Wednesday, October 1, 2008

Is There Really Fat in Corn Syrup?!

Most people probably know more than they think they do about chemistry, but it can still take real effort to recognize non-sense.  Last weekend’s Parade magazine, which comes with our Sunday paper, had an article on arthritis.  The author is an MD, but I really wonder if he was paying attention when he wrote it because there are a number of really silly statements in the section on diet.  

#1 “Red meat and high-fructose corn syrup both are loaded with omega-6 fatty acids ....”

I don’t have any argument with saying there is fat in red meat, but fat in Corn Syrup?!?  This is the stuff used to sweeten almost everything.  Corn syrup, whether or not it is high in fructose, is pure sugar.  It is made from corn starch which is a carbohydrate, not a fat.

To a chemist, "sugar" refers to a whole class of related molecules.  Glucose is the most important fuel sugar in living organisms and most carbohydrates are converted into glucose when you digest them.  Starch is basically a bunch of glucose molecules strung together in a long chain.  Plants use starch as a way to store glucose, and animals use a similar compound called glycogen to store glucose in the liver and muscles.  

When you think of sugar, you probably think "sweet."  Despite being made of glucose, most people would not consider starch to be very sweet.  If you chew a piece of bread for a while and keep it in your mouth, you should notice a slight sweet taste as the enzymes in your mouth convert the starch to individual glucose molecules.   Table sugar is the molecule sucrose, which consists of one glucose and one fructose connected to one another to form a disaccharide.  In high fructose corn syrup, the corn starch has been disassembled into the individual glucose molecules and about half of the glucose turned into fructose.  The reason for doing this is that fructose is much sweeter than glucose or sucrose - you need less to produce the same level of sweetness.

I quite agree that you should not go overboard with a high sugar diet, but to claim that things like pepsi are an important source of any kind of fat in your diet is laughable.

#2 sources of omega-6 fatty acids: deep-sea fish, flaxseed, brightly colored fruits, dark green leafy vegetables, and olive oil

The health benefits of fish oil and olive oil are well known, but when I think of “brightly colored fruits” I think of things like oranges - not exactly known as a source of fat in the diet.  And “dark green leafy vegetables” are also known to be good for you, but I have my doubts about the fat content of things like spinach.  I won't dispute that you should eat these foods, but the claim about fat makes me scratch my head. A check on wikipedia for omega-3 fatty acid turns up a list of dietary sources that include meat, fish, flaxseed, some nuts.  Somehow brightly colored fruits and leafy greens vegetables don't seem to be a major source, unless you want to include krill and microalgae.

#3 “Our prehistoric ancestors, to whom arthritis was virtually unknown" 

According to the Arthritis Foundation  osteoarthritis, the most common kind of arthritis, is mostly a result of wear and tear on joints.  Am I to believe that arthritis is a purely modern condition?  That our prehistoric ancestors didn’t wear out their joints?  That is just plain silly, and a quick search for "arthritis archaeology" on PubMed turned up a free review article on the subject:  Skeletal evidence of osteoarthritis: a palaeopathological perspective.  This article discusses evidence for arthritis in archaeological finds, and even mentions arthritis observed in dinosaurs.

The general public is confused enough as it is about general health, but when experts publish such silliness it just compounds the problem.  This just points out the need to pay attention so that you notice when you read something that doesn't make sense, rather than swallowing misinformation without a second thought.

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