Category Archives: Insulin

Is Insulin Making You Hungry All the Time?

So easy to over-eat!

So easy to over-eat! Is it the insulin release?

No, insulin probably isn’t the cause of constant hunger, according to Dr. Stephan Guyenet. Dr. G gives 11 points of evidence in support of his conclusion. Read them for yourself. Here are a few:

  • multiple brain-based mechanisms (including non-insulin hormones and neurotransmitters) probably have more influence on hunger than do the pure effect of insulin
  • weight loss reduces insulin levels, yet it gets harder to lose excess weight the more you lose
  • at least one clinical study (in 1996) in young healthy people found that foods with higher insulin responses were linked to greater satiety, not greater hunger
  • billions of people around the world eat high-carb diets yet remain thin

An oft-cited explanation for the success of low-carbohydrate diets involves insulin, specifically the lower insulin levels and reduced insulin resistance seen in low-carb dieters. They often report less trouble with hunger than other dieters.

Here’s the theory. When we eat carbohydrates, the pancreas releases insulin into the bloodstream to keep blood sugar levels from rising too high as we digest the carbohydrates. Insulin drives the bloodstream sugar (glucose) into cells to be used as energy or stored as fat or glycogen. High doses of refined sugars and starches over-stimulate the production of insulin, so blood sugar falls too much, over-shootinging the mark, leading to hypoglycemia, an undeniably strong appetite stimulant. So you go back for more carbohydrate to relieve the hunger induced by low blood sugar. That leads to overeating and weight gain.

Read Dr. Guyenet’s post for reasons why he thinks this explanation of constant or recurring bothersome hunger is wrong or too simplistic. I agree with him.

The insulin-hypoglycemia-hunger theory may indeed be at play in a few folks. Twenty years ago, it was popular to call this “reactive hypoglycemia.” For unclear reasons, I don’t see it that often now. It was always hard to document that hypoglycemia unless it appeared on a glucose tolerance test.

Regardless of the underlying explanation, low-carb diets undoubtedly are very effective in many folks. And low-carbing is what I always recommend to my patients with carbohydrate intolerance: diabetics and prediabetics.

Steve Parker, M.D.

front cover

front cover

No Great Benefit to Carb Counting Compared to Other Insulin-Dosing Methods

…according to an article at MedPageToday. Briefly, carb counting involves estimating the digestible carbohydrate grams in a meal (often called net carbs), then dosing rapid-acting insulin based on those grams and the individual’s prior responses to insulin. It turns out there’s not a lot of hard clinical evidence to back up the practice. A quote from the article:

Carbohydrate counting is the best known method for matching insulin dosing to meals, and is the recommended dietary strategy for achieving glycemic control in type 1 diabetes, though that recommendation has been largely based on expert consensus, Bell said.

One commentator said it doesn’t work very well because most folks aren’t very good at it, they’re not vigilant enough. Why do we so often want to blame the patient?

A review panel “compared carbohydrate counting with usual care, which consisted of either general nutrition advice or low dietary glycemic index (GI) advice.” They found no significant differences in hemoglobin a1c between the approaches.

Read the rest.

Do High Insulin Levels Cause Memory Loss and Dementia?

dementia, memory loss, Mediterranean diet, low-carb diet, glycemic index, dementia memory loss

Don’t wait to take action until it’s too late

Insulin resistance and high blood insulin levels promote age-related degeneration of the brain, leading to memory loss and dementia according to Robert Krikorian, Ph.D. He’s a professor in the Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati Academic Health Center.  He has an article in a recent issue of Current Psychiatry – Online.

Proper insulin signaling in the brain is important for healthy functioning of our brains’ memory centers.  This signaling breaks down in the setting of insulin resistance and the associated high insulin levels.  Dr. Krikorian makes much of the fact that high insulin levels and insulin resistance are closely tied to obesity.  He writes that:

Waist circumference of ≥100 cm (39 inches) is a sensitive, specific, and independent predictor of hyperinsulinemia for men and women and a stronger predictor than body mass index, waist-to-hip ratio, and other measures of body fat.

Take-Home Points

Dr. Krikorian thinks that dietary approaches to the prevention of dementia are effective yet underutilized.  He mentions reduction of insulin levels by restricting calories or a ketogenic diet: they’ve been linked with improved memory in middle-aged and older adults. His theory is also consistent with the commonly seen association of type 2 diabetes with dementia: overweight and obese type 2’s quite often have high insulin levels, at least in the early years.

Dr. K suggests the following measures to prevent dementia and memory loss:

  • eliminate high-glycemic foods like processed carbohydrates and sweets
  • replace high-glycemic foods with fruits and vegetables (the higher polyphenol intake may help by itself)
  • certain polyphenols, such as those found in berries, may be particularly helpful in improving brain metabolic function
  • keep your waist size under 39 inches (99 cm), or aim for that if you’re higher and overweight

Nearly all popular versions of the paleo diet would qualify as being low glycemic index.

I must mention that many dementia experts, probably most, are not as confident  as Dr. Krikorian that these dietary changes are effective.  I think they are, to a degree.

The Mediterranean diet is high in fruits and vegetables and relatively low-glycemic.  It’s usually mentioned by experts as the diet that may prevent dementia and slow its progression.

Read the full article.

I’ve written before about how blood sugars in the upper normal range are linked to brain degeneration.  Dr. Krikorian’s recommendations would tend to keep blood sugar levels in the lower end of the normal range.

Steve Parker, M.D.

PS: Speaking of dementia and ketogenic, have you ever heard of the Ketogenic Mediterranean Diet?  (Free condensed version here.)

Elizabeth Hughes, Dogs, and the Discovery of Insulin

Man’s best friend, especially if you have take insulin

Dr. Harriet Hall over at Science-Based Medicine reviews the Canadian  discovery and purification of insulin, truly a modern medical miracle.  Thanks to Banting and Best.  One of the first human users was Elizabeth Hughes.

—Steve

What’s Wrong With Type 2 Diabetics?

Type 2 diabetes and prediabetes are epidemics because of excessive consumption of refined sugars and starches, and lack of physical activity.  I can’t prove it; nevertheless that’s my impression after years of reading the nutrition science literature and thinking about it.

I could be wrong.  I reserve the option to change my mind based on evidence as it becomes available.  That’s one of the great things about science.  Accurately identifying the cause of diabetes could provide strong clues about optimal prevention and treatment strategies.

Genetics undoubtedly plays a major role in diabetes, but the gene pool hasn’t changed much over the last several decades as type 2 diabetes rates have soared.

The problem in type 2 diabetes and prediabetes is that the body cannot handle ingested carbohydrates in the normal fashion. In a way, dietary carbohydrates (carbs) have become toxic instead of nourishing. This is a critical point, so let’s take time to understand it.

NORMAL DIGESTION AND CARBOHYDRATE HANDLING

The major components of food are proteins, fats, and carbohydrates. We digest food either to get energy, or to use individual components of food in growth, maintenance, or repair of our own body parts.

We need some sugar (also called glucose) in our bloodstream at all times to supply us with immediate energy. “Energy” refers not only to a sense of muscular strength and vitality, but also to fuel for our brain, heart, and other automatic systems. Our brains especially need a reliable supply of bloodstream glucose.

In a normal, healthy state, our blood contains very little sugar—about a teaspoon (5 ml) of glucose. (We have about one and a third gallons (5 liters) of blood circulating. A normal blood sugar of 100 mg/dl (5.56 mmol/l) equates to about a teaspoon of glucose in the bloodstream.)

Our bodies have elaborate natural mechanisms for keeping blood sugar normal. They work continuously, a combination of adding and removing sugar from the bloodstream to keep it in a healthy range (70 to 140 mg/dl, or 3.9 to 7.8 mmol/l). These homeostatic mechanisms are out of balance in people with diabetes and prediabetes.

By the way, glucose in the bloodstream is commonly referred to as “blood sugar,” even though there are many other types of sugar other than glucose. In the U.S., blood sugar is measured in units of milligrams per deciliter (mg/dl), but other places measure in millimoles per liter (mmol/l).

When blood sugar levels start to rise in response to food, the pancreas gland—its beta cells, specifically—secrete insulin into the bloodstream to keep sugar levels from rising too high. The insulin drives the excess sugar out of the blood, into our tissues. Once inside the tissues’ cells, the glucose will be used as an immediate energy source or stored for later use. Excessive sugar is stored either as body fat or as glycogen in liver and muscle.

When we digest fats, we see very little direct effect on blood sugar levels. That’s because fat contains almost no carbohydrates. In fact, when fats are eaten with high-carb foods, they tend to slow the rise and peak in blood sugar you would see if you had eaten the carbs alone.

Ingested protein can and does raise blood sugar, usually to a mild degree. As proteins are digested, our bodies can make sugar (glucose) out of the breakdown products. The healthy pancreas releases some insulin to keep the blood sugar from going too high.

In contrast to fats and proteins, carbohydrates in food cause significant—often dramatic—rises in blood sugar. Our pancreas, in turn, secretes higher amounts of insulin to prevent excessive elevation of blood glucose. Carbohydrates are easily digested and converted into blood sugar. The exception is fiber, which is indigestible and passes through us unchanged.

During the course of a day, the pancreas of a healthy person produces an average of 40 to 60 units of insulin. Half of that insulin is secreted in response to meals, the other half is steady state or “basal” insulin. The exact amount of insulin depends quite heavily on the amount and timing of carbohydrates eaten. Dietary protein has much less influence. A pancreas in a healthy person eating a very-low-carb diet will release substantially less than 50 units of insulin a day.

To summarize thus far: dietary carbs are the major source of blood sugar for most people eating “normally.” Carbs are, in turn, the main cause for insulin release by the pancreas, to keep blood sugar levels in a safe, healthy range.

Hang on, because we’re almost done with the basic science!

You deserve a break

CARBOHYDRATE  HANDLING  IN  DIABETES  &  PREDIABETES

Type 2 diabetics and prediabetics absorb carbohydrates and break them down into glucose just fine. Problem is, they can’t clear the glucose out of the bloodstream normally. So blood sugar levels are often in the elevated, poisonous range, leading to many of the complications of diabetes.

Remember that insulin’s primary function is to drive blood glucose out of the bloodstream, into our tissues, for use as immediate energy or stored energy (as fat or glycogen).

In diabetes and prediabetes, this function of insulin is impaired.

The tissues have lost some of their sensitivity to insulin’s action. This critical concept is called insulin resistance. Insulin still has some effect on the tissues, but not as much as it should. Different diabetics have different degrees of insulin resistance, and you can’t tell by just looking.  (There are several other hormones involved in regulation of blood sugar.)

Did you know that people who work at garbage dumps, sewage treatment plants, and cattle feedlots get used to the noxious fumes after a while? They aren’t bothered by them as much as they were at first. Their noses are less sensitive to the fumes. You could call it fume resistance. In the same fashion, cells exposed to high insulin levels over time become resistant to insulin.

Insulin resistance occurs in most cases of type 2 diabetes and prediabetes. So what causes the insulin resistance? It’s debatable. In many cases it’s related to overweight, physical inactivity, and genetics. A high-carbohydrate diet may contribute. A few cases are caused by drugs. Some cases are a mystery.

To overcome the body tissue’s resistance to insulin’s effect, the pancreas beta cells pump even more insulin into the bloodstream, a condition called hyperinsulinemia. Some scientists believe high insulin levels alone cause some of the damage associated with diabetes. Whereas a healthy person without diabetes needs about 50 units of insulin a day, an obese non-diabetic needs about twice that to keep blood sugars in check. Eventually, in those who develop diabetes or prediabetes, the pancreas can’t keep up with the demand for more insulin to overcome insulin resistance. The pancreas beta cells get exhausted and start to “burn out.” That’s when blood sugars start to rise and diabetes and prediabetes are easily diagnosed. So, insulin resistance and high insulin production have been going on for years before diagnosis. By the time of diagnosis, 50% of beta cell function is lost.

Steve Parker, M.D.

EXTRA  CREDIT  FOR  INQUISITIVE  MINDS

You’ve learned that insulin’s main action is to lower blood sugar by transporting it into the cells of various tissues. But that’s not all insulin does. It also 1) impairs breakdown of glycogen into glucose, 2) stimulates glycogen formation, 3) inhibits formation of new glucose molecules by the body, 4) promotes storage of triglycerides in fat cells (i.e., lipogenesis, fat accumulation), 5) promotes formation of fatty acids (triglyceride building blocks) by the liver, 6) inhibits breakdown of stored triglycerides, and 7) supports body protein production.

In his fascinating book, Cheating Destiny: Living With Diabetes, America’s Biggest Epidemic, James Hirsch describes what happened to type 1 diabetics before insulin injections were available. Type 1 diabetics produce no insulin. Until Frederick Banting and Charles Best isolated and injected insulin in the 1920s, type 1 diabetes was a death sentence characterized not only by high blood sugars, but also extreme weight loss as muscle and fat tissue wasted away. The tissue wasting reflects insulin actions No. 4, 5, 6, and 7 above.

Banting and Best worked at the University of Toronto in Canada. Their “discovery” of insulin is one of the greatest medical achievements of all time.

Metabolic Improvements From a Paleolithic Diet in San Francisco

A Paleolithic diet improved metabolic status with respect to cardiovascular and carbohydrate physiology, according to a 2009 study at the University of California San Francisco.

Here are the specific changes, all statistically significant unless otherwise noted:

  • total cholesterol decreased by 16%
  • LDL cholesterol (“bad cholesterol”) decreased by 22% (no change in HDL)
  • triglycerides decreased by 35%
  • strong trend toward reduced fasting insulin (P=0.07)
  • average diastolic blood pressure down by 3 mmHg (no change in systolic pressure)
  • improved insulin sensitivity and reduced insulin resistance; i.e., improved glucose tolerance

Methodology

This was a small, preliminary study: only 11 participants (six male, three female, all healthy (non-diabetic), average age 38, average BMI 28, sedentary, mixed Black/Caucasian/Asian).

Baseline diet characteristics were determined by dietitians, then all participants were placed on a paleo diet, starting with a 7-day ramp-up (increasing fiber and potassium gradually), then a 10-day paleo diet.

The paleo diet: meat, fish, poultry, eggs, fruits, vegetables, tree nuts, canola oil, mayonnaise, and honey.  No dairy legumes, cereals, grains, potatoes.  Alcohol not mentioned ever.  Caloric intake was adjusted to avoid weight change during the study, and participants were told to remain sedentary.  They ate one meal daily at the research center and were sent home with the other meals and snacks pre-packed.

Compared with baseline diets, the paleo diet reduced salt consumption by half while doubling potassium and magnesium intake.  Baseline diet macronutrient calories were 17% from protein, 44% carbohydrate, 38% fat.  Paleo diet macronutrients were 30% protein, 38% carb, 32% fat.  Fiber content wasn’t reported. 

I’m guessing there were no adverse effects.

Comments

This study sounds like fun, easy, basic science: “Hey, let’s do this and see what happens!”

I don’t know a lot about canola oil, but it’s considered one of the healthy oils by folks like Walter Willett.  It sounds more appealing than rapeseed, from whence it comes.

I agree with the investigators that this tiny preliminary study is promising; the paleo diet (aka Stone Age or caveman diet) has potential benefits for prevention and treatment for metabolic syndrome, diabetes, and cardiovascular disease such as heart attack and stroke.

The researchers mentioned their plans to study the paleo diet in patients with type 2 diabetes.  Any results yet?

Are you working with a physician on a medical issue that may improve or resolve with the paleo diet?  Most doctors don’t know much about the paleo diet yet.  You may convince yours to be open-minded by trying the diet yourself—not always a safe way to go—and showing her your improved clinical results.  Or show her studies such as this.

Steve Parker, M.D.

Disclaimer:  All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status.  Always consult your personal physician before making any dietary or exercise changes.

Reference:  Frassetto, L.A., et al.  Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type dietEuropean Journal of Clinical Nutrition, advance online publication, February 11, 2009.   doi: 10.1038/ejcn.2009.4