QI have been reading your column for two years now and love it.
What can you tell me about high-fructose corn syrup? I have heard it is bad and one of the reasons Americans are so fat. It is in almost everything, even breadcrumbs!
--N.F., Stafford
ACorn-syrup sweeteners were almost nonexistent in the early 1900s, but their use has grown since then, according to researchers. At the same time, Americans have grown heavier and the rate of diabetes has soared.
I don't think it's fair to blame America's collective weight gain entirely on high-fructose corn syrup, but it may have played a role.
In addition to slurping more sodas than ever before, we are eating larger portions of all foods, moving less and eating mindlessly, often while standing, watching TV or driving, rather than savoring our food.
Still, consuming high-fructose corn syrup is linked to a higher risk of diabetes and may cause indigestion and diarrhea for some people.
Sweeter than everAfter some technological improvements in the 1970s, corn syrup became cheaper than crystalline table sugar, which is derived from sugar cane and sugar beets. Nowadays most sodas, lemonades and fruit punches are sweetened with high-fructose corn syrup, and the sweetener turns up in unexpected places as well, such as in hot dogs.
In 1970, each American ate about half a pound of high-fructose corn syrup per year. By 1997, we averaged 62.5 pounds of high-fructose corn syrup a year.
Even when taking into account that Americans eat more calories now than in the past, high-fructose corn syrup is associated with a higher risk of diabetes, according to agriculture records analyzed in the American Journal of Clinical Nutrition.
And women who drank one or more sodas or fruit-flavored drinks made with high-fructose corn syrup per day were 83 percent more likely to develop diabetes, according to a Nurses Health Study.
That high-fructose feelingLarge amounts of fructose sometimes cause embarrassing symptoms such as a rumbling belly, gas pains, bloating, flatulence and diarrhea, according to research in the Journal of the American Dietetic Association.
About half of healthy people reported these symptoms when they took 25 grams of crystalline fructose, and about three-fourths of people reported discomfort when they consumed 50 grams of fructose.
Researchers at University of Kansas Medical Center did breath tests showing that people who felt uncomfortable could not absorb 25 to 50 grams of fructose.
To put that into perspective, heavy soda drinkers can easily consume 100 grams of fructose. A 22-ounce soda contains 30 to 40 grams of fructose from corn syrup, enough to cause discomfort for sensitive people. (To be fair, corn syrup contains not just fructose but also glucose, so it is not exactly the same as the pure fructose used in the study.)
Certain juices, such as apple and pear juices, naturally contain high amounts of fructose and can cause similar indigestion if someone drinks 16 ounces of juice. Whole fruits contain less fructose and usually don't cause problems.
Since caveman times, people have consumed about 16 to 20 grams of fructose per day, mostly from whole fruit and honey, according to researchers at the University of Toronto.
A half-cup of fresh fruit contains 0.5 gram to 7 grams of naturally occurring fructose, depending on the fruit, according to U.S. Department of Agriculture reports. Fiber and vitamins accompany the natural fructose in whole fruit, but not in corn syrup.
The bottom line is that we should keep eating fresh fruit and limit added sugar and corn syrup.
People of normal weight might consider limiting added sugars to about 10 teaspoons a day, according to the Department of Agriculture. That is about the amount in a 12-ounce soda or 1 cups of sweetened yogurt.
QIn a recent article, you mentioned vitamin D supplements. The pill form of vitamin D is mainly vitamin D2 from plants, rather than the vitamin D3 that is produced and utilized in humans. Mild exposure to sunlight makes our skin produce all the vitamin D3 that we need. We simply need to educate the population on the differences between moderate exposure for their skin type and dangerous overexposure.
--M.G., Toronto, Canada
AYou are right in pointing out that there are several forms of vitamin D.
Vitamin D3 seems most effective for treating vitamin D deficiency. Vitamin D2 seems less powerful.
I disagree that most supplements have vitamin D2, though. Many major brands, such as Nature Made and One-A-Day, use vitamin D3. Readers can check their own supplements. While the "Nutrition Facts" panel on the label will likely just say "vitamin D," the ingredients list on the bottom of the label should specify the type. Look for the words "vitamin D3" or "cholecalciferol."
For now, most experts recommend vitamin D supplements rather than sunlight because it's hard to predict how much sunlight people of different skin colors need to make enough vitamin D without raising the risk of skin cancer. Darker skin pigments can slow the formation of vitamin D.
Also, the farther from the equator we live, the weaker the sun and the less vitamin D we can make, especially in winter.
The only way to be sure is to ask your doctor to test for 25-hydroxy-vitamin D, the form found in blood. For most people, it's easier and less expensive to pop a multivitamin.
JENNIFER MOTL, a registered dietitian, welcomes reader questions via her Web site, brighteating.com, or mailed to Nutrition, The Free Lance-Star, 616 Amelia St., Fredericksburg, Va. 22401.