies for lowering your blood sugar and A1c. These include:
Nutrition
Nutrition is one of the best tools available to help lower A1c. However, it can be confusing to know what meal choices are best in diabetes. One of the first steps to taking control of your diet is learning about the nutrients in everyday foods. These include:
- Carbohydrates, or carbs: These nutrients are the body’s main source of energy and are converted into sugar in the bloodstream. Carbs include sugars, fibers and starches found in grains, fruits, vegetables and dairy.
- Protein: These nutrients help cells in the body repair and replace themselves. As such, they are also involved in growth and development, especially in children and pregnant women. Sources of protein include many animal products like meat, fish, and eggs. Vegetarian-friendly protein options include soy, beans and nuts.
- Fat: Fats are key nutrients in energy production and can also help your body absorb other nutrients. They also play a role in hormone production. Sources of fat include olive oil, butter, cream, and fatty meats and fish.
Experts do not think there is an ideal balance of carbs, protein and fats for people with diabetes to control their A1c. However, they recommend dietary changes that can improve blood sugar and lower A1c. These include:
- Eating non-starchy vegetables: Starchy vegetables like potatoes and corn break down quickly in the body. In turn, this leads to spikes in blood sugar as well as A1c. Choosing non-starchy vegetables can improve blood sugar and A1c because they break down slowly, leading to less of an increase in blood sugar. Further, non-starchy vegetables often contain high amounts of fiber, which can help you feel fuller for a longer period of time. Diabetes experts recommend 3 to 5 servings of non-starchy vegetables daily. Ideally, the vegetables should be fresh or frozen without sauce. Although canned vegetables may be used, canned goods often contain added sodium which can increase blood pressure. Healthy non-starchy vegetable choices include:
- Artichoke
- Broccoli
- Cabbage
- Carrots
- Cauliflower
- Celery
- Coleslaw
- Cucumber
- Eggplant
- Greens like collard greens, kale, and mustard greens
- Peppers
- Salad greens like lettuce
- Squash
- Tomato
- Reduce sugars and processed grains: One of the common causes of high blood sugar and A1c is sugar-containing food like sweets and candies, as well as processed grains like white rice and flour found in breads, cereals, pastries, crackers and cereals. Although sugar and processed grains are carbs, they break down very quickly in the bloodstream, leading to blood sugar spikes which, over time, can increase your A1c. Avoiding sugars and processed grains can help to ensure that your blood sugar and A1c stay well-controlled.
- Choose whole foods over processed foods: Whole foods, which have not been processed, refined, and have not had other ingredients mixed into them, can help to lower blood sugar and A1c. Because processed foods often contain little fiber, and may contain extra sugar and processed grains, whole foods can help lower blood sugar. An example of a whole food is pork, while sausage and bacon are processed foods. Similarly, an apple is a whole food, whereas apple pie is a processed food.
Weight Loss
Weight loss can help to control A1c, especially in people with prediabetes or type 2 Diabetes.
If you have prediabetes losing 7% to 10% of your body weight can help stop type 2 diabetes from developing. If you have type 2 diabetes, losing as little as 5% of your body weight can start to improve your blood sugar, blood pressure, and cholesterol levels.
Some people may see even more dramatic improvements in health with more weight loss, however, additional weight loss should be discussed with your doctor to make sure that it is safe for you. Long-term health benefits can result from weight loss, especially if you are able to keep the weight off in the long term.
Exercise
Exercise plays a big role in A1c lowering. Experts recommend that adults with diabetes spend at least 150 minutes a week doing at least moderate exercise, and that this time can be spread across several days. Further, resistance training 2 to 3 times a week is also beneficial, especially when combined with aerobic exercise. Even in people who do not lose weight, exercise can improve both A1c and overall health.
A1C Medications
Many people who need to lower their A1c need to rely on medications to achieve this. For example, people with type 1 diabetes no longer make insulin and need to take insulin for the rest of their lives as a result. Although people with type 2 diabetes may be able to control their disease with diet, exercise and weight loss, others will need medication to help control their blood sugar and A1c.
Diabetes medications work in different ways and can often be used together. Some people may prefer to take supplements to try to lower their A1c. However, because supplements and medications can have drug interactions and increase the risk of side effects like low blood sugar, it is important to tell your doctor or pharmacist what medications and supplements you are taking.
Some common medications for A1c lowering include:
Diabetes medication | How they work | Common side effects |
Metformin, sold under the brand names Fortamet, Glucophage, Glutmetza and Riomet | Makes your cells more sensitive to insulin and stops your liver from making sugar | Diarrhea, gas |
Insulin, sold under various brand names | Synthetic insulin that replaces the insulin that your body can no longer make | Low blood sugar |
SLGT2 inhibitors, like Farxiga (dapagliflozin) Invokana (canagliflozin) Jardiance (empagliflozin) Steglatro (ertugliflozin) | Increase the amount of sugar your body releases in the urine, lowering your blood sugar in the process | Urinary tract infections, yeast infection |
Sulfonylureas, like Amaryl (glimepiride) Diabeta (glyburide) Glynase (glyburide) Diabinese (chlorpropamide) Glucotrol (glipizide) | Cause your pancreas to release insulin. In turn, insulin makes the cells in your body take up sugar from the blood | Low blood sugar |
DPP4 inhibitors, like Januvia (sitagliptin) Onglyza (saxagliptin) Nesina (alogliptin) Tradjenta (linagliptin) | Cause your pancreas to release insulin in response to a meal. In turn, insulin makes the cells in your body take up sugar from the blood | Nausea, diarrhea |
GLP-1 agonists, like Byetta, Bydureon (exenatide) Eperzan, Tanzeum (albiglutide) Trulicity (dulaglutide) Victoza (liraglutide) Ozempic (semaglutide) Adlyxin (lixisenatide) | Increase the amount of insulin your pancreas makes. Insulin then causes your body’s cells to take up sugar from the blood. These medications also slow down how fast the contents of your stomach are processed, which in turn slows down spikes in blood sugar. | Nausea, diarrhea |
Supplements to Lower A1c
Researchers are studying several different supplements for A1c lowering. Although information is sparse about the A1c lowering effects of many commonly used supplements, several are promising.
However, because many people also need to take prescription medications to lower their A1c, it is important to tell your healthcare provider if you decide to try a supplement as well. Combining supplements with other diabetes medications can lead to an increased risk of side effects like low blood sugar.
Further, since diabetes increases the risk for many major health problems like heart attack and stroke, it is important to make sure your doctor knows what supplements you are taking in case the supplement has an impact on those health conditions.
Fenugreek
Fenugreek is a common herb used in cooking in many countries. Fenugreek has been shown to have a small effect on blood sugar lowering in several studies. However, this blood sugar lowering effect is only around 17 mg/dl, which is around a half-point of A1c.
Researchers think that fenugreek may reduce the amount of sugar absorbed in the intestines, and may also slow down digestion, leading to fewer blood sugar spikes. Scientists suspect that these effects are due to the high fiber and pectin contents of fenugreek.
Researchers have studied several different forms of fenugreek, finding that high-dose debitterized fenugreek seed powder may have more blood sugar lowering effects than other forms of the herb.
Researchers also suspect that the more fenugreek a person takes, the more their blood sugar is lowered. Studies that used less than 5 grams of fenugreek a day showed little impact on blood sugar, while studies that used higher doses, up to 100 grams in some cases, showed more blood sugar and A1c lowering.
Fenugreek
Researchers have found that high-dose fenugreek has the potential to lower blood sugar. There is also evidence that taking a fenugreek supplement might slow digestion, which can reduce the number of blood sugar spikes you experience.
Cinnamon
Cinnamon is a common spice used in cooking that has also been used for centuries in traditional medicine. Studies have shown that cinnamon may have a small effect on blood sugar lowering. On average, studies have shown that cinnamon lowers blood sugar by less than 25 mg/dl, which is less than a full point of A1c.
Researchers are not sure what chemicals in cinnamon cause this. However, researchers suspect that cinnamon somehow may activate the insulin receptor on cells, making them more sensitive to insulin. When cells become more sensitive to insulin, which triggers the cells to take up sugar, blood sugar levels are lowered.
However, both doses of cinnamon and even species of cinnamon have varied widely when tested. Some studies have used as little as 120 mg daily of cinnamon, while others have used up to 6000 mg daily.
Most studies on cinnamon have not taken the step to confirm the purity and chemical contents of the product. Further, more than 250 species of cinnamon exist, and there is no consensus on which ones are best for blood sugar and A1c lowering. For this reason, although cinnamon may help lower A1c, very little information is available on what the best cinnamon type and dose would be.
Researchers believe that cinnamon may help lower A1C because this supplement could make cells more active to insulin. Studies have found that on average, cinnamon lowers blood sugar by less than 25 mg/dl.
Chromium
Chromium is a trace element that is found in many foods like fish, nuts and whole grains. Chromium levels tend to be much lower in people with type 2 diabetes than in those without the disorder, although it is unclear if there is such a thing as chromium deficiency.
For this reason, researchers have been studying chromium in people with diabetes. Researchers think that chromium may stimulate the insulin receptor on cells, making the cells take up more blood sugar and thereby lower both blood sugar levels and A1c.
Chromium has been found to lower blood sugar levels and symptoms of high blood sugar in some studies, however different types of chromium were used, as well as a wide range of doses.
Maintaining good control of your A1c is important, whether you have prediabetes, type 1 diabetes or type 2 diabetes.
By controlling your A1c, you decrease your chances of having some of the complications of diabetes including nerve, eye and kidney problems.
Diet, exercise, weight loss, medications and occasionally supplements may help to control A1c. By working closely with your doctor, you can control your A1c and live a healthy life despite a diabetes diagnosis.
Chromium
Some studies have shown a potential for chromium to reduce A1C and blood sugar. This may be because chromium can stimulate cells’ insulin receptors, making them take up more blood sugar.
Dr. Jessica Pyhtila
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