"If they're laughing, they're listening."

That statement has always been part of my teaching creed. It's why I'm always looking to add levity to any school lesson I teach. But, there's a potential problem in that.Some students don't see the silliness as the table setting. They feel it's the meal and feast upon it. Which isn't good when they need to be chewing on something else.The serious stuff.That potential problem could occur in this column, too, and caused me to scrap a fairly funny introduction that incorporated Captain Obvious from the Hotels.com commercials. Instead, I'll tell you a story about my mother's mother, the only grandmother I ever knew.She suffered a stroke while I was taking finals in December of my junior college year. I was not surprised. Nor was I surprised that Nana's forgetfulness, what we had jokingly called "Half-'heimer's" for years, had morphed into mid-stage Alzheimer's disease.She passed away before the spring semester started.But what surprises me today is that she was never diagnosed as having type 2 diabetes.For years, she had high blood pressure, high triglyceride levels, and a comically large waistline risk factors for what's now called metabolic syndrome, often a precursor for type 2 diabetes. The link is so strong, in fact, that you are five times as likely to get type 2 diabetes if you have metabolic syndrome than if you do not.Combine that with her constant complaints of fatigue and bad jokes about always needing to pee, and you should understand why I now believe she was one of millions of Americans (current estimate is 7 million) who go through life with undiagnosed type 2 diabetes. Especially when you read what I remember about her diet.She never, I mean never, had more than coffee and a cigarette for breakfast, but she would have two of those oh-so-healthy breakfast foods creamed chipped beef and scrapple sometimes for lunch. It was more likely, however, that lunch consisted of two crab cakes that she crooked from the bar where she worked drowned in ketchup or tartar sauce.Her entrees at a restaurant were always fried liver and onions was her favorite and her desserts were always pie, mostly with ice cream on top. She always got fried fish at fast food restaurants and washed it down with a milk shake.And she could never get her sweet tea quite sweet enough.Home after taking finals, I drove my mother to the nursing home one day to see my grandmother. I wasn't particularly close to Nana, but seeing a 69-year-old lady trapped inside a 96-year-old body acting like a 3-year-old really hit me like the flu.My belly did backflips. My face felt feverish. My balance betrayed me, so I sat on a chair even though what I really wanted was to get out of there.As I sat, I realized that something had bothered me more: my mother's reaction though she had visited Nana a number of times before. Her anguish was obvious; her pain, palpable.I knew I never wanted to make someone I loved hurt like that.While the story about Nana's demise is more than 30 years old, it deserves retelling in light of two studies, one that shows healthy diets sustain brain health and one that further links diabetes to Alzheimer's disease.In the first study published this May in the journal Neurology, researchers monitored the diets for five years of more than 27,000 adults judged to be at high cardiovascular risk and aged 55 and older. Before the monitoring, two years into the monitoring, and at the conclusion, the subjects took tests to determine cognitive health and any decline in thinking or memory.When the test results at the two-year mark or the conclusion dropped 10 percent or more below the first, the researchers recorded that as significant decline, a decline that was 24 percent less likely to occur in the subjects who followed the healthiest diets ones characterized by consuming ample amounts of fruits, fish, nuts, and vegetables and only moderate amounts (if that) of red meat as opposed to those determined to be eating the least healthiest diets.If you are surprised that the difference was merely 24 percent, consider the scrutiny placed on the subjects. Although they were deemed to be at high cardiovascular risk, their overall health was quite good and so were their past medical histories.No subject had diabetes, heart disease, a stroke, or a history of any of these. And if such a condition occurred during the study's five-year span, that subject was dismissed.In essence, the study only included exceptionally healthy senior citizens some just happened to be poor eaters so the fact that diet played such a part in retaining brain power in such a relatively short period of time speaks volumes.The second study showed that high blood sugar levels help create a substance linked to Alzheimer's disease. Previous research discovered that beta-amyloid, a "bad" protein, produces a plaque related to Alzheimer's. A School of Medicine at Washington University in St. Louis study published in The Journal of Clinical Investigation found that the doubling of blood glucose in mice created 20 percent more of that bad protein.Furthermore, when blood sugar levels were doubled in older mice already found to have the plaque buildup, their levels rose by 40 percent.In either case, researchers were able to determine that the spikes in blood glucose created additional neuron activity in the brain that promotes production of the bad protein.In short, whether you're 18, 85, or anywhere in between, you should really care about what you eat.If you really care about someone.