On Nutrition: Sorting the facts

I have a very nice patient who comes to appointments with questions about everything except his main medical problem. These are from his last visit:

“My sister told me not to drink diet sodas because they have toxic chemicals. I’ve heard pasta is really bad for you. Eating meat is not good for the environment, right?”

So, are these statement true, or not? Take your guess and then we’ll see what the science says.

Sugar substitute ingredients used in diet beverages and a host of other products have been studied intensely for decades. And while there are still some questions about their actual impact on our health, several products have met strict safety standards by the U.S. Food and Drug Administration. Those currently approved for general use include saccharin (Sweet’N Low), aspartame (Nutrasweet, Equal, Sugar Twin), Acesulfame potassium (Sweet One), sucralose (Splenda), neotame (Newtame) and Advantame, the newest on the block.

Plant-based sweeteners stevia and monk fruit are deemed “generally recognized as safe” (GRAS) by the FDA. That means the product either has a history of safe use or has been determined by scientific data to be safe for a particular use.

Each of the approved sugar substitutes also has an acceptable daily intake (ADI) set by the FDA. This is the maximum amount of sweetener considered safe to consume if a person used it daily over a lifetime. And the margin of safety is pretty high. A 150-pound person, for example, would need to consume 24 packets of Splenda before they reached the ADI for the sweetener. That said, most experts advise us to limit our intake to one or two servings of sugar substitute a day.

Here’s an interesting kicker about pasta. It is high in carbohydrates, yes. And like white rice, it’s considered a refined carb. Yet some of the carbs in pasta are in the form of “resistant starch” that travels slower through the digestive track and thus has a lower impact on blood sugars than other refined carbs. In fact, pasta (as opposed to white rice) is considered a low GI (glycemic index) food.

Here’s where portion control is important, however. For people with diabetes, one cup of cooked pasta might be OK. Fill up your plate with seconds and thirds and all bets are off.

One more intriguing tidbit about pasta. Participants in a recent study experienced higher rises in blood sugars after they ate freshly cooked (hot) pasta compared to when they ate the same amount of pasta that had been cooled and reheated. Researchers surmise that pasta produces more resistant starch when it is cooled and then reheated. Let’s hear it for leftovers!

Lastly, “foregoing meat may may not be the environmental panacea many would have us believe,” says University of California at Davis professor and air quality expert Dr. Frank Mitloehner. More on that next week.