Defensive strategies lower risk of diabetes
We’ve been hearing a lot about the epidemic of type 2 diabetes, which now even affects children. Unfortunately, just mentioning it, or quoting the rising percentage of diabetes related to obesity, doesn’t tell us enough. The average health segment on a TV program shows little more than that stupid pill-pushing shot or a clip featuring massive behinds waddling down a city street.
The September edition of Nutrition Action Health Letter, published by the Center for Science in the Public Interest, tells it all in great detail. The cover story, “Diabetes: How to Play Defense,” explains that in type 1 (often inherited), the beta cells in the pancreas no longer produce insulin, the hormone that admits blood sugar into muscle and other body tissues. People with type 2 (about 90 percent of diabetics) produce insulin that has trouble opening insulin receptors on cell surfaces.
Writer Bonnie Liebman lays out the case for prevention with more than statistics and in quotes from prominent scientists.
The Centers for Disease Control and Prevention announced in June that one out of four Americans aged 60 or older now has the disease and another 57 million people-40 percent of people aged 40 to 70-have pre-diabetes (fasting levels of 100 mg per dl or higher).
The bad news is the disease can be managed but not cured. The good news is that it is an almost totally avoidable disease, says Walter Willett of the Harvard School of Public Health in Boston. “We estimate that more than 92 percent of the cases could be avoided by diet and lifestyle.”
A recent study of 3,000 people with elevated blood sugar levels randomly assigned one third to a placebo, one third to metformin (a drug that lowers blood sugar) and one third to “lifestyle” changes, losing weight through exercise and a low-fat diet. The results were so dramatic the study had to be stopped early.
Weight loss (initially14 pounds on average) cut the risk of diabetes by half and was twice as effective as metformin. Some physicians, however, translated the study results as a reason to put all at-risk people on the drug. How discouraging.
Here’s how the disease works. A leading hypothesis is that fat cells produce hormones and other chemical messengers called adipokines, some of which produce inflammation that interferes with insulin receptors on cells.
When it comes to diet change, the difference between good fats and bad fats is key. Trans fats, which are fast disappearing from market shelves and restaurant foods in some cities, seem to be the worst. The Nurses’ Health Study, which tracked more than 84,000 women for 14 years, found a 30 percent higher risk of diabetes in those who reported eating the most trans fat, and a 25 percent lower risk in those eating the most polyunsaturated fats (mostly nuts and fish). Why the difference? Polyunsaturated fats may alter the structure of cell membranes making them fluid, thus reducing insulin resistance. Also, trans fats increase inflammation while polyunsaturates reduce it.
Trans fats may also promote that dreaded but ubiquitous belly fat and decrease levels of HDL (good) cholesterol and increase (bad) LDL.
In a six-year study, monkeys were fed diets rich in either oleic acid (the fat in olive oil) or an equal amount of trans fat (from partially hydrogenated soybean oil). Researchers tried to keep the diets equal in calories but the trans fat monkeys gained weight and developed pre-diabetes.
Like fats, there are both good and bad carbohydrates. The refined ones (think white) have a high glycemic load while whole grains and fiber (think brown) have lower glycemic loads and hence lower risk of diabetes. Potatoes also contribute to the glycemic load.
Sweet drinks, sodas made with high fructose corn syrup and fruit juices (but not whole fruit) seem to raise the risk of diabetes more than most people think. Women who drank at least one sweetened soft drink or fruit punch a day had twice the risk of those who drank less than one a month. While other sweets aren’t harmless, scientists say the beverages are worse because it’s so easy to take in large amounts. Sodas are rarely available in 8 oz. bottles, 12 oz. being the norm and 20 oz. prevalent in fast food restaurants.
Two other beverages turn out to be beneficial. Coffee, both decaf and regular, reduces diabetes risk. Oxidative stress is one of the pathways by which diabetes develops and coffee is a huge source of antioxidants, considered by most scientists to be way ahead of fruit and vegetables. Who knew?
Moderate alcohol consumption is also linked to a lower risk of diabetes (up to 43 percent in those who had at least one drink a day). Alcohol seems to reduce glucose production by the liver and may even have a direct effect on insulin resistance.
The newest star on the supplement scene is Vitamin D. Studied extensively in relation to osteoporosis, it also was found to be beneficial in lowering inflammation and strengthening immune function. Stored in adipose tissue, called fat sequestration, more fat means less vitamin D in circulation.
Diabetes is the leading cause of blindness in adults aged 20 to 74. It also causes kidney disease, nerve damage, and mini-strokes often resulting in dementia, heart attacks and more than 60 percent of foot and leg amputations not due to accidents.
If that doesn’t scare you into walking at least two and a half hours a week, keeping active in between walks, and changing key ingredients in your diet, read on at www.spinet.org