Our family recently did a big trip to the USA from Australia.
The trip had us go through customs in:
Sydney, Australia -> Hawaii
Hawaii -> New York via Los Angeles
New York -> Los Angeles
Los Angeles -> Sydney, Australia
I thought this would give me a good opportunity to try out carrying my insulin using a vacuum flask. I could test the flask in a real world scenario and see how it fared through customs. This was the rig I used.
The digital display is for a temperature sensor inside, held onto the flask with a rubber band. Yes, it looks like a pipe bomb (or a sex toy according to some of the folk on Facebook but that probably says more about them than the rig). Please note it is recommended that insulin is taken in your carry-on luggage as the temperature in the cargo hold is not as predictable and frozen insulin is useless.
Some of the predictions from the JDRF 25+ Facebook group (where I posted my intentions) included:
“I’ll be surprised if you don’t get shot in the US with that… Any cylindrical tube with a screen and wires on it will cause a lockdown.”
“Expect long delays”
“Kinda glad I’m not flying anywhere today as the airport will probably go into lock down… if it somehow gets through Australia I guess we will see on the news tomorrow of ‘Australian shot by American airport police and airport in lockdown dew to fake bomb found’ “
Given I am writing this blog I clearly did not get shot. So how did I go?
Sydney -> Hawaii
At every location where an x-ray of bags was happening, I took the rig out of my bag, put it in the tray and alerted the security officer that it was insulin.
In Sydney, this information brought a smile and the response “You know what it looks like, right?” Knowing full well one does not say the b-word (bomb) at an airport, I acknowledged I did and he waved me through. He also told me that insulin is allowed to be carried through Australian customs with ice or gel packs in the special case of diabetics.
As I walked through the metal detector, the officer called his colleague over to watch the x-ray screen, using my device as an exercise to show the difference between insulin pens and incendiary devices.
All went well.
For the record, the officer is correct in regards to gels and ice packs, although finding the details on the Australian Home Affairs site is difficult. Eventually I found this page which quotes:
“If you plan to bring medication onboard, remember to:
obtain supporting documentation, such as a medical identification card or a letter from a doctor. The letter should itemise any prescription and non-prescription powder, liquid, aerosol or gel medication, prescribed medical devices or equipment, for example, ice or gel packs used to regulate temperatures, or the need for hypodermic needles.
have medication and accompanying documents ready for inspection before you arrive at the airport security screening point.
For prescription medication, make sure the name on the prescription label matches the name on your boarding pass or the name of the person travelling in your care.”
The medical identification card for Australian diabetics is the NDSS card. You will know if you have one. Interestingly, while I was carrying a letter from my endocrinologist, it did not explicitly say the insulin needed a gel or ice pack to keep it viable. Also, while I do carry prescription pills, the doctor’s itemised list of medications I carried was old and did not correctly list them.
In principle, a fussy customs officer could have confiscated any ice packs I was carrying and confiscated my pills. This did not happen, thankfully.
While not explicitly stated on this site, the NDSS site states diabetic medication is exempt from the 100mL rule for liquids (although it does need to be presented at the security point). My endocrinologist letter also mentioned my need for juice boxes so, based on the above, these would also be exempt.
Landing in Hawaii there were no scans or checkpoints so things were uneventful at that end.
Hawaii -> New York via Los Angeles
As with Sydney, I pulled the device out of my bag, put it in the tray and announced what it was. While my pipe bomb was not used as a learning opportunity for another officer in Hawaii, they were fine with me carrying it through. They did insist I open it up for a visual inspection and asked if there was anything sharp in there. There were the needles but, as I explained, they are all sealed up and safe.
After a quick visual inspection I was good to go. Again I asked if insulin can be carried through US customer in ice or with a gel pack and they confirmed it can be.
This is confirmed on the TSA website. Also, the Medtronic web site says if you encounter problems to ask to speak to the TSA Ground Security Commissioner.
New York (JFK) -> Los Angeles
Mostly incident free. I put it in the tray, said what it was and they did not bat an eyelid. They did ask me what the device on my arm was which, I explained, was a CGM for monitoring my blood sugar. They accepted this and waved me on.
Los Angeles -> Sydney
Almost incident free. It turns out the coconut flavored peanut butter I bought in Hawaii is considered a liquid/gel and being over 100mL (3.4 ounces) it had to be confiscated. I tried playing the diabetes card but to no avail. Peanut butter was not considered essential to my medical condition (it certainly is not mentioned on the doctor’s list of medications.)
How Did The Container Fare?
My initial tests at home with ice inside were promising. The temperature stayed cool for over a day. On the trip, as the container had actual insulin pens in it, I was reluctant to put ice in there as well (frozen insulin = bad insulin). So there was nothing to keep the insulin cool in the wild. I simply removed it from the fridge at home and took it on the flight with a view of putting it in the fridge on arrival. This plan worked fine, except the initial leg (Sydney to Hawaii, 9 hour flight). By the time we got to the house where we were staying, the internal temperature was matching the outside (28C/82F). This is at the upper limits for insulin so on my next trip I will see how gel or evaporative cooling fares. However, for shorter trips, the vacuum flask would work fine and is easy to carry.
I often see people claim on social media that glucose spikes above 110/120/140 mg/dl (roughly 6/7/8 mmol/l) cause damage and diabetics should religiously keep their blood sugars below this level to prevent long term complications.
While the research to verify this assertion could well be done with the wealth of data now captured by continuous glucose monitors (CGMs), to my knowledge, it has not been done. My concern is that being this fixated on your glucose levels would be a great way to drive yourself crazy and a tragedy if it was for no benefit.
So what does science know? In this article I will review the literature as well as show you what to look for in other medical papers. As usual, feel free to go to tl;dr if reading scientific paper summaries is not your thing.
My first source is a recent study from Sweden which suggests there is a ‘goldilocks zone’ for diabetics where the HbA1c is not too high to cause complications and not too low to increase the risk of severe hypoglycemia. Their conclusion is an HbA1c between 6.5% and 6.9% is optimal to avoid these two extremes.
My second list of sources come from Blood Sugar 101. This is a site that claims their cited scientific papers “make a cogent case that post-meal blood sugars of 140 mg/dl … cause both permanent organ damage and the worsening of diabetes.” I am keen to review their papers to see if the papers actually support this position. I have nothing against the site, I barely know it. I chose it simply because it was cited in social media and I assume they have chosen papers to give the most compelling case for their claim.
What To Look For In Medical Papers
When reviewing papers and their findings, I look at two things: their ‘n’ and ‘p’ values. The ‘n’ is the number of people involved in the study (obviously the bigger, the better) and the ‘p’ value which measures statistical significance. The lower the ‘p’ value, the more reliable the conclusions with a value below 0.05 generally considered to be statistically significant.
For example, the Swedish study mentioned above had n=10,398. That is quite a big study. The Results section says the following:
“Mean age of participants was 14.7 years (43.4% female), mean duration of diabetes was 1.3 years, and mean HbA1c level was 8.0% (63.4 mmol/mol). After adjustment for age, sex, duration of diabetes, blood pressure, blood lipid levels, body mass index, and smoking, the odds ratio for mean HbA1c <6.5% (<48 mmol/mol) compared with 6.5-6.9% (48-52 mmol/mol) for any retinopathy (simplex or worse) was 0.77 (95% confidence interval 0.56 to 1.05, P=0.10), for preproliferative diabetic retinopathy or worse was 3.29 (0.99 to 10.96, P=0.05), for proliferative diabetic retinopathy was 2.48 (0.71 to 8.62, P=0.15), for microalbuminuria or worse was 0.98 (0.60 to 1.61, P=0.95), and for macroalbuminuria was 2.47 (0.69 to 8.87, P=0.17). Compared with HbA1c levels 6.5-6.9%, HbA1c levels 7.0-7.4% (53-57 mmol/mol) were associated with an increased risk of any retinopathy (1.31, 1.05 to 1.64, P=0.02) and microalbuminuria (1.55, 1.03 to 2.32, P=0.03). The risk for proliferative retinopathy (5.98, 2.10 to 17.06, P<0.001) and macroalbuminuria (3.43, 1.14 to 10.26, P=0.03) increased at HbA1c levels >8.6% (>70 mmol/mol). The risk for severe hypoglycaemia was increased at mean HbA1c <6.5% compared with 6.5-6.9% (relative risk 1.34, 95% confidence interval 1.09 to 1.64, P=0.005). “
It looks complicated but we can break it down. When it compares the risk of any retinopathy between those with an HbA1c < 6.5% and those with 6.5-6.9% the odds ratio is 0.77 (you are less likely to get retinopathy with the higher HbA1c) BUT the ‘p’ value is 0.10 so it is not statistically significant and we can ignore it. In fact, in comparing the <6.5% group to the 6.5-6.9% group, the only statistically significant result was for preproliferative diabetic retinopathy which was right at the edge of significance (p=0.05).
However, when comparing <6.5% to 7.0-7.4% and >8.6%, across the board, there was a statistically significant increase in risk for all of the examined complications.
Finally, when comparing the risk of severe hypoglycemia between <6.5% and 6.5-6.9% there was a statistically significant increase in risk below 6.5% (34% higher).
The paper’s conclusion is:
“Risk of retinopathy and nephropathy did not differ at HbA1c levels <6.5% but increased for severe hypoglycaemia compared with HbA1c levels 6.5-6.9%. The risk for severe complications mainly occurred at HbA1c levels >8.6%, but for milder complications was increased at HbA1c levels >7.0%”.
This makes sense and I believe the “mainly” is inserted to cover the borderline preproliferative diabetic retinopathy risk increase for the 6.5-6.9% group.
Now let us look at the case for “140 mg/dl does damage” by going through the Blood Sugar 101 sources.
Reviewing the Papers
Some of the Blood Sugar 101 links were broken but here are the ones which actually went somewhere or which I could find by Googling the title.
n=107 of which only 13 had diabetes and 36 had impaired glucose tolerance (IGT) and all had idiopathic (unknown cause) neuropathy.
The paper found people with IGT (defined as having a blood glucose of 140-200 after two hours in an oral glucose tolerance test (OGTT)) had a statistically significant higher change of having neuropathy BUT no such conclusion was made for diabetics. In other words, the low population of the study, combined with the low population of diabetics means this paper offers little value to diabetics and yet I have seen it quoted on a few sites claiming it backs the “over 140 mg/dl does damage” claim. At best, we can say it supports the claim that people who are prediabetic are at a greater risk of neuropathy, but that is about it.
This study mirrored the previous one with n=73. Of these patients, 26 had IGT, and 15 had diabetes. This paper shows that diabetics that have neuropathy have it more severely than those just with IGT. So, in this case, the conclusion is if someone is at 200 after two hours of an OGTT (the definition of ‘frank’ diabetes) if they get neuropathy it will likely be more severe than their prediabetic counterparts.
In this one n=100, all with chronic idiopathic axonal polyneuropathy (CIAP). They were given an OGTT and 62 of them had abnormal results, twice as high as general population groups. Statistical significance was a little light on the ground in this study but it is aligned to the previous two studies’ findings.
This study had n=195 diabetics and n=198 control subjects. It found diabetes was a risk factor for polyneuropathy and, within the diabetic group, age, waist circumference, and peripheral arterial disease were associated with polyneuropathy.
This study tried to keep n=800 critically ill patients patients below 140 mg/dl while in the Intensive Care Unit (ICU) over a period of 11 months and compared them to patients who were not intensively managed. The populations were not all diabetic with the only common factor being admission to ICU.
The following were shown to have a decreased incident rate in the intensively managed patients: poor kidney function (renal insufficiency), blood transfusions, hospital mortality rates, and length of stay in the ICU. Hypoglcemia rates did not significantly change.
This one is in mmol/l but I will convert for the US diabetics. Essentially it showed that when blood glucose goes above 100 mg/dl, the ratio of insulin sensitivity to insulin resistance declined. However, the paper failed to report the level of statistical significance of the results. It did say it used n=388 though of which 250 had IGT or Type 2 diabetes. So, assuming the results were significant, it tells us that either resistance increases or sensitivity decreased as blood glucose levels go up.
This study reviewed the beta cell mass of bodies from 124 autopsies. Of the 124, 91 were obese and 33 were lean. They found that obese patients had roughly a 50% larger beta cell volume (possibly influenced by the younger age at which the obese population died). Of the obese individuals, the Type 2s had a 63% smaller beta cell volume than their non-diabetic obese counterparts.
The rest of the paper talks at the possible mechanisms for this difference is volumes, looking at beta cell replication rates and beta cell death rates.
This is a mice study and, given the number of ‘cures’ for diabetes found for mice, I am a little skeptical to apply the findings to humans. The paper was looking at the survival rate of transplants between mice with insulin treatment to keep their glucose below 150 mg/dl and mice with no such treatment.
The paper found:
“…insulin treatment did not improve the initial preservation of transplanted β-cell mass in the initial days after transplantation. In contrast, increased apoptosis (cell death) and reduced β-cell mass were found in islets exposed to long-term hyperglycemia but not in normoglycemic mice, suggesting that sustained hyperglycemia increased β-cell death in transplanted islets.”
So transplanted beta cells in mice did not appreciate long term exposure to elevated glucose levels.
This study gave n=1062 patients an OGTT and measured their blood glucose after one hour. Those above 155 mg/dl had elevated inflammatory markers and lipid ratios. The author goes on to suggest these increases could be a marker for cardiovascular risk but does not provide evidence linking the markers to heart disease.
This was a link to another Blood Sugar 101 page which had a bunch more links but, given the length of this article already, I am focusing on the ones just on the original page. If enough people call this out, I am happy to review the heart disease one in another article.
Broken link and could not find the source on Google. I did find this summary but without indication of statistical significance it is hard to confirm the findings. Also, the paper focused on pre-diabetes so its relevance to diabetics is limited especially when no blood glucose levels are mentioned. I expect it found conclusions similar to papers (1), (2), (3), and (4).
This paper looked at the data of three populations (n=3162, n=2182, and n=6079). Its conclusion was:
“We saw no evidence of a clear and consistent glycaemic threshold for the presence or incidence of retinopathy across different populations. The current FPG cutoff of 7·0 mmol/l used to diagnose diabetes did not accurately identify people with and without retinopathy.”
In other words, they found that a person’s fasting plasma glucose (FPG) was a poor predictor of retinopathy.
This paper is looking at FPG and HbA1c to see if it is predictive for diabetic retinopathy. With an n=1066 (not all diabetics) they concluded that the greatest increase in prevalence for retinopathy occurred for HbA1c above 5.5% and FPG above 5.8 mmol/L (105mg/dl). It also found that HbA1c was a better predictor than FPG. Here are their curves.
For the HbA1c curve, while the uptick is at 5.5%, we see the dip before this means the prevalence, relative to the baseline prevalence of around 10% only starts inceasing past this above 6%. Similarly, to escape baseline required an FPG above around 6.5 mmol/l
This study combined the results of nine studies to get a whopping n=44,623. They looked at FPG (n=41,411), two-hour OGTT (n=21,344), and HbA1c (n=28,010).
While no ‘p’ values were given, their results concluded that an HbA1c above 6% has an increased prevalence of retinopathy with the threshold for significant risk at above 6.4%. For FPG the threshold was 6.6mmol/l (120 mg/dl). OGTT proved to be a poor predictor.
n=700 with the aim to determine the HbA1c and FPG for predicting retinopathy after 10 years.
Here are the results.
While the paper’s conclusions were thresholds of 108 mg/dL for FPG and from 6.0% for HbA1c, we can see above the prevalence only jumps up significantly after >7.0 mmol/L (126 mg/dl) for FPG and >7.0% for HbA1c.
This was a press release talking about two studies, rather than the studies themselves. Given it is light on details, I am ignoring it for this analysis. It did say this though:
“No one is claiming, based on current evidence, that either fasting glucose or HbA1C is a viable target for therapy of heart failure specifically; that would have to be established in prospective, randomized trials, all three researchers emphasized.”
This paper looked at n=33,293 women and 31,304 men (for a total of n=64,597). Of these, 2,478 people had cancer. The big takeaway of this study was the difference in risk profile between men and women. It found “abnormal glucose metabolism was associated with a statistically significantly increased risk of cancer overall in women but not in men.”
To put it another way: “In men, overall, no statistically significant associations were observed between glucose levels and cancer risk”.
Like study (9), this was a study of cells in a lab, rather than a study of humans. The main conclusion was a fluctuation in glucose levels aligned to the kinds of fluctuations a human body is exposed to through three meals a day and 12 hours of fasting is more damaging than constantly high glucose levels.
n=1871, all diabetics, had their HbA1c measured and then were followed up over a period of 11 years. The groups were split into people with HbA1cs of <6%, 6-7%, 7-8%, and >8%. Groups above <6% had a higher relative risk of chronic kidney disease (CKD).
This means, if there is a threshold for HbA1c, above which CKD begins to increase in risk it probably lies somewhere between 6 and 7%.
This study involves n=19,019 men but the analysis only looked at the non-diabetic ones (n=18,406). The men did a test similar to an OGTT but not quite following modern protocols and if they exceeded 200 mg/dl they were excluded (n=56). Also those with missing data were excluded (n=134) leaving a total of n=18,216.
The study found that for non-diabetics, the risk of stroke mortality increased if the patient’s blood sugar went over 4.6mmol/l (82.8 mg/dl) as part of their pseudo-OGTT. Given my focus is on diabetics, a paper studying non-diabetics is of limited relevance.
Summary Of All The Paper’s Conclusions
So this is what we know from the 21 papers.
If you have impaired glucose tolerance (IGT) you are more likely to get neuropathy
Diabetics who fail an OGTT are at risk of more severe neuropathy than those with just IGT
If you have IGT you are more like to get chronic idiopathic axonal polyneuropathy (CIAP)
Diabetes is a risk factor for polyneuropathy
If you use insulin to keep patients in intensive care under 140 mg/dl, they tend to fare better
Either insulin resistance increases or sensitivity decreases as blood glucose levels go up (this is anecdotally confirmed by Type 1s I know who say it takes much more insulin to come down from a large high than a smaller one.)
Obese Type 2s have a smaller beta cell volume than their obese non-diabetic counterparts
Keeping glucose levels lower in mice with pancreatic transplants improves the longer term prospects of the transplant
Cells in a dish do not like higher glucose levels
People with IGT get inflammation when they spike
Study not found but likely found that people with IGT are at a higher risk of neuropathy
Fasting Plasma Glucose (FPG) is a poor predictor of retinopathy
HbA1c is a better predictor of retinopathy than FPG and to get above the baseline risk, required an HbA1c of greater than 6% or a FPG of 6.5 mmol/l (around 120 mg/dl)
HbA1c above 6% has an increased prevalence of retinopathy with the threshold for significant risk at above 6.4%. For FPG the threshold was 6.6mmol/l (120mg/dl). OGTT proved to be a poor predictor.
The risk for retinopathy significantly increases when HbA1c is above 7% or when FPG is above 7 mmol/l (around 130 mg/dl). There is a smaller increase when the HbA1c is above 6.5%
Neither HbA1c nor FPG were seen as viable targets for heart failure therapy
Women with high glucose levels are at a greater risk of getting cancer
Cells in a lab will tolerate high levels of glucose exposure better than fluctuating levels of glucose
If there is an HbA1c threshold for chronic kidney disease, it is probably somewhere between 6-7%
A study exclusively focusing on non-diabetics using a non-standard OGTT. Therefore it is of limited relevance to Type 1s
You will see above that not one of these papers directly examined blood spikes over 110/120/140 mg/dl. The 140 mg/dl probably comes from the OGTT where IGT is defined as someone who has a blood glucose of 140 mg/dl after two hours. This says nothing about the number of glucose spikes a patient has had before the test or how high those spikes went. The 140 mg/dl limit in an OGTT tells us nothing about the level at which individual glucose spikes do damage to the body.
The 120 mg/dl may come from (15) where it was shown that an FPG above this led to an increased risk of retinopathy but a fasting glucose level says nothing about someone who is below this FPG level and occasionally spikes above 140 mg/dl.
As for the 110 mg/dl, I have no idea where this one comes from. Regardless, none of the 21 references provided evidence to support a “cogent case” that occasional spiking leads to long term damage.
So What Can We Conclude?
Summarizing my summary and including my original Swedish study, we get the following in regards to Type 1s and what blood levels make sense to stay healthy:
(Swedish study) An HbA1c below 6.5% increases the risk of severe hypoglcemia
(Swedish study) An HbA1c above 6.9% increased the risk of complications, including retinopathy
(Swedish study) There is an increased risk of preproliferative diabetic retinopathy above an HbA1c of 6.5%
(1), (2), (3), (4), (12) People who fail an OGTT have an increased risk of neuropathy
(13), (14), (15) FPG is a poor predictor of retinopathy but risk appears to increase above 120 mg/dl
(14), (15) HbA1c is a better predictor of retinopathy and risk increases above 6%, with significant risk above 6.4%
(16) There is a small increase in risk of retinopathy for an HbA1c above 6.4% with a significant risk above 7.0%
(16) An FPG above 130 mg/dl increases the risk of retinopathy
(20) If there is an HbA1c threshold for chronic kidney disease, it is probably somewhere between 6-7%. If there is no threshold, an HbA1c above 6% increases the risk
Clearly Fasting Plasma Glucose (FPG) and HbA1c have multiple studies examining at what point a diabetic has an increased risk of complications with retinopathy being a common complication studied.
Based on the above, it is clear that an HbA1c below 7.0% is desirable (Swedish study, (16)) and, likely, an HbA1c below 6.4% is better (Swedish study, (14), (15), (16), (20)). However, an Hba1c below 6.4% does put an insulin-dependent diabetic at an increased risk of a severe hypo (Swedish study) so, therefore, depending on how well you can manage the fluctuations may determine where your target HbA1c range will sit.
For Fasting Plasma Glucose, while not as strong a predictor as HbA1c, keeping it below 120 mg/dl would be prudent (13), (14), (15), (16).
Reviewing the multiple studies of a site which makes the claim that blood sugars above 140 mg/dl cause damage and worsen diabetes, not one directly studied meal spikes and their long term effects.
However, when these studies were combined with a recent Swedish study, we can conclude that keeping your HbA1c below 7.0%, and for those who have a low risk of hypo, below 6.4% will minimize the risk of complications, especially retinopathy.
For fasting plasma glucose (FPG), keeping this below 120 mg/dl (6.7 mmol/l) is also desirable to reduce the risk of complications but it should be acknowledged that FPG is not as reliable as a predictor of complications as HbA1c.
Finally, given there was no study examining the damage of meal spikes and assessing a ‘safe’ level, it is reasonable to ask whether religiously guarding your blood glucose levels is worth it; whether the mental fatigue of constant monitoring, and risk of burnout, is outweighed by the unproven benefits. Perhaps it is better to focus on longer term measures such as HbA1c, the standard deviation of glucose levels over time, and time in range. Perhaps it is better to see an occasional high spike as an unfortunate day on a much longer journey rather than as a defeat or failure.
If you are a Type 1 diabetic then you will know the truth is there is a myriad of things which can affect your blood sugars and they are inherently unpredictable. It reminds me a little of the stock market. It is impossible to predict what the final price of a stock will be on a given day but you can predict the trend over time. Anyone that tells you differently is, most likely, trying to sell you something.
So too with with blood glucose. It is very hard to accurately predict your body’s reaction to the various forces acting on your blood on a given day but, over time, you can get an idea of the trends and general principles. Anyone that tells you otherwise is probably selling a book or supplements.
The upshot of this is that you should never beat yourself up for having a bad day with your blood sugar. Focus on the game and not a given play. Let measures such as your HbA1c, percentage in range, and the standard deviation be your guide more than a moment in time on your glucometer.
Knowing how different forces act on your blood glucose can help you manage these long term trends so here are some of the big influences on your blood sugar. As usual, there is a tl;dr summary at the end for the time deprived.
Clearly one of the biggest forces on blood glucose are carbohydrates. We can divide carbohydrates into three categories for this discussion:
Fast Acting: Sugars/Simple Carbohydrates/High Glycemic Index (GI) Foods
Slow Acting: Starches/Complex Carbohydrates/Low GI Foods
No Acting: Inedible Carbohydrates/Fiber
Fast acting carbohydrates will spike the blood and make it very difficult to manage. If you take insulin you will need to try and match the insulin activity with the blood sugar spike. Get this wrong and your blood sugar starts roller-coasting. For the diabetics who can still produce their own insulin, fast acting sugars in sufficient quantities can overwhelm your pancreas and spike your blood.
Slower acting carbohydrates still need to be covered by insulin but the slower rise can make it easier to manage. The slower rise also means those with an impaired pancreas may be able to produce enough insulin to stop them spiking too high.
Fiber, by definition, is not broken down by the body so it is physically impossible for it to directly affect blood sugars. This being said, there are insulin dependent diabetics who factor fiber in their calculations. My guess is because, in certain countries like the USA, food labeling puts fiber in with the rest of the carbohydrates so it simply makes things easier to calculate a ratio including the fiber, even if it makes no metabolic sense.
There is no direct metabolic path to convert digested fat into glucose so eating fat will not raise your blood sugars. However, like fiber, it will slow down the absorption of carbohydrates. Also, digested fats readily enter the bloodstream, temporarily increasing insulin resistance. This leads to some people concluding it raises blood sugar when the reality is their insulin is simply not as effective.
As an example, let us consider a slice of toast with 15g of carbohydrates. While this may normally require ‘x’ units of insulin to be covered, if it is eaten with avocado on top, which is 15% fat, this may raise insulin resistance and the normal amount of insulin will be insufficient, leading to a spike. It is not the fat turning to glucose which causes this spike, it is the temporary increase in insulin resistance. Also the insulin resistance may influence the effectiveness of a Type 1’s basal insulin leading to increased glucose output by the liver.
Usually proteins will not significantly affect your glucose as the body does not convert a lot of protein to glucose but, for someone eating a low carbohydrate diet, the body ramps up a metabolic process called gluconeogenesis which is the one which converts protein to glucose. There is no hard rule for bolusing for proteins under these circumstances but some find success by finding a ‘protein ratio’ similar to their insulin to carbohydrate ratio.
This is a bottle of almost pure alcohol (95% alcohol by volume, I use it to make sugar-free liqueurs). Like fats, alcohol does not convert directly to glucose so, in principle, it will not affect blood sugar. However, also like fats, this is not the full story.
Alcohol is seen as a poison in the body so the liver will drop everything to remove it from the blood. This includes releasing glucose into the blood which, usually, the liver does constantly and is the reason Type 1 diabetics use a long acting insulin to keep their liver from releasing too much glucose (basal insulin).
So, in theory, alcohol will lead to a drop in blood glucose but no one drinks pure alcohol. Liqueurs usually contain sugar syrup (sugar dissolved in water) and the fermentation process demands the use of sugars to feed the yeast and residual sugars often end up in the final product.
So alcoholic drinks are a mixed bag. The alcohol has the potential to lower blood sugar but the things it is mixed with may raise blood sugars. This makes alcoholic drinks quite dangerous for Type 1s in large quantities because the effects are inherently unpredictable.
In the short term, aerobic exercise will lower blood glucose as the body makes use of it to run muscles. Moreover, it is believed that the glucose enters the muscles through pathways opened up by exercise which do not require insulin. Short term anaerobic exercise (more strenuous exercise) can raise blood sugar as the liver releases glucose into the blood to help feed the muscles.
Also, the effects of exercise on the blood can continue well after exercise has stopped so monitoring of blood glucose is very important.
In the long term, exercise can reduce fat stores in the body, lowering insulin resistance, as well as increasing muscle mass to store glucose.
The human body is a complex interplay of hormones so when one increases or decreases, this has an effect on others. Insulin is no exception. For diabetics going through puberty this is a minefield. For women, their monthly cycle can also cause insulin resistance to fluctuate, throwing out insulin ratios and interfering with blood glucose management.
Stress and Illness
Given both stress and illness affect hormones in the body, it is unsurprising that they affect blood sugar levels. Try to avoid unnecessary stress and carefully check blood glucose levels during illness. Strategies which work to reduce stress hormones and lower blood glucose for some include meditation and massage.
The act of going to sleep can affect your blood sugar or, more accurately, the act of the waking up. Dawn phenomenon is an increase in blood sugar (probably) due to the shifts in hormones as someone moves from sleep to being awake. There is not a huge amount that can be done about the dawn phenomenon but, if it is causing blood glucose to be consistently high in the mornings at a level to potentially cause long damage to the body, it may be worth discussing, with your health care team, changing your basal insulin routine.
Medications can affect blood sugars with a common complaint coming from the injection or ingestion of steroids for medical treatment. Steroids tend to spike the blood, especially if injected. If you are taking a new medication, it makes sense to ask your health care team how it may affect your blood sugar and insulin resistance.
Strategies For Management
As you can see above, there are a range of factors which can affect blood glucose levels. For this reason, an approach which primarily relies on looking at food, such as Dr Bernstein and Forks Over Knives, may well work for some but has no guarantee of working for everyone.
In my opinion, a better approach is to adjust insulin, rather than trying to adjust everything else. Looping (the linking of a continuous glucose monitor and an insulin pump for automatic blood glucose management) and books like Sugar Surfing or Think Like a Pancreas adopt this approach.
This being said, diet moderation still has a place. Modern insulins have their limitations so it make sense to be careful not to test those limitations with a diet filled with fast-acting carbohydrates.
A healthy human body does a remarkable job of keeping blood sugars in check. For those of us with impaired or non-existent insulin production replicating this job can be very hard. With so many factors affecting blood sugar levels, it is impossible to have perfect management every day. Therefore, it is better to manage glucose levels for the long term, rather than fixating on how your levels are on a given day.
Some of the factors affecting blood glucose are:
Fast and slow acting carbohydrates: Increase blood glucose
Fiber: No direct effect on glucose levels but can slow the absorption of digestible carbohydrates, stretching out the blood glucose response curve
Fats: No direct effect on glucose levels but they can temporarily increase insulin resistance leading to increased liver glucose production, and a spike in blood glucose in response to food as the on board insulin proves to be not as effective as it otherwise would be. In contrast, like fiber, fats can slow the digestion of glucose, widening the response curve.
Proteins: No direct effect unless the person is not eating enough carbohydrate for their body’s needs. In this case, the body uses gluconeogenesis to directly convert proteins to glucose, raising blood glucose levels
Alcohol: While pure alcohol has the potential to lower glucose, not many people drink pure alcohol. Many people drink either a fermented drink like beer which has sugar as an integral part of the process or they drink liqueurs which are a combination of alcohol, sugar syrup and flavoring. Therefore, depending on the alcoholic drink at hand, it can raise or lower blood glucose levels
Exercise: Gentle (aerobic) exercise usually lowers blood glucose while more strenuous (anaerobic) exercise can raise blood glucose levels. In the long term exercise can be beneficial in reducing insulin resistance and increasing muscle mass, used for glucose storage.
Hormones: Different hormones of the body can also affect insulin resistance and, therefore, blood glucose levels. This is especially problematic for diabetics going through puberty and for women who are menstruating
Stress, Illness, and the Dawn Phenomenon: As all of these affect the body’s hormones, it is no surprise they also affect blood glucose levels
Medications: These can affect the body and blood glucose levels. If you are unsure if a specific medication will affect you, talk to your health care team
There are a range of factors which can influence blood glucose levels and, often, in unpredictable ways. While some advocate for strictly controlling major factors, such as food, others advocate adjusting insulin to accommodate all of these influencing factors. Every person is different so it will be a case of taking the elements from both approaches which work for you.
I often see posts asking how to keep continuous and flash glucose sensors on for more than a week. As I pay full retail price for my CGM (it is not easy to get a CGM subsidy in Australia), I try to get every last bit of performance out of them before throwing them away.
My record so far for a Dexcom G5 was seven weeks and I gave up at that point because the sensor wound had healed enough that it was no longer registering the spikes; the line just slowly rose and fell in a dampened response to the glucose levels.
These days I change the sensor in the first weekend of the month, getting around four weeks per sensor.
Here is how I do it.
I bought a bottle of this on eBay but you can also buy wipes with the same name that do the job. The very first thing I do is apply it, using the sponge applicator, to the area where the sensor is going to sit.
To wipe off any excess, simply use Methylated Spirits (Denatured Alcohol).
Prepare the Sensor, Rocktape and Opsite
While the Skin Tac dries and gets sticky, I prepare the other components. Firstly, I take sensor out of its packet ready for application, then I prepare the RockTape.
I use the Rocktape to keep the sensor’s sticky material in place. The white gauze that comes with the Dexcom is good for about one week so the Skin Tac and Rocktape help extend this.
I cut a little rectangle out of the Rocktape for the transmitter to fit through and keep the rectangle for later.
I also cut off the corners of the main piece of Rocktape and this stops it from peeling away from the skin as readily.
With the Skin Tac now nice and sticky, I apply the sensor, attach the transmitter, and start the soak-in period on the receiving app.
If the transmitter looks a little unusual, I use a modified G5 transmitter with a rechargeable battery attached to replace the embedded batteries. It is a little experimental but it has saved me a fortune in new transmitters.
Next I put on the RockTape on top of the gauze.
This is a transparent, breathable covering which sits on the skin. There are cheaper alternatives in the market though so do shop around. The idea is to cover the sensor and Rocktape completely to help prevent the sensor getting knocked out by leaning or bumping into things.
The rectangle of Rocktape we reserved sits in the middle of the Opsite to stop the Opsite getting stuck to the transmitter. The adhesive attaches very strongly to the resin on the transmitter making it difficult to remove when we want to change the dressing.
We now apply the Opsite to the sensor, keeping the backing on the Rocktape rectangle and we have a secure sensor with its own Rocktape camouflage. With the backing on the Rocktape still in place, the dressing comes away easily when we want to replace it.
Once a week I check for peeling and, if it is coming away, I reapply the Rocktape and Opsite, removing the old dressing by peeling sidways to or away from the transmitter to minimize the risk of dislodging.
In my last blog I showed how you can link a Dexcom CGM to an Amazon Echo via the SugarMate Skill. This time I have taken it a little further to see what can be done with the Echo Spot. The Echo Spot is like the Echo (a voice-enabled speaker) only it also has a screen. This means if we open up the SugarMate skill, we not only get told our blood sugar, but we also get to see the graph of latest results.
Unfortunately, in the middle of the night, when you are sleepy and potentially have low blood sugar, remembering to say “Alexa, ask SugarMate for my latest reading” is a little too much. I was hoping to create a custom voice command but this proved impossible at this point. While there are custom ‘Routines’, these cannot be linked to skills and neither could Amazon Blueprints.
I did find a way to invoke the Skill without speaking though through “Tap to Alexa”. Tap to Alexa is activated through the Accessibility areas in Settings and is then configured through the Home screen by swiping until you get to Tap to Alexa and touching ‘Manage’.
Once there you can pick a command and link it to a named icon. It took me a while to get this set up right because it turns out Alexa has big problems with the word ‘SugarMate’ (one word). It works fine with ‘Sugar Mate’ (two words) though. So, by linking the command “Open Sugar Mate and get latest reading” to an icon, I could invoke SugarMate with nothing more than a swipe left and a tap.
Amazon Alexa: Invoke the SugarMate app and you have your BGL and when it was last checked
Not much to do here. Attach it to your arm.
Install the app, go to the Settings and connect your Dexcom.
You will know if it is working because you will get a pretty graph of results when they come in.
Dexcom Share Server
To get the data from xDrip+ to the Dexcom Share Server we first need an account on the Dexcom site.
Once we have this we go to the xDrip+ Cloud Upload Settings, choose Dexcom Share Server Upload and give it the Dexcom account details.
As I am in Australia I am not using the US servers. If you are in the USA, your setting may be different. Also, as I am not using a Dexcom Receiver, I left the 10 Character Serial Number blank.
I will work backwards from here (it just makes life a little easier). Firstly, enable the SugarMate skill through the Alexa app on your phone. This will give you the option of signing up for SugarMate and it will also give you an email address to add as a follower.
Once signed up and linked to Dexcom, go back to xDrip+ and add the email address as a Follower (the other name fields do not matter so make them something friendly for you).
That is it. With all that in place you can simply say “Alexa, ask Sugarmate for my latest reading” and it will tell you your reading and when it was last checked.
I was hoping I could use a Routine to modify the invocation command to something more ‘middle of the night’ friendly such as “Alexa, what is my BGL?” but at this stage it is not possible to invoke a Skill from a Routine.
Using xDrip+ with your preferred CGM/Flash Monitor, uploading to the Dexcon Share Servers, linking it to SugarMate and enabling the SugarMate Alexa skill, anyone in your household can ask Alexa what your blood glucose is.
This is useful in the middle of the night or if a loved one is at home and concerned. It is also useful if sight impairment is an issue.
Unfortunately I have found no way to simply the invocation phrase “Alexa, ask Sugarmate for my latest reading” but if I do I will add it to the article.
Diabetics get a lot of blood tests done and sometimes we should ask for others. Here they are broken down so you know what you are getting done and what you should ask for.
Summary at the end for those who find the article tl;dr.
‘Sugariness’ And Insulin Measures
Practically every diabetic knows their HbA1c (Hemoglobin A1c). This is a measure of the number of hemoglobin proteins in the blood with glucose attached. This gives an indication of how sugary a person’s blood has been for the last three months.
Why three months? Hemoglobin is part of your blood’s red blood cells. In a healthy human, red blood cells survive for around three months in the blood before dying.
This has a few implications. Firstly, if you have a disease which affects the life of your red blood cells, such as anemia, this will throw off your HbA1c measure, shortening the time over which the HbA1c is a representative average. Also, the measure is not a linear average; the result is biased to the more recent ‘sugariness’ because not every red blood cell lives for exactly three months. Not all of those ‘born’ three months ago will be around but most of the one born a month ago will.
It should be noted that there is around a 10% relative error in this test so if you have, say, an HbA1c of 7% and it moves on your next test by less than 0.7%, this could be nothing more than measurement error.
Finally, while a lot of emphasis is put on the HbA1c, it is only a number to indicate your average blood glucose level (BGL); it says nothing of the fluctuations. Some doctors will get nervous at lower HbA1c results because they have no visibility of the fluctuations. If you have excellent blood glucose control do not be afraid of lower HbA1c results.
When beta cells produce insulin they actually produce a thing called proinsulin which is two halves of the insulin molecule and a ‘connecting peptide’ (c-peptide) which joins them. Through the magic of biology this eventually transforms into insulin and a residual c-peptide molecule.
By measuring the amount of c-peptide in the blood we can get an indication of how much insulin the pancreas is producing (injected insulin is not in the form of proinsulin so there is no c-peptide residue).
A typical Type 2 will have a high c-peptide reading because their pancreas is trying to overcome their insulin resistance. A typical Type 1 will have a low c-peptide because the immune system has destroyed their beta cells and with it the ability to produce proinsulin. I say typical because for a LADA like me with insulin resistance, my c-peptide is normal/high even though I am Type 1.
This measures the level of insulin in the blood for a fasting individual. Unlike c-peptide this cannot distinguish between insulin made by the body and injected insulin.
The blood sugar level when fasting. For an individual producing enough insulin to keep their liver in check, this should be normal.
The ‘Homeostatic Model Assessment of Insulin Resistance’ (HOMA-IR) and the ‘Homeostasis Model Assessment of β-Cell Function’ (HOMA-β) are mathematical formulae using the blood’s (fasting) insulin and glucose levels to give an indication of the individual’s insulin resistance and beta cell function.
In other words, for someone not using insulin, their fasting insulin and glucose results can be used to determine how much insulin resistance they have and how much beta cell function they still have.
Linked to insulin sensitivity, this may be useful to see if you are low (many of us office workers are).
Vitamin B12/Active B12
If you are taking Metformin/Diabex/Glucophage (different names for the same thing), you should check your B12 levels as Metformin can affect the body’s ability of absorb vitamin B12 from food. The difference between ‘B12’ and ‘Active B12’ is that, while different forms of B12 are circulating in the blood only the ‘active’ form can be used by cells in the body.
Autoantibodies Against Islet Cells (ICA), GAD, IA2, ZnT8, and Insulin
This is the definitive test for determining if someone is a Type 1 diabetic as it proves the immune system is attacking the body’s insulin production machinery.
If this test is positive, you are Type 1, by definition. However, there are people with all the hallmarks of Type 1 diabetes who do not get a positive result on autoantibody tests. Possible reasons for this include:
The person has had Type 1 diabetes for so long that there are no longer any beta cells left to provoke an immune response
Their Type 1 diabetes is caused by an as yet unknown autoantibody
Whether these ‘idiopathic’ Type 1s should be classified as Type 1, given the lack of autoimmunity evidence, is a matter of debate but, from a treatment perspective, it makes sense to align them to ‘classic’ Type 1s.
Body Mass Index and Waist Measurement
While not blood tests, the Body Mass Index (BMI) and a person’s waist measurement give a general indication of obesity. Obesity is linked to insulin resistance so, in an ideal world, diabetics of any Type would stay within a healthy weight range.
Oral Glucose Tolerance Test (OGTT)
Although I never had one of these myself (presenting with mild DKA at diagnosis was enough to establish I had diabetes), it is something often used to determine if a person has diabetes.
The test is relatively simple: the patient, who has fasted, is given a fixed measure of glucose syrup and blood is taken at the one, two, and maybe the three hour mark to measure the patient’s glucose response. If the patient cannot bring the blood glucose levels down fast enough and they go too high, the patient is diabetic.
Heart and Kidney Disease
Diabetics, due to damage from high BGLs, are prone to kidney disease and have a higher rate of heart disease, compared to the general population
Not a blood test, but the test the doctor does with the arm band and an air pump. A high blood pressure can be a risk factor for kidney and heart disease.
This is a urine test and, for healthy functioning kidneys, there should be little to no albumin in the urine. It is measured as a ratio because creatinine is generated at a reasonably constant rate in the body so, if creatinine fluctuates in urine, this is likely due to relative levels of hydration in the body. So, by measuring the ratio, we get a stable indicator of albumin in the urine, independent of hydration levels.
The prevailing thinking in conventional medicine is that the different types of cholesterol play a role in a person’s risk of heart disease. A metastudy (review/compilation of multiple actual studies) in 2016 found the evidence for this was not strong. I am not going to settle this debate in this blog article so discuss this with your health care team and do your own research if it is important to you.
For myself, I eat a lowish carbohydrate diet which means I have moved to eating more proteins and fats. My thinking is that, even if there is an increased risk of long term heart disease, this is outweighed by my short term desire to preserve my beta cells and remain insulin free for as long as I can, while keeping my BGLs in a healthy range.
Assuming cholesterol measures are relevant to a person’s heart health, here are the measures on interest:
Total cholesterol: ideally low
LDL: ideally low
HDL: ideally high
Triglycerides: ideally low
Cholesterol/HDL ratio: ideally low i.e. you want relatively low cholesterol or high HDL with the absolute amount being less important (useful for diets higher in fat)
LDL/HDL ratio: ideally low based on the above and again, talks at relative levels, rather than absolute levels
High levels of sodium can indicate kidney dysfunction.
This is a measure of how acidic your blood is (low levels suggest more acidic blood). Again, this can be an indicator of kidney health but, be warned, if you are engaging in a low carbohydrate diet and producing ketones, these are acidic and may throw off the test. I have seen this in my test results on occasion.
The idea that one blood test can be the result of one of many causes speaks to the need to get multiple tests done to confirm something like kidney disease. While my blood may sometimes be slightly acidic, my albumin/creatinine ratio is always within range, confirming it is my keto-like diet that is the cause and not organ damage.
Like the bicarbonate test, urea can be indicative of a number of things. Most importantly it can indicate kidney damage or heart failure. Urea in the blood is a result of protein breakdown so, again, if you are engaging in a low carbohydrate diet and eating more protein, a higher urea level may be the cause. It is no coincidence that on those blood tests where my bicarbonate was low, my urea was also high and was indicative of nothing more than me being a little more keto than usual.
The other organ that gets a battering from diabetes is the liver. We have a raft of tests available to us to ensure our liver is doing its job and keeping us healthy.
These are enzymes found in the liver and usually only in small amounts in the blood. An elevated level of them in the blood can indicate kidney damage. It can also indicate a bumpy ride on a motorcycle leading up to the test so always regard blood test results with caution until confirmation tests have been conducted.
This is related to the Albumin/Creatinine test as Albumin is a protein. Abnormal total protein levels in the blood can indicate kidney damage but can also indicate liver disease. A high protein diet has no effect on protein in the blood.
Total Protein = Albumin + Globulin so, again this is a protein test where abnormal results can indicate kidney or liver disease, among other things.
Another protein test which can test for severe liver disorders in non-pregnant people.
White Cell Count/ Lymphocytes/ Eosinophils/ Monocytes
Lymphocytes, Eosinophils, and Monocytes are all types of white blood cells. All of these can be tested to get an idea of infections, allergies, and other disorders which may be affecting the body.
While I occasionally have elevated levels of these, it generally settles down by the time of my next quarterly/biannual blood test. If it did not, it could be indicative of an undiagnosed prevailing condition e.g. cancer or infection and would warrant further investigation.
Here is the list of common blood (and other) tests done for diabetics and their meaning.
‘Sugariness’ and Insulin Measures
HbA1c: An average of your last three months of blood sugars
C-Peptide: A measure of how much insulin your body is still producing
Fasting Insulin: How much insulin is in your blood to keep your liver in check
Fasting Glucose: How sugary you are without food
HOMA-IR/HOMA-β: Mathematical formulae using the fasting insulin and glucose used to determine insulin resistance levels and beta cell function
Vitamin D: Low levels can contribute to insulin resistance
Vitamin B12/Active B12: B12 absorption can be hindered by diabetic medications such as metformin
Autoantibodies Against Islet Cells (ICA), GAD, IA2, ZnT8, and Insulin: Tests whether diabetes is caused by an autoimmune response and is therefore Type 1 diabetes
Body Mass Index and Waist Measurement: Body measurement tests to give an indication of obesity and potential insulin resistance
Oral Glucose Tolerance Test (OGTT): A test involving the drinking of glucose syrup to assess whether a person is a diabetic
Heart and Kidney Disease
Blood Pressure: The test with the armband and pump. This can indicate an increased risk of heart and kidney disease
Albumin/Creatinine Ratio: A urine test for kidney health
Cholesterol (LDL/HDL/Triglycerides): Measures of fatty acids and fatty acid transporters in the blood. Abnormal levels are traditionally considered a risk factor for heart disease
Sodium: High levels can indicate kidney disease
Bicarbonate: Low levels can indicate kidney disease but can also result from a ketogenic diet
Urea: Used as an indicator for heart or kidney disease but can also be indicative of a high protein diet
Gamma Glutamyltransferase (GGT)/ Lactate Dehydrogenase (LD, LDH)/ Aspartate Aminotransferase (AST)/ Alanine Transaminase (ALT): Liver enzymes not usually found in the blood which can indicate liver damage
Total Protein: Abnormal levels can indicate liver or kidney damage. Not affected by dietary protein intake
Globulin: Abnormal levels can indicate liver or kidney disease
Alpha-Fetoprotein: Can indicate severe liver damage/disease
White Cell Count/ Lymphocytes/ Eosinophils/ Monocytes: White cell tests which can indicate infection, allergy or disease.