February 21, 2013

Another Dangerously Misinterpreted Study: Insulin Doesn't Raise Cancer & Heart Disese Risk--High Blood Sugars Do

A huge, long-term UK study appears to show that for people with Type 2 Diabetes injecting insulin raises the risk of both cancer and heart disease.

The study is:

Mortality and Other Important Diabetes-Related Outcomes With Insulin vs Other Antihyperglycemic Therapies in Type 2 Diabetes
Craig J. Currie et al.  The Journal of Clinical Endocrinology & Metabolism February 1, 2013 vol. 98 no. 2 668-677

The study examined the records of 84,622 people with Type 2 Diabetes treated with 5 different drug combinations. It concludes: " In people with T2DM, exogenous insulin therapy was associated with an increased risk of diabetes-related complications, cancer, and all-cause mortality."

This conclusion is likely to lead insurance companies and physicians to deny insulin to people with Type 2 diabetes. This is tragic and very ill advised.

That is because what this study shows is a correlation between insulin use and heart disease and cancer, not causation. In fact, these results are easily explained when you understand that insulin use in people with Type 2 Diabetes in UK is a marker for long-term exposure to very high, uncontrolled blood sugars, and conclude that it is the high blood sugars, not the insulin causing the increase in mortality.

Indeed, the way that insulin is prescribed in the UK makes it so that patients aren't given insulin until they have had extremely high blood sugars for many years, and when insulin finally is prescribed it is done so in a way that does not bring blood sugars down to safe, physiologically normal levels.

So it isn't the insulin that is to blame here, it is the high blood sugars, which a great deal of research has shown cause all the classic diabetic complications as well as heart disease and cancer.

Let's look a bit more closely at how Type 2 Diabetes is treated in the UK where this study was conducted. Because the UK has a National Health Service, patients and to some extent doctors are not given choices about what treatment to use for Type 2 Diabetes. Treatment is based on the use of a rigid set of guidelines that links the treatment to long term blood sugar level. The guidelines consider 7.0% a safe and healthy blood sugar level for people with Type 2 diabetes. So no interventions occur when blood sugars are that high, though we know that level is high enough to produce all the classic diabetic complications. (You can read about the research connecting complications to blood sugar levels HERE and HERE.

At diagnosis, with A1c over 7.0%, patients in the UK are told to change their lifestyle--to exercise and eat the low fat/high carb diets that do little to lower blood sugar. Only if their A1cs continue to climb well above 7.5% are they put on oral drugs.

As we know, studies presented in the prescribing information included with diabetic oral drugs show that none of these oral drugs lower A1c more than about .5%. (I.e. from 8.5% to 8.0%.)  Patients are left on these drugs, with their A1cs in the 7-9% range for years.

Only when A1cs climb much higher are patients prescribed insulin. Unfortunately, they are not prescribed the basal/bolus insulin regimens that make it possible to get normal, physiological blood sugars. Instead, they are given only enough insulin to lower fasting blood sugars to a level that will produce A1cs in the 7-7.5% range. This basal insulin does nothing to lower the post meal blood sugar spikes that research suggests cause heart disease and promote cancer. (You can learn more about the right way to use insulin for Type 2 diabetes HERE.)

When basal insulin isn't enough, most patients are given the worst form of insulin, the 70/30 mix which combines fast and slow-acting insulin in a way that makes it impossible to cover meals tightly without risking hypos.  Patients are forced to eat high carb meals to avoid hypos with this nasty insulin blend and are unlikely to be able to lower A1c below or even to 7.0%.

Insulin under this regimen is dosed by the health professional who issues a simple guideline. As a result patients must eat a lot of carbohydrate to avoid hyping. This way of using insulin is like driving with one foot on the accelerator and one on the brake.

So patients "on insulin" at best end up with A1cs between 7.0 and 8.0%, and this occurs only  after years of exposure to the much higher blood sugars that almost certainly explain the depressing rates of heart attack and cancer seen in this study.

The outcomes of patients using insulin who use it properly are much better. But using insulin safely to normalize blood sugars require education and a lot of careful observation and adjustment of doses. It can't be done with one appointment but takes time and training. Most if not all family physicians do not understand the proper dosing of insulin. Many don't even know there is such a thing, as they refer their patients with Type 1 Diabetes  to endocrinologists. (And sadly, not all endocrinologists are familiar with how to dose insulin properly, especially not those trained before the mid 1990s.)

Used properly, the right combination of basal insulin to lower fasting blood sugars and fast-acting insulin to cover the carbohydrates in meals can make it possible to get A1cs in the 5% to low 6% range and avoid the classic diabetic complications.

To be fair to the researchers who publishsed this study, they concluded at the end of the report, "Differences in baseline characteristics between treatment groups should be considered when interpreting these results." But because they don't spell out what those differences are--that it means that the people on insulin are those with the very worst blood sugars who have lived with these very bad blood sugars for years and whose insulin did not really reverse them--this statement is very likely to be ignored.

Instead, because most U.S. physicians in general practice--the people who treat most people with Type 2 Diabetes--have almost no familiarity with the research explaining how blood sugar causes complications, this study is likely to result in fewer people with Type 2 Diabetes being given access to insulin when they need it.

Drug company marketers will use this result to pressure doctors to prescribe more  of the dangerous, heavily marketed and very expensive DPP-4 inhibitors like Januvia and Onglyza (which also cause cancer) and the GLP-1 analogs like Byetta and Victoza (the latter of which as been linked to Thyroid cancer.) Neither class of drugs lower blood sugar in people whose beta cells aren't able to secrete insulin or have been killed by very high blood sugars. These are the very people who need insulin the most.

So if doctors use this result to deny patients insulin it will, in fact,  raise the number of heart attacks and cancers over time. But it will save insurers money to deny people insulin, so expect to see this happening


Anand Srivastava said...

But there is a silver lining.

If the insurance companies stops paying for insulin, many people will get on a low carb diet to control their blood sugars. Doctors will have to come to terms with the fact that the patient cannot pay for the insulin and they have to come up with a different strategy.

In the long term it will be very good for the patients.

Jenny said...


Low carb doesn't work for the people who really need insulin. Some years ago I was seeing blood sugars over 140 mg/dl after eating as little as 10g of carbs at once.

Low carb works best for people whose diabetes is mostly due to insulin resistance and who are still producing significant amounts of insulin.

If your beta cells aren't producing insulin or are dead, low carb lowers blood sugar some, but not enough to avoid complications over time, especially heart disease.

Beyond that, the vast majority of people with Type 2 are still completely unaware that lowering carbs will lower blood sugar and their doctors are still telling them to cut FAT, not carbs, out of their diets.

Jackie Patti said...

I did see a study a while back... apparently, Lantus raises the risk of congestive heart failure (not heart attack, as discussed here). Not too surprising because ALL insulin, even the homemade stuff, causes potassium loss, which shifts the body to fluid-retention and higher sodium (and hence high bp).

I am of the opinion that insulin is a very good mode of treatment for T2 diabetes (only metformin being better). However, the worse the insulin resistance, the more insulin needed. And that IS a problem, as some of us need WAY more than physiological doses of insulin - and that can't be good.

Jenny said...


Re Lantus, it is possible the link with congestive heart failure has to do with Avandia, which is known to greatly increase that risk, not insulin, since they were prescribing Avandia with insulin for many years under the belief that the Avandia would lower the needed insulin dose. That turned out to be a toxic combination.

The big fear with Lantus was the possibility it raised cancer risk, but subsequent study has not confirmed that as a real link as far as I know.

Simon said...

Can you explain your comment ..
"Low carb doesn't work for the people who really need insulin. Some years ago I was seeing blood sugars over 140 mg/dl after eating as little as 10g of carbs at once.

Low carb works best for people whose diabetes is mostly due to insulin resistance and who are still producing significant amounts of insulin."

Surely low carb is complementary for those who need insulin (I am LADA and on a basal regime - managing to avoid bolus at present). My low carb (60g) diet allows me to maintain an acceptable hba1c when accompanied by a relatively small basal dose.


Jenny said...

What I mean to get across is that cutting carbs alone is not enough to normalize blood sugars in people who don't secrete insulin properly.

A person with advanced LADA who attempts to control with only a low carb diet will have the same problems someone with Type 1 has--and over time would experience muscle wasting and long term even perhaps death, as happened to those with Type 1 diabetes before the discovery of insulin.

Once you have access to insulin, yes, cutting carbs makes it a lot easer to control blood sugars.

Unknown said...

Diabetes is NOT a disease of blood sugar, but rather a disorder of insulin and leptin signaling. Type 2 diabetes is completely preventable and virtually 100 percent reversible, simply by implementing simple, inexpensive lifestyle changes, one of the most important of which is eliminating sugar (especially fructose) and grains from your diet

Jenny said...


You are 100% wrong unless you are talking about a small subset of obese people diagnosed with Type 2. There are almost 100 gene defects already known to be associated with Type 2 diabetes, all of them slightly different. Most of them affect the ability to secrete insulin.

The only people who would make a statement like the one you cite are those who make their money by peddling simple solutions to medically ignorant people. Sadly, there are many of them.

Plenty of people who eliminate sugar and grain from their diets will still see higher than normal blood sugars.

roadrunner said...

This is off topic, but I don't know how else to reach you. Searching for "berberine" I find no hits on your website. Since Jimmy Moore has recently made such a big deal of it, I'd like to know your opinion.

Jenny said...


The claims made for berberine are based on studies published in marginal journals, some of them look to me like "pay to publish" vanity journals. While it is possible it has an effect on blood sugar, we don't know enough about it to know if it has other, dangerous effects that would only show up in larger, well-conducted studies.

On top of that, with the long history we have of herbal supplements either a) not containing the advertised herb or b) being contaminated with heavy metals, pesticides, and other toxins since they come from countries with no regulation of these factors, you really are taking a risk with them.

It's important to note that a study found that the rate of kidney cancer and death among Chinese herbalists is FAR higher than normal, so there is nothing magical and safe about using these kinds of herbs.

At least with metformin you have some assurance about what you are getting and about what the very long term side effects will be.

Unknown said...

Is the old story true that if you use insulin, you will get fatter and fatter, since higher insulin levels for a type 2 makes you store sugar as fat?

Jenny said...

It certainly wasn't true for me. I lost weight after starting insulin without consciously dieting--and lost enough that I got a bit scared! I think that was because controlling my blood sugars stopped me from getting the hunger caused by those steep ups and downs so I ate less.

Doctors dose insulin with "one size fits all" dosages which leave people with those rollercoastering blood sugars that cause hunger. They also give people too little insulin because they fear hypos and assume you are eating 300 g of carbs a day. It is the drops in blood sugar from a high that cause hunger. If your insulin is promoting steeper drops you will get hungrier and eat more.

If insulin is matched to the carbs you eat which flattens your blood sugar eliminating hunger, you should not gain weight. Weight is about how many calories you eat, despite a ton of rhetoric to the contrary that ties it to carbs and insulin. I cover the research backing this claim in my Diet 101 book.

Finally, don't forget that people differ greatly in the degree to which they are insulin resistant. If a person's blood sugar is high because they are not making insulin, they may need a surprisingly small amount of insulin to drop their blood sugars, because quite a few people diagnosed as "Type 2" are pretty insulin sensitive. This is particularly true of people who do not see dramatic improvements when they cut back on carbs.

Avandia and Actos, in contrast, make people fat no matter what they do to blood sugar because the mechanism by which they work is to lower blood sugar by turning blood glucose into fat and storing it in new fat cells that the drug stimulates--the cells that turn into fat cells include bone stem cells, which over time leads to osteoporosis, too.