We outline the relationship between sugar and disease such as diabetes, depression, dementia, cancer, and metabolic syndrome based on numerous scientific studies.
Spoiler alert: High blood sugar levels harm our health. Read on and discover why that is.
Relationship between sugar and disease: Introduction
There is a lot to say about the relationship between sugar and disease.
So in this article, we'll take a closer look at the link between sugar and disease and what's true and false about sugar as a cause of several diseases.
Ahead of the 2012 London Olympics, British cardiologist Aseem Malhotra was concerned that McDonald's, Coca-Cola, Cadbury's, and Heineken were sponsoring the event.
Watch his 9-minute BBC documentary via this link.
An epidemic of obesity in the future
In the documentary, the cardiologist explains why as much as 90% of all British adults will be overweight by 2050.
The main factors of this frightening evolution are sugar and carbohydrates added to refined foods.
Cardiologist Malhotra also interviews an expert on obesity in the video.
Overweight by 2050
This expert argues that the human body knows how to process fat and protein but has no idea what to do with all those added sugars (such as fructose which is stored as fat).
In fact, unlike proteins, minerals, fats, or vitamins, these added sugars have no nutritional value.
Sugar affects our body reserves
The video shows that eating these added sugars makes us fat.
And we also sometimes eat sugars instead of something else, depriving us of functional nutritional elements.
Our body uses trace elements, vitamins, and minerals to process sugar.
In other words, the body has to dip into its reserves to digest sugar. Sugars, therefore, cause us to get sick and fat in the medium to long term.
Sugar causes premature skin aging
Are you concerned about your appearance?
And are you always striving for radiant and healthy skin?
If so, you must definitely watch your sugar intake!
Did you know that sugar makes us look older (indeed, one of the surprising facts about sugar)?
This was concluded by a team of scientists in the Netherlands.
Indeed, like sun exposure, smoking, and a low body mass index, sugar intake through food and drink is associated with an older appearance and a less than ideal presentation of oneself.
This 2011 study on a sample of 602 adults revealed that people around 60 years old with high blood sugar levels look older than those with low blood sugar levels. In other words, this study suggests that exposure to elevated glucose levels may lead to premature aging of the skin.
Thus, high blood sugar levels resulting from sugar consumption are the enemy of anyone who wants to stay looking young.
The devastating effect of sugar on heart and blood vessels
Results of extensive studies from 2014 and 2017 show that sugar has a negative effect on cardiovascular disease.
New Zealand researcher Lisa A. Te Morenga concludes from this study that sugar significantly affects our blood fats and blood pressure.
In other words, our bodies seem to handle sugar differently than other carbohydrates.
The link between sugar and dementia
Diabetes-2 and dementia
Numerous studies have shown a link between diabetes-2 and brain shrinkage and dementia.
People with type-2 diabetes are 1.5 to 2.5 times more at risk of dementia than people who do not have diabetes.
But this is not all because the disastrous effects of sugar go much further...
High blood sugar and dementia
Based on a study published in the scientific journal Neurology, there is a link between relatively high normal blood sugar levels and dementia.
For this scientific study by N. Cherbuin et al., brain scans of 266 adults between 60 and 64 years old with normal blood sugar levels were taken.
Some were on the high side regarding blood sugar levels, while others showed relatively low plasma glucose levels.
After 4 years, people with relatively high normal blood sugar levels were found to have an increased risk of dementia.
The areas of their brains responsible for things like understanding, learning, and remembering had shrunk 6 to 10% more than those with relatively low normal blood sugar levels.
This Australian study also showed that people with relatively high normal blood sugar levels may experience negative effects on their brain function, even if they don't have diabetes!
The results of this study suggest that even for people who do not have diabetes, blood sugar levels may be important for healthy brains.
The link between sugar and cancer
Cancer cells feed on fructose
A 2010 study was one of the first ever to reveal that cancer cells feed on fructose.
The human body appears to use fructose differently from glucose.
A study by H. Liu et al. shows the following:
Obesity or diabetes increases cancer risk
Other studies have revealed that the risk of cancer increases the more obese or diabetic a person is.
For example, the scientific study by T. Scully et al. revealed a significant interaction between adipose (fatty) tissue and tumor cells. Moreover, this interaction contributes to tumor growth associated with obesity.
Another study by E. Giovannucci et al. states that epidemiological evidence suggests that people with diabetes are at significantly higher risk for many cancers.
Mainly type 2 diabetes is associated with an increased risk of certain cancers, such as cancers of the pancreas, liver, colon, endometrium, rectum, breast, and bladder.
Greater risk of cancer with a Western diet
Our Western diet increases the risk of (dying from) cancer.
Western diet and increased risk of death from cancer
For example, a study by M. Yang et al. revealed that a Western diet may increase the risk of death after a diagnosis of prostate cancer.
A Western diet includes red and processed meat, high-fat dairy products, and refined grains.
After prostate cancer diagnosis, a Western diet can lead to a significantly higher risk of both prostate cancer-related mortality and overall mortality.
While this risk is significantly lower with a diet rich in vegetables without chemicals, fruits, fish, whole grains, and healthy oils.
Sugar as a cause of cancer
The study of Y. Onodera et al. from 2014 studied the role of sugar in breast cancer.
Using three-dimensional techniques, the research team uncovered that sugar could be a cause of cancer.
This study was groundbreaking and innovative as it showed for the first time that normal cells turn into cancer cells as a result of sugar.
The link between insulin and cancer
Lewis Cantley, the director of the Sandra and Edward Meyer Cancer Center at Weill Cornell Medicine, states that about one-third of all cancers create tumors with insulin receptors.
As a result, Cantley says, cancer cells can use glucose as a nutrient for their growth.
This is not the first time that the link between sugar and physical diseases, including cancer, has been noted.
Indeed, in the previous century, doctors working in overseas colonies independently reported that groups without obesity, cancer, and cardiovascular disease lost their good health once sugar consumption per person per year exceeded a certain amount.
So a diet low in sugar with mostly fish, vegetables, fruits, nuts, eggs, butter, olive oil, and unsweetened dairy products can be a smart move to prevent cancer.
Carbohydrates and depression
The study Inflammatory dietary pattern and risk of depression among women examined 43,685 women aged 50 to 77.
Carbohydrates in women: Increased risk of depression
Women who consume a lot of carbohydrates are 29 to 41% more likely to develop depression or inflammation.
This is what scientists M. Lucas et al. found, in contrast to women who consumed fewer carbohydrates.
Carbohydrates in men: More likely to experience depression
Another team of scientists made similar observations during a study of 1,003 middle-aged or older Finnish men.
A prudent diet is associated with a 25% lower chance of increased depressive symptoms.
In contrast, a Western diet is associated with a greater likelihood of increased depressive symptoms.
Over the 16 follow-up years, a prudent diet significantly reduced the risk of developing officially diagnosed depression.
So, avoiding fast sugars is the message for men to avoid depression!
Sugar makes you sleepy instead of more energetic
Have you ever heard of the idea that you can use sugar to boost energy? Well, this turns out to be a myth...
Researchers M.M. Karnani et al. found that sugar blocks the substance orexin in the brain, making you sleepy instead of giving you energy.
Consequently, it also makes you less active, causing you to burn fewer calories.
In short, sugar makes you sleepy, sluggish, and fatter...
Good to know: The opposite happens when you eat protein. Protein stimulates orexin cells, thus urging your body to burn calories (even more than you take in, which can help you lose weight). So, an occasional fried or boiled egg is good to stay awake!
Tip: If you do eat sugar at certain times... A small amount of protein negates the negative effect of sugar on orexin cells.
Conclusion: Protein, not sugar, activates the cells responsible for keeping us awake and burning calories.
For more information regarding the relationship between sugar and disease, we would like to point you to our other in-depth articles, which discuss many more facets of sugar in our American society:
Is sugar the cause of diabetes?
Diabetes distinguishes between diabetes type 1 and type 2.
Type 2 diabetes is the most common, and there is debate about whether sugar plays a significant role in causing it.
The view of the IDF (International Diabetes Federation)
Views of scientists
The role of sugar in diabetes has often been the subject of various studies.
An interesting example is a study led by Dr. Sanjay Basu of Stanford University, whose results were presented in 2013.
By the way: This research team included Professor Robert Lustig, someone who knows quite a bit about sugar.
The study of data from 175 countries concludes that diabetes does not have a single cause but results from a complex of causes...
The researchers write that sugar is one of the causes of diabetes, albeit an important one.
The complex of causes includes what can be called an increase in affluence: that is, sugar, but also rising Gross Domestic Product (GDP), overweight, and obesity.
The study also showed that where there was a lot of sugar, there was also a lot of diabetes, and vice versa.
And this despite considering all other possible factors that could affect it.
80% of food products contain sugar in the U.S.
We should be very concerned since sugar is really everywhere in our society and foods.
The research of S.W. Ng et al. is quite worthwhile in this context. Of 85,451 different food products purchased in U.S. supermarkets between 2005 and 2009, as much as 75% were found to contain sugar.
Look for yourself on the labels of foods for sale in the supermarket...
Once you're aware of those intentionally confusing names for sugar, you'll be surprised at how many products contain one or more different types of sugar.
Time for change
As with alcohol, a little sugar is not a problem. But consuming a lot of sugar, on the other hand, is not ok at all.
The reality is that the food industry has already pushed us way past our limits by now.
Several scientists, meanwhile, are calling for action.
After all, how much more circumstantial evidence is needed to go to war against the excess of sugar in our society? Of course, the lobbying by the sugar industry makes this very difficult...
Scientist Lustig also makes an interesting comparison to the cigarette issue that raged for decades.
At the time, no rock-solid scientific evidence was available about the devastating impact of smoking on our bodies.
On top of that, the tobacco lobby was very powerful, and cigarettes were part of family life (like smoking at the table after meals), advertising, and Hollywood.
But to anyone with some common sense, it was pretty evident by the 1960s that you could get lung cancer from smoking. In short, it's best to watch out for sugars... They are bad for our health, and on top of that, sugar is addictive.
The link between sugar and metabolic syndrome
Sugar causes all diseases associated with metabolic syndrome, such as:
Example of someone with metabolic syndrome
An unexpected example of someone who developed metabolic syndrome is Peter Attia.
Peter Attia lives in America, is a surgeon, exercised more than 3 hours a day, and followed government dietary guidelines.
A key feature of his condition was that he had become insulin resistant. Watch his 15-minute TED speech below:
What is insulin?
Insulin is the substance in our body that determines whether we burn or store energy.
In other words, insulin is an essential part of our bodily functioning.
It is the substance that causes our cells to burn or store the sugars that are in the blood after a meal.
Too many sugars can lead to too much insulin, which, in turn, can lead to insulin resistance.
What is insulin resistance?
Insulin resistance is a severe condition that means the cells have developed a defense against insulin.
So, in that situation, insulin can no longer do what it is supposed to do, which is to cause the muscles to burn the energy or store the energy as fat.
Once insulin-resistant, you are on your way to becoming diabetic.
This is because your pancreas can no longer keep up with the production of enough insulin to combat this resistance.
If the energy cannot be converted, the logical consequence is that your blood sugar levels will rise, causing many problems...
Ultimately, such insulin resistance can lead to heart disease, cancer, Alzheimer's, and even amputations.
Temporary insulin resistance versus chronic insulin resistance
Insulin resistance is a serious and widespread problem. What helps in understanding this problem is realizing that insulin resistance is not just a bug of nature that we suffer from.
Indeed, insulin resistance can be life-saving when the human body faces significant challenges such as hunger, infections, and pregnancy:
The solution to these physical challenges is a phenomenon we know only as a disease: insulin resistance!
How does insulin resistance work?
When glucose availability is low, the body takes emergency measures in the form of insulin resistance.
We have already discussed insulin resistance due to too much insulin. However, this is about insulin resistance when there is too little glucose.
Similarly, the body uses the mechanism of insulin resistance to ensure that the parts of the body that matter most are supplied with energy.
Physical hierarchy for energy supply
To do this, the human body maintains a tight hierarchy that ensures that less relevant parts have to wait a while in terms of energy supply.
The highest priority is the brain, followed by the unborn child in the case of pregnancy.
The parts of our body that are lower in the bodily hierarchy than the brain or the unborn child but also need glucose are forced by insulin resistance to switch to fat burning.
What also ranks high in the hierarchy is the immune system. When we are at rest, the body uses minimal energy and, therefore, a minimal amount of glucose. This state is called the basal metabolic rate.
More than 20% of the energy we use then is needed for our immune system.
The immune system requires even more energy when we are active, especially when something goes wrong, such as bone fractures and burns.
It can consume half to just about all of our energy in severe cases.
And insulin resistance helps us survive in these kinds of exceptions.
When the natural, temporary mechanism becomes chronic
Insulin resistance is a natural and healthy mechanism to cope with a temporary situation.
The problem, however, is that we are all suffering more and more from chronic emergencies, such as chronic inflammation.
As a result, the solution to the chronic problem is also chronic.
Insulin resistance then gets out of control, and the characteristics of metabolic syndrome develop.
The ironic part of the whole story is that we have caused this chronicity ourselves as a society.
In other words, the cause is our Western lifestyle and, among other things, excessive sugar consumption that continuously keeps our insulin levels high.
Insulin resistance as a cause of obesity
Surgeon Peter Attia (see video above) publicly questions whether insulin resistance is the cause of obesity.
This is contrary to countless others who question whether obesity is the cause of insulin resistance...
Surgeon Attia compares it to a bruise you get on your shin from banging it against a coffee table.
The bruise is the body's natural and logical reaction to that event and problem. So, of course, it would not be correct to see the bruise as the problem.
In other words, it would be the wrong response to organize and set up an entire medical industry to treat bruises while we do nothing to prevent people from further bumping into coffee tables.
Anyone with some common sense knows it is better to do something about the cause rather than the effect.
According to Attia, insulin resistance is at the root of weight gain and obesity-related diseases. And according to him, insulin resistance may well be caused by too many sugars, rather than by eating too much and exercising too little.