Methionine Restriction and Longevity
A fair weight of research suggests that lower intake of methionine plays a large role in the effects of calorie restriction: "Available information indicates that long-lived mammals have low rates of reactive oxygen species (ROS) generation and oxidative damage at their mitochondria. On the other hand, many studies have consistently shown that dietary restriction (DR) in rodents also decreases mitochondrial ROS (mtROS) production and oxidative damage to mitochondrial DNA and proteins. It has been observed that protein restriction also decreases mtROS generation and oxidative stress in rat liver, whereas neither carbohydrate nor lipid restriction change these parameters. This is interesting because protein restriction also increases maximum longevity in rodents (although to a lower extent than DR) and is a much more practicable intervention for humans than DR, whereas neither carbohydrate nor lipid restriction seem to change rodent longevity. Moreover, it has been found that isocaloric methionine restriction also decreases mtROS generation and oxidative stress in rodent tissues, and this manipulation also increases maximum longevity in rats and mice. In addition, excessive dietary methionine also increases mtROS generation in rat liver. These studies suggest that the reduced intake of dietary methionine can be responsible for the decrease in mitochondrial ROS generation and the ensuing oxidative damage that occurs during DR, as well as for part of the increase in maximum longevity induced by this dietary manipulation."
Having tried to access the document provided from Pubmed, it was not the correct one and needs a 1 in front of the number sequence for the study I believe that was more related.
To briefly state my opinion on this subject, I personally found it quite interesting, the CR debate has been going on for a while now. There are also many, many nutritional factors that play a role in increasing mitochondrial efficiacy and lowering oxidant production (ie. lipoic acid, B vitamins, anti-oxidants).
I have found the diet lowest in both the sulfur containing amino-acids (MET,CYS) is frugivorous, as well as highest in the micro-nutrients that were mentioned. The foods that are particularly high in in the amino acid are animal products and varieties of Brazil nuts. Could it be our possible natural diet?
Are there any other possible contents that are lower in a CR diet that specifically derive its known benefits? Although such a finding is extremely revealing, it's wise to try to find many other dependant factors on top of this. - Guy
One more note as to this, I quote from the article:
"whereas neither carbohydrate nor lipid restriction seem to change rodent longevity."
This came from the two sentences that were left out from mentioning:
"In addition, the mean intake of proteins (and thus methionine) of Western human populations is much higher than needed. Therefore, decreasing such levels to the recommended ones has a great potential to lower tissue oxidative stress and to increase healthy life span in humans while avoiding the possible undesirable effects of DR diets."
Possibly just reduce the intake of methionine while providing sufficient calories from majority of carbohydrates (as excess lipids provide insulin resistance) from whole foods such as raw fruits and vegetables as in a frugivorous diet that is implemented by our most genetically related species, including chimpanzees, bonobos, and orangutans? While decreasing/eliminating animal foods and heightening amounts of antioxidants, and B vitamins.
Thank you again for your post.
Guy
@Guy B. - Thank you for noticing that broken link. It is corrected now.
Posting by Guy B. on 10/2/2011 states as if factual that "excess lipids provide insulin resistance," with no explanation or reference. Despite the NIH's monumental MRFIT study failing to demonstrate that low fat diets either reduced obesity (and its bosom buddy insulin resistance) or rates of heart disease, the Senate (McGovern) Committee on Nutrition and Human Needs decided about 1971 that despite no scientific evidence that dietary fat caused obesity or heart disease, it would nonetheless be the government's position that Americans should adopt a low fat diet. A good read reviewing what macronutrient does make us fat is Gary Taubes' "Why We Get Fat (and What to Do about it)." It is not "excess lipids."