REPORTING POINT 04/09
HEALTH NEWS
“Live healthy...Live well”
Dedicated to providing pertinent information on health, fitness, and nutrition to foster a culture of wellness among Southwest Airlines flight crews and their families.
by Larry Kline
SWAPA Voice Mailbox 4337/email: livehealthy-livewell@cox.net
Past issues of “Health News” are available at http://health.theballfamily.org. It includes a search engine; just enter a key word to find past articles. LK
DIABETES 101 – 57 million people - 40 percent of those aged 40 to 70 – have pre-diabetes in America. One out of four Americans aged 60 or older now have the disease.
Diabetes is an almost totally avoidable disease – it is estimated that more than 92 percent of the cases could be avoided by diet and lifestyle.
Weight, especially around the waist, is the strongest risk factor by far for diabetes. But losing excess pounds is not the only strategy. Most people will not get down to their optimum weight, so diet quality is almost as important as weight control.
In type 1 diabetes, the beta-cells in the pancreas no longer produce insulin, the hormone that works like a key to admit fuel (blood sugar) into muscle, fat, and other body cells. Scientists believe that type 1 diabetes is triggered by genes, viruses, or an auto-immune disorder, rather than by diet, inactivity, or obesity.
Roughly 90 to 95 percent of people with diabetes have type 2, which means that their insulin does not do its job well. Their bodies require more and more insulin to metabolize blood glucose until the pancreas can no longer keep up with the demand. That “insulin resistance” leaves excess sugar in the bloodstream, which damages small blood vessels in the eyes, kidneys, and other organs
Getting blood sugar levels reasonably well controlled can dramatically lower the risk of eye and kidney disease, which lead to blindness and dialysis.
Diabetes makes larger blood vessels more susceptible to heart attacks and strokes. Seventy percent of people with diabetes die of cardiovascular disease.
The 57 million Americans who have pre-diabetes (fasting blood sugar levels between 100 and 125) do not know that they have a problem as their blood sugar levels are not normal. These people are at risk for complications that ultimately can lead to kidney failure, blindness, and amputations and they are already at excess risk for cardiovascular disease.
Clearly, the answer for everyone – those who have or want to avoid both diabetes and pre-diabetes – is to keep blood sugar levels in or near the normal range. The question is how?
WEIGHT & EXERCISE
There is a definite link between weight and diabetes. More than 80 percent of people with diabetes are overweight or obese.
Scientists know that fat cells, especially in the deeper visceral fat around the belly, produce hormones and other chemical messengers called adipokines. These can produce a state of inflammation, and that interferes with the insulin receptors on cells. (Inflammation is the body’s immune response to injury. Very low levels of chronic inflammation throughout the body – with no visible signs like redness, swelling, or pain – may raise the risk of diabetes, heart disease, and other illnesses.)
It is not necessary to lose all the extra fat cells in the body to minimize risk. In the Diabetes Prevention Program, researchers randomly assigned more than 3,000 people with blood sugar levels at or just below the pre-diabetes range to a placebo, metformin (a drug that lowers blood sugar), or to “lifestyle” changes.
The goal was to have the “lifestyle” people lose weight by boosting exercise (to 2 ½ hours a week of brisk walking or a similar activity) and adopting a healthy lower-fat diet. The results were so dramatic that the study had to be stopped early. After three years, the “lifestyle intervention” cut the risk of diabetes in these high-risk individuals by more than half. The key to prevention is weight loss.
Weight loss is really driving the benefit. Exercise contributed to weight loss, and in people who did not lose weight, exercise was helpful in reducing risk, but weight loss trumped exercise.
The participants did not have to lose that much weight – the average was about 14 pounds initially, and it dropped to about 9 pounds after three years. That is only about a 7 percent weight loss initially and a 4.5 percent weight loss after three years. People are surprised that preventing diabetes does not require a bigger weight loss. The drug that lowered blood sugar also works, but only about half as well as weight loss did.
The Diabetes Prevention Program is extremely strong proof that weight loss that is achievable can have tremendous effect.
FATS
Polyunsaturated fats are beneficial for a reduction of diabetes risk – identical to what we see for cardiovascular disease risk while trans fats are adverse and increase risk.
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 than those eating the least.
The study also found a 25 percent lower risk in those who reported eating the most polyunsaturated fats (found in foods like soybean oil, nuts, and fish) than in those who reported eating the least.
Fats probably alter the structure of cell membranes. Polyunsaturated fats may make membranes more fluid, and that probably reduces insulin resistance.
Trans fat increases inflammation factors, while most polyunsaturated fats reduce them. Consumption of polyunsaturated fats may help explain why women who reported eating nuts and peanut butter at least five times a week had a 20 to 30 percent lower risk of diabetes than those who almost never ate these foods.
But polyunsaturated fats are only part of the explanation. The fiber, magnesium, or other nutrients in nuts may also matter. Trans fat may promote diabetes by boosting belly fat.
Trans fat is rapidly disappearing from supermarkets, though it is still added to some pie crusts, cake frostings, frozen pizzas, microwave popcorns, and refrigerated biscuits, among other foods. Also restaurant foods like French fries, fried chicken, and pastries that are made with partially hydrogenated oils contain trans fats. [When shopping, search the labels to see if any hydrogenated or partially hydrogenated oils are used – these are the ingredients that contain harmful trans fats (under FDA guidelines, a food can contain up to ½ gram of trans fat per serving and show “trans fat free” on the label – LK)].
CARBS
The evidence is moderately strong that refined carbohydrates and a high glycemic load increase the risk of diabetes, while a diet high in whole grains and fiber and a low glycemic load are associated with a lower risk.
A study of more than 42,000 men and another study of 75,000 women showed those who ate the most whole grains had a 40 percent lower risk of diabetes than those who ate the least.
It is not just the fiber in these whole grains; it is also the nutrients, which get stripped away when grains are refined.
Among those nutrients are magnesium and chromium. Those people who ate the most magnesium-rich foods (like whole grains, nuts, leafy greens, and beans) had about a 20 percent lower risk of diabetes. There is a lot of evidence that magnesium improves insulin resistance and this is also true for chromium.
Whole grains may also lower the risk of diabetes because some of them have a lower glycemic load – causing less of a jump in blood sugar levels when compared to refined grains.
Whole grains are more likely to slow the absorption of food if they are intact and not finely milled so you are better off with whole wheat bulgur than whole wheat bread.
SWEET DRINKS
When it comes to diabetes, sweet beverages seem to be a special problem. Their high-fructose corn syrup and other sugars increase the demand for insulin and have a high glycemic load. It appears that the sugar that you drink may add more fat than the sugar that you chew. Liquid calories do not seem to lead to satiety and the reduction in the subsequent food intake that one might have with solid food calories.
This may explain why people who drank at least one sugar-sweetened soft drink or fruit punch a day had nearly twice the risk of diabetes over four years as those who drink less than one a month.
Fruit juice may also promote diabetes. Fruit juice and fruit punch, but not fruit, are associated with an increased risk of diabetes.
Other sweets are not harmless. Any kinds of sugars are adverse, but consuming sugars as beverages does seem to be worse because you can take in such large amounts so easily.
MEAT & IRON
In a study of roughly 70,000 women, those who ate the most red meat (about one serving a day) had a 22 percent higher risk of diabetes than those who the least (about one serving per week).
One possible explanation: iron, or more precisely, the heme iron found in animal foods. Heme iron is much more readily absorbed, even if you already have enough in your body. The body is better at regulating the non-heme iron that we get from plants and supplements.
Another study of more than 35,000 women, those who consumed the most heme iron had a higher risk of diabetes that those who consumed the least. It appears that in extreme cases of iron overload, called hemochromatosis, there is damage to the beta-cells in the pancreas that secrete insulin, making the iron act toxic in the body.
Also, the sodium nitrite that is added to processed meats (like hot dogs, bacon, and lunch meats) for color and as a preservative could also play a role. Those who eat the most processed meats (five times a week) have a 46 percent higher risk of diabetes than those who eat the least (twice a month). The nitrosated compounds could be directly toxic to beta-cells.
COFFEE
The evidence is very consistent that both caffeinated and decaf coffees reduce the risk of diabetes.
One study showed the risk of diabetes was 13 percent lower for those who drank one cup a day, 42 percent lower for those who drank two to three cups a day, and 47 percent lower for those who drank at least four cups a day. Tea did not raise or lower the risk.
Coffee is a huge source of antioxidants. In some people it may be the most important source of antioxidants if these people avoid fruits and vegetables.
ALCOHOL
Moderate, not heavy, alcohol consumption – one or two drinks a day for men and one drink for women – is linked to a lower risk of diabetes.
Alcohol seems to reduce glucose production by the liver and may have a direct effect on insulin resistance that may be due to reduced inflammation.
Inflammation seems to interfere with insulin signaling which is a major risk factor for diabetes.
VITAMIN D
Numerous studies have shown people with higher blood levels of vitamin D (usually higher dairy or calcium intakes) are less likely to have diabetes.
Those with lower vitamin D levels (older people, those who exercise less, have less exposure to sunlight, and those who eat a less healthy diet) are at greater risk for the disease, especially those who are overweight. Obesity itself means lower vitamin D levels.
Vitamin D is stored in adipose tissue, so if you have more fat, more vitamin D is stored and less is available to circulate. Researchers have tried to increase the intake of vitamin D to see if it keeps blood sugar levels or diabetes rates from climbing and the results appear promising.
Vitamin D may ward off diabetes because beta-cells in the pancreas convert vitamin D into the active form. Vitamin D reduces inflammation, which is a cause of insulin resistance. However, vitamin D does not seem to help people who already have the disease as the beta-cells are no longer working.
OTHER FACTORS
An hour a day of brisk walking trims the risk of diabetes by 34 percent.
Smoking raises the risk of diabetes and of course, genetics place a large role. Diet and lifestyle factors become even more important if you have a close relative with diabetes. Nutrition Action Healthletter 9/08, Bicycling 10/08.
