As a follow-up to my post “The Truth About Cholesterol“, here’s a report from Slate showing that all LDLs are not created equal, and some types are more dangerous than others.  Moreover, the article discusses how America’s “War on Fat” steered us away from butter and lard, but led us to an arguably more dangerous food, the refined carbohydrate.  Post your thoughts!

Check out this study.

Researchers found that when “teenage” rats (30-45 days old) consumed massive amounts of sugar, they became extremely difficult to train as adults. For two weeks or so during adolescence, one group of rats had free access to a tasty 5% sucrose solution, while the control group only had water available. Similar to some American teenagers, the experimental group of rats consumed about 20% of their daily caloric intake as simple sugar.

To give you some background, it’s extremely easy to train adult rats to perform simple tasks, such as pulling levers or pressing buttons in return for a food reward. However, the researchers couldn’t motivate the rats that had consumed large amounts of sugar as teenagers to learn the task. My first reaction while reading this paper was: “Big deal. That group of rats just had sugar overload. It no longer had any real value for them, so there was no incentive to learn the new task”.

But here’s where the story gets interesting: if you repeat the experiment, but replace the teenage rats with adult rats, you get strikingly different results. When adult rats have free access to a sugary drink for two weeks, they never lose motivation for the sweet reward, and easily learn the new lever-pull task later in life. So it’s not that rats are simply sick of the sweet reward, but rather, it seems the sweet drink over-stimulated the reward pathway in the brain during adolescent development, leading to problems with motivation in adulthood.

Were the calories in the sugary drink or the sweet taste to blame for hyper-activating the reward circuits in the brain? To answer this, the authors took another group of teenage rats and gave them free access to a drink flavored with artificial sweetener, which has no calories. These rats were also unmotivated and rather difficult to train later in life, so the authors concluded that the sweet taste, but not the sugar itself, was hyper-activating the brain’s reward circuits.

Besides, ahem, crazy neuroscientists writing for health blogs, who cares about lazy rats? Well, the authors argue that a sign of depression in rodents is lack of motivation to perform simple tasks. Given that incidence rates for depression and other psychological illness are increasing in today’s society, it’s interesting to see how seemingly benign events during adolescence — a critical time in brain development — affect the mental state of adult animals.

Diets high in simple sugars and refined carbs cause metabolic disorders and Type II diabetes in millions of Americans. But to make matters worse, new evidence suggests that high sugar diets may be even more dangerous than we initially thought.

Having too much excess sugar in the bloodstream is never a good thing, and can lead to medical complications such as kidney failure, cardiovascular disease, and eye problems. But could high blood sugar also cause cancer? A Swedish research team addressed this question by tracking over 500,000 patients for 10-25 yeas, and published their results in the December issue of PLoS Medicine.

Similar to the findings of a study conducted in Korea in 2005, the European research team discovered that having elevated blood glucose levels increased the risk of developing certain types cancer later in life, such as pancreatic tumors in women and liver tumors in men. Not only had more cases of cancer occurred when people had high blood sugar, but the chance of survival also plummeted, especially when the person had cervical, espohageal, or colorectal cancers.

The authors present two theories on why elevated blood glucose levels could cause cancer: 1.) high sugar diets may cause an overproduction of insulin or insulin-like growth factor 1 (IGF-1), both of which promote rapid growth of new cells, the catalyzing step to tumor formation. 2.) More glucose in the blood stream could simply be adding fuel to the fire, feeding rogue tumor cells that need lots of energy to run.

Because the studies lacked certain controls, we can’t say for sure whether elevated blood glucose levels cause certain tumors to form. For example, the people with high blood glucose levels may have been sedentary, and so the lack of exercise may be what’s actually increasing the chances of developing cancer. Regardless, this study gives yet another example of unhealthy lifestyles contributing to comorbidity, a topic discussed at length by Thomas in The Decision Tree book.

Since the 1980′s, American soft drinks have been sweetened with high fructose corn syrup (HFCS), and it’s rapidly becoming the sweetener of choice in most processed foods.  Critics are quick to point a finger at this enigmatic sugar as the root of all evil, claiming its empty calories are contributing to the obesity epidemic, and the numerous chemical processes needed to make it are simply “unnatural”.  These accusations didn’t sit well with “King Corn”, and The Corn Refiners Association fired back with a series of TV commercials stating that HFCS was in fact natural, and completely safe in moderation.  Government officials have been talking out of both sides of their mouths on the issue, first allowing HFCS to be called natural, then recently proposing it be taxed, thereby equating it to other unhealthy items, such as cigarettes.  With all this conflicting information, what should the public think?  Should we avoid HFCS at all costs?  How does HFCS compare to other sugar sweeteners?
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