Fructose conversion to glucose & triglycerides

[sunpungi]

please someone read this article post your opinion.

http://www.ajcn.org/cgi/content/full/76/5/911


I was concerned since we exclusively eat plenty of fruits and moderate amounts of fats and occasional raw proteins.
According to this article, we could gain lots of TG and increasing chance of coronary artery problem.

thanks

[Oscar]

First of all, our diet is not a high fructose diet. Even though fruit is commonly associated with containing mainly fructose, this is not true. Some fruits do contain more fructose than glucose, for instance apples, where the average ratio glucose/fructose is about 2.00% : 6.50%. Some fruits have an equal ratio, like orange juice: 2.36% : 2.38%. And others contain more glucose than fructose, like bananas: 5.82% : 3.78%.

High fructose, especially the high fructose corn syrup, might well disrupt the balance, since we need both glucose and fructose. Plus the intake might be in big meals too.

I think we eat quite a bit of fats.

So I think the article is less of an issue for us anyway. There are some things with the article too, but not too important now.

[sunpungi]

thanks for your response,

I was just concerned after reading this article.
According to this article, it doesn't say about the high fat protects fructose induced lipogenesis. So I don't understand you are mentioning that we are eating a lot of fats. Actually above the fructuse induced lipogenesis, eating more fat exaggerate the triglyceride production, if I understood correctly.

Anyway, it's good thing to hear that fruit is not only full of fructose.
I just want to check with you guys before I make any presumption on this diet.

I will welcome more responses.

thanks

[Oscar]

I was concerned since we exclusively eat plenty of fruits and moderate amounts of fats and occasional raw proteins.

My response about fats was to your 'moderate' amounts.

We need fats for energy and fatty acids to form bodyfat, when excess energy cannot be stored in the blood or glycogen depots.

I don't know whether the blood triglycerids are indeed a problem with high fructose intake or not.

[huntress]

That is a very interesting article sunpungi.

"The consumption of fructose has increased, largely because of an increased consumption of soft drinks and many other beverages that are high in fructose and because of the consumption of foods such as breakfast cereals, baked goods, condiments, and prepared desserts sweetened with sucrose and high-fructose corn syrup (HFCS). HFCS is produced by the enzymatic isomerization of dextrose to fructose."

Clearly they are talking about non-natural sweeteners that are present in the said prepared foods. In this diet (100%), we don't consume them.

"Second, the concerns raised about the addition of fructose to the diet as sucrose or HFCS should not be extended to naturally occurring fructose from fruit and vegetables. The consumption of fruit and vegetables should continue to be encouraged because of the resulting increased intake of fiber, micronutrients, and antioxidants. In addition, the intake of naturally occurring fructose is low, 15 g/d, and is unlikely to contribute significantly to the untoward metabolic consequences associated with the consumption of large amounts of fructose"

Fruits are safe...

However, it raises some of my concerns about dried fruits though. Since dried fruits are laden with natural sugars, could it be possible that it brings the same effect as consuming HFCS?

[Oscar]

However, it raises some of my concerns about dried fruits though. Since dried fruits are laden with natural sugars, could it be possible that it brings the same effect as consuming HFCS?

See my first post...the ratios aren't extreme, I think.

[huntress]

But what if I consumed dried fruits and nothing but dried fruits in a day?

[RRM]

I don't know whether the blood triglycerids are indeed a problem with high fructose intake or not.

High blood triglycerides are associated with a high turnaround of fat deposits (triglycerides); meaning a high rate of storing and subsequently utilizing body fats. Which is inevitable when you eat big meals, and not an issue when you eat very small meals very frequently.

But what if I consumed dried fruits and nothing but dried fruits in a day?

That depends on the size of your meals; if your intake is according to your direct energy requirements (only replenishing lost energy), its perfectly ok.
Dried fruits = fruits minus a great deal of the water

[Oscar]

Ah gotcha. So a high fructose intake in itself doesn't cause it, only when it's ingested in big meals.

[RRM]

Yes.
High fructose may be associated with over-consuming though, because fructose is much more slowly converted into directly available energy than glucose, so that there is a less direct negative feedback effect as with glucose.
Nevertheless, if your fructose intake is according your direct energy requirements, there is no way this can be associated with increased blood triglyceride levels.

Scientifically 'found' associations should be regarded with care, as the processes and conditions involved are normally quite complex.
Also, first of all; if "an association" is found between fructose intake and coronary artery problems, this may, for example, be only a single digit percentage association.
And what is a high fructose diet? Sucrose is 50% fructose, so that a diet rich in added sugar is higher in fructose than a diet containing a little more starch. Apart from sucrose, glucose and fructose are also independantly present in foods, and will be associated to food-groups. Therefore it is likely that you will find many associations between fructose contents and, for example, the color, size, weight, etc of those foods, so that there will be many associations with other properties besides fructose contents.
Usually, many many associations are found (besides the ones present but not found!) within only one single study, while mostly only one association is singled out and presented.

To find a causative relationship between a nutrient and a disease, you need much more than an association.
For example; its easy to state that sugar causes diabetes, that cholesterol causes heart attacks and that fat causes obesity.
Its easy to point a finger, but if you want to accuse, you need to make a really solid case.

[CurlyGirl]

Oh goodness, I love this forum. I keep learning things, all the time.

[Oscar]

Scientifically 'found' associations should be regarded with care, as the processes and conditions involved are normally quite complex.

Yeah, this was one of the issues with the article too. It must be 'very hard' to draw such specific conclusions, from animal tests which seem simple, but are very complex. Not to mention the fact that lots of researchers draw their conclusions towards their theory (or that of their financier), or want to show some results in order to be able to publish an article. All in all I think it's better to read an article thoroughly (how exactly the test was done, what the exact results were) and draw your own conclusions.

[Wintran]

I recently re-read Wikpedia's article on fructose and was a bit surprised by its quite biased stance regarding negative health effects:
http://en.wikipedia.org/wiki/Fructose

Fructose depends on glucose to carry it into the blood stream via GLUT-5 and then GLUT-2 [1]. Absorption of fructose without glucose present is very poor, and excess fructose is carried into the lower intestine where it provides nutrients for the existing flora, which produce gas. It may also cause water retention in the intestine. These effects may lead to bloating, excessive flatulence, loose stools, and even diarrhea depending on the amounts eaten and other factors.

Fructose has been hypothesized to cause obesity [2], elevated LDL cholesterol and triglycerides, leading to metabolic syndrome. Unlike animal experiments, some human experiments have failed to show a correlation between fructose consumption and obesity. Short term tests, lack of dietary control, and lack of a non-fructose consuming control group are all confounding factors in human experiments. However, there are now a number of reports showing correlation of fructose consumption to obesity, especially central obesity which is generally regarded as the most dangerous type. (Wylie-Rosett, 2004)(Havel, 2005)(Bray, 2004) (Dennison, 1997)

Fructose also chelates minerals in the blood. This effect is especially important with micronutrients such as copper, chromium and zinc. Since these solutes are normally present in small quantities, chelation of small numbers of ions may lead to deficiency diseases, immune system impairment and even insulin resistance, a component of type II diabetes (Higdon).

Fructose is a reducing sugar, as are all monosaccharides. The spontaneous addition of single sugar molecules to proteins, known as glycation, is a significant cause of damage in diabetics. Fructose appears to be as dangerous as glucose in this regard and so does not seem to be the answer for diabetes (McPherson et al, 1988) This may be an important contribution to senescence and many age-related chronic diseases (Levi & Werman 1998).

I might try adding some more positive sources of researching to neutralize the article, but I'd love to hear some comments on the supposedly negative health effects of fructose here.

[Oscar]

Fructose depends on glucose to carry it into the blood stream via GLUT-5 and then GLUT-2 [1]. Absorption of fructose without glucose present is very poor, and excess fructose is carried into the lower intestine where it provides nutrients for the existing flora, which produce gas. It may also cause water retention in the intestine. These effects may lead to bloating, excessive flatulence, loose stools, and even diarrhea depending on the amounts eaten and other factors.

Since all fruits contain fructose AND glucose, this shouldn't be a problem.

Fructose has been hypothesized to cause obesity [2], elevated LDL cholesterol and triglycerides, leading to metabolic syndrome. Unlike animal experiments, some human experiments have failed to show a correlation between fructose consumption and obesity. Short term tests, lack of dietary control, and lack of a non-fructose consuming control group are all confounding factors in human experiments. However, there are now a number of reports showing correlation of fructose consumption to obesity, especially central obesity which is generally regarded as the most dangerous type. (Wylie-Rosett, 2004)(Havel, 2005)(Bray, 2004) (Dennison, 1997)

Obesity is a matter of energy mismanagement, so I guess we could make a case for glucose, fructose, or sucrose.

Fructose also chelates minerals in the blood. This effect is especially important with micronutrients such as copper, chromium and zinc. Since these solutes are normally present in small quantities, chelation of small numbers of ions may lead to deficiency diseases, immune system impairment and even insulin resistance, a component of type II diabetes (Higdon).

So did they actually see the diseases appear?

Fructose is a reducing sugar, as are all monosaccharides. The spontaneous addition of single sugar molecules to proteins, known as glycation, is a significant cause of damage in diabetics. Fructose appears to be as dangerous as glucose in this regard and so does not seem to be the answer for diabetes (McPherson et al, 1988) This may be an important contribution to senescence and many age-related chronic diseases (Levi & Werman 1998).

Interestingly enough, glycation happens either inside the body or outside. The latter is also known as the Maillard reaction, which happens what heating protein and carbohydrates, and which is what originates 'dirty' protein or HCA's. I think the Maillard reaction also happens at lower temperatures, if you wait long enough. My guess is that in a SAD, the amount of 'dirty' protein formed inside the body, is insignificant compared to the amount ingested through the diet.

[sungvimil]

I remember time back when RRM wrote about fructose conversion to glucose, but can´t find it.

I would like to know if I am correct when stating that fructose can be converted to glucose by the liver with the objective of raising blood sugar levels, and not necessarily enter the lipogenic route. This assertion is present in any biochemistry book, but I would like to know if RRM or anyone else is familiar with human studies showing this.

If this is true, then all the ¨health experts¨ talking about fructose toxicity are ignoring simple biochemistry facts, since the danger would be from excessive fructose consumption. On the other hand, eating fructose when you need the energy will not be converted to fatty acids, and will not produce decreased NO synthesis (high blood prerssure), excessive urea formation (gout) and ROS generation (oxidative damage), as those Dr. Lustig argues.
http://www.youtube.com/watch?v=dBnniua6 ... r_embedded

Thanks.