Diabetes Can Increase Complications of COVID-19

Analysis by Dr. Joseph Mercola Fact Checked

Story at-a-glance -

  • For a limited time only, PBS is streaming a free documentary on America’s diabetes epidemic
  • More than 114 million American adults have diabetes or prediabetes and the economic ramifications of this condition are enormous. The U.S. spent $350 billion treating diabetes in 2019 alone
  • One of the best strategies to beat COVID-19 is to get any underlying chronic conditions under control; Type 2 diabetes and high blood pressure can often be reversed via healthy diet and lifestyle
  • Type 2 diabetes is a diet-derived condition. It’s rooted in insulin resistance and faulty leptin signaling, caused by chronically elevated insulin and leptin levels. As such, it can be effectively treated and reversed through dietary and other lifestyle means
  • Research has shown fasting and a cyclical ketogenic diet can improve insulin sensitivity and reverse diabetes. Staying physically active is also important, as excessive sitting blocks a number of insulin-mediated systems, including muscular and cellular systems that process blood sugar

For a limited time only, PBS is streaming a free documentary on America’s diabetes epidemic (it may not be available in all areas; check your local PBS to see if it’s in your area). Coincidentally, diabetes is a comorbidity that can increase your chances of contracting and even dying from COVID-19,1 making this documentary particularly timely.

One of the best strategies to beat COVID-19 is to get any underlying chronic conditions under control. Type 2 diabetes and high blood pressure — both of which have been implicated as underlying factors causing serious COVID-19 disease — can often be reversed via healthy diet and lifestyle.

According to a January 2019 update by the U.S. Centers for Disease Control and Prevention, more than 122 million American adults have diabetes or prediabetes,2 and the economic ramifications of this condition are enormous. The U.S. spent $350 billion treating diabetes in 2019 alone, according to the film.

Also according to the film, projections predict half the American population will be prediabetic or diabetic by 2025. Such predictions reflect poor research because if you use insulin resistance as your definition, 80% of the country is diabetic or prediabetic already.3,4

Glucose Metabolism Influences Cytokine Storms

An April 15, 2020, article5 in The Scientist reviews evidence6,7 that helps explain why obesity and diabetes are such potent risk factors for severe COVID-19 infection.

In a nutshell, higher blood glucose levels appear to play a significant role in viral replication and the development of cytokine storms. While the research in question looked at influenza A-induced cytokine storms, these findings may well be applicable in COVID-19 as well.

Cytokines are signaling molecules that are released by your immune system in response to foreign invaders. They, in turn, act as messengers that instruct other immune cells to fight the pathogen. In some cases, this immune response goes into overdrive, resulting in what’s known as a “cytokine storm” that can cause severe tissue damage and lead to death.

A cytokine storm response is typically the primary reason why people die from infections, be it the seasonal flu, Ebola, urinary tract infection or COVID-19. A critical player in cytokine production is the transcription factor interferon regulatory factor 5 (IRF5). In mice, genetically eliminating IRF5 protects them from influenza-induced cytokine storms.8

Interestingly, “the inflammatory response to influenza infections is also known to drive up glucose metabolism,” The Scientist reports,9 “in part so that immune cells have the necessary energy to mount a strong response, and also because the virus needs the sugar to replicate.”

According to researchers at the State Key Laboratory of Virology at Wuhan University, the hexosamine biosynthesis pathway — a glucose metabolism pathway — is responsible for activating IRF5-induced cytokine production in cells and mice. The same pathway is also responsible for viral replication, they say.10,11,12 As reported by The Scientist:13

“Hexosamine biosynthesis starts with glucose and results in an end product called uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) … Liu’s team now shows that O-GlcNAcylation of IRF5 is necessary for the transcription factor’s cytokine-producing activity …

The team also showed that patients infected with influenza have higher blood glucose levels and more O-GlcNacylation of IRF5 than healthy controls. Furthermore, blood glucose levels correlated tightly with levels of inflammatory cytokines.

The results show that ‘there is a connection [between] influenza virus infection, enhanced glucose metabolism and cytokine storm, all linked through O-GlcNAcylation of IFR-5,’ Mengji Lu, a virologist at the University Hospital Essen and a coauthor of the study, writes in an email to The Scientist ...”

In a Science Advances press release, co-author Shi Liu states:14

“We believe that glucose metabolism contributes to various COVID-19 outcomes since both influenza and COVID-19 can induce a cytokine storm, and since COVID-19 patients with diabetes have shown higher mortality.”

influenza virus

Insulin Resistance Is the Real Pandemic

So, the real pandemic here appears to be dysregulated glucose metabolism; in other words, insulin resistance, which is exceedingly prevalent in the U.S.15,16 Insulin resistance, in turn, is a diet-induced condition. Unless addressed, insulin resistance eventually develops into full-blown Type 2 diabetes. As mentioned earlier, if you use sensitive measure for insulin resistance, approximately 80% of the population has this metabolic dysfunction.17,18

Processed foods — which are loaded with added sugars, processed grains and industrially processed omega-6 vegetable oils — are the primary culprits causing insulin resistance, Type 2 diabetes and obesity and, according to FoodNavigator.com,19 doctors are finally starting to talk about the food industry’s role in the COVID-19 pandemic:

“A cardiologist has blamed the food industry for ‘normalizing’ ultra-processed junk food as more evidence emerges suggesting poor diet is the root cause behind increased mortality from COVID-19,” FoodNavigator states, adding:20

“In light of the mounting evidence that obesity and poor diet increases the risk of a severe response to COVID-19 infection, medical professionals now want the public health message urgently updated. And this, they warn, means the food industry bracing itself for regulation, such as bans on advertising and taxes …

Dr. Aseem Malhotra, a London-based cardiologist, told the BBC that a Government and Public Health England failure to tell the public to change its diet would represent an act of ‘negligence and ignorance’ … For him, the pandemic highlighted that it was in the interest of everybody, including those in the food industry, to make sure the population was as healthy as possible.”

Diabetes Is Reversible

As noted by PBS, Type 2 diabetes can be very difficult to control when relying on drugs alone and not doing anything about the underlying lifestyle factors actually causing the problem. While not addressed in the film, the use of insulin in Type 2 diabetes is particularly problematic. If the underlying lifestyle factors are properly addressed, Type 2 diabetes is entirely reversible in most people, and rather easily so.

The reason for this is because Type 2 diabetes is a diet-derived condition. It’s rooted in insulin resistance and faulty leptin signaling, caused by chronically elevated insulin and leptin levels. As such, it can be effectively treated and reversed through dietary and other lifestyle means.

For example, as detailed in my 2019 article “Fasting Prevents and Halts Diabetes,” research has shown fasting can improve insulin sensitivity,21 reverse diabetes22 and support your weight management efforts when combined with exercise.23 While “Blood Sugar Rising” discusses the foundational role of diet in this disease, it does not touch on fasting at all.

This is unfortunate, considering how effective it can be. In a case series paper24,25 published in BMJ Case Reports, Dr. Jason Fung and associates details how fasting can actually be used as a therapeutic alternative for Type 2 diabetes. As noted by the authors, their paper:

“… demonstrates the effectiveness of therapeutic fasting to reverse insulin resistance, resulting in cessation of insulin therapy while maintaining control of blood sugars. In addition, these patients were able to lose significant amounts of body weight, reduce their waist circumference and also reduce their glycated hemoglobin levels.”

Now, a case series paper is not a controlled study; rather, it simply presents the case history of one or more patients and may propose a hypothesis for why a treatment did or did not work. In this case, three diabetic patients between the ages of 40 and 67 participated in a supervised fasting regimen to evaluate the effects on their insulin requirements.

The patients had been diagnosed with Type 2 diabetes for 10, 20 and 25 years respectively, and were taking insulin daily. Of the three patients, two did alternating-day, 24-hour fasts, while one fasted for 24 hours three times a week over a period of several months. The complete manual of the fasting regimen used is described in Fung’s book, “The Complete Guide to Fasting.”26

Two of the patients were able to discontinue all of their diabetes medications while the third was able to discontinue three of his four drugs. All three also lost between 10% and 18% of their body weight.

With another similar trial, The Guardian reported on,27 Type 2 diabetics were placed on a severely restricted calorie diet where they ate just 600 calories a day for eight weeks. By the end of their fast, all were disease-free, and three months later, having returned to their regular diet, seven of the 11 participants remained free of diabetes.

There’s Hope Even for Severe Diabetes

Several studies have even found that repeated episodes of fasting can induce cell growth of pancreatic beta cells in mice.28 The growth is associated with an increased expression of Ngn3,29 a protein involved in converting DNA into RNA critical for endocrine cells in the pancreatic islets of langerhans, the cells responsible for producing insulin.

The increase in islet beta cells induced through intermittent fasting was accompanied by a marked improvement in blood sugar control in the animals. While individuals suffering from Type 1 diabetes often experience near complete inflammatory destruction of the islet beta cells, the same occurs in the later stages of severe Type 2 diabetes as well.

In a BMJ editorial,30 research scientist James DiNicolantonio, PharmD.,31 discusses these results, noting the findings may open the path to reversing Type 2 diabetes in those with “enough discipline and commitment to adopt a lifestyle that would have prevented diabetes in the first place.”32

As a first step, he recommends you first practice a diabetes preventive lifestyle — eating a diet primarily of whole foods, complemented with regular exercise. This will help improve your insulin sensitivity and may prove sufficient for those with a recent diagnosis of diabetes to reverse their condition over time.

In those who fail to respond, he recommends a time-restricted eating protocol, which provides many of the same benefits as longer fasting while being much easier to comply with. Supplemental measures may also be implemented to shield the beta cells from toxicity so they retain functional capacity. For example, reducing islet oxidative stress may be accomplished using spirulina, NAC and/or berberine.33

Ultimately, the goal is to achieve normal blood sugar control without drugs and maintain compliance with a diabetic preventive diet and lifestyle. This also includes physical activity.

Chronic inactivity such as extended sitting is one of the primary risk factors for insulin resistance and Type 2 diabetes. The reason for this is because sitting shuts down or blocks a number of insulin-mediated systems, including muscular and cellular systems that process blood sugar, triglycerides and cholesterol. Standing up activates all of these systems at the molecular level. Dr. James Levine detailed the science of this in our 2014 interview.

Diabetes Takes a Heavy Toll on Health

As detailed in the film, chronically high blood sugar from poor nutrition and lack of exercise can trigger long-term damage to your body and make you more prone to other chronic health problems and diseases, including but not limited to:34,35,36

Neuropathy (nerve damage) and amputation

Glaucoma, cataracts and blindness

Infections

Kidney disease and kidney failure

High blood pressure, heart disease, heart attacks and stroke

Dementia and Alzheimer’s disease

Sugar-Rich Diets Are a Primary Culprit

While PBS largely focuses on the conventional treatment of diabetes, which typically involves insulin and other drugs, it thankfully highlights the fact that sugar- and carb-rich diets are a primary driver.37 Research38 shows that once you reach 18% of your daily calories from sugar, there’s a twofold increase in metabolic harm that promote prediabetes and diabetes.

As a standard recommendation, I strongly advise keeping your total sugar consumption below 25 grams per day, which is about 6 teaspoons. If you have signs of insulin resistance such as hypertension, obesity or heart disease, you’d be wise to limit sugar to 15 grams or less until your weight and other health conditions have normalized.

Sadly, as noted by PBS, “the game is rigged.” Food products are allowed to state “sugar free” on the package, even though they’re loaded with carbohydrates and sugar alternatives. As noted in the film, it’s not just sugar itself that must be avoided, but anything that turns into sugar in your body as well, most notably grains.

In short, a high-grain, low-fat diet is a perfect prescription for diabetes, yet these kinds of foods are allowed to make a number of health claims. This kind of misleading labeling is causing many to think they’re making wise food choices when in fact they’re not.

It would help to remember that just about all processed foods are best avoided. Rather than trying to decipher labels, ditch the processed foods and fast food restaurants and cook from scratch using whole, unprocessed foods. This is by far the easiest and most effective way to improve your diet.

Soybean Oil Promotes Diabetes

One dietary factor not directly addressed in the film is processed vegetable oils. These may actually be worse than fructose in terms of the metabolic harm they cause.39 Soybean oil in particular has a questionable safety profile, and processed foods are positively loaded with it.

Whether partially hydrogenated, organic or genetically modified to be low in linoleic acid, soybean oil can cause dysfunction at a cellular level. Unfortunately, many health authorities have insisted omega-6-rich vegetable oils like soybean oil are healthier than saturated animal fats such as butter, lard and coconut oil, and this myth has been a tough one to dismantle, despite the evidence against it.

Most recently, research40,41,42 published in the January 2020 issue of Endocrinology found soybean oil — the most widely consumed cooking oil in America — can cause metabolic changes associated with:

Autism

Alzheimer’s disease

Anxiety

Depression

Obesity

Insulin resistance

Type 2 diabetes

Fatty liver disease

According to the authors, both conventional and genetically engineered soybean oil caused dysfunction in about 100 different genes in the hypothalamus, including genes associated with “inflammation, neuroendocrine, neurochemical and insulin signaling.”

Similar results were reported in a 2015 study,43 in which soybean oil was found to increase weight gain, body fat, diabetes, glucose intolerance and insulin resistance. Here too, soybean oil diets upregulated genes involved in diabetes, obesity, inflammation, mitochondrial function and cancer.

Ketogenic Diet Improves Insulin Sensitivity

Aside from fasting or time-restricted eating, a cyclical ketogenic diet is an effective way to improve your insulin sensitivity and reverse diabetes. A cyclical ketogenic diet — as detailed in my book “KetoFast” — shifts your body's metabolic engine from burning carbohydrates to burning fats.

Your cells have the metabolic flexibility to adapt from using glucose for fuel to using ketone bodies, which come from the breakdown of fats, hence, the name "ketogenic." Another term for this is nutritional ketosis. One of the fastest ways to prevent nutritional ketosis is by consuming sugar or refined carbohydrates.

A ketogenic diet calls for 50% to 70% of your daily calories to come from beneficial fats such as coconut oil, grass-pastured butter, organic pastured eggs, avocado or ketone producing fats like MCT oils, particularly C-8, while restricting your carbohydrates to 30 or 40 grams per day. Along with an appropriate amount of protein, this is typically enough to get you into ketosis.

Watch ‘Blood Sugar Rising’

“Blood Sugar Rising” provides an eye-opening glimpse into the very real struggles of Type 2 diabetics, as well as the around-the-clock challenges faced by those with Type 1 diabetes — a genetic condition in which your body produces no insulin at all — and groundbreaking inventions such as a bionic pancreas that automatically delivers the appropriate insulin dose as needed.

The film also reviews the real-world ramifications of skyrocketing insulin prices. The two types of diabetes differ in terms of their origin, and while insulin is typically ill advised for Type 2 diabetics,44 Type 1 diabetics die without it.

It also highlights the role of food as a cultural component, and how food-centered cultures can be guided to make healthier choices. For example, saying you have to abstain from rice, pasta or potatoes can be nearly impossible in certain families and cultures. Instead, you may need to approach it in terms of better and worse ways of preparing these foods, and restricting the amounts.

Diabetes, or more accurately insulin resistance with metabolic inflexibility, is a health accident waiting to happen, but it’s important to realize that you have control and can do something about it. In virtually all cases, it will require making more or less drastic changes to your diet and lifestyle, but the payoff goes beyond preventing diabetes. Concomitant with that, you’re also protecting your vision and lowering your risk of most of the chronic diseases that lead to an early grave.