From the Fat Front
Your government wants you to cut down on trans fatty acids. So do the American Heart Association and virtually every other health authority. Trans fats are created when liquid oils are solidified by partial hydrogenation, a process that stretches foods’ shelf life and changes “safe” unsaturated fats into dangerous ones. Trans fats are concentrated in stick margarine, solid vegetable shortening, doughnuts, crackers, cookies, chips, cakes, pies, some breads and foods fried in hydrogenated fat (chicken, fish, potatoes). Harvard nutritionist Walter Willett blames trans fats for at least 30,000 premature deaths a year, calling their introduction in the 1940s the “biggest food-processing disaster in U.S. history.” And pioneering trans-fats researcher Mary G. Enig, Ph.D., formerly at the University of Maryland, says: “Several decades of research show consumption of trans fatty acids promotes heart disease, cancer, diabetes, immune dysfunction, obesity and reproductive problems.” If Americans could detect the danger on food labels, they would cut back on trans fats, reasons the U.S. Food and Drug Administration. The FDA wants new food labels to reveal trans fats, contending such labels would save lives by forcing food manufacturers to eliminate trans fats. Just removing trans fatty acids from all margarines (70% now are high in trans fats) would prevent 6,300 heart attacks a year. Also eliminating trans fats in just 3% of breads and cakes and 15% of cookies and crackers would save up to $59 billion in health care costs in the next 20 years, the FDA predicts.
What’s bad about trans fats?
When it comes to the heart, just about everything is bad about trans fats, Willett says. Mainly, trans fats increase bad LDL cholesterol, triglycerides and insulin levels, and reduce beneficial HDL cholesterol, promoting heart attacks. In research at Harvard, women who ate the most trans fats, primarily in margarine and baked goods, had 1.5 times the heart attack risk of women who ate the least. In men, the risk was more than double. Special villain: margarine. It accounts for about 20% to 25% of all trans fats consumed, Enig says.
Eating an extra teaspoon of trans fat-rich margarine a day boosted men’s chances of heart attack 10%, according to the famed Framingham Heart Study. Generally, the harder the margarine, the more trans fat. Recent Tufts research shows that eating hard stick margarine sent triglycerides 18% higher than did eating semi-liquid squeeze-bottle margarine. In fact, trans fat-rich margarines are twice as bad as butter, Willett says. Butter’s saturated fat raises bad LDL, but margarine’s trans fats both boost LDL and depress good HDL cholesterol, doubling the damage. Thus, eating trans fats is extra harmful if you already have low HDLs, experts warn. Further, trans fats raise Lp(a), another artery-destroying blood fat. Butter isn’t always better, either: A tablespoon still has 7 grams of saturated fat. And new research at the University of Texas Southwestern Medical Center found that substituting very low trans fat margarine for butter reduced bad LDL cholesterol 11%. But it wasn’t as effective for obese people.
Other possible dangers
Cancer. A Dutch study found a higher concentration of trans fats in the breast tissue of women with breast cancer. A recent University of North Carolina study reported high consumption of oils, condiments and sweetened baked goods high in trans fats doubled the odds of colon polyps that may lead to cancer.
Reproductive problems. Pregnant and lactating women really should cut down on trans fats. Recent research shows pregnant women with the highest levels of a common trans fat had seven times the risk of preeclampsia, the complication of pregnancy characterized by edema and high blood pressure. High trans fats also may harm fetal and infant development. Mothers who eat trans fats pass them on to infants during breast-feeding. Infants feasting on trans fats may have diminished visual acuity and brain development.
Diabetes. Trans fats appear to reduce the body’s ability to handle blood sugar by lowering responses to the hormone insulin, which is particularly dangerous to diabetics.
How much trans fat is OK for the heart?
Virtually none, according to a recent analysis of 59 heart-diet studies by Dutch researcher Peter L. Zock at the Wageningen Center for Food Sciences. He finds the best diet strategy is not to lower total fat, but to severely restrict saturated fats (animal fats from meat and dairy) and to get near zero intake of trans fats. Enig finds that some Americans, including teenagers, eat 30-40 grams of trans fat daily.
SCIENTIFIC SOURCES FOR THIS ARTICLE
Margarine.
Alice Lichtenstein, Tufts, at the American Heart Association;s New Orleans meeting, Nov. 15, 2000
Low HDLs and eating trans fats
New England Jounral of Medicine, June 24, 1999.
Low trans-fat margarine
American Heart Association meeting, New Orleans, November, 2000
Cancer
Epidemiology 2000 Jul; 11(4): 469-73)
How much is OK?
American Heart Association meeting, June 7, 2000, Reston, Virginia.
This EatSmart column is reprinted from USAWEEKEND Magazine and is copyrighted by Jean Carper. It cannot be reprinted without permission from Jean Carper.
