The Trouble with Sweet Part 6: Fructose: America’s Most Dangerous FoodDecember 18, 2007
The Trouble with Sweet Part 6: Fructose: America’s Most Dangerous Food
Competency # 11 Sugar Reference: Review Article, American Journal Clinical Nutrition, Nov 2007Sugar is killing us!
Ok, ok. It’s just a hypothesis. But it’s the lead article in the prestigious American Journal of Clinical Nutrition. This isn’t just a random fly-by-night new idea. It’s in the leading journal in nutrition in the world. That gives it heft and weight. Yes, it’s about how we gain weight and how we end up with heart disease. I believe this has major implications for you and me. Here is the logic.
See if you can follow this. The connections are all evidence-based. In 1890, only 4% of American’s were obese. Heart attacks were rare. High blood pressure was rare. As our consumption of table sugar accelerated in the twentieth century, vascular disease began to appear. Hypertension started showing up. Cardiology was born. Lots of cardiologists’ kids went to college on new cardiac procedures. I learned Advanced Cardiac Life Support. We decided heart attacks were caused by fat. We’ve barked up the wrong tree.
Sugar is the only food that’s been correlated with scientific certainty with our epidemic of obesity, and our epidemic of vascular disease. Now, every developing country in the world is going through the same cycle along with the level of their sugar consumption. Remember: table sugar is two “sugars” attached. Glucose and fructose. It’s NOT the glucose. It’s the fructose in table sugar that’s implicated.
When we invented HFCS (high fructose corn syrup), we added another 25 pounds a year, per capita, of sugar consumption, and we got fatter along with that consumption. We are now consuming 150 lbs a year of sugar: 75 lbs per year of fructose for each and every one of us. Fructose is what’s in fruit, but only in tiny amounts (5-6%). Fructose is not digested like glucose. Your liver takes it up and burns it immediately. There is no feedback loop to digest it slowly. Sort of like throwing gasoline on a campfire, fructose revs up your liver cells and forces them to go into hyperdrive. It burns up all the ATP into ADP. That’s your basic energy-supplying molecule. When all the ATP is gone, your liver cell is in a metabolic panic and has to make triacylglycerol (the beginning of blood fats) and URIC acid. Uric acid is the breakdown product of ADP metabolism.
Uric acid? We always thought it was an innocuous chemical that caused gout in some folks. Turns out it is a precise predictor of vascular disease. Obese teenagers with new-onset hypertension all have elevated uric acid. Lower the uric acid and the hypertension gets better. Have a big meal of fructose and your uric acid goes up. If you have a big meal of fructose, your liver gets fatty. Same thing in animals.
So what is it that uric acid does? Here is the hypothesis. Uric acid is a potent consumer of nitric oxide. Nitric oxide allows your arteries to be supple and respond to high blood pressure. Without it, you have stiff, rigid arteries and you get “endothelial” dysfunction. More than that, you get all the hallmarks of metabolic syndrome with insulin resistance, hypertension, and weight gain. Nitric oxide is hard to measure as it’s rapidly digested and processed. But it’s a universal signal that you need to keep your arteries functioning.
Fructose is the beginning of the chain of events that lowers its level. All the studies are there. You can show that on a diet of fructose we will gain weight. The exact same diet of glucose, we don’t. Same thing for becoming hypertensive. Fructose does it. On and on. The uric acid idea is there, and the research has been done in small studies. Time to go big time and larger studies.
This has major implications. It’s not the sugar per se. It’s not the calories, per se. It’s the forced “hyper-metabolism” your liver is forced into once you eat too much fructose. It’s almost as if our bodies were designed to go into fat storage mode when we ate too much fructose. Well, maybe we were. In bygone years, when the mango tree was ripe, we were designed to gorge and that sweet taste of fructose drove us to eat till we went blind. In that era, the mango tree was ripe for 7 days of the year. Now, we can get fructose 24/365.
This is a major new hypothesis. It suggests we may be able to help control hypertension and adult diabetes by way of managing our fructose intake and our uric acid. That would be unique, and is certainly untested. We have certainly clued into not eating sugar for quite a while. But the ring of evidence is closing in. And it goes through fructose to uric acid to nitric oxide into endothelial dysfunction, into hypertension, into vascular damage, into a heart attack.
WWW: What Will Work for Me: This is the last of the series on sugar and my addiction to sweet. And this idea strikes me as being huge. I’m now thinking about how much sugar I eat each and every day. I like the taste of a sweet pear, or a luscious apple (6% fructose). Apparently, the threshold of metabolism isn’t reached with eating whole foods. It’s the rush of sugar from full sugared sodas and candies that’s the enemy (50% fructose). Or ice cream, Danish, cookies, chocolate… it goes on and on. But this suggests to me that if I want to lose weight and keep myself lean, I’m swimming upstream each and every time I give in to my sweet tooth. So, I’ve created a mental image. I have a cup of gasoline over a nice campfire. And I think of throwing it on the flames each time I eat a sugar load. My eyebrows got singed a couple of times today.
The column written by Dr. John E. Whitcomb, MD, Brookfield Longevity, Brookfield, WI (262-784-5300)