Doctor explains how a simple test and change in diet may hold the key to reducing the discomfort and side effects of digestive disorders

How much fructose does the average American consume each day?

The average fructose consumption is about 37 grams to 40 grams per day. However, in the last three decades, the amount of fructose, from primarily high fructose corn syrup and juices, but also fruits, has just about tripled. Part of it is that high fructose corn syrup is highly desirable because it is sweeter than sucrose — regular table sugar — and it imparts a different mouth feel, taste, and even appearance to some foods so that people prefer actually the foods sweetened with high fructose corn syrup or fructose than to sucrose. The other part is now we’re super-sizing juices as well as McDonald’s hamburgers, croissants, muffins, cookies and everything else.

What are some of the most common products that contain fructose?

Probably the biggest ones are soft drinks — the regular soft drinks, not the diet type — apple juice, honey and then a long litany of other fruits like pears, prunes, plums, peaches, cherries — standard ordinary foods. Fruit contains fructose in varying amounts. Apples and pears are among the highest in terms of fructose content.

How much fructose should you consume? How much fructose is too much?

What has been recommended is that we limit the amount of total sugars in our diet to about 12 teaspoons — that’s the upper limit. Right now we’re at 32 teaspoons of sugar, per person, per day. We’ve known for a long time that there’s a limit to the amount of fructose that we can consume. But, what’s happened is that we have increased the total amount of sugar. The amount of fructose has replaced sucrose in the diet, and fructose is more slowly absorbed. It interacts with some other sugars to decrease absorption as well.

Why do we need to limit our intake of fructose?

Fructose is more slowly absorbed than regular table sugar, and there are some other factors that interfere with its absorption as well, and so it’s easy to exceed the amount of fructose that we can absorb. What happens then is the sugar is left over for the bacteria in the colon to ferment it. That results in a gassy, bloated kind of feeling, and even some people with large amounts will have some diarrhea. That’s in normal individuals, so part of concern is not only that it may be causing some GI complaints in normal, healthy individuals, but it may also be making matters worse for people who have gastrointestinal disorders. For most of us, we can find a level where we can feed you enough fructose to cause GI problems and GI complaints. Now, again, fructose is not causing disease, it’s not adding to the GI disease, but people who have GI disease, it may make the symptoms worse.

Explain fructose intolerance. Is that something that everybody has some degree of that eventually?

Fructose intolerance is just basically the effects of malabsorption that is perceived by the individual, so an individual may malabsorb or may not absorb all of the fructose. It doesn’t necessarily mean automatically that they will be intolerant. In other words, they may not really experience any symptoms. Some individuals will have more intolerance at the same dose of fructose than others.

Run down the symptoms again of fructose intolerance.

One of the things certainly is more gas is produced in the colon, so that may produce some distention and some crampy kind of pain, and bloated or feeling of fullness. A few people may also have diarrhea, or at least loose stools.

Basically, when any carbohydrate is not absorbed, the leftover amount of carbohydrate or sugar ends up in the colon and in the colon live very large amounts of bacteria that can ferment that carbohydrate or that sugar to organic acids and gases. When those gases then are produced, they are absorbed into the bowel, part of it, and then it’s passed through circulation and the gasses are exhaled in the lungs. So, we can measure the hydrogen that is produced in the fermentation by measuring the amount of hydrogen that is expelled. So, if the individual has more than 20 parts per million increase in hydrogen after taking the sugar, that’s considered malabsorption or a objective measure that they’re not absorbing the fructose.

What’s a healthy number in the parts per million?

Well, normally, day-to-day fluctuations during fasting would be less than 10 parts per million. After a meal, because we may also ferment fibrous foods, it may rise to those 20 parts per million level, but we understand why that is. It’s because you’re malabsorbing other forms of carbohydrate.

Do you recommend for Crohn’s patients or colitis patients that they limit fructose?

That’s been recommended for probably about three decades, at least by gastroenterologists. We didn’t know how much really we should limit and from what foods, so this gives us a little bit better handle in terms of to what level most people can tolerate. In small, divided doses, in combinations, it’s probably better-tolerated than as free fructose or fructose, for example, in the form of apple juice.

If people are fructose intolerant, if you find this and they present with these GI symptoms and they don’t feel good afterwards, what’s the suggested treatment?

One is to watch the amount of fructose that’s consumed or fructose-containing foods that are consumed at one time, that’s the common, simple way to do that. And probably, it will be better-tolerated in small, frequent doses during the day rather than one large amount. Certainly, if you need to be convinced and if you’re not sure whether or not this is really happening, then do a hydrogen breath test. It’s a relatively simple procedure. It can be done across the country and many gastroenterologists are well-equipped to do this test. It’s a very common procedure.

So if you have a guy that has a six-pack of regular coke or Mountain Dew a day, that’s really six-times the amount that you should have, correct?

Yes. And that individual might indeed have some bellyaches or may have some gastrointestinal complaints like bloating or loose stools and doesn’t understand the relationship between the consumption of fructose or sugars and his symptoms.

Going back to the fructose intolerance, do you know the cause of it? Is it genetic?

There seems to be a gender difference that females tend to have a little bit higher incidence of fructose intolerance than males. There doesn’t seem to be an ethnic difference in fructose tolerance. That’s what we hope to continue to study as to see if there are individuals that are more susceptible than others besides the obvious of having gastrointestinal disorders or pieces of bowel removed. But, we also want to investigate the presentation of different kinds of foods. In other words, that the different sugars that are inherent in foods already change the way fructose is absorbed. Some enhance it and some make it worse.

The fructose consumption in the United States has increased rather significantly and fructose can be identified in just a few foods. So, it’s not a difficult thing to avoid or identify in your diet. Then people who have preexisting, or who already have gastrointestinal disorders, may be even more intolerant of sugars than the normal individual and may want to be either evaluated in terms of their dietary intake or tested to see if indeed they are more fructose intolerant than normal individuals.

Fructose is absorbed along with glucose. It’s sort of like the fructose can’t get across the gut wall, but if glucose comes along and fructose hops in its wagon, it can go right across, so glucose serves as a carrier for the fructose. If fructose is combined with sorbitol, which is sort of a smooth alcohol, sugar that’s in dietetic foods, dietetic syrups, and breath mints, that actually will reduce the amount of fructose and those two sugars. Even relatively small amounts can make the symptoms worse.

When you see those foods that are sugar free, they always cause cramps. That’s the reason?

Yes. Now they’re combining fructose with sorbitol, especially for diabetics because fructose, as you know, doesn’t raise blood sugar as much as sucrose does, but then when you put those two together, then malabsorption is even more likely.

Source: Ivanhoe News