A red apple with engraved heart on a wooden table - by Doug Cook RDn

Inflammation, Diabetes And Heart Disease. How Are They Linked?

Chronic inflammation - Inflammation, Diabetes And Heart Disease. How Are They Linked?

Diabetes and heart disease are on the rise worldwide.


Both are serious chronic (long-term) conditions that have a couple of things in common.


For one, they’re both considered “lifestyle” diseases. This means they’re related to various lifestyle choices such as smoking, alcohol use, poor nutrition and exercise habits.


They’re also linked with excess body fat, as well as, inflammation.


While there are several risk factors for diabetes and heart disease, one that doesn’t get a lot of attention is inflammation.  This post will review this under appreciated connection with tips on how to put out the flames.


NOTE: None of these are a substitute for professional medical advice. If you have any of these conditions, make sure you’re being monitored regularly by a licensed healthcare professional.




You might be wondering “What is inflammation?” Many find it a bit abstract. Why should you even be concerned?


Inflammation has been getting a lot of bad press lately, but it’s not always a bad thing. As in most areas of health, it’s the balance that’s important.


Inflammation is a natural process that our body uses to protect against infections, irritants, and damage. Inflammation helps our bodies eliminate damaged cells and tissues and helps them to repair. It also helps to eliminate the very thing causing the inflammation in the first place, for example, by fighting an infection.


The word inflammation comes from the Latin word “inflammo,” meaning “I set alight, I ignite.”


Inflammation is a natural process to protect and heal our bodies. However, it can become self-perpetuating and stick around way longer than necessary. This long-term (chronic) inflammation is often associated with several health conditions, including diabetes, heart disease, and excess body weight.


Types of inflammation – acute vs chronic

Acute vs chronic inflammation. What’s the difference?


When inflammation happens in a big way, for a short time, this is known as acute inflammation. Signs of acute inflammation include redness, heat, swelling, pain, and loss of function.


Strong, short acting inflammation can help the body heal injuries and infections.


On the other hand, when inflammation sticks around longer than necessary, it’s called chronic inflammation. Chronic inflammation can damage the body over time, and it can be ongoing without any noticeable signs or symptoms at all.


It’s this type of inflammation that’s linked to conditions like diabetes, heart disease, and excess body fat. It’s also linked with many other conditions of the body (arthritis), brain, and even mental health concerns (depression and anxiety).


What inflammation does


Where does inflammation come from? It stems from the immune system’s response, and also involves our blood vessels (arteries and veins) and other molecules.


One of these molecules is the infamous “free radical.” These highly reactive molecules (oxidants) help to fight infectious agents, and also help cells to communicate. But, when they are in overdrive, and they’re not counteracted with antioxidants, they can tip the balance and cause damage to healthy cells.


There are several other inflammatory molecules, one of which can be measured with a blood test. This is C-reactive protein (CRP). CRP is considered one of the “markers” of inflammation. When CRP is elevated, there’s excess inflammation in the body.


High blood levels of inflammatory markers like CRP are associated with increased risk of diabetes and heart disease. Studies show that levels of inflammatory markers in the blood can actually predict whether someone is going to eventually develop chronic disease in the future.


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Chronic inflammation and diabetes


Diabetes is a complex condition of metabolism where our bodies don’t manage blood sugar levels very well.


Blood sugar levels naturally go up and down throughout the day. Up after you eat; and are low when you’re hungry. When things are working well, your body will release insulin appropriately in after you eat foods with carbohydrate. This tells your cells to absorb sugar, which removes it form your blood to level it out.


Blood sugar level is a tightly controlled system.


But when the control of the blood sugar levels isn’t as good, for example they stay too high for too long (i.e. because of insulin issues), this can lead to diabetes. And having diabetes can have many long-term serious health consequences like amputation, blindness, and kidney disease.


About 95% of diabetes is type 2 diabetes (T2DM), formerly known as “adult-onset” diabetes. This is because there are a whole bunch of nutrition and lifestyle habits, which, over the years, contribute to this diagnosis.


Poorer food choices, inactivity, regular alcohol consumption etc. can promote excess body fat and inflammation, and lead to problems with how your body produces and uses insulin.


Inflammation is thought to be a key factor when it comes to diabetes. It can negatively affect insulin-producing cells in the pancreas. Inflammation is also one of the causes of insulin resistance. In fact, some researchers argue that virtually all of the factors that promote diabetes are linked with inflammation.


Chronic inflammation and heart disease


Heart disease is a major cause of death in countries such as Australia, the US, Canada, and the European Union.


The link between inflammation and heart disease was discovered back in 2006. The first stage of heart disease is called “atherosclerosis.” Inflammation is a key issue linked with both atherosclerosis, heart attacks and cardiovascular disease in general.


In fact, more forward thinking health practitioners see cardiovascular and heart disease as a disorder of inflammation and NOT a disease of ‘cholesterol’.


Atherosclerosis (hardening of the arteries) starts when there are too many “free radicals” inside the blood vessels. This can be from high blood sugar, high levels of oxidized fats in the blood (from too many free radicals), high levels of homocysteine (an anti-inflammatory molecule), and more


These lead to damage of the inside surfaces of the blood vessels which increases chronic inflammation. As well, free radicals oxidize, or rust, lipoproteins such as LDL cholesterol. These damaged LDL cholesterol molecules can penetrate the the blood vessel walls allowing buildup of plaque (which is a build up of damage LDL and immune cells).


Over time, this plaque narrows the inside of the blood vessels, and can lead to complications like heart attacks. And after a heart attack, inflammation increases to even higher levels. It becomes a vicious circle


Research is underway specifically targeting inflammation to try to reduce heart and blood vessel injury, reduce the worsening of heart disease, and to promote healing.


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Inflammation and excess body fat


Excess body fat is linked with both diabetes and heart disease. And in 2003, researchers found that it’s also linked with inflammation.


Body fat itself can promote activation of immune cells. The fat tissue can even produce its own inflammatory markers. This is particularly true for internal fat around the belly, liver, and heart.


Excess body fat also increases the body’s need for insulin, and negatively affects insulin-producing cells.


Excess body fat is also linked with the same nutrition and lifestyle factors as diabetes and heart disease.


Losing weight (i.e. excess body fat) reduces inflammation in belly fat as well as the rest of the body, and can also reduce the risk of many chronic diseases. While this is a lot of stigma with the idea of being overweight or targeting weight loss as a strategy; it remains one of the most powerful ways to reduce obesity-related inflammation and cancer risk.


Nutrition and lifestyle upgrades


There is a lot of evidence that improving nutrition and lifestyle can help many factors associated with chronic diseases, including reducing inflammation.


In fact, according to the NIH:


“People with insulin resistance and prediabetes can decrease their risk for diabetes by eating a healthy diet and reaching and maintaining a healthy weight, increasing physical activity, not smoking, and taking medication.”


“The main treatment for atherosclerosis is lifestyle changes.”


Here are several ways you can upgrade your nutrition and lifestyle.


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Anti-inflammatory diet


A nutritious diet promotes health, reduces risk of many chronic diseases, and can reduce inflammation.


Some areas that are being researched now are anti-inflammatory diets and foods.


One diet has a lot of science supporting its health promoting, emotional well-being improving, and life extending properties. This is the Mediterranean diet.


The Mediterranean diet includes a lot of vegetables, fruits, and legumes; some fish, whole grains, tree nuts, and dairy; and small amounts of olive oil, tea, cocoa, red wine, herbs, and spices. It also has low levels of red meat and salt, and a low glycemic index (it doesn’t raise blood sugar very high).


The Mediterranean diet can lower risk of diabetes and adverse effects of obesity, even without weight loss. One of the reasons why is thought to be because of its anti-inflammatory properties.


Foods common in the Mediterranean diet contain substances that are both anti-inflammatory and antioxidant. Substances like polyphenols, flavonoids, pigments, unsaturated fats (including omega-3s), and anti-inflammatory vitamins and minerals like vitamin E and selenium. These foods may also help to improve insulin sensitivity, quality of blood lipids, and the gut microbiota.


FUN FACT: Most people get the highest amount of dietary polyphenols from coffee and/or tea (but I don’t recommend a lot of cream and sugar).


Many anti-inflammatory effects of these foods have been demonstrated in a lab or in animals. Extra-virgin olive oil, tree nuts, and cocoa have been associated with anti-inflammatory effects, like reducing blood levels of CRP, in people.


Even when we look at individual components in a food, we should keep in mind that it’s the whole diet, with all foods and lifestyle components that help to promote health. One or two individual aspects don’t have the same effect as a holistic approach to improving overall nutrition and lifestyle.


Sugar and starch


Does sugar cause inflammation? Excess sugars and starches put stress on our blood sugar levels and increase our risk of chronic diseases. They also promote inflammation in the body.


Animals who eat sweets and white bread, and drink a lot of sugar-sweetened beverages have higher levels of inflammatory markers like CRP. Studies in people also show that diets low in sugar and starch have lower than average levels of CRP.


One possible reason is that more sugar and starch may increase production of inflammatory molecules and free radicals by giving immune cells more fuel and increase their activity.


You can upgrade your nutrition in this area by eating fewer sugars (especially “added” sugars) and starches (especially “refined” starches).


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Dietary fat


Some lab and animal studies show that very high levels of saturated fats can increase production of inflammatory markers and free radicals. Meals with unsaturated fats seem to reduce the inflammatory response after the meal.


Unsaturated fats like omega-3’s from fish seem to be particularly healthful. People who eat more fish tend to have lower levels of atherosclerosis and heart disease.


Fish-based omega-3 unsaturated fats reduce inflammation in several ways. They reduce the source of inflammation, as well as increase the amount of anti-inflammatory molecules.


Tree nuts are another good source of unsaturated fats and anti-inflammatory polyphenols. While nuts do contain a fair amount of fat, many studies show that people who regularly eat nuts do not tend to have a higher BMI (body mass index) or more body fat. Even adding nuts to the diet doesn’t seem to promote weight gain compared to the amount of calories they contain. And that is if there even is any weight gain at all, because many studies show no weight gain after adding nuts to the diet.


What about nuts?

Why don’t fat-containing nuts promote weight gain? Several studies show an increase in the resting metabolic rate in people who eat nuts – they seem to burn more calories even when they’re not active. This may be because of the type of fat (unsaturated), protein, fibre and/or the polyphenol content in the nuts.


You can upgrade your dietary fats by eating more fish and nuts. Fish and nuts contain unsaturated fats that have anti-inflammatory effects. They can also improve insulin sensitivity and even improve the health of insulin-producing cells.


When it comes to fish oil supplements, many studies show reduction in risk factors for heart disease by improving the way our bodies metabolize fats and its ability to “thin” the blood. However, fish oil supplements have mixed reviews when it comes to reducing inflammation. They can be helpful for some, but I recommend eating the fish itself.


Dietary fiber


People who eat more fiber tend to have lower risks of diabetes and heart disease. There are a few ways this is thought to work, one is from reduced inflammation. This is because people who eat more fiber, fruits, and vegetables tend to have lower levels of CRP.


In fact, animal studies show that eating fiber reduces the levels of inflammatory markers and also reduces excess body fat.


This effect can be because fiber slows down absorption of food from the body, reducing blood sugar spikes. It can also be because of its interaction with the friendly microbes in our gut.


Foods that are high in fiber include whole grains, legumes (i.e. beans and lentils), cocoa, seeds (e.g. sesame), tree nuts (e.g. almonds), avocados, raspberries, and squash.


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Lifestyle and inflammation



Regular exercise helps with many chronic diseases, as well as helping to reduce inflammation.


Levels of inflammatory markers are lower in people who exercise regularly, than those who do not. Plus, the people who exercise at a higher intensity tend to have even lower levels of CRP.


In fact, adding regular moderate exercise to a nutritious anti-inflammatory diet has benefits beyond the dietary benefits, like even lower levels of inflammatory markers in the blood (i.e. like CRP).


I encourage you to reduce the amount of time you are sedentary, and take active breaks.




Both acute and chronic sleep deprivation cause an increase in inflammatory markers in the blood.


In fact, sleep loss is a risk factor for insulin resistance and diabetes. When healthy volunteers have restricted sleep, this causes decreased insulin sensitivity.


Upgrade your sleep by making it more of a priority.


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Diabetes and heart disease are serious conditions. They have a few things in common, namely excess body fat and increased levels of inflammation. Inflammation can be healthy if its fighting an infection or healing a wound, but chronic inflammation is associated with many serious conditions.


There are a lot of nutrition and lifestyle issues that can contribute to chronic diseases. There are several ways they can do this; inflammation is just one of them.


The good news is that there are are several nutrition and lifestyle factors you can improve. These include eating less sugars and starches, eating more fish, nuts and dietary fibre, and getting regular exercise and quality sleep.


Doug Cook RDN is a Toronto based integrative and functional nutritionist and dietitian with a focus on digestive, gut, mental health.  Follow me on FacebookInstagram and Twitter.




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