I Wish I Were Far From the Madding Crowd

April 18, 2010

Sugar is sugar … or not?

If you’ve followed any of the discussion about high fructose corn syrup (HFCS) vs. sucrose, you’ve probably heard representatives of the soft drink industry and HFCS refiners repeatedly say that fructose is no different than sucrose and that they’re metabolized the same (which, according to more and more research, is debatable).  I’ll get to that a little further on.

How much sugar we’re consuming

Amber Waves article “Behind the Data: Estimating Consumption of Caloric Sweeteners.” (April 2003)

Amount of HFCS and refined sugar delivered to food and beverage manufacturers in 2001

Intake levels represent the difference between total deliveries of calorie sweeteners for food and beverage use and estimated losses
Graphics from http://www.ers.usda.gov/AmberWaves/April03/Indicators/behinddata.htm

Make note of that 31.1 teaspoons per day figure for 2001.  (Daily intake in teaspoons = average annual intake in pounds / 365 days per year x 16 ounces per pound x 28.3495 grams per ounce / 4.2 grams per teaspoon.)

Think about the last item in that formula.  If the label on a box of cereal says 9 g of sugars, that means that a single serving contains 2 tsps of sugar.  A 12 oz. soda containing 39 g of sugars contains more than NINE teaspoons of sugar.  You get the idea.

According to Dietary Assessment of Major Trends in U.S. Food Consumption, 1970-2005 (see references), for 2005 it was down to 30 teaspoons per day.

What does this tell us?

Several points, one, representatives of the Corn Refiners Association and beverage manufacturers are right when they say that whether it’s fructose or sucrose doesn’t really matter.  If you’re consuming almost 4 times the amount of added sugars you should be, you are going to have problems!

Two, sucrose contained in beverages begins to undergo hydrolysis once it’s bottled and separates into its component parts (that is, fructose and glucose).  So in many cases when you’re drinking a sugar-sweetened soda you’re not drinking sucrose in solution, but sucrose, fructose, and glucose.  If enough time goes by most of the sucrose turns into free fructose and glucose.

A number of studies have shown that fructose is metabolized differently than glucose, but other studies seem to indicate that’s not as much of a concern, except possibly in two cases: one, when the ratio of fructose to glucose consumption is high, or in cases of high consumption of calories.  I would say that we have a combination of those, a relatively high ratio of fructose to glucose consumption (look at the relative amounts of HFCS to refined sugars used by beverage manufacturers!) together with consuming too many calories from sugar.  (And remember, that’s just the average amount.  Some people are consuming even larger amounts of sugar.)

Background on high fructose syrups

I recently came across a very interesting article, coauthored by John S. White, who is, or at least has been, a consultant to the Corn Refiners Association.

“Manufacturing, composition, and applications of fructose.”  L. Mark Hanover and John S. White.  American Journal of Clinical Nutrition, 1993, v.58(suppl.), 724S-732S.
http://www.ajcn.org/cgi/content/abstract/58/5/724S

The article describes the manufacturing and refining process of HFCS (or, as the authors call it, HFS), the composition of various grades of HFCS (as well as crystalline fructose and crystalline fructose syrup), functional properties and uses, and regulatory status.

What I found so fascinating about this particular article though, were these bits of information scattered throughout it.  According to the authors , HFS-42 (that is, HFCS that is 42% fructose) was the “first generation syrup of commerce.”  (p.726S)

They go on to note that :

Japanese and US manufacturers were producing HFS containing 55% fructose by the late 1970s.  HFS-55 was adopted by the carbonated-beverage industry and became the predominant sweetener in colas by late 1984. (p.726S)

On p. 727S, a table showing the typical composition of the various grades of fructose (ranging from 42% all the way up to 80% and 95%).

  • HFS-42 is 42% fructose, 53% dextrose (i.e. glucose), and 5% oligosaccharides
  • HFS-55 is 55% fructose, 42% glucose, and 3% oligosaccharides
  • HFS-80 is 80% fructose, 18% glucose, and 2% oligosaccharides
  • HFS-95 is 95% fructose, 4% glucose, and 1% oligosaccharides

One of the minor differences between HFS-80 and HFS-95 is that they, unlike the other two, contain less sulfated ash and no sulfur dioxide.  (Okay, the HFS-42 and -55 contain only 2 parts per million.)

The crystalline fructose and crystalline fructose syrup are both 99.5% or greater fructose.

What is interesting is that the authors note, p. 731S, that HFS-55 was being used in colas by late 1984, but that in 1988 the FDA had “proposed to recognize the long history of safety for fructose and reaffirm the GRAS status of HFS as a direct human food ingredient.” (FDA, 1992, 21 CFR 182.1866)  GRAS = “Generally Recognized As Safe” (for particular uses of a substance), CFR = Code of Federal Regulations

They go on to note: “The petition is specific for HFS-42, but may include HFS-55 on review of its additional processing steps.”

I’m not a lawyer, but to me that sounds like HFS-55 had not actually been approved for use as a direct human food ingredient at the time that cola manufacturers were starting to use it.  (I guess they must have just done that after the fact.)

HFS-55 vs. HFS-42

“The carbonated beverage industry is the largest user of HFS-42 and -55.” (p. 729S)  HFS-42 is primarily used in non-colas and HFS-55 in many colas, though colas can also be made using more HFS-42.  (See the graphic above about the use of sugar vs. HFCS by food vs. beverage manufacturers.)

In 1993 more than than 90% of energy-containing carbonated beverages produced in the U.S. were sweetened with HFS.

If I understand Hannover and White correctly, before 1984 most colas apparently were sweetened with HFS-42 and after 1984 with HFS-55.  In other words, the HFCS had approximately a 13% increase in the amount of fructose in it after the switch.

More importantly, the ratio of fructose to glucose changed from 42:53 to 55:42.  Why is that important?

Fructose malabsorption

Too much fructose in the diet can cause irritable bowel syndrome and other gastrointestinal problems.  However, studies have found that the problems are reduced when fructose is consumed with glucose.  (A certain percentage of the population is more prone to this, but it doesn’t seem to be an issue for most people.)

This is where you run into the problems of fructose metabolic products related to metabolic syndrome.   (The results of some studies also suggested that fructose malabsorption and metabolism problems were more likely to be associated with copper deficiency.)

Is HFCS the biggest problem?

I was going to say that HFCS is not the innocent player some portray it to be, then I realized that’s not really accurate.  The use of HFCS is not in and of itself the problem; the problem is food and beverage manufacturers putting it in almost every food and beverage they can.  It’s cheaper than refined sugar.  And most fast food places and restaurants reportedly make a higher profit margin off of soft drinks.  Once HFCS was introduced soft drink ingredients became so inexpensive that a lot of places started offering free refills.  I’m sure someone has brought that up before, but perhaps free refills are one of the main contributing factors to the increase in obesity (!?).   When people had to pay for a second glass of soda, they drank less.  Sorry, I don’t have a citation for that, but that seems obvious.  (Okay, I had to check.  I did a search on Google Scholar on +”obesity epidemic” +”free refills” and got 21 hits.   Google Scholar searches the scientific literature and books, as opposed to the entire Web.)

One example (with excerpt containing search terms):

Fructose, insulin resistance, and metabolic dyslipidemia

H Basciano, L Federico, K Adeli – Nutrition & Metabolism, 2005 – biomedcentral.com
in humans and animals, but the emphasis on fat reductions has had no significant benefits relative to the obesity epidemic. bombarded by huge million-dollar advertising campaigns for soft drinks, offered extra-extra-large serving sizes with free refills.

Apparently this is known as “portion distortion.”

Put that together with chronic overconsumption of sugar (regardless of whether they’re fructose or sucrose), unbalanced diets (deficiencies in vitamin D?), and not as much exercise as we should be getting.

Then throw in genetics, add a good dose of epigenetics in the form of gene-environment interactions, and you have all the conditions for development of metabolic syndrome and an obesity epidemic.

More on this in another post.

References

Dietary Assessment of Major Trends in U.S. Food Consumption, 1970-2005, by Hodan Farah Wells and Jean C. Buzby, Economic Information Bulletin No. (EIB-33) 27 pp, March 2008, http://www.ers.usda.gov/Publications/EIB33/

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March 19, 2010

Update on fructose – Dr. Lustig on Nightline

From post by Michelle Burton – “Dr. Robert Lustig on ABC’s Nightline”

Check out Dr. Robert Lustig on ABC’s Nightline discussing sugar and the damage it is taking on American’s Health.  (See post for link to video.)

Fructose overdose

Went grocery shopping after work today.  After listening to Dr. Lustig’s presentation on fructose (video itself) (see my post, “The toxic effects of … sugar“), I decided to pay a lot more attention to the labels on packages (that is to say, the area labeled as “Nutrition Facts”).

High fructose corn syrup here, high fructose corn syrup there.  Sugar here, sugar there.  What’s this?!  Ooh, I have to buy this!

I had been looking reading the labels on yogurt containers.  Some said “high fructose corn syrup,” some “sugar,” a couple even “fructose.”  Then I found the pièce de résistance!  99% fat free yogurt (with fruit on bottom).  Ingredients: Cultured Grade A low fat milk, fructose syrup, strawberries, sugar, high fructose corn syrup, blueberries, fructose….  23 g of sugars!

I won’t name the brand, but I think no matter which brand you look at you’ll find something similar.

March 14, 2010

The toxic effects of … sugar

UCSF Lecture on Sugar & Obesity Goes Viral as Experts Confront Health Crisis

March 10, 2010 UCSF news release (University of California San Francisco)

Background

Metabolic syndrome (from National Library of Medicine) – a group of conditions that put you at risk for heart disease and diabetes. These conditions are

See also Metabolic Syndrome from the Nemours Foundation.

Connection between sugar and the metabolic syndrome

The news release includes a presentation by Dr. Robert H. Lustig, UCSF, on “Sugar: The Bitter Truth” (approx. 1h, 30min.)

Dr. Lustig explores the damage caused by sugary foods. He argues that fructose (too much) and fiber (not enough) appear to be cornerstones of the obesity epidemic through their effects on insulin. Series: UCSF Mini Medical School for the Public [7/2009].  (In case you don’t have an hour and a half to spare, I found a basic version of Lustig’s presentation on the NIEHS website.  Also includes a QuickTime version of the presentation Lustig gave at that workshop.)

I’m still convinced that environmental chemicals could be contributing to occurrence of metabolic syndrome, but Dr. Lustig’s presentation was eye-opening.  I don’t understand all the biochemistry, but he makes what I think is a convincing argument that fructose, whether from high fructose corn syrup (HFCS) or from refined sugar (sugar = fructose + glucose), is responsible for the development of metabolic syndrome.

The basic reason is not because we’re taking in too many calories, but that fructose is metabolized differently than glucose is.

Lustig goes through the history of sugar in drinks and food and the production of HFCS before diving into biochemistry.  He compares the metabolism of glucose, ethanol, and fructose, covering all the metabolic pathways for each.

All of the cells in the body can metabolize glucose, some ethanol is absorbed bv the gastrointestinal tract, then metabolized by the brain and liver.

Fructose is primarily metabolized by the liver.  I won’t go into the details here, but fructose increases the level of triglycerides, messes with the insulin and leptin processes, makes the pancreas work harder, and has other negative effects on your body.

Dr. Lustig makes a very convincing argument that overconsumption of fructose has causes metabolic syndrome and had led to the obesity epidemic.

Some people argue that it’s Americans’ eating habits and lack of exercise that have caused the obesity epidemic.  Lustig asks, if that’s true, how do you explain the epidemic of obese six-month-olds? (Lustig looks at the amount of sugar contained in many formulas.)

Lustig also notes that the role of exercise isn’t really to burn calories, but to keep our bodies’ metabolic processes running smoothly and discusses the important role of fiber in fructose metabolism.

From the NIEHS website (a basic version of Lustig’s presentation)

(presented at a workshop on “Children’s Environmental Health Research: Past, Present & Future,” Jan. 2007) – this workshop had sessions focusing on lead and neurotoxicity, asthma, metabolic disorders, and ADHD)

Summary

Fructose (sucrose or HFCS) consumption has increased in the past 30 years, coinciding with the obesity epidemic

  • Fructose is everywhere
  • Fructose is not glucose

• Hepatic fructose metabolism leads to all the manifestations of the Metabolic Syndrome:

      • hypertension
      • de novo lipogenesis, dyslipidemia, and hepatic steatosis
      • inflammation
      • hepatic insulin resistance
      • obesity
      • CNS leptin resistance, promoting continuous consumption

• Fructose ingestion interferes with obesity intervention
• Fructose is a chronic toxin (it’s metabolized like ethanol)

Links (from UCSF)

UCSF Center for Obesity Assessment, Study & Treatment (COAST)

WATCH Clinic
UCSF Children’s Hospital

Adult Weight Management Program
UCSF Medical Center

New Center to Focus on Effects of Stress, Socioeconomic Status on Obesity
UCSF Today, August 11, 2009

Sugar is a Poison, Says UCSF Obesity Expert
Science Café, June 25, 2009

The Biology of Fat (or Why Literally Running Away from Stress Is a Good Idea)
Science Café, July 6, 2007

Note: A much briefer (and less rigorous) discussion of the harmful effects of HFCS can be found at High-Fructose Corn Syrup Truth, Still Not Sexy, HFCS.

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