An A1C blood test measures average blood sugar levels over the past 2 to 3 months.

The American Diabetes Association (ADA) recommend using A1C tests to help diagnose prediabetes, type 1, and type 2 diabetes.

Doctors also use A1C tests to monitor diabetes treatment plans.

If a person's A1C levels are too high, this means their blood sugar levels are too high. Lowering blood sugar levels will reduce a person's A1C percentage.

Why is this important? Read on to find out.

Nurse takes a blood test for A1CShare on Pinterest
A doctor or nurse will take a blood test to assess a person's A1C levels.

An A1C test measures how well the body is maintaining blood glucose levels. It shows the average percentage of sugar-bound hemoglobin in a blood sample.

When glucose enters the blood, it binds to a red blood cell protein called hemoglobin. Hemoglobin carries oxygen around the body.

The higher blood glucose levels are, the more hemoglobin it binds.

Red blood cells live for around 4 months, so A1C results reflect long-term blood glucose levels.

A1C tests use blood from a finger prick or blood draw.

Physicians will usually do more than one A1C test before diagnosing diabetes.

The first test will help a physician work out an individual's baseline A1C level for later comparison.

How often a person with a diagnosis of diabetes needs to do an A1C test will vary, depending on the type of diabetes and management factors.

Many studies have shown that lowering A1C levels can help slow the progression of diabetes and reduce the risk of complications — such as nerve damage and cardiovascular disease — in both type 1 and type 2 diabetes.

Even small changes in A1C levels can have significant effects.

The American Diabetes Association recommend maintaining A1C levels below 7 percent for most people.

A doctor will diagnose diabetes if a person's A1C level is 6.5 percent or higher on two separate occasions.

Physical activity, diet, and possibly medication, can help manage blood glucose levels, and therefore also A1C levels.

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Regular exercise can help manage glucose levels and boost overall wellbeing.

Exercise and lifestyle tips to help lower A1C levels include:

  • Physical activity: Current guidelines recommend that adults should do 150–300 minutes of moderate physical exercise each week. People who use insulin should talk to their doctor about a suitable plan.
  • Routine activities: Housework, gardening, and other routine activities can all help keep a person moving.
  • Monitoring blood glucose: This is crucial to ensure the person meets their targets and makes any necessary changes.
  • Following the treatment plan: This includes the use of medications and lifestyle therapies.
  • Target weight: The person should work on setting and achieving any weight loss goals.
  • Tracking progress: This is useful for self-motivation, for monitoring changes, and for identifying which strategies work for an individual.
  • Getting others involved: Lifestyle changes are often easier to adopt if other people can encourage and monitor progress.

Everyone, especially people with diabetes, can benefit from a healthful diet that includes plenty of fresh fruit and vegetables and whole foods and is low in sugar, salt, and fat.

Monitoring carbohydrate intake can help a person manage their glucose levels.

General diet tips to lower A1C levels include:

  • being mindful of portion sizes
  • eating regularly, 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

A healthcare professional will advise each person on their dietary needs, including the number of carbs they should consume. This will depend on individual factors, including the person's exercise levels and treatment plan.

Food that takes longer to digest, such as whole grains, will have a slower and less significant impact on blood sugar levels.

A person will digest simple sugars — present in candies and white bread — more quickly. This can trigger a blood sugar spike.

Frequent glucose spikes can speed up the development of diabetes and increase the risk of complications.

Carbohydrates

A person with diabetes needs to manage their carb intake, but they do not need to avoid carbs altogether. Carbohydrates are the body and brain's main fuel source and contain important nutrients.

Tips for a healthful carb intake include:

  • spreading carb intake throughout the day
  • choosing the right kinds of carb

There are three types of carbohydrate:

  • Sugars: The body absorbs these quickly, causing blood glucose level to spike.
  • Starch: These take longer to absorb, and are less likely to cause a glucose spike.
  • Fiber: This is essential for health. Its benefits include reducing the risk of high blood sugar levels.

Fiber

Fiber is complex and takes longer to break down, so it provides more sustainable energy and decreases the risk of a spike in blood sugar. Fiber also helps keep the digestive tract healthy.

Research has found that when women consume at least 25 grams (g) of fiber a day and men 38 g or more, the chance of developing type 2 diabetes can fall by 20–30 percent.

Sources of fiber include whole grains, nuts, and whole fruits and vegetables. Fresh, whole fruit contains more fiber than fruit juice made with fresh fruits.

Natural sugar

The body absorbs refined sugars, such as candies, quickly, and this can lead to dangerous rises in blood glucose.

Fruits, vegetables, and low-fat dairy products contain less processed sugars that are more healthful than refined sugars.

Whole fruits, vegetables, and dairy products all contain far higher levels of vital nutrients than most processed foods and less sugar.

All whole fruits and vegetables contain natural sugars, but they also tend to be rich in other nutrients, including fiber.

Low-sugar options

Low-sugar fruit and vegetable options include:

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Many berries are considered to be relatively low in sugar.
  • lemon
  • rhubarb
  • lime
  • guava
  • kiwifruit
  • tangerines, nectarines, and plums
  • olives
  • avocados
  • grapefruit
  • broccoli and cauliflower
  • kale, cabbage, bok choy, and Brussels sprouts
  • lettuce
  • spinaches, collard greens, and Swiss chard
  • cucumbers and zucchini
  • tomatoes
  • mushrooms
  • celery
  • cranberries, raspberries, blackberries, and strawberries

People with diabetes do not need to avoid fruits, but they should account for the carbohydrates and sugars they contain. They should also eat fruits in moderation.

Dried fruits contain more sugar than fresh fruits.

Lactose

Lactose is the sugar that occurs in dairy products. One cup of 1-percent fortified milk contains 12.8 grams of carbohydrate, which is mostly lactose.

Low-sugar, dairy-free options include unflavored, fortified soy, rice, almond, flax, and coconut milk or products

    Lactose levels are similar in full-fat, reduced-fat, and non-fat milk, but people with type 2 diabetes often need to take care of their weight. For this reason, a low-fat version may be a better option.

    Whole grains

    Starches or complex carbohydrates include:

    • grains
    • starchy vegetables
    • legumes

    Most of a person's carbohydrate consumption should consist of these. For most grains and starches, half a cup contains one 15 gram serving of carbohydrates.

    Starches are better carbohydrate choices than simple sugars, but the body can absorb highly processed starches rapidly, leading to increases in blood sugar levels.

    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.

    Some products that claim to contain whole wheat still have high levels of refined grains, and they may contain added sugar.

    The best whole-grain options include:

    • whole-wheat flour
    • buckwheat or buckwheat flour
    • cracked wheat
    • whole-grain barley
    • whole rye
    • millet
    • sorghum
    • whole oats
    • brown rice
    • wild rice
    • quinoa
    • whole faro
    • popcorn
    • whole-grain corn or corn meal
    • triticale
    • amaranth

    A healthcare professional will advise on how much carbohydrate a person should consume each day.

    Starchy vegetables and legumes

    Share on Pinterest
    Vegetables are a good source of fiber and other nutrients.

    Plenty of starchy vegetables and legumes also contain high levels of nutrients and fiber in their skins or pods.

    Some vegetables have higher concentrations of starch than others. These include root vegetables like potatoes. People should monitor their consumption of these vegetables more closely than others.

    Healthful, starchy vegetable and legume options include:

    • corn
    • green peas
    • black, lima, and pinto beans
    • butternut, acorn, and spring squash
    • pumpkin
    • parsnip
    • plantain
    • dried black-eyed or split peas
    • lentils
    • low-fat refried beans or baked beans
    • yams or sweet potatoes
    • taro
    • palm hearts
    • garlic

    A1C test results appear as a percentage. A higher A1C level means a greater risk of diabetes and its complications.

    Physicians may also refer to average glucose, or eAG, when they talk about A1C levels. The eAG corresponds to A1C, but it appears as milligrams per deciliter (mg/dl), like blood sugar.

    Both A1C results and eAG refer to a person's average 3-month blood glucose levels.

    A1C valueeAG valueADA diagnosis
    5.6% or less117 mg/dl or lessNormal
    5.7-6.4%117–137 mg/dlPrediabetes
    6.5% or more137 mg/dlDiabetes

    A person with prediabetes has a good chance of reversing their high blood sugar levels and preventing diabetes from developing. Get some tips and strategies for managing prediabetes here.

    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 valueeAG valueADA recommended goal for
    5.6% or below117 mg/dl or belowHealthy, adults without diabetes
    6.5%140 mg/dlPeople with short-term diabetes, managed type 2 diabetes, no cardiovascular disease, long life expectancy
    7% or less154 mg/dl or lessMost non-pregnant adults with diabetes
    8% or less183 mg/dl or lessPeople with long-standing or severe diabetes, limited life expectancy, extensive additional health complications, or poor treatment response

    A1C levels are a measure of blood glucose over 2–3 months. A person whose A1C level is 6.5 percent or more will need to take steps to lower their levels.

    Strategies include healthful dietary choices, exercise, and medication, for some people.

    Click here to find out more about healthy blood glucose levels.