Molecule of the Week: Sorbitol

American food is full of chemicals, and I am not limiting my statement to ultra-processed foods with ingredients that are hard to pronounce. All food is composed of chemicals. Whole foods do not have an ingredient list, but, just the same, they are composed of chemicals. For example, a total of 51 chemical compounds have been isolated and identified that have a direct impact on the aroma of fresh orange juice (1). We are told to choose pure vanilla extract over vanillin, but the extract contains additional chemicals including vanillic acid, isovanillin, ethyl vanillin, and coumarin (2). BTW, the author of The Dorito Effect, not a fan of processed food, correctly states that most processed foods contain a narrower range of chemical components than whole foods. I contend that it is better to know whether a specific chemical or ingredient contributes to good health than to judge it by its name. Too many ingredients are demonized using scare tactics.

In Molecules, Microbes, and Meals Alan Kelly uses the more palatable term ‘molecule’ instead of ‘chemical.’ In the context of its use by Kelly or critics of ultra-processed foods, the terms chemical and molecule mean the same thing. During the next three weeks I will write about the three M words highlighted in the title of his book. Today I will start with Molecules and illustrate it with a common additive found in a few diet products—sorbitol, shown below in all of its glory. For my former students in Food Issues and Choices (FDST 2010) or Food Chemistry (FDST 4040) this format will look somewhat familiar.

molecular structure
Structure of sorbitol courtesy of Dr. Ron Pegg

Sorbitol is a molecule that demonstrates the complexity of the whole debate over chemicals in our food. It is a food additive, but its name is not as scary or hard to pronounce as aspartame, butylated hydroxyanisole, monosodium glutamate, pyridoxine hydrochoride, or theobromine.  The molecular (chemical) structure shown above looks kind of scary but not as frightening as many others that we find in food. It is actually a rather small molecule in the grand scheme of things. A food product developer selects an ingredient based on what specific function(s) it performs in the food. Sorbitol is specifically used as an alternative sweetener in sugar-free or reduced-sugar foods. Unlike other sweetener alternatives, it does contribute calories, slightly less than the calories contributed by natural sugars. Sorbitol is superior to sugar, however, in that it will not interact with teeth to promote tooth decay making it great as a sweetener in sugar-free gum.

Benefits from sorbitol include the enjoyment of chewing gum and some sweet baked goods without consuming large amounts of sugar. Ever celebrated a birthday without a cake? Such a practice would be considered un-American in many households. The pressure to eat copious amounts of sweets in celebration is baked into our culture. Sorbitol is a sugar alcohol, distinguished in its chemical structure by two extra Hydrogen atoms. Unlike ethanol, the molecule many of us consume in beer and other alcoholic beverages, sorbitol does not cause intoxication. This molecular additive is generally found only in sugar-free gum and some baked products.

Problems can result if sorbitol is overconsumed, just like with most food chemicals. The dark side of this molecule is that it has a laxative effect when consumed to excess. It is part of P (polyol) in FODMAP, those pesky molecules that can ferment in our gut leading to Irritable Bowel Syndrome. Overconsumption of sorbitol can be uncomfortable, but at least it gives us a sign, excess gas, a warning we don’t receive from overconsumption of sugars. The long-term consequences of excess sugar in the diet are much greater than the long-term consequences of too much sorbitol. This effect is not the same as abuse of laxatives, particularly in bulimia cases, which can lead to long-term health consequences.

But wait! There is more! Sorbitol is also found in many fruits and vegetables including apples, avocados, blackberries, broccoli, cabbage, cherries, green bell peppers, pears, peaches, plums and prunes. So, sorbitol is a natural chemical! Thus, many of these whole foods are part of the initial elimination phase of a low-FODMAP diet. Chances are that most consumers are ingesting more sorbitol from fruits and vegetables than from sugar-free gum, sugar-free birthday cakes, or low-sugar energy bars. Can the body distinguish between naturally occurring and added sorbitol? Probably not. Once a food is ingested, body chemistry is responsible for breaking down, absorbing, and distributing molecules throughout the body. Eliminating the few categories of packaged foods that contain sorbitol is much easier than eliminating sorbitol-containing fruits and vegetables, particularly for vegans and vegetarians.

tee shirt design urging us to "never trust an atom" as "they make up everything."
especially molecules!

The bottom line is that sorbitol, like most molecules—natural or added, provides benefits and has its limitations. It comes down to how much we consume, the benefits we derive from it, and our ability to identify which foods contribute to potential problems. Let’s compare sorbitol with caffeine. Sorbitol allows those people limiting their sugar consumption to enjoy sweets while caffeine helps with alertness. When overconsumed, sorbitol may produce a laxative effect while excess caffeine can lead to jitters and irritability. Both molecules are present in foods, either naturally occurring or as an added ingredient, but there is little evidence to indicate that natural molecules convey any benefit over added ones.

It is generally easier to identify which processed products have sorbitol or caffeine, because it is clearly stated on the label. Identifying natural sources of the two molecules is more difficult. It is important that for any food chemical that we balance out the benefits and the risks. We do not live in a two-dimensional world. Life is complicated, and we need to view food chemicals or molecules or additives with the nuance they deserve.

Next week: Microbes of the Week: Lactobacillus gasseri: Bifidobacterium bifidium, Bifidobacterium longum

References

(1) Sellami, I., V. Mall, P. Schieberle, 2018. Changes in the key odorants and aroma profiles of Hamlin and Valencia orange juices not from concentrate (NFC) during chilled storage. Journal of Agricultural and Food Chemistry 66:7428-7440.

(2) Lavine, B.K., D.T. Corona, U.D.N.T. Perera, 2012. Analysis of vanilla extract by reversed phase liquid chromatography using water rich mobile phases. Microchemical Journal 103:49-61.

 

 

 

 

 

 

 

3 thoughts on “Molecule of the Week: Sorbitol

    1. Thank you, Aaron, for your comment, but time waits for no one. Next month we move on from molecules, microbes, and meals to the interface between food science and nutrition with particular respect to what makes a healthy food, meal, and diet with some perspective from dietitians.

      BTW, another comment on my FB post is that sorbitol is a “[g]reat stabilizer for frozen foods. Modulates crystals.”

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s