RoR: Forum

The diet I'm proposing -- the diet Nature is proposing (I like to say that) -- is a very low glycemic load diet. There isn't any direct evidence that CRON is any better than this diet that I'm proposing, although I'll be keeping my eyes open on the evidence horizon with a newly-found zeal.

Is there *any* evidence that the diet you are proposing actually alters the rate of every measurable aspect of physiological aging? If so, I'd be interested in checking it out.

Thanks for making that bold conjecture that CRON is better. I can understand why you would say such a thing (with boatloads of empirical evidence backing it).

Not sure if that is supposed to be sarcasm or not, but there are no diets which have been empirically shown to surpass the health effectiveness of even a mild CRON diet, and CRON is one of the most most empirically verified diets there has ever been. To claim that the "Healthiest Diet" as that Paleo Diet page claims is ludicrious, does the "Paleo Diet" slow the aging process, and virtually all diseases related to it?

Google scholar shows 45,500 hits for "Caloric Restriction"
http://scholar.google.com/scholar?hl=en&lr=&q=caloric+restriction&btnG=Search

The top 5 are:
- Gene Expression Profile of Aging and Its Retardation by Caloric Restriction
- Oxidative stress, caloric restriction, and aging.
- Calorie Restriction Promotes Mammalian Cell Survival by Inducing the SIRT1 Deacetylase
- Caloric restriction and aging: an update
- Treatment of Obesity by Moderate and Severe Caloric Restriction: Results of Clinical Research Trials

Gene Expression Profile of Aging and Its Retardation by Caloric Restriction
ABSTRACT - The gene expression profile of the aging process was analyzed in skeletal muscle of mice. Use of high-density oligonucleotide arrays representing 6347 genes revealed that aging resulted in a differential gene expression pattern indicative of a marked stress response and lower expression of metabolic and biosynthetic genes. Most alterations were either completely or partially prevented by caloric restriction, the only intervention known to retard aging in mammals. Transcriptional patterns of calorie-restricted animals suggest that caloric restriction retards the aging process by causing a metabolic shift toward increased protein turnover and decreased macromolecular damage

Calorie Restriction Promotes Mammalian Cell Survival by Inducing the SIRT1 Deacetylase
A major cause of aging is thought to result from the cumulative effects of cell loss over time. In yeast, caloric restriction (CR) delays aging by activating the Sir2 deacetylase. Here we show that expression of mammalian Sir2 (SIRT1) is induced in CR rats as well as in human cells that are treated with serum from these animals. Insulin and insulin-like growth factor 1 (IGF-1) attenuated this response. SIRT1 deacetylates the DNA repair factor Ku70, causing it to sequester the proapoptotic factor Bax away from mitochondria, thereby inhibiting stress-induced apoptotic cell death. Thus, CR could extend life-span by inducing SIRT1 expression and promoting the long-term survival of irreplaceable cells.

Calorie Restriction, Aging, and Cancer Prevention: Mechanisms of Action and Applicability to Humans
Calorie restriction (CR) is the most effective and reproducible intervention for increasing lifespan in a variety of animal species, including mammals. CR is also the most potent, broadly acting cancer-prevention regimen in experimental carcinogenesis models. Translation of the knowledge gained from CR research to human chronic disease prevention and the promotion of healthy aging is critical, especially because obesity, which is an important risk factor for several chronic diseases, including many cancers, is alarmingly increasing in the Western world

etc. etc.

Now, I should say that the basis behind the "paleo diet" and variations seem a plausible enough foundation from which to initially judge and to test various foods and compounds on, but it should not be used to de facto exclude all other compounds and foods. Many modern 'man made' chemicals are much better for you than their 'natural' equivalents, even though we've been around and consuming those natural equivalents for tens of thousands of years.

It would be interesting to see if a Caloric Restriction diet based on a paleo diet achieved better results than a Caloric Restriction diet achieved through any available food stuffs (which will normally tend to be healthier foods anyway, given the difficulty of getting the required nutrients absent the empty calories) I have not been active on the CRON mailing list in some time, though I would wager this topic has been discussed and that some CRON practitioners are in fact engaging in a diet like that.

Post 41

Thursday, March 13, 2008 - 2:40pm

Michael, our posts crossed.

Good points about "old" food not necessarily being better than "new" -- though I'd argue that old food is "overwhelmingly" better!

:-)

I put up a trio of studies making my point -- studies which verify the superiority of the Paleo Diet (a diet with a gene-friendly ratio of carbs-to-protein) via reference to its expected anti-aging effects through modulation of insulin and DHEA levels.

Check out my reasoning ...

Ed

Post 42

Friday, March 14, 2008 - 1:10am

Bill,

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It is true that a diet very light in protein, such as a macrobiotic diet, can result in reduced bone density, but diets very high in protein can also cause thinner bones. The Eskimos have a very high-protein diet and more osteoporosis than the average American, because their diet is sorely lacking in fruits and vegetables.
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But low protein diets always reduce bone mineral density (because nothing can replace the protein needed for bone), while high protein diets don't always do this. Similar but not equal to what you said, it can come down to the balance of fruits and veggies against the sum total of all the grains, dairy, legumes, and meats. High protein diets can be healthy for bones. Low protein diets can't.

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What�s important for bone mineral density is not so much whether the diet is grain-based or meat based, but whether or not it contains enough (but not too much) protein and sufficient fruits and vegetables to balance out the other acid-forming components of the diet.
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Acid-base balance isn't the only thing -- it isn't necessarily even an over-riding thing (as you imply) -- for building and maintaining bone mineral density. There are several nutrients which each contribute at least 1% of the variance in human bone mineral density. Meats are often some of the best sources available for many of these nutrients. Here's a worrisome review:

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... The final pattern of meat (and other ASF) use before the modern era is associated with the shift from hunting and gathering beginning approximately 10,000 y ago. This fundamental dietary change resulted in a narrowing of diet, reduced consumption of meat and increased focus on domesticated grains.

The study of archaeological human remains from around the world reveals that this period in human dietary history saw a decline in health, including increased evidence of morbidity (poorer dental health, increased occlusal abnormalities, increased iron deficiency anemia, increased infection and bone loss). ...

Animal source foods and human health during evolution. J Nutr. 2003 Nov;133(11 Suppl 2):3893S-3897S.
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Recap:
Bone loss from switching off of meats and onto grains.

Here are some things bones need that meats provide better than grains do:

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... RESULTS:: Showed independent influence of calcium, energy, and protein, examined separately and in multiple regression models on BMD of several skeletal sites. Magnesium, zinc and vitamin C were significantly related to BMD of several skeletal sites in multiple regression models (controlled for age, fat and lean tissue, physical activity and energy intake), each contributing more than 1% of variance. ...

Bone and nutrition in elderly women: protein, energy, and calcium as main determinants of bone mineral density. Eur J Clin Nutr. 2003 Apr;57(4):554-65.
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Recap:
Some key factors for good bones are calcium, calories, protein, magnesium, zinc, and vitamin C. Missing any one of these can lead to osteoporosis.

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... Iron and zinc are two micronutrients for which the concentrations in human milk are relatively independent of maternal intake, and for which the older infant is most dependent on complementary foods to meet requirements. Traditional feeding practices, including reliance on cereals and plant-based diets, do not complement these recognized gaps in human milk. Meats or cellular animal proteins are richer sources of these critical minerals as well as other essential nutrients. ...

Meat as an early complementary food for infants: implications for macro- and micronutrient intakes. Nestle Nutr Workshop Ser Pediatr Program. 2007;60:221-9; discussion 229-33.
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Recap:
Bones need zinc and meats provide zinc better than grains do.

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... With increasing age, the kidney's ability to excrete daily net acid loads declines, invoking homeostatically increased utilization of base stores (bone, skeletal muscle) on a daily basis to mitigate the otherwise increasing baseline metabolic acidosis, which results in increased calciuria and net losses of body calcium.

Those effects of net acid production and its attendant increased body fluid acidity may contribute to development of osteoporosis and renal stones, loss of muscle mass, and age-related renal insufficiency. The inverted ratio of potassium to sodium in the diet compared with preagricultural diets affects cardiovascular function adversely and contributes to hypertension and stroke.

The diet can return to its evolutionary norms of net base production inducing low-grade metabolic alkalosis and a high potassium-to-sodium ratio by 1) greatly reducing content of energy-dense nutrient-poor foods and potassium-poor acid-producing cereal grains, which would entail increasing consumption of potassium-rich net base-producing fruits and vegetables for maintenance of energy balance ...

Adverse effects of sodium chloride on bone in the aging human population resulting from habitual consumption of typical American diets. J Nutr. 2008 Feb;138(2):419S-422S.
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Recap:
Replacing grains (which are, as a whole, potassium-poor and acid-producing) with fruits and/or veggies would help with bones. Replacing meats with fruits and/or veggies wouldn't have as great of an effect (and may hurt bone health, if protein or zinc became low in the process).

Ed

Post 43

Friday, March 14, 2008 - 3:14am

Bill,

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In any case, the point is that a diet that increases bone density may not be ideal in other respects. You can�t automatically conclude that because one diet results in greater height and bone density than another, it is therefore optimal, any more than you can conclude that because our forebears ate a certain way, we should therefore eat that way.
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Right.

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Another problem with high-protein diets is that they can be hard on the kidneys.

The Nurses� Health Study showed that women with mildly decreased kidney function (estimated GFR (glomerular filtration rate) between 55 and 80 ml/min per 1.73 m2) had a 3.5-fold increased risk for losing kidney function when protein intake was in the highest (90 g/d) versus lowest (60 g/d) quintile.

Importantly, the increased risk of dietary protein was confined to intake of animal meats. Vegetable or dairy-based protein sources did not adversely affect kidney function.

A Dutch study of 680 white individuals between the ages of 50 and 75 yr found that each 0.1-g/kg per d increment of dietary protein intake was associated with a 20% increased risk for microalbuminuria after adjustment for age, gender, and traditional cardiovascular risk factors.
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The issue is not this simple. Weight training "can be hard on the" muscles, but that doesn't make it bad for you. In fact, if you want kidney disease by the end of the year, you can have it -- simply cut your protein intake to 0.3 g/kg, and you will have AT LEAST mildly decreased kidney function (GFR < 80 mL/min per 1.73 m^2). You can't say the same about high protein diets.

Nevertheless, the 1998 Dutch (Hoorn) study stands out as unique. Apparently, it is the first and only study to find increased dietary protein harming healthy kidneys (assuming microalbuminuria is a sufficient surrogate marker for kidney disease).

In spite of the 1982 Brenner Hypothesis (that protein may harm healthy kidneys), the evidence that protein could be a problem has only ever came up with pre-established kidney disease -- such as the early renal insufficiency in the Nurses' Health Study cohort which you had mentioned. In contrast, there have been numerous studies showing that protein intakes in excess of 300% of the RDA don't hurt healthy kidneys.

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Ed, did you really think that I was advocating Hostess Twinkies as an alternative to the diet you�re recommending? To say that the diet our forebears consumed is not necessarily optimal is not to say that Hostess Twinkies and other forms of junk food are.

If ever there was a non-sequitur, that certainly is!
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Non-sequi-who??

;-)

Actually -- ironically -- you started this whole non-sequitor business! Nothing follows -- abolutely nothing -- from the fact that we live and reproduce "satisfactorily" on our current "Cafeteria" diet.

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But if you agree with me, than why do you use the argument that because we evolved on such a diet, it is therefore optimal?
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You caught me (in a contradiction).

:-(

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By the way, I see in the latest issue of Life Extension magazine that �Foods in the fat and meat (protein) groups contain thirty-fold and twelve-fold higher AGE content (advanced glycation end products) respectively, than foods in the carbohydrate group ...
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That's disturbing. I will have to hit the drawing board on that and get back to you.

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Of course, nuts contain a lot of fat too, so go light on the nuts.
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Nuts usually have good fats, especially the Top-5 nuts for human health: almonds, hazelnuts (or filberts), macadamia nuts, pecans, and walnuts. With a few currently-unmentioned qualifications, you might be able to eat them until they are coming out of your ears (and still remain free of disease or disorder).

Ed

Post 44

Friday, March 14, 2008 - 1:57pm