There is considerable debate about what factors lead to obesity, diabetes and heart disease. There is mounting evidence that fructose could be a significant contributor to obesity, fatty liver disease, metabolic syndrome and insulin resistance to name a few. In this blog I want to focus on some key differences between fructose and glucose and how these two monosaccharides are metabolized in the body:
Glucose for one is metabolized by different tissues in the body including the liver, muscle, fat, brain etc. In contrast, fructose is exclusively handled by the liver. Secondly, the intake of fructose does not elicit the secretion of insulin or leptin, two key hormones involved in central regulation of hunger. This of course might lead to increased caloric intake without decreasing appetite. Then, there is little evidence that extra fructose in the liver is utilized to produce glycogen even though the pathway theoretically exists. All research points to the rapid formation of fatty acids increasing the secretion of serum lipids by the liver (leading to dyslipidemia) and/or the accumulation of excess fat in the liver (fatty liver disease).
It is undisputed that the intake of sugars in the US has dramatically increased in the past 30 years. The two most consumed sugars are sucrose (table sugar; 50% glucose and 50% fructose) and high fructose corn syrup HFCS (either 42% or 55% fructose). As the intake of table sugar has decreased some, the intake of HCFS has dramatically increased resulting in a net increase of glucose and fructose intake all together. Considering the fact that most Americans have been urged to shun fat in their diet to maintain proper weight, it appears more than plausible that the increased intake of sugars is a stronger contributor to obesity and associated risk factors than fat intake. Fructose consumed in high amounts may ultimately be the strongest trigger for obesity given its effect on liver metabolism and lack of hormonal impact on insulin and leptin.
http://www.ajcn.org/cgi/content/full/76/5/911
http://www.medbio.info/Horn/PDF%20files/carbohydrate_metabolism_March_2007b.pdf
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A very interesting topic, indeed! Does all of this sugar intake bog us down so much so that our vital organs aren't functioning properly in the first place? I had a patient come in last week who is cutting out all artificial sweeteners from her diet. We had a conversation about what she was cutting out, but she was missing the fact that they are in everthing, not just diet soda. When I showed her the list of foods with added sugars and sweeteners she about fell off her chair. We are working together to cut the bad sugars, not just a few bad sources. The topic of nutrition continues to surprise us...ah the things we know now!
ReplyDeleteGreat Job Fred :) Thanks for this blog in particular. I have so many patients that are on "low fat" diets, but just cannot seem to get rid of the mid-section "squishy." What they don't realize is that to make foods more palatable, sugar/sugar substitutes are added since the fat is removed. I will pass this info along to them. Maybe if they read it from another doc, it will start to sink in!
ReplyDeleteImportant topic considering how difficult it is to avoid these added sugars. Great links to some great articles!
ReplyDeleteDr. Falentin,
ReplyDeleteNice aware on an important topic.
As Casi and Alison noted it in their comments, HFCS is in every single packaged foods and not only in soda and low fat foods or diets.
It would have been nice and very interesting that you could have posted or provided a link with some of the classical foods that high in HFCS and that Americans are consuming it daily and they might even think they are eating “healthy” foods.
Dr. G
P.S.: Thanks for sharing something in my blog as well as putting my suggestions in your blog. See you next month in MSP.