Dietary Restriction vs. Dietary 'Balance'

[Dean Pomerleau]

All,

 

There is an interesting new review paper [1] on the relative effectiveness and potential synergy between dietary / calorie restriction and 'dietary balance' - i.e. optimized nutrition without reduced calories. Here are the passages from the free full text that I found most interesting, for those without the time to read it all:

 

 In rodents, increasing the P[rotein] : C[arbohydrate] ratio affects longevity without being influenced by total calorie intake, ultimately leading to an increased mTOR activation. The longest lifespan extension was achieved by a low protein / high carbohydrate diet, which the authors believe to result from low mTOR activation and low insulin levels. Inhibition of mTOR, a proaging pathway, by manipulating the ratio of macronutrients is believed to extend longevity in rodents [14]. As described above, mTOR and IGF-1 signalling by amino acids and the effect of low protein diets on longevity regulation suggest further investigation into how dietary balance affects aging.

 

Also in primates, DR composition has a major impact in results regarding lifespan extension, supporting the notion that balance of nutrients in the diet might be more important in healthy lifespan extension than dietary restriction. Two studies, one from the Wisconsin National Primate Research Centre (WNPRC) and another from the National Institute on Aging (NIA) presented different results when subjecting rhesus monkeys to 30% CR regimen. The WNPRC study reported a decreased mortality in the CR group in comparison to the control group with a 50% lower incidence of diabetes, cancer, and cardiovascular diseases [17, 86]. On the other hand, the NIA study did not find significant differences between CR and control groups, although supporting the beneficial impact of CR on healthspan [87]. The major differences between these two studies were the dietary regimens and the protein and carbohydrate sources used in each study. In the WNPRC study, the protein source used was lactalbumin and the carbohydrate source derived from corn, starch, and 28.5% sucrose, whereas, in the NIA study, the protein source used derived from wheat, corn, soybean, fish, and alfalfa meal, and the carbohydrate source derived from ground wheat and corn with 3.9% sucrose [81]. The differences in results from the two studies could be attributed to the variations in food ingredients and possibly to the protein source; one derived from animal and the other derived from plant sources that have been previously described to affect aging [81, 88].

 

In humans, very recent cohort studies suggest a correlation between age-related diseases and high protein diets from animal sources. Based on the US national survey of health and nutrition, NHANES III database, a recent article reports that the 50-to-65 age group with high protein intake had a 75% increase in overall mortality and a fourfold increased risk of cancer mortality in comparison to individuals with low protein intake, which was attenuated or abolished when protein intake was derived from plants. Interestingly, in individuals over 65 years, the high protein intake was reported to reduce cancer and overall mortality. These results were confirmed in mice, proving that protein absorption is affected by aging. The study also confirms the correlation between higher IGF-1 levels with more dietary protein and the incidence and progression of both melanoma and breast cancer [15]. Likewise, a Swedish cohort reported that low carbohydrate high protein diets are associated with increased risk of cardiovascular diseases [89].

 

Michael may disagree, but the evidence, including the primate studies, seem to be shifting the scientific consensus towards the perspective that it isn't just about "calories, calories, calories" when it comes to health (which has been known for a long time) but also when it comes to longevity.

 

--Dean

 

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[1] Oxid Med Cell Longev. 2016;2016:4010357. doi: 10.1155/2016/4010357. Epub 2015 Nov
23.

Dietary Restriction and Nutrient Balance in Aging.

Santos J(1), Leitão-Correia F(1), Sousa MJ(2), Leão C(1).

 

Free Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4670908/

Dietary regimens that favour reduced calorie intake delay aging and
age-associated diseases. New evidences revealed that nutritional balance of
dietary components without food restriction increases lifespan. Particular
nutrients as several nitrogen sources, proteins, amino acid, and ammonium are
implicated in life and healthspan regulation in different model organisms from
yeast to mammals. Aging and dietary restriction interact through partially
overlapping mechanisms in the activation of the conserved nutrient-signalling
pathways, mainly the insulin/insulin-like growth factor (IIS) and the Target Of
Rapamycin (TOR). The specific nutrients of dietary regimens, their balance, and
how they interact with different genes and pathways are currently being
uncovered. Taking into account that dietary regimes can largely influence overall
human health and changes in risk factors such as cholesterol level and blood
pressure, these new findings are of great importance to fully comprehend the
interplay between diet and humans health.

PMCID: PMC4670908
PMID: 26682004