By
Michael Joseph, MSc
This excellent report by Michael Joseph provides a wealth of information on hyperinsulinaemia/insulin resistance, which is crucial to understanding how and why most common chronic diseases develop. I am most grateful to Michael for permission to publish his article here. The original can be accessed here:
http://nutritionadvance.com/hyperinsulinemia-insulin-resistance/

Background
When we think about the world’s biggest killer, different things come to mind.
Guns?
Or possibly heart disease, cancer, or maybe even dementia?
Well, those three chronic diseases are all good bets. But what if they are just the result of something else, and they all have a common cause?
In that case, that common cause could be the world’s biggest killer – and it goes by the name of hyperinsulinaemia.
This article takes a look at the rapidly growing problem of hyperinsulinaemia and insulin resistance.

What is Insulin Resistance?
Insulin resistance is a term to describe when our body develops a resistance to the effects of the hormone insulin (1).
As a result, we experience increasing blood sugar levels and higher levels of circulating insulin (2, 3).

What is Hyperinsulinaemia?Hyperinsulinaemia refers to the situation where we have a constant elevation of insulin levels (4).
The literal definition is simply an excess amount of insulin in the blood.
Insulin resistance is the usual cause of hyperinsulinaemia, and the resulting high insulin levels can be very damaging to our body (5).
Is Hyperinsulinemia Type 2 Diabetes?
There is a strong connection between hyperinsulinaemia and type 2 diabetes, but they are not the same thing.
Type 2 diabetes occurs when the pancreas fails to produce enough insulin to maintain normal blood sugar levels (6). Invariably this happens because of excess consumption of sugar and carbohydrates.
However, hyperinsulinaemia refers to when the body is producing too much insulin to keep high blood sugar levels in check (7).
Without adequate intervention, chronic hyperinsulinemia can lead to type 2 diabetes (8).
But it must be remembered: hyperinsulinaemia is associated with metabolic syndrome, and it’s harmful independently of diabetes.
Key Point: Insulin resistance leads to hyperinsulinaemia – excess amounts of circulating insulin in the body.

What Causes High Insulin Levels?
As shown above, insulin resistance leads to higher blood sugar levels. And the result of this is that the pancreas releases excessive levels of insulin to try and compensate.
But what causes insulin resistance?
Risk Factors
In the first place, there are some general risk factors/symptoms for insulin resistance which include the following (9, 10):
• Age: insulin resistance is usually diagnosed in those aged over 40
• Obesity (especially relating to abdominal fat)
• Hypertension
• Prediabetes
• Genetics: a family history increases risk
• A lack of physical activity
• Sedentary lifestyle
• Low HDL and high triglyceride levels
More Importantly: The Cause of the Risk Factors
Knowing the risk factors for a health condition isn’t actionable if we aren’t aware of the cause of those risk factors.
Prediabetes and obesity certainly don’t just appear overnight; they have a common cause.
And that cause is often diet.
Exhibit One: The Modern Diet

In contrast to a century ago, the food we eat now is almost unrecognizable.
While great grandma may have spent an hour or two making a thick broth of meat, veg, and maybe a few potatoes, it’s completely different now.
Nowadays, the average person eats:
• Cakes, cookies, pastries
• Candy
• Cereal (let’s be honest, we can call most of the stuff ‘breakfast candy’)
• Fast food
• Microwaveable meals full of refined carbohydrate, vegetable oils, and sugar
• Sugar-sweetened beverages
• Ultra-processed bread containing a variety of additives and oils (again, not like grandma’s bread)
Sure; some of those foods have always been on the menu, but not in the frequency they are now.
And if you look at each of those categories, you’ll see a common theme: highly processed carbohydrates. In fact, estimates say that 58% of all calories in the ‘standard American diet’ come from ultra-processed food (11).
Key Point: There are many different risk factors for insulin resistance, but many people believe our modern diet is the most significant.

How the Food We Eat Links to Insulin Resistance
Want to eat a chocolate cake for your birthday? Providing you’re healthy, that’s likely no problem.
Enjoy an occasional pizza with your friends? I’m not saying it’s healthy, but again – it’s unlikely to cause problems.
But when we constantly eat excessive amounts of carbohydrate, problems do occur.
Here’s what happens in a healthy person:
• Firstly, the pancreas releases insulin when it detects rising glucose levels, following digestion of carbohydrate.
• Second, this insulin shuttles glucose (as well as fats in the blood) into the body’s cells.
However, far too many people are eating refined carbohydrates in the form of grains and sugars every few hours.
And the modern cocktail of vegetable oils, grains, and sugar (high carb, high fat) is the very worst culprit.

How Insulin Resistance Develops
• If we are eating refined carbohydrates and sugars every few hours, then the result is a constant elevation in blood glucose levels.
• As a result, the pancreas is working overtime to release insulin and reduce these blood sugars.
• On the negative side, this situation cannot last forever, and over time the body’s cells become resistant to the effects of insulin.
• In this case, as insulin resistance builds, there is a corresponding higher amount of glucose in the blood.
• This large amount of blood glucose results in constant higher circulating levels of insulin to try and control the blood sugars. This is otherwise known as hyperinsulinemia.
Key Point: The modern diet plays a large role in the development of insulin resistance. Specifically, continuous elevations in blood sugars from excessive carbohydrate causes the body’s cells to become resistant to insulin.

Link Between Hyperinsulinaemia and Chronic Disease
Many people know that a type 2 diabetes diagnosis leads to an increased risk of cardiovascular disease, cancer, and dementia.
However, high blood sugar levels (and hyperinsulinemia) are damaging alone–whether diabetes is present or not.
Alzheimer’s
• Hyperinsulinaemia has a “robust association” with a higher risk of Alzheimer’s disease (12).
• High insulin levels inhibit the breakdown of amyloid beta (which contributes to plaque in the brain). Additionally, sample studies suggest hyperinsulinaemia is associated with nearly half of Alzheimer’s cases (13).
• Hyperinsulinaemia may lead to brain insulin resistance, and a longitudinal study shows that high insulin levels–without diabetes–double the risk of developing Alzheimer’s disease (14).
Cancer
• Individuals with the highest levels of insulin in the blood have a 62% higher risk of cancer mortality. In particular, they also have a 161% increased risk of gastrointestinal mortality (15).
• Chronic hyperinsulinaemia may raise cancer risk by increasing the biological activity of IGF-1 (insulin-like growth factor,) which can help tumors grow. Insulin can also directly influence tumor growth (16).

Cardiovascular Disease (CVD)
• Hyperinsulinaemia stimulates the production of proinflammatory cytokines in vascular systems and endothelial cells (17).
• High insulin levels can lead to the development of hypertension (high blood pressure) through impaired insulin signalling and other metabolic derangements (18).
• Raised fasting insulin levels increase the risk of CVD, regardless of other CVD risk factors (19).

Chronic Kidney Disease (CKD)
• Insulin resistance is visible in early stages of chronic kidney disease (20).
• Hyperinsulinaemia can lead to CKD independently of type 2 diabetes through oxidative stress, stimulating growth factors, and downregulating renal receptors (21).

All Chronic Diseases
• Insulin resistance, hyperinsulinaemia, and the metabolic syndrome are parts of a “systematic disease that affect all major organs,” in addition to our nervous system and immune system (22).
Key Point: Insulin resistance and hyperinsulinaemia appear to play a pivotal role in the pathology of major chronic diseases.

Hyperinsulinaemia: Signs and Symptoms
It’s important to realize the signs and symptoms of hyperinsulinaemia.
The sooner it’s recognized, the sooner you can halt the damage.
Given this, here are some signs to watch out for:
Fatigue / Lack of Energy Weight Gain
Blurry Vision Intense Hunger / Sugar Cravings
Inability to Focus Muscular Weakness
Brain Fog Constant Thirst
However, bear in mind that hyperinsulinaemia is often asymptomatic. In other words, there may be no visible indicators and a complete lack of symptoms.
Key Point: Hyperinsulinaemia has a range of symptoms to look out for, but sometimes there can be no indication of a problem.

When to Seek Medical Advice
Hyperinsulinemia is a serious medical condition that can lead to potentially life-threatening complications.
As a result, if you suspect any problem relating to insulin resistance or hyperinsulinemia then don’t self-diagnose.
Seek medical advice and work with your practitioner as accurate diagnosis requires medical tests.
Doing this will let you know for certain, and allow you to discuss possible treatment options with a medical professional.
Key Point: Hyperinsulinemia is a serious medical issue, so consult with a medical professional if you have any concerns.

Hyperinsulinaemia Diet: Can We Reverse Insulin Resistance?
Insulin resistance has a significant connection with the food we eat. To be specific: foods that massively increase blood sugar.
To reverse hyperinsulinaemia, it’s essential to remove the underlying problem of excessive blood glucose levels.
And many people have enjoyed success in doing this by adopting a carbohydrate-restricted diet.
The general makeup of these diets is extremely low in carbohydrate (<10%), with moderate protein and higher amounts of healthy fat.
For an idea of how such a diet would look, the following foods are emphasized:
• Meat
• Vegetables
• Low-sugar fruits (avocados, berries, olives)
• Fish
• Nuts
• Seeds
• Low sugar snacks (for example, extra dark chocolate)

What Does the Science Say?
On the positive side, there are dozens of studies which support low carbohydrate diets as a possible intervention for high blood sugar levels (and hyperinsulinaemia).
Here is just a small selection of the findings:
• Low-carbohydrate diets induce several favourable metabolic effects, including lowered blood sugar and a reduction in insulin levels (23).
• In women with obesity, a low carbohydrate ketogenic diet resulted in a significant reduction in fasting insulin levels (-54%) over 24 weeks (24).
• Carbohydrate restriction in obese elderly patients leads to improvements in insulin sensitivity (25).
• In a randomized trial involving diabetic patients, a low carbohydrate intervention showed lower glucose and insulin levels compared to a high carbohydrate diet. Both of these diets induced similar reductions in weight, so the benefits of the low carb diet were independent of weight loss (26).
Key Point: Adherence to low carbohydrate diets reliably reduces circulating blood sugar and insulin levels.

Sleep and Its Role in Hyperinsulinemia
It’s not just diet that affects blood glucose and insulin, but also sleep–or more accurately–our quality of sleep.
• Sleep deprivation in young healthy males induces higher fasting insulin levels. Furthermore, sleep loss has links to increased inflammation which may predispose the body to higher insulin levels (27).
• Even short-term changes in sleep can seriously affect glucose metabolism. Sleep deprivation lasting between 24 hours and 5 days results in impaired glucose levels (28).
• In a study following 1455 adults over 6 years, subjects sleeping less than 6 hours per night had significantly higher fasting glucose levels (29).
• A study analyzed healthy subjects after both a typical 8-hour night of sleep and then a 4-hour night of sleep. This single night of sleep deprivation reduced the glucose infusion rate of the subjects by 25% (30).
Although it’s something we often overlook, sufficient sleep is paramount to our overall health.
Key Point: Our blood sugar and insulin levels are not only determined by diet, but also the quality of sleep we get.

Exercise Reduces Fasting Insulin Levels Too
Another key point to remember is the benefits that physical exercise bring to the table.
• High-intensity exercise improves blood glucose levels for 1-3 days post-exercise in both diabetics and non-diabetics. Also, it lowers fasting insulin levels for up to 3 days (31).
• Exercise improves fasting blood-glucose and insulin levels in combination with a low-glycaemic-index (GI) diet, but insulin levels remain elevated with a high-GI diet – even with exercise (32).
• Exercise lowers blood sugar levels, reduces body fat, and increases insulin sensitivity- both short and long-term (33).
Key Point: Exercise helps improve all health markers relating to blood sugar levels and insulin. Markedly, this effect remains for several days post-exercise.

Final Thoughts and Conclusion
Is hyperinsulinaemia a unifying, underlying cause of the majority of chronic disease? Some people think so and–looking at the evidence–they may be right.
It’s important to remember that high blood sugar and insulin levels are damaging to everyone, not just those who have diabetes.
And we can all take simple steps to improve our health by minimizing the amount of sugar/refined carbohydrates we consume.
Lastly, we shouldn’t neglect the benefits of sleep and exercise – both of which play an invaluable role in our overall health.

References

  1. https://www.ncbi.nlm.nih.gov/pubmed/11460565
  2. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance
  3. https://www.ncbi.nlm.nih.gov/pubmed/17380029
  4. http://medical-dictionary.thefreedictionary.com/hyperinsulinemia
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2579903/
  6. https://www.ncbi.nlm.nih.gov/pubmed/15662003
  7. http://medical-dictionary.thefreedictionary.com/hyperinsulinemia
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3507594/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129661/
  10. http://onlinelibrary.wiley.com/doi/10.1038/oby.2009.381/full
  11. http://bmjopen.bmj.com/content/6/3/e009892
  12. http://www.alzheimersanddementia.com/article/S1552-5260(09)01739-7/abstract
  13. http://content.iospress.com/articles/journal-of-alzheimers-disease/jad150980
  14. http://jem.rupress.org/content/213/8/1375
  15. https://www.ncbi.nlm.nih.gov/pubmed/22215126
  16. https://www.hindawi.com/journals/jdr/2012/789174/
  17. http://www.revespcardiol.org/en/atherogenesis-and-diabetes-focus-on/articulo/90113980/
  18. http://jasn.asnjournals.org/content/15/11/2816.full.pdf
  19. http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0040263
  20. http://cjasn.asnjournals.org/content/9/4/638.full
  21. http://www.sciencedirect.com/science/article/pii/S1016319010600298
  22. http://onlinelibrary.wiley.com/doi/10.1002/hep.20920/full
  23. https://www.ncbi.nlm.nih.gov/pubmed/16436102
  24. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1334192/
  25. https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-8-5
  26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1188071/
  27. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018785/
  28. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767932/
  29. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3132857/
  30. https://www.ncbi.nlm.nih.gov/pubmed/20371664
  31. https://www.ncbi.nlm.nih.gov/pubmed/23467903
  32. https://www.ncbi.nlm.nih.gov/pubmed/20980494
  33. https://www.ncbi.nlm.nih.gov/pubmed/21323815