垃圾食品與老年痴呆症的關係

The New Junk Food Danger—Dementia?By Lisa Collier CoolSeptember13, 2012 .at300bs,.at300bs.at15t_compact{background-image:none;} Health Experts Main

Day in HealthNot only does junk food make you fat, but it could cause dementia. New research shows that our calorie-laden diet boosts risk for dementia, a memory-robbing disorder some experts now call 「type 3 diabetes.」

「Americans are literally eating a 『diabetes diet』 that』s very toxic to the brain and other vital organs,」 says Dr. Joel Zonszein, medical director of the diabetes clinic at Montefiore Medical Center in New York City. 「And the one of the most terrible complications—brain damage—is occurring in younger and younger patients.」

In fact, a shocking new study reports that teenagers who eat a diet that』s high in fat and calories already show 「accelerated cognitive decline.」 The researchers blame rising rates of dementia on our increasingly unhealthy eating habits and couch potato lifestyle.

The Insulin Connection

While it』s long been known that type 2 diabetics are at higher risk for memory loss, another new study found that damage to key brain areas involved in memory and cognitive skills starts when blood sugar hits the high end of the 「normal」 range, even when other risk factors, such as smoking, high blood pressure, and alcohol consumption are taken into account.

The two studies reveal the hazards of a pre-diabetic condition called insulin resistance (IR), which tends to strike people who have a large waistline (even if their weight is normal), eat a poor diet, and spend long hours sitting in front of a computer (or the TV), says Dr. Zonszein.

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Link to Alzheimer』s Disease

Another new study found that both IR and diabetes contribute to formation of a type of brain plaque linked to Alzheimer』s disease, the memory-stealing disease that affects 5.4 million Americans.

In the August 25 issue of Neurology, Japanese scientists wrote, 「adequate control of diabetes might contribute to a strategy for the prevention of Alzheimer"s disease.」 Several clinical trials are now testing the effects of medication to improve insulin sensitivity in older people with cognitive impairment to see if this approach helps protect the brain.

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Fire in the Arteries

What』s the link between a poor diet and dementia? 「Junk food contributes to both central adiposity and chronic inflammation that damages small and large blood vessels that supply the brain,」 says Dr. Zonszein. That』s dangerous, since microvessel disease is the leading cause of dementia.

Although people with big bellies have lots of fat cells, adds Dr. Zonszein, 「their cells are very inefficient in the metabolic process (converting food into energy to power the body). As a result, fat is stored in places it shouldn』t be, such as the liver and heart, and rising levels of blood sugar start to injure the brain.」 In addition, people with IR have lower levels of HDL, the good cholesterol that helps keep the heart and brain healthy.

A Dangerous Gang of Metabolic Villains

「We』re now seeing diabetic patients as young as 50 with significant brain damage—and the new research is telling us that people with insulin resistance and metabolic syndrome are at much higher risk for dementia than was previously believed,」 notes Dr. Zonszein.

About 50 million Americans, many of whom are undiagnosed, have metabolic syndrome--a gang of five cardiometabolic thugs that quintuple a person"s risk for type 2 diabetes and triple it for heart attack. By definition, everyone with metabolic syndrome has insulin resistance. If you have three of more of the following disorders, you have metabolic syndrome:

A large waistline (above 40 inches for a man or 35 inches for a woman). This also is called "an apple shape."

High triglycerides: a level of this blood fat that』s above 150 mg/dL

Low HDL (less than 50 mg/dL for women and less than 40 mg/dL for men). HDL is the good cholesterol that keeps the heart and brain healthy. In fact, some research indicates that HDL is the best 「food」 for the brain.

High blood pressure: 130/85 mmHg or higher (or you』re on blood pressure medicine).

High fasting blood sugar: 100 mg/dL or above (or you"re on medicine to treat high blood sugar).

How to Protect Your Brain

The good news is that the right diet, regular exercise—and keeping your weight down—dramatically reduce risk for metabolic syndrome and diabetes, which in turn helps lower risk for dementia.

「Most people with insulin resistance graze all day on high-calorie foods,」 says Dr. Zonszein. 「What they should do is eat three heart-healthy, low-fat meals a day with colorful fruits and vegetables, high-fiber whole grains, and lean protein, such as fish or chicken, on their plate.」

Also limit—or better still, avoid—sweet drinks, including fruit juice and sports drinks. A recent study shows that high-fructose sweeteners, in particular, may be driving the development of brain-harming microvessel disease.

This sweetener, ubiquitous in processed foods, appears to boost levels of a cell-damaging toxin called uric acid, the researchers report, magnifying risk for vascular dementia, chronic kidney disease, stroke, and heart disease.

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