More On Health Benefits Of Restricting Protein

Restricting protein, without inducing malnutrition, has been found to increase life span and health span in several organisms, including yeast, worms, fruit flies, and mice.

I recently posted about a study that found mice live longer when they experience a mild amino acid deficiency. The deficiency was triggered by giving the mice ibuprofen, a common NSAID, which inhibited the uptake of aromatic amino acids. Here’s a new study that found something similar, although the amino acids were different. It also offers a mechanism:

Endogenous Hydrogen Sulfide Production Is Essential for Dietary Restriction Benefits, Cell, 23 December 2014

Molecular Mechanism Behind Health Benefits Of Dietary Restriction Identified, Science Daily, 23 December 2014

The findings here show that restricting two amino acids, methionine and cysteine, results in increased hydrogen sulfide (H2S) production and protection against ischemia reperfusion injury, damage to tissue that occurs following the interruption of blood flow as during organ transplantation and stroke.

When the diet was supplemented with these two amino acids, increased H2S production and dietary restriction benefits were both lost.

Here’s another similar study, also led by Harvard’s James Mitchell, from a couple years ago:

Surgical Stress Resistance Induced by Single Amino Acid Deprivation Requires Gcn2 in Mice, Science, January 2012

Limiting Protein Or Certain Amino Acids Before Surgery May Reduce Risk Of Surgical Complications, Science Daily, January 2012

One group [of mice] was allowed to eat normally for 6 to 14 days; the other group was given a diet free of protein or lacking a single amino acid [tryptophan]. Both groups were then subjected to surgical stress that could potentially harm the kidneys or liver. In the mice that were allowed to eat as usual, about 40 percent died. The protein- and amino acid-free mice all survived.

The researchers also found that removing the gene that senses levels of any type of amino acid eliminated the protective effect. This suggests that the pathway activated by amino acid deficiency — rather than the absence of any particular amino acid — is responsible for the observed benefits, and opens up the potential for targeting drugs toward that pathway.

The results are significant because they pinpoint protein as an important substance to eliminate from the diet before surgery to avoid complications.

In this second study, the mice experiencing protein restriction had less inflammation and improved organ function after injury.

So far, I’ve read that restricting any one of the following amino acids: methionine, cysteine, lysine, any of the aromatic amino acids (phenylalanine, tryptophan, histidine, tyrosine), or, as the second study above found, any amino acid, results in longer life, and better quality of life, for several species. There may be more than one mechanism.

We’re right back to eating a vegan diet. Even if you eat animal food, it wouldn’t be a bad idea to restrict it for a week prior to surgery.

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