Accepted medical opinion regarding fructose

[.Scott]

I am asking about what is the accepted medical opinion regarding fructose - and specifically whether there are common conditions when it should be avoided?

My interest started about a year ago when my doctor said that I was glucose-intolerant and that I should avoid foods with a high glycemic index. There was some ambiguity in the details, so I saw a nutritionist and got some specific diet guidance.

As I approached a birthday this year, I decided I would prepare a birthday cake for myself that would be healthy for all members of my family - allowing for food allergies and glucose intolerance's.

I needed a good substitute for sugar and with a little research I quickly discovered that High Fructose Corn Syrup had about the same amount of glucose as sugar - and as it turned out roughly the same amount of fructose as well. So I decided on fructose: 70% sweeter that sugar, no glucose, works similarly to sugar while cooking.

Fortunately, I had to mail order the fructose because that gave me time to further research fructose. And I found many articles with varying opinions - everything from "poison" to simply "watch calories". One item was this 2011 thread: https://www.physicsforums.com/threads/high-fructose-corn-syrup-hfcs.479962/

So, is there an accepted medical opinion of fructose - and if there is, what is it?

One item (the one that casts fructose as a "poison" is this:

In that video (90 minutes long), Dr. Robert Lustig says that fructose is only metabolizes by the liver and the results are not good - especially if you (as I am) glucose intolerant. He specifically counts it as a cause for Type 2 Diabetes.

Are Dr. Robert Lustig views mainstream?

Thanks

 

[DaveC426913]

All foods are, to a greater or lesser degree, partially good for you, partially not good for you.

An orange might contain as much sugar as a chocolate bar, suggesting to the uninformed that it might not be good for you.
But an orange provides many, many more micronutrients, macronutrients and fibre, and that is what makes it good.

Food is a balance - a compromise of competing needs. As with all things, moderation and balance are key.

The reason fructose is relatively unhealthy, compared to other sugars, is because it is a simple sugar - very easy to absorb and digest, which means your body has to do very little work to extract the energy out of it. That leads to storage rather than expenditure.

The real problem with fructose is the sheer quantity of it added to everything we eat.

Words like 'poison' - in the context of foods - are sensationalist.

 

[.Scott]

The real problem with fructose is the sheer quantity of it added to everything we eat.

What's "added to everything we eat" is sugar (sucrose) and High Fructose Corn Syrup (HFCS). Both contain roughly equal parts fructose and glucose. HFCS is added to food because it is inexpensive and roughly equivalent to sucrose in taste, calories, etc.

Words like 'poison' - in the context of foods - are sensationalist.

Over 500 years ago, Paracelsus said "All things are poison and nothing is without poison; only the dose makes a thing not a poison." (or the Latin equivalent).
Still if Lustig's descriptions are correct, there is a vast difference between the toxic potential of fructose and glucose.
He has 125 articles listed in PubMed: https://www.ncbi.nlm.nih.gov/pubmed?term=Lustig+RH&cmd=DetailsSearch

The reason fructose is relatively unhealthy, compared to other sugars, is because it is a simple sugar - very easy to absorb and digest, which means your body has to do very little work to extract the energy out of it. That leads to storage rather than expenditure.

That is at odds with Lustig's descriptions. His description is that both glucose and fructose are easy to digest and pass readily into the blood stream (perhaps limited by other stomach content). Organs can then readily turn the glucose to useful energy, but (per Lustig) only the liver can deal with fructose - and "very little work" doesn't really describe that process very well.

 

[Evo]

This may be getting too close to the line of not giving medical advice. Here is an opinion piece about fructose that might explain what Lustig is talking about.

http://www.health.harvard.edu/blog/is-fructose-bad-for-you-201104262425

 

[jim mcnamara]

Glucose intolerance is the hallmark of pre-diabetic patients, Type II diabetes. This is usually part of a set of patient conditions, called metabolic disease in the US.

Type I diabetes is an autoimmune condition that kills insulin producing cells - the Islets of Langerhans. Type I is usually early onset. And is generally unrelated to diet. Type II used to be a disease of middle age, it now has becoming prevalent in young people, teenagers. It is considered to be strongly related to bad diet and lack of exercise. There is a genetic component to Type I; to a lesser extent Type II.

One other point - carbohydrates like starch, sucrose, fructose, glucose ALL have high Glycemic Indices. They all impact blood sugar levels. White potatoes, pasta, white rice, white flour products -- all fall into this category.

 

[DaveC426913]

One other point - carbohydrates like starch, sucrose, fructose, glucose ALL have high Glycemic Indices. They all impact blood sugar levels. White potatoes, pasta, white rice, white flour products -- all fall into this category.

Yep. Nothing more sad than an Irishman having to avoid potatoes.

 

[.Scott]

This may be getting too close to the line of not giving medical advice. Here is an opinion piece about fructose that might explain what Lustig is talking about.

http://www.health.harvard.edu/blog/is-fructose-bad-for-you-201104262425

First of all, thanks for the reply - I was waiting for your input.
The article that you cite, Patrick Skerret, Harvard Health Publications, 2011, is certainly evidence that Lustig's ideas are either mainstream of becoming mainstream. That article links to the same video as I posted in the OP. I particularly found the two closing paragraphs interesting:

Experts still have a long way to go to connect the dots between fructose and nonalcoholic fatty liver disease, obesity, diabetes, heart disease, and cancer. Higher intakes of fructose are associated with these conditions, but clinical trials have yet to show that it causes them. There are plenty of reasons to avoid sugary drinks and foods with added sugar, like empty calories, weight gain, and blood sugar swings. Lustig offers another.

Every year I attend scores of talks on health and nutrition. Few prompt me to change what I do or what I eat. Lustig’s talk has me looking at the amount of sugar I take in, and thinking hard about sugar in my children’s diets.

It appears that Lustig is contributing to the effort to "connect the dots between fructose" and MetS. Here are some of hie recent PubMed listings of his research:
October 2016: https://www.ncbi.nlm.nih.gov/pubmed/27451002By substituting glucose for fructose they conclude (n=37):

Isocaloric fructose restriction for 9 days improved lipoprotein markers of CVD risk in children with obesity and MetS. The most dramatic reduction was seen for apoC-III, which has been associated with atherogenic hypertriglyceridemia.

February 2016: https://www.ncbi.nlm.nih.gov/pubmed/26499447Concludes (N=43):

Isocaloric fructose restriction improved surrogate metabolic parameters in children with obesity and metabolic syndrome irrespective of weight change.

March 2013: https://www.ncbi.nlm.nih.gov/pubmed/23283181Summary of Review:

Overall reductions in body weight, through reduced calorie intake and increased physical activity, are the current mainstays of NASH treatment. Reducing fructose and trans-fat intake, independent of weight loss, may be critical to improving or preventing progression of NASH.

I did find an article that contains most of the information in the video: http://advances.nutrition.org/content/4/2/226.long. The big advantage to this article is that it includes tons of citations. On the other hand, it's missing some incidentals (ex, the Coca Cola review) from the talk.

 

[.Scott]

One other point - carbohydrates like starch, sucrose, fructose, glucose ALL have high Glycemic Indices. They all impact blood sugar levels. White potatoes, pasta, white rice, white flour products -- all fall into this category.

From the Calorie Control Council http://caloriecontrol.org/fructose/:

Unlike table sugar or HFCS, fructose does not cause a rapid rise and subsequent large fall in blood glucose levels, which means it has a low glycemic load or glycemic index (GI). Glycemic index (glycemic load per gram carbohydrate) is a measure of how carbohydrates affect blood glucose concentrations. As expected, glucose itself has a high value because it is rapidly absorbed into the blood stream; its GI or glycemic load per gram is 100. In contrast, the glycemic load per gram fructose is only 19, while that of table sugar is 65 – midway between its component parts glucose and fructose. HFCS has a similar GI value to table sugar, though its precise value depends on the fructose content of the HFCS that is used.

A word of caution: In that last quote, they are setting the GI of glucose to 100. In most diet guides, white bread is set to 100. The conversion factor is about 1.5, as seen in this table that lists both: http://ajcn.nutrition.org/content/76/1/5/T1.expansion.html.
So this would put fructose at a white-bread-based GI of roughly 29. Any diet guide would consider this a low value; for example:https://blog.iafstore.com/en/glycemic-index-and-glycemic-load-of-foods-a336. By the way, that last source shows fructose with a GI of 32, but does not cite a source.

To the rest of your point, starch, sucrose, and glucose do have high GIs.
And that makes fructose look great for someone with MetS who is told to avoid high GI in their diets. So I bought 2 3-lb bags of fructose - which I may now dump. I used some of it to make a cake - and the cake has a fructose-to-fiber ratio that is lower than most fruits. But based on those isocaloric studies, it's looking to me as though I would have been better off using regular sugar.
I have set up another appt with the nutritionist (my doctor has handed this off to her), but I am not fully confident that she is well-enough briefed on fructose.

 

[gleem]

Have you considered a sugar substitute like Stevia which can be used in baking? Only problem some people perceive that it has a bitter taste.

 

[.Scott]

Have you considered a sugar substitute like Stevia which can be used in baking? Only problem some people perceive that it has a bitter taste.

I have always shied away from artificial sweeteners - on the basis that making the body think that it was about to get calories when it wasn't couldn't be a good idea. More recently, there have been articles such as this one: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3772345/.

Also, I find the blood glucose pretty apparent. Not only do I feel satiated after eating calories, but I think and work better. I have a sense of "enough calories". So I'm looking for "enough calories" without MetS. The prescribed method for this is to make the glucose supply from food slower and steadier.

 

[jim mcnamara]

@.Scott yup. You are correct. My bad. I should have read what I wrote. However, GI notwithstanding :
from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682989:

Absorbed glucose and fructose differ in that glucose largely escapes first-pass removal by the liver, whereas fructose does not, resulting in different metabolic effects of these 2 monosaccharides. In short-term controlled feeding studies, dietary fructose significantly increases postprandial triglyceride (TG) levels and has little effect on serum glucose concentrations, whereas dietary glucose has the opposite effects.

In English the above says: fructose impacts blood fats called triglycerides. Substantially. Next. Are triglycerides bad for those with metabolic disease?

from: https://www.nhlbi.nih.gov/health/health-topics/topics/ms
[section on list of risk factors in metabolic syndrome (disease)]

A high triglyceride level (or you're on medicine to treat high triglycerides). Triglycerides are a type of fat found in the blood.

Being on that list means triglycerides are contributory to future really bad news. If your physician specifically told you to use fructose, go for it. I'd guess s/he did not do that...

 

[.Scott]

Being on that list means triglycerides are contributory to future really bad news. If your physician specifically told you to use fructose, go for it. I'd guess s/he did not do that...

All my physician said was to avoid foods with high glucose index - to get my calories through other means. The same with the nutritionist. What they didn't say was that fructose should be avoided as well.

But the more I look at fructose (and therefore sugar and HFCS), the more it seems as though it would be worse for me than glucose.

 

[jim mcnamara]

Good conclusion. @.Scott I used to be current on all of this because I had several diabetic Type I kids. I'm not diabetic at all. From early on, most articles indicated that simple carbs (monosaccharides and some disaccharides) were not a great choice, but were unavoidable in fruit, which you should eat. So the diabetic exchange diet was born. 1 Fruit exchange (about an apple or a pear) per meal maximum usually. 15g - circa one teaspoon. Fructose counted, too, back then. Still does on the exchange diet.

 

[Evo]

All my physician said was to avoid foods with high glucose index - to get my calories through other means. The same with the nutritionist. What they didn't say was that fructose should be avoided as well.

But the more I look at fructose (and therefore sugar and HFCS), the more it seems as though it would be worse for me than glucose.

@.Scott, I am so glad that you started this thread, I have a number of illnesses where I really need to be watching my fructose intake. Very timely as a friend of mine was just told yesterday to try the fodmap system of identifying foods that may be aggravating his IBS, which I also have.

Can you get referred to a Registered Dietitian Nutritionist instead of a plain nutritionist? RDN's are required to have more advanced degrees and ongoing certification than a nutritionist that may have little to none. If you are serious, and it seems you are, I think the RDN would be the better choice.

I'm finding out so many of the foods I thought were good are actually bad for me, I'm having to rethink everything. I also have Metabolic syndrome, among other problems, of course one food that's good for one condition is bad for another. I won't go into the list, but right now it appears the answer is to just stop eating.

 

[.Scott]

Can you get referred to a Registered Dietitian Nutritionist instead of a plain nutritionist? RDN's are required to have more advanced degrees and ongoing certification than a nutritionist that may have little to none. If you are serious, and it seems you are, I think the RDN would be the better choice.

I didn't know there was a difference between an RDN and a nutritionist. The one I went to works at Lowell General Hospital. I will check to make certain she is an RDN.

And I am glad you find the thread useful.
I hope many others do as well.

 

[.Scott]

Just as a follow-up:
My nutritionist is an RDN. More precisely, the letters after her name are MS, RN, LPN. She said that the Lustig research is very much mainline.

Her advice was to avoid large amounts of added sugar and HFCS in my diet.
I have found it easier to just avoid those entirely. And the extra sweetness of fructose (HFCS and sugar) is starting to taste unnatural to me. Per doctors orders, I am also on a low glycemic index diet.

That together with exercise (mostly walking) has had yielded good results. HbA1c: last year 6.1, now 5.6. Triglycerides: last year 234, now 118. All current blood work results (Chol, HDL, LDL, HbA1c, Trig.) are in the normal range.
My primary concern now is whether the exercising is sustainable. Spring is easiest with mild temperatures and lots of daylight. Summer is often too hot for me to tolerate - but I squeezing it in when I can. Fall and winter are the problems. There are very few sidewalk in the town where I live and the traffic is very dangerous for pedestrians in the dark.

 

[Evo]

Just as a follow-up:
My nutritionist is an RDN. More precisely, the letters after her name are MS, RN, LPN. She said that the Lustig research is very much mainline.

Her advice was to avoid large amounts of added sugar and HFCS in my diet.
I have found it easier to just avoid those entirely. And the extra sweetness of fructose (HFCS and sugar) is starting to taste unnatural to me. Per doctors orders, I am also on a low glycemic index diet.

That together with exercise (mostly walking) has had yielded good results. HbA1c: last year 6.1, now 5.6. Triglycerides: last year 234, now 118. All current blood work results (Chol, HDL, LDL, HbA1c, Trig.) are in the normal range.
My primary concern now is whether the exercising is sustainable. Spring is easiest with mild temperatures and lots of daylight. Summer is often too hot for me to tolerate - but I squeezing it in when I can. Fall and winter are the problems. There are very few sidewalk in the town where I live and the traffic is very dangerous for pedestrians in the dark.

Thanks for the follow up, and good luck!

 

[jim mcnamara]

Great posts, .Scott. Time roll up the curtains on a good thread.