A new resistant starch review paper explains how numerous studies point to healthy aging benefits. While it focuses on mostly animal studies, it’s still intriguing.

There are 3 types of healthy aging benefits described in this review paper:

1. Improved muscular motor coordination
2. Normalized eating patterns and appetite
3. Improved disposal of nitrogen and reduction of uremic toxins

One of the serious aspects of aging is frailty, characterized by reduced muscle and motor control. It sounds strange but researchers test motor control in animals by the use of a rotating, accelerating rod. As the rod rotates, the animals have to stay balanced on it in order not to fall off. The length of time that they can stay balanced on this rotating rod is used as a measure of their motor control. Aged animals have less motor control and can stay balanced for less time than younger animals.

• Aged, resistant starch-fed mice were able to stay balanced on the rotating rod significantly longer than aged mice fed the control diet. Click here for this study. While there are many biochemical changes that result from resistant starch’s fermentation within the large intestine, researchers aren’t clear which biochemical pathways might be responsible for enhanced muscular motor control in the older animals.

Another characteristic of aging and frailty has been called the “anorexia of aging”, or the reduced ability to sense when and how much food is needed. When a younger person or animal is underfed, they will compensate when food is once again available and overeat. They quickly return to their normal weight. In contrast, an aged person or animal does not compensate for the lack of food. If they have lost weight due to under-eating, they will not eat enough afterwards to re-gain the weight. The energy balance and nutrient sensing mechanisms in the brain are thought to be responsible for this “anorexia of aging.”

• Aged, resistant starch-fed mice ate more food following food deprivation compared to aged mice fed the control diet. It appears that consumption of resistant starch enhances brain signaling of energy status in aged mice. Click here for this study. Resistant starch increases the production of satiety hormones, GLP-1 and PYY within the large intestine in animal studies. These hormones are likely involved in this aspect of hunger and eating.

Finally, reduced kidney health is very common in elderly individuals. The review paper reports that nearly half of adults 70 years or older have impaired kidney function and meet the definition of chronic kidney disease. Under normal circumstances, the kidney excretes a wide range of compounds. While hemodialysis effectively removes many of these compounds, it does not remove certain protein-bound compounds produced within the intestinal tract. Individuals undergoing dialysis can experience toxic build-up of these protein-bound compounds (namely indoxyl sulfate and p-cresol), which are linked to increased infections, cardiovascular disease and mortality of dialysis patients.

• A 2014 clinical study found that adults with chronic kidney disease who consumed resistant starch had reduced levels of colon-produced toxins (indoxyl sulfate and p-cresol, although the reduction in p-cresol was not statistically significant).
• Another clinical study found similar reductions of the toxins when the with probiotics from Yakult® combined with galacto-oligosaccharide (GOS), another type of fermentable dietary fiber.
• A 2014 animal study found that resistant starch reduced the progression of chronic kidney disease and moderated oxidative stress and inflammation in rats.

Fermentable dietary fibers increase fecal bulking, increases bacterial mass, and dispose of the nitrogen that otherwise would be excreted through the kidneys. This shift in nitrogen disposal effectively reduces the production of these protein-bound toxins. Additional animal studies are needed to identify the range of biochemical pathways involved in reducing the progression of kidney disease.

Healthy aging sounds like a dream and a wish. I know I’m going to get older, but I sure don’t want to get old! It becomes more and more important as I start to experience more and more symptoms of aging! I never dreamed that resistant starch would develop solid data pointing to anti-aging benefits in the brain, muscles and kidneys. Especially because it works in the gut!  I love these kinds of surprises.