Researchers here demonstrate that diluting calorie intake with non-digestible fiber produces similar outcomes in the health and longevity of mice as does moderate calorie restriction. The researchers also combined this intervention with exome matching of amino acid composition of dietary protein. Exome matching implies that the amino acid composition of proteins in the body is matched to that of the diet; interestingly, mice prefer such exome matched chow over other options. The degree to which either of these approaches can be implemented on a practical basis in a human diet is an interesting question, certainly some discussion and research would be needed. Adding cellulose starch as non-digestible fiber to the diet is certainly possible, but at 30% of all food intake by weight, the amount used here, that may produce complications, logistical and otherwise.
Caloric restriction (CR) is the most extensively studied dietary approach for delaying ageing and extending lifespan across many taxa. In vertebrates such as mice, rats and nonhuman primates, CR is typically implemented by restricting food intake to 50%-80% of ad libitum-fed consumption, provided as a single daily portion with micronutrient supplementation. This feeding regimen induces both energy restriction and extended fasting periods because animals usually consume all available food within a few hours and then fast until the next feeding cycle.
In our previous work with ad libitum-fed mice, we applied this framework and demonstrated that the ratio of dietary protein to carbohydrates influences lifespan. In that study, we incorporated non-digestible cellulose into certain diets to simulate the effects of CR in ad libitum-fed animals. This marked the first instance of CR achieved by dietary dilution in mice. As anticipated, mice consuming the high-cellulose diets increased their food intake as a compensatory response to nutrient dilution, yet their overall energy intake decreased. However, that previous study did not include a comparison to a conventional CR-treated group.
A recent nutritional intervention that may influence growth and longevity is exome-matching. This involves manipulating dietary protein so that dietary amino acids are at a ratio matched with the exome, thereby meeting (without excess) the predicted requirements for protein translation under physiological conditions. Here, we compared longevity and ageing in mice on three diets: an ad libitum-fed control diet (Con); a conventional 20% CR diet; and a low-protein, high-carbohydrate (LPHC) ad libitum-fed diet, which caused caloric restriction through dilution with non-digestible fibre. The amino acid composition of dietary protein in all diets was exome-matched to reduce variation in food intake caused by an imbalance of amino acids.
Survival curves show that the LPHC and CR diets had similar effects on lifespan compared with the ad libitum control diet. LPHC and CR diets significantly increased median lifespan by 17% and 11%, respectively, compared to the control diet. There was no statistically significant difference between median lifespans of the CR versus LPHC. Maximum lifespans were 1008 days for controls, 1179 days for CR, and 1115 days for LPHC diets. Sex was not a significant effect modifier.
Link: https://doi.org/10.1111/acel.70269
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