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Type 1, Type 2, Diabetes Community

How Too Much Sugar in the Blood Causes Damage in the Body

By: Editorial Staff

When faced with a diabetes diagnosis, some people have a hard time wrapping their heads around the complications that may come with the disease and why the complications happen. That is understandable, since there is so much information to absorb and the explanations can seem scary.  

Learning how to prevent complications can be easier when you understand the science behind WHY they happen.

When medical professionals talk about diabetes, they usually mention the complications of damage to the eyes, kidneys, heart and nerves. These all have one thing in common- blood vessel damage. Blood vessels play a key role helping to transport glucose (sugar) and insulin throughout the body. Diabetes contributes to high blood sugar (hyperglycemia) and high blood sugar, over time, causes damage to blood vessels.1

When there’s a high level of sugar in your blood, and your body or medications are not lowering it, the excess sugar starts attaching to proteins in blood cells, forming advanced glycation end products (AGEs).2 When your healthcare provider orders a glycated hemoglobin (A1C) test, they are measuring one type of AGE.2

AGEs are present in all of our bodies, even in babies.2 But AGEs form at a faster pace, and accumulate, in people with diabetes because of the available excess sugar in the blood.2 These AGEs cause damage to the interior wall of blood vessels, causing inflammation, formation of blood clots, stiffness, and decreases their ability to regenerate.3 These disruptions affect blood circulation in small vessels causing tissue and organ damage, leading to vision loss and kidney failure. Over time this process can also lead to clogging of larger vessels, which may lead to heart attack and stroke.4


Smoking increases the concentration of AGEs in blood, leading to more severe blood vessel damage and risk of vascular-related diseases in people living with diabetes.3

The good news is that you can prevent further damage by keeping your blood sugar in a healthy range. Studies show that following a diet high in fresh, unprocessed foods, cooked briefly with ample water (like steaming) can decrease AGE intake by more than 50%.2 Consistent lifestyle changes, such as eating a healthy diet and adding moderate exercise to your routine, are helpful to keeping diabetes in check and avoiding complications.5,6 Keeping A1C levels below 7% decreases the risk of cardiovascular diseases and other complications.7,8

You’ll work closely with your healthcare provider to set what your target blood sugar levels should be, and when you should be checking. It's important to test your blood sugar levels frequently- especially when starting medications for the first time. You can track your blood sugar levels using our blood sugar log template. Share your results with your healthcare provider who can help determine how well your treatment program is working for you.

With the help of your physician and other health professionals, it is possible to maintain good health and avoid complications in the future.

The information provided on this blog is for general educational, communication and information purposes only and is not intended to replace medical advice, treatments or diagnosis by your own healthcare provider.

Articles are written by MannKind Corporation staff and contributors from the diabetes community.


[1] Kolluru GK, Bir SC, Kevil CG. Endothelial Dysfunction and Diabetes: Effects on Angiogenesis, Vascular Remodeling, and Wound Healing. International Journal of Vascular Medicine. 2012;2012:918267. doi:10.1155/2012/918267.

[2] Peppa M, Uribarri J, Vlassara H. Glucose, Advanced Glycation End Products, and Diabetes Complications: What Is New and What Works. Clinical Diabetes. 2003;21(4):186-187. doi:10.2337/diaclin.21.4.186.

[3] Tabit CE, Chung WB, Hamburg NM, Vita JA. Endothelial dysfunction in diabetes mellitus: Molecular mechanisms and clinical implications. Reviews in endocrine & metabolic disorders. 2010;11(1):61-74. doi:10.1007/s11154-010-9134-4.

[4] Wei X, Schneider JG, Shenouda SM, et al. De NovoLipogenesis Maintains Vascular Homeostasis through Endothelial Nitric-oxide Synthase (eNOS) Palmitoylation. Journal of Biological Chemistry. 2010;286(4):2933-2945. doi:10.1074/jbc.m110.193037.

[5] Fox CS, Golden SH, Anderson C, et al. Update on Prevention of Cardiovascular Disease in Adults With Type 2 Diabetes Mellitus in Light of Recent Evidence: A Scientific Statement From the American Heart Association and the American Diabetes Association. Diabetes Care. 2015;38(9):1777-1803. doi:10.2337/dci15-0012.

[6] Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and Type 2 Diabetes: The American College of Sports Medicine and the American Diabetes Association: joint position statement. Diabetes Care. 2010;33(12):e147-e167. doi:10.2337/dc10-9990.

[7] American Diabetes Association. Standards of Medical Care in Diabetes 2018. Diabetes Care 2018 Jan; vol41 (Supplement 1): S1 -S2. doi: 10.2337/dc18-S004.

[8] Kilpatrick ES, Rigby AS, Atkin SL. A1C Variability and the Risk of Microvascular Complications in Type 1 Diabetes: Data from the Diabetes Control and Complications Trial. Diabetes Care. 2008;31(11):2198-2202. doi:10.2337/dc08-0864.

Important Safety Information for Afrezza (insulin human) Inhalation Powder

Afrezza can cause serious side effects, including: Sudden lung problems (bronchospasms). Do not use Afrezza if you have long-term (chronic) lung problems such as asthma or chronic obstructive pulmonary disease (COPD). Before starting Afrezza, your healthcare provider will give you a breathing test to check how your lungs are working.


Afrezza can cause serious side effects, including: Sudden lung problems (bronchospasms). Do not use Afrezza if you have long-term (chronic) lung problems such as asthma or chronic obstructive pulmonary disease (COPD).


What is the most important information I should know about Afrezza?

Afrezza can cause serious side effects, including:

Sudden lung problems (bronchospasms). Do not use Afrezza if you have long-term (chronic) lung problems such as asthma or chronic obstructive pulmonary disease (COPD). Before starting Afrezza, your healthcare provider will give you a breathing test to check how your lungs are working.

  • Afrezza is a man-made insulin that is breathed-in through your lungs (inhaled) and is used to control high blood sugar in adults with diabetes mellitus. 
  • Afrezza is not for use in place of long-acting insulin. Afrezza must be used with long-acting insulin in people who have type 1 diabetes mellitus. 
  • Afrezza is not for use to treat diabetic ketoacidosis. 
  • It is not known if Afrezza is safe and effective for use in people who smoke. Afrezza is not for use in people who smoke or have recently stopped smoking (less than 6 months). 
  • It is not known if Afrezza is safe and effective in children under 18 years of age.

Do not use Afrezza if you:

  • Have chronic lung problems such as asthma or COPD.
  • Are allergic to regular human insulin or any of the ingredients in Afrezza. See the end of this Medication Guide for a complete list of ingredients in Afrezza. 

Before using Afrezza, tell your healthcare provider about all your medical conditions, including if you:

  • Have lung problems such as asthma or COPD
  • Have or have had lung cancer
  • Are using any inhaled medications
  • Smoke or have recently stopped smoking
  • Have kidney or liver problems
  • Are pregnant, planning to become pregnant, or are breastfeeding. Afrezza may harm your unborn or breastfeeding baby.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins or herbal supplements.

Before you start using Afrezza, talk to your healthcare provider about low blood sugar and how to manage it.

  • Read the detailed Instructions for Use that comes with your Afrezza.
  • Take Afrezza exactly as your healthcare provider tells you to. Your healthcare provider should tell you how much Afrezza to use and when to use it.
  • Know the strength of Afrezza you use. Do not change the amount of Afrezza you use unless your healthcare provider tells you to.
  • Take Afrezza at the beginning of your meal.
  • Check your blood sugar levels. Ask your healthcare provider what your blood sugar should be and when you should check your blood sugar levels.
  • Keep Afrezza and all medicines out of the reach of children.
  • Change in level of physical activity or exercise, weight gain or loss, increased stress, illness, change in diet, or because of other medicines you take. 

While using Afrezza do not:

  • Drive or operate heavy machinery, until you know how Afrezza affects you.
  • Drink alcohol or use over-the-counter medicines that contain alcohol.
  • Smoke.

Afrezza may cause serious side effects that can lead to death, including:

See “What is the most important information I should know about Afrezza?” at the top of this page.

  • Low blood sugar (hypoglycemia). Signs and symptoms that may indicate low blood sugar include:
    • Dizziness or light-headedness, sweating, confusion, headache, blurred vision, slurred speech, shakiness, fast heartbeat, anxiety, irritability or mood change, hunger.
  • Decreased lung function. Your healthcare provider should check how your lungs are working before you start using Afrezza, 6 months after you start using it and yearly after that.
  • Lung cancer. In studies of Afrezza in people with diabetes, lung cancer occurred in a few more people who were taking Afrezza than in people who were taking other diabetes medications. There were too few cases to know if lung cancer was related to Afrezza. If you have lung cancer, you and your healthcare provider should decide if you should use Afrezza.
  • Diabetic ketoacidosis. Talk to your healthcare provider if you have an illness. Your Afrezza dose or how often you check your blood sugar may need to be changed.
  • Severe allergic reaction (whole body reaction). Get medical help right away if you have any of these signs or symptoms of a severe allergic reaction:
    • A rash over your whole body, trouble breathing, a fast heartbeat, or sweating.
  • Low potassium in your blood (hypokalemia).
  • Heart failure. Taking certain diabetes pills called thiazolidinediones or “TZDs” with Afrezza may cause heart failure in some people. This can happen even if you have never had heart failure or heart problems before. If you already have heart failure it may get worse while you take TZDs with Afrezza. Your healthcare provider should monitor you closely while you are taking TZDs with Afrezza. Tell your healthcare provider if you have any new or worse symptoms of heart failure including:
    • Shortness of breath, swelling of your ankles or feet, sudden weight gain.

Treatment with TZDs and Afrezza may need to be changed or stopped by your healthcare provider if you have new or worse heart failure.

Get emergency medical help if you have:

• Trouble breathing, shortness of breath, fast heartbeat, swelling of your face, tongue, or throat, sweating, extreme drowsiness, dizziness, confusion.

The most common side effects of Afrezza include:

  • Low blood sugar (hypoglycemia), cough, sore throat

These are not all the possible side effects of Afrezza. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088).

Active ingredient: human insulin

Inactive ingredients: fumaryl diketopiperazine, polysorbate 80

General information about the safe and effective use of Afrezza.

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use Afrezza for a condition for which it was not prescribed. Do not give Afrezza to other people, even if they have the same symptoms that you have. It may harm them.

This Medication Guide summarizes the most important information about Afrezza. If you would like more information, talk with your healthcare provider. You can ask your pharmacist or healthcare provider for information about Afrezza that is written for health professionals.