How Sugar Destroys Your Liver and Brain

Dr Mercola

At one point in time, sugar was a delicacy, a condiment that was difficult to come by. If you were lucky, you may have added it to your coffee or tea.

But according to Dr. Robert Lustig, professor of Pediatric Endocrinology at the University of California, San Francisco (USCF), sugar was “still extraordinarily expensive until the middle of the 18th to 19th century.”

That expense may have been a blessing in disguise, as it made it virtually impossible for mot people to consume in excess. And therein lies the problem. Sugar acts as a chronic, dose-dependent liver toxin (poison) when consumed in excess, Dr. Lustig has stated.

In fact, the rise of chronic metabolic disease in the U.S. follows the growth of the U.S. sugar industry and increases in per capita sugar consumption.

Today, we consume about 20 times more sugar than our ancestors did, and we have very little control over the amount since what was once a condiment has now become a dietary staple.

Why Is Sugar Bad for Your Liver?

The main problem with sugar, and processed fructose in particular, is the fact that your liver has a very limited capacity to metabolize it. In the video above, Dr. Lustig explains why sugar is so damaging for your liver and how it may lead to diabetes.

Part of the problem, according to Dr. Lustig, is that you can safely metabolize only about six teaspoons of added sugar per day.

However, the average American consumes 20 teaspoons of added sugar a day.1 All that excess sugar is metabolized into body fat, and leads to many chronic metabolic diseases, including but not limited to:

  • Type 2 diabetes
  • Cardiovascular disease
  • Hypertension (high blood pressure)
  • Dementia
  • Cancer

According to SugarScience.org, a product of Dr. Robert Lustig and colleagues, who have reviewed more than 8,000 independent studies on sugar and its role in heart disease, type 2 diabetes, liver disease and more:2,3

“Over time, consuming large quantities of added sugar can stress and damage critical organs, including the pancreas and liver. When the pancreas, which produces insulin to process sugars, becomes overworked, it can fail to regulate blood sugar properly.

Large doses of the sugar fructose also can overwhelm the liver, which metabolizes fructose. In the process, the liver will convert excess fructose to fat, which is stored in the liver and also released into the bloodstream.

This process contributes to key elements of MetS [metabolic syndrome], including high blood fats or triglycerides, high cholesterol, high blood pressure and extra body fat in the form of a sugar belly.”

Borderline High Blood Sugar Levels Linked to Kidney Damage

Your body is designed to have just one teaspoon of sugar in your blood at all times — if that. If your blood sugar level were to rise to one tablespoon of sugar you would run the risk of going into a hyperglycemic coma and even dying.

Your body works very hard to prevent this from happening by producing insulin to keep your blood sugar at the appropriate level. Any meal or snack high in grain and sugar carbohydrates typically generates a rapid rise in blood glucose.

To compensate for this, your pancreas secretes insulin into your bloodstream, which lowers your blood sugar to keep you from dying. Insulin, however, is also very efficient at lowering your blood sugar by turning it into fat — so the more you secrete, the fatter you become.

If you consume a diet consistently high in sugar and grains, your blood glucose levels will be correspondingly high and over time your body becomes “desensitized” to insulin and requires more and more of it to get the job done.

Eventually, you become insulin resistant, and then full-blown diabetic. But as a recent study showed, health effects of this elevated blood sugar/insulin cycle begin to occur even before insulin resistance sets in.

The study found that people with only slightly elevated blood sugar levels have a greater risk of kidney disease, as evidenced by two problems often associated with the disease — abnormal blood filtration (hyperfiltration) and more albumin protein in their urine.4,5

Those with the slightly abnormal blood sugar levels were 95 percent more likely to have hyperfiltration, which may contribute to kidney damage in diabetes.

They were also 83 percent more likely to have elevated albumin in their urine, which is a marker of early kidney damage.6,7 Past research has also found that people with slightly elevated blood sugar levels (but no diabetes or pre-diabetes) scored lower on memory tests.8

Type 2 Diabetes Raises Your Risk of Dementia

Download Interview Transcript

While insulin is usually associated with its role in keeping your blood sugar levels in a healthy range, it also plays a role in brain signaling. In one animal study, when researchers disrupted the proper signaling of insulin in the brain, they were able to induce many of the characteristic brain changes seen with Alzheimer’s disease (disorientation, confusion, inability to learn and remember).9

It’s becoming increasingly clear that the same pathological process that leads to insulin and leptin resistance and type 2 diabetes may also hold true for your brain.

As you over-indulge on sugar and grains, your brain becomes overwhelmed by the consistently high levels of insulin and eventually insulin and leptin levels and signaling become profoundly disrupted, leading to impairments in your thinking and memory abilities.

Eventually this may cause permanent brain damage, among other health issues. So it’s not surprising that a new study published in Diabetes Care found that type 2 diabetes is associated with a 60 percent increased risk of dementia in men and women.10

A past study — published in the New England Journal of Medicine in 2013 — demonstrated that a mild elevation of blood sugar — a level of around 105 or 110 — is also associated with an elevated risk for dementia.11

Neurologist Dr. David Perlmutter, author of the books “Grain Brain” and “Brain Maker,” has concluded that Alzheimer’s disease is primarily predicated on lifestyle choices and, in a nutshell, anything that promotes insulin resistance will ultimately also raise your risk of Alzheimer’s.

He also believes a blood sugar level of 92 or higher is too high and the ideal fasting blood sugar level is somewhere around 70 to 85, with 95 as the maximum.

Hedonic Hunger: Junk Foods Trick Your Brain into Wanting More Food

“Hedonic hunger” is a relatively new term. It describes the desire for food even when your body isn’t biologically in need of it. This phenomenon is thought to be contributing to rising rates of obesity in the U.S., and it almost always involves cravings for highly palatable foods, like those high in sugar and unhealthy fats.

These calorie-dense foods would have offered a survival advantage for most of history, when food wasn’t always readily available. This isn’t the case for many of us anymore, but your body may still be hard-wired to respond in over-drive when you taste extremely sweet foods.

Further, the more you eat junk foods, the more your body becomes used to them and requires more to give you the same pleasurable feelings, much like an addiction to drugs. Eventually, you may need to eat junk food in order to maintain a feeling of well-being. Scientific American reported:12

“Research has shown that the brain begins responding to fatty and sugary foods even before they enter our mouth. Merely seeing a desirable item excites the reward circuit. As soon as such a dish touches the tongue, taste buds send signals to various regions of the brain, which in turn responds by spewing the neurochemical dopamine. The result is an intense feeling of pleasure.

Frequently overeating highly palatable foods saturates the brain with so much dopamine that it eventually adapts by desensitizing itself, reducing the number of cellular receptors that recognize and respond to the neurochemical. Consequently, the brains of overeaters demand a lot more sugar and fat to reach the same threshold of pleasure as they once experienced with smaller amounts of the foods. These people may, in fact, continue to overeat as a way of recapturing or even maintaining a sense of well-being.”

Reengineering Your Food Environment to Break Junk Food Cravings

For people addicted to junk food, simple will power may not be enough to break the cycle of addiction. Some experts, like Michael Lowe, a clinical psychologist at Drexel University (who also coined the term “hedonic hunger”), suggest reengineering your personal food environment as a form of treatment.

This means not bringing junk food into your home and even avoiding venues that sell it if necessary. The good news is that the less sugar you eat, the faster your cravings will go away. In the video below, you can see what happens when one man gave up sugar.

While initially he was struck by cravings and irritability, after a week or so the cravings went away. He was awestruck when he finally woke up one morning and had no desire to eat something sweet. What’s more, his health measures, including weight and blood sugar, improved, as did his energy and fitness levels.

Are You Addicted to Sugar? Here’s How to Break Free

Eliminating excess sugar from your diet is a foundational element of reaching optimal health. If you currently eat sugar, there’s a good chance you’re struggling with sugar addiction. So I highly recommend trying an energy psychology technique called Turbo Tapping, which has helped many “soda addicts” kick their sweet habit, and it should work for any type of sweet craving you may have.

In order to minimize your sugar intake you’ll need to avoid most processed foods, as added sugars hide in 74 percent of processed foods under more than 60 different names.13 If you’re insulin/leptin resistant, have diabetes, high blood pressure, heart disease, or are overweight, you’d be wise to limit your total fructose/sugar intake to 15 grams per day until your insulin/leptin resistance has resolved.

For all others, I recommend limiting your daily fructose consumption to 25 grams or less. Please refer to my free nutrition plan for a step-by-step guide to making positive changes in your diet. You simply cannot achieve optimal health on a diet of processed foods and sugar. A few other tricks to try to kick your sugar cravings:

  • Exercise: Anyone who exercises intensely on a regular basis will know that significant amounts of cardiovascular exercise is one of the best “cures” for food cravings. It always amazes me how my appetite, especially for sweets, dramatically decreases after a good workout.

I believe the mechanism is related to the dramatic reduction in insulin levels that occurs after exercise. Additionally, if you do eat sugars or fruits around the time of the exercise, your sugar levels will not rise as it will metabolized for fuel

Organic, black coffee: Coffee is a potent opioid receptor antagonist, and contains compounds such as cafestrol — found plentifully in both caffeinated and decaffeinated coffee — which can bind to your opioid receptors, occupy them and essentially block your addiction to other opioid-releasing food.14,15 This may profoundly reduce the addictive power of other substances, such as sugar.

Sour taste, such as that from cultured vegetables, helps to reduce sweet cravings, too. This is doubly beneficial, as fermented vegetables also promote gut health. You can also try adding lemon or lime juice to your water.

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