Diabetes Complications

The Dawn Phenomenon: A Diabetes Puzzle Solved

The dawn phenomenon is one of the most disturbing challenges for those of us who have diabetes. Many of us wonder about the puzzle of why our blood sugar level spontaneously rises during the last hours of sleep each night.

This has also mystified our doctors and medical researchers, so much that they have published at least 187 articles in the professional literature during the past three decades since the first study of the subject appeared. But four new studies by European researchers just published in American professional journals have shown a bright light that clarifies the major questions we have had about the dawn phenomenon. We now know who gets it, how bad it is, how much it impacts our A1C levels, and how to prevent it.

Whether you have type 1 or type 2 diabetes you are likely to have the dawn phenomenon. However, dawn levels among people who don’t have diabetes rise only slightly, if at all, “because they secrete insulin to prevent it,” according Francesca Porcellati, MD, and her associates at Italy’s University of Perugia. Their study, “Thirty Years of Research on the Dawn Phenomenon: Lessons to Optimize Blood Glucose Control in Diabetes,” appears in the December 2013 issue of Diabetes Care, a professional journal of the American Diabetes Association. The full-text of this study is free online.

Whether you are managing your diabetes with diet alone, an insulin sensitizer alone (like metformin or Avandia or Actos), or an insulin secretagogue (like the sulfonylureas or Prandin or Starlix or Januvia) combined with an insulin sensitizer also doesn’t make a difference. This is one result of research led by Louis Monnier, M.D., of France’s University Montpellier and his associates. Dr. Monnier is one of the world’s most respected diabetes researcher, and his study, “Magnitude of the Dawn Phenomenon and Its Impact on the Overall Glucose Exposure in Type 2 Diabetes:Is this of concern?” appears in the same December 2013 issue of Diabetes Care as the Porcellati study. While only the abstract of this study is available online, my friend and associate at HealthCentral, Dr. Bill Quick, kindly shared his full-text copy with me.

How old you are also doesn’t make a difference. Dr. Monnier and his associates studied age in relation to the dawn phenomenon and reported their finding a year ago in “Frequency and severity of the dawn phenomenon in type 2 diabetes: relationship to age.”

For most of us how much our blood sugar level rises during the last hours of the night varies tremendously from day to day. This is another important finding that Dr. Monnier and his associate reported in their new study.

But how much does our level have to rise to justify calling it the dawn phenomenon? Some earlier studies chose an increase of 10 mg/dl as the threshold. But Dr. Monnier’s group selected an increase of 20 mg/dl as the threshold for several reasons, including their observation that this is closer to the average amount of the rise among people with type 2 diabetes.

This typical increase in our blood sugar levels from the low near the middle of the night to our pre-breakfast level naturally impacts our overall diabetes control. But until now, we haven’t known how much difference the dawn phenomenon makes.

We do now. On average among the 248 people whom Dr. Monnier and his associates studied for their most recent report, A1C levels increased 0.39 percent because of the dawn phenomenon. For example, someone who has the dawn phenomenon and an A1C level of 7.0 would have had an A1C level of 6.61 if he or she had been able to manage it.

Let’s put this in context. Some of the diabetes drugs we take don’t make a bigger difference.

So controlling the dawn phenomenon is clearly worth our attention. The biggest question is how. Comments on three earlier articles that I have written here about the dawn phenomenon show that those of us who have diabetes have attempted many different strategies. The one that seems to work, however, is not one mentioned in any of the more than 100 online comments to these articles.

What works, according to the new study by Dr. Porcellati and her associates, is taking basal insulin at bedtime. It “abolishes the dawn phenomenon [and] is an effective treatment.” It mimics way that insulin works among people who don’t have diabetes. The Porcellati study cites their poster presentation at the ADA’s June 2013 convention in Chicago that Diabetes reprinted in that professional journal’s annual supplement.

These basal insulins include Lantus and Levemir. They give us a very long-acting insulin boost — as much as 24 hours — and they aren’t tricky to handle like the short-acting bolus insulins that need to be matched in amount and time with the food we eat and the activity we get.

I have one caveat. A conflict of interest can subconsciously bias the thinking of anyone, and each of the four co-authors of the Porcellati study in Diabetes Care report receiving honoraria or travel grants from Sanofi or serving on one of that company’s advisory panels. Sanofi makes Lantus, which controls 80 percent of the basal insulin market.

Still, using one of the basal insulins to manage the dawn phenomenon makes sense. You don’t need to believe or disbelieve this recommendation. You can check it out for yourself.

This article is based on an earlier version of my article published by HealthCentral.

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  • Reply Al Merchant February 14, 2015 at 2:24 am

    I am particularly New to this website.
    MY story is I am 42 Yo Male Asian (India), was diagnosed DM2 0n 19th Feb 2012 (RBS 368mg/dl/20MMol) and decided to change my lifestyle. By doing so I started eating very small portions (i am 188cms and 290Lbs) In a short span of 4 months with a reduced diet came to FBS of 90~95 and PPBS of 100~140.
    Also dropped 30Lbs. Slowly over a period of 2 years by end of 2014 I saw my PPBS rise to 12.2MMol and FBS between 6.7~7.8.
    On Jan 8 2015 I started on LCHF and totally removed CARBS. Whatever carbs I get are indirect from Veggies or Protein. I have not eaten any grains or cereals etc.
    MY typical diet is
    3/4 Eggs with a lot of butter(50~60gm) and Veggies Like capsicum made into an omlette.
    I drink 2 to 3 cups of Coffee (each about 60Ml)
    Dinner Typically is Any protein mixed with some Veggies and Butter(30/40g).
    SOmetimes I may drink a cup of Full Fat milk 200Ml of which half is 30% Full fat Cream.
    Occassionally I could munch on Nuts but again restricted to a max of 20Nuts(Almonds Pistachio or Cashewnuts or Walnuts) at the most.
    My sugar levels
    FBS between 100~110
    PPbs 96~107
    Random Between 96(at 6 In the Evening)~110 (At 11pm)
    I walk 30/40 Mins daily.
    I had burning in the soles of my feet (since feb 2012)which disappeared and is slowly making a come back.
    I do not know what to do now?
    I look at the burning in my soles as diabetes making inroads into my body.
    Overall My health parameters have improved, I feel full of vitality and energy, There are no dull aches pains anywhere in my body(which I read as No inflammations). When my sugars were high I felt a Buzz after every meal. This is gone. I felt as If I was more anxious and easily irritable when Sugars were always above 7.2MMol, Now, I also look more fit and youthful

    At the back of my mind are these questions.
    1. How Long can I be on this kind of diet?
    Ans: All MY life?
    Ans: I can take a break once a week and fall back
    Ans: Follow this pattern all my life.
    2. What can be the Long term effects of this diet(‘O’ CarbHigh Fat) on my health.
    Will A High Fat diet not affect other parameters Like Cholestrol, Uric Acid,etc
    3. I eat No fruits. I take VIT D, B Complex, Omega 3, Vit C.
    Will I suffer from any form of Malnutrition considering I am omitting a common source
    4. What kind of tests should I do to keep a constant watch on my parameters
    5. What is happening inside my Body by this Diet. YES SUgars are largely controlled its not at the compromise of some other organ system?
    Thanks In advance
    Sorry for this rather Lengthy COmment.
    Any Help is greatly appreciated

    • Reply David Mendosa February 14, 2015 at 9:54 pm

      Dear Al,

      What a wonderful testimony to success on a very low-carb diet! You have all my congratulations.

      In your description of what you eat, I have only one suggestion. You may want to rethink your consumption of cashews. They are the nuts that are by far the highest in carbohydrates. See http://www.nal.usda.gov/fnic/foodcomp/search/

      And here are my responses to your questions:

      The burning of the soles of your feet is probably because you have peripheral neuropathy from your years of high blood sugar. You can reverse it with years of very low blood sugar.

      1. Absolutely!
      2. Yes and Yes.
      3. No, because no carbs are essential for our diets.
      4. A1C
      5.No compromise

      With metta,

  • Reply JoeN November 8, 2014 at 6:19 am

    I have tested my blood sugars before bedtime 12 am
    my reading was 110. I set my alarm alerts(alarms) for every hour and had a test strip ready at bedtime for each hour. my readings every hour increased. 1am = 115, 2am = 125 3am 156, 4am = 138, 5am = 136, 6am = 130, 7am =125 , 8am = 130, 9am= 115.
    after breakfast only 1 cup of brocolli and 3 eggs and a quarter pound burger, just the meat , my sugars drop to between 98 to 110 throughout the day and evening up until 12am. Is this dawn phenomenon?. I take 2 500 mg of metformin er at bedtime with a slice of swiss cheese .

    • Reply David Mendosa November 8, 2014 at 2:21 pm

      Dear Joe,

      That seems a couple of hours too early from the dawn phenomenon, but it probably is. The other other thing that I could think of us a delayed reaction from carbs when they are combined with fat. For example, pizza, which will keep blood sugar high for hours. Yet I doubt that even pizza will make the level rise so much from midnight until 3 a.m.


  • Reply Mama Owl March 24, 2014 at 8:54 am

    Thanks! 🙂

  • Reply Mama Owl March 22, 2014 at 10:59 am

    Yes, I understand that. I use diet to control my blood sugars very well. My problem is still my morning fasting ones. I have tried it all… eating only fat, eating only protein, eating a combo, not eating after 8, eating something right before bed… you name it. But, my morning fastings are still higher than “normal”. I can have a morning fasting as high as the 120’s… even with it being in the low 90’s before bed. I was just wondering if there was something… other than drugs… to counteract this, or is this something I just need to accept? My blood sugars do come down to normal range after breakfast… I do have to make sure to do absolutely no carbs for breakfast though… and they stay within normal ranges throughout the day. It’s just those pesky morning fasting ones!

    • Reply David Mendosa March 22, 2014 at 9:11 pm

      Dear Mama Owl,

      I understand your concern. I do think that you are doing all that you can without drugs. Do please consider that the dawn phenomenon affects almost everyone, even many people who don’t have diabetes. To the small degree that you have it, what you have is normal.



  • Reply Sharlene Rank March 20, 2014 at 10:35 am

    I have Dawn Phenomonen and fear side effects of either Lantis or Levemir. Is Levemir the only thing you take and you only inject at night?

    • Reply David Mendosa March 21, 2014 at 4:51 pm

      Dear Sharlene,

      I don’t personally take any diabetes drugs or insulin since I follow a very low-carb diet that makes it possible to keep my blood sugar within normal range at all times. But either Lantus or Levemir are among the easiest insulins to use and they can be taken at any time of the day. That’s because they work around the clock to help your manage blood sugar.



  • Reply Amanda March 6, 2014 at 8:33 pm

    I have been using this method since I switched from Lantys to Levemir over a year ago and it works great for me. Not sure why I never tried it when I was on Lantys but better late than never. My Dr had commented that people usually don’t split their Levemir at the dose I take, but when I explained how it kept my levels good when I wake up he agreed with me.

    • Reply David Mendosa March 6, 2014 at 9:18 pm

      Dear Amanda,

      Smart! Sometimes each of these insulins don’t last as long as advertised.



  • Reply RTF February 15, 2014 at 2:22 pm

    I second Ana’s question. My issues are a result of a the stress of living with very painful and difficult to manage neurological condition. Diet is excellent- modified paleo style.

    • Reply David Mendosa February 21, 2014 at 2:38 pm

      Dear RTF,

      I just replied to Ana. Hope it helps you too.



  • Reply Mama Owl February 14, 2014 at 11:06 am

    Yes, please! What about those of us who are not on meds and are using diet to control? Is there a way to counteract this?

    • Reply David Mendosa February 21, 2014 at 2:40 pm

      Dear Mama Owl,

      Absolutely! That’s precisely my strategy. I manage my diabetes without drugs. A very low-carb diet is by far the best way to counteract it.



  • Reply Ana February 13, 2014 at 4:24 pm

    Any tips for people who are managing pre-diabetes or are like you, take no drugs?

    • Reply David Mendosa February 21, 2014 at 2:38 pm

      Dear Ana,

      Actually, while I address essentially all of my articles to people with diabetes, I can’t think of a single recommendation — except in regards to diabetes drugs — that aren’t applicable to people with pre-diabetes too. The question of drugs is first that your insurance is almost certain not to approve payment for them. I have written about 4,000 articles about managing diabetes, which means about 4,000 or 5,000 tips. A few too many to summarize here. Please start by reading my most recent articles, which I hope are better than those I wrote two decades ago!



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