Everywhere in the medical world, we learn that advancing age is a major risk factor for any chronic disease, so I was delighted to read this fairly new article that takes that idea and runs somewhere helpful with it. I concede that there is no avoiding everything, but there is much we can regulate by our life choices. The authors look more closely at the aging process and rightly, in my mind, identify the "lack of adequate glucoregulatory control" as a recurrent theme in the picture of chronic illness. At its simplest level, "glucoregulatory control" means keeping your blood sugar from getting too high: avoiding diabetes. Digging a little deeper, I would identify the goal as getting out of the sugar rut, getting a bit more flexible.
Metabolic Flexibility
Most of us hop from meal to snack to next meal keeping our blood sugar in a comfortable range by eating fuels (mostly carbohydrates and proteins) that can be converted into sugar in our bloodstream. Our entire body runs quite well on sugar as a fuel, but that's only part of a healthy fuel picture.
Other fuels would include amino acids (components of protein) or fatty acids (from dietary fats.) Most of our body works fairly well with these non-sugar fuels, but our brain isn't happy without sugar or ketones. You've heard the word ketones if you've read about ketogenic diets on this site or elsewhere, but they're not well understood. Even ketone scientists are learning new things about ketones on a regular basis.
Our bodies make ketones from fat, fat we eat or fat "downloaded" from our body's fat supplies, and ketones can be used for energy, particularly brain energy. Your brain loves ketones. As newborn babies, we're quite skillful at making ketones from the fat in our favorite food: breast milk. As we age, we tend to rely increasingly on sugar for fuel and miss the opportunity to use ketones instead. To make ketones, our blood sugar has to fall sufficiently that our insulin levels also fall. When those two values are low, our liver gets the message to convert fat to ketones. I was reminded at a recent conference (report to come: Physicians and Ancestral Health) by wise words of Dr. Ron Rosedale, words I read years ago but hadn't repeated recently. To paraphrase: the best predictor of healthy longevity is our ability to burn fat as a fuel. We'll only burn fat into ketones if we "deprive" ourselves of regular sugar feeds. (By sugar I mean sugar-rich carbohydrates: cotton candy, whole wheat bread, even starchy vegetables and msot fruits.) Even high levels of protein can distract our liver: we can break down proteins into components that effectively take the place of sugar.
Our ability to skip meals and switch over to fat-burning is dependent upon having normal levels of sugar and therefore normal levels of insulin. In my book, the "normals" are a bit below what a conventional lab range would be. You are likely to be an adequate fat burner if your fasting level of insulin is < 8mIU/L. Your lab will say that < 25 is normal... common perhaps, but not normal and certainly not optimal. Next time you have a fasting lab test, ask your doc to include a glucose (always included in a chemistry test) and an insulin as well.
Back to the News
I do want to return to the article I mentioned above, because there are some simple, usable tips hidden within it! While the authors concede the health benefits of fasting (skipping meals), they first turn to the fasting-mimicking drugs such as acarbose, the drugs that keep some of your food in your gut, preventing the absorption of calories and nutrients. Not such a good idea. Particularly as we age, we want every calorie to count: we want it to nourish us with energy (calories) and nutrients, the vitamins and minerals that enable all our physiological functions to keep working.
The authors go on to name three foods, two of which I would highly recommend: sweet potatoes and berries. In moderate doses, these foods work a little bit like acarbose, in that they slow the absorption of glucose and calories from the intestine. Yet unlike a drug, both of these foods are rich in micronutrients (especially colorful orange sweet potatoes) that the body can absorb, even if one of the actions of the food itself is to slow sugar absorption.
Bottom Line
While sweet potatoes and berries are wonderful foods, and healthy in any diet (so long as quantities are individually chosen: eat less if you're trying to be ketogenic), and certainly preferable to a drug such as acarbose, your real goal for a healthy later life is to keep your calories, sugars, and meals at a low enough level that you easily switch to using fat as a fuel. Almost all of us have plenty of stored fat as a fuel. (Seriously underweight people present completely different challenges, but that is a subject for another day.) Look around your body, see if you have a bit of fat you could use in a pinch if you skipped a meal or two, and give it a try.
(If you do skip meals, it's a bit easier if you indulge in a cup of boullion or salty bone broth. Follow your blood sugars if you are a diabetic.)
