Reducing One Amino Acid Could Increase Lifespan 286
John Bryson writes "Eating less of one amino acid might lengthen your life. There have been lots of previous studies showing that many species live long on highly restricted calories, but a lot of this benefit may be possible by only restricting one amino acid. Amino acids that have shown this have been tryptophan and methionine. A recent study, published online December 2 in Nature, a highly respected journal, may help explain some of the health benefits of restricted-calorie diets."
Re:No Turkey for you... (Score:4, Informative)
Tryptophan also naturally occurs in bananas. It metabolizes through a few stages into serotonin.
Re:No Turkey for you... (Score:5, Informative)
The sleep inducing factor in your favorite November holiday is actually the fact that you stuff yourself. Eat four pounds of chicken and gravy, and then we'll see if you stay awake.
Re:No Turkey for you... (Score:3, Informative)
Re:No Turkey for you... (Score:3, Informative)
Re:Yes, but... (Score:5, Informative)
TFA directly addresses that point:
Piper and his colleagues don’t know what the correct amino acid balance might be for humans, and he says it would be a nearly impossible feat to adjust people’s diets to get just the right mix. Instead, the team is investigating how tweaking amino acid content in the diet affects cells. If the researchers can identify pathways affected by amino acid imbalances, they might be able to design drugs or other therapies that could give the benefits of caloric restriction without cutting calories.
Re:No Turkey for you... (Score:2, Informative)
Link to actual study (Score:5, Informative)
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08619.html for the actual study
No tryptophan in TFA (Score:5, Informative)
I am the one slashdotter that reads TFA (the full article) before posting. I even did a search for tryptophan. Nope, it's not there. Maybe the submitter forgot a link, but tryptophan is never mentioned in the sciencenews.org article.
Tryptophan? (Score:2, Informative)
The summary mentions tryptophan but it isn't anywhere in the article. And I wonder if the decreased longevity is due to the excessive methionine itself or a result of its byproducts such as SAM and homocysteine.
Re:No Turkey for you... (Score:2, Informative)
If you are interested, here is a list of food products containing high levels of methionine:
http://www.nutritiondata.com/foods-000084000000000000000-w.html [nutritiondata.com]
And tryptophan:
http://www.nutritiondata.com/foods-000079000000000000000-w.html [nutritiondata.com]
Re:No Turkey for you... (Score:5, Informative)
anecdotes =/= science
Not sure what your point was. Were you saying that there isn't any science in your post?
I found the answer in a wikipedia link [wikipedia.org] provided in another message. The link suggests that the sleepiness is not caused by tryptophan alone. Rather, carbohydrates trigger the release of insulin. Insulin causes muscle to take in LNAA, but not tryptophan. This leaves a larger ratio of tryptophan in the blood to be taken across the blood-brain barrier into the central nervous system. There it is converted into serotonin. The serotonin is metabolized into melatonin. Melatonin makes you sleepy.
So, tryptophan by itself does not make you sleepy. However, tryptophan combined with carbohydrates leads to the right conditions needed to make you sleepy. It has nothing to do with stuffing yourself. Nor is tryptophan's involvement a myth. It just needs the right conditions. Skip the mashed potatoes and you shouldn't get sleepy from turkey.
Re:Yes, but... (Score:5, Informative)
``Ideally, if giving up Trytophan is beneficial with no negative side effects, they'd create a pill that prevents your body from digesting it.''
Interestingly, there are actually pills that contain tryptophan. Tryptophan is an essential amino acid and is one of the precursors to serotonine. Serotonine is a neurotransmitter, and low serotonine levels are associated with such conditions as depression and anxiety disorders. So people take extra tryptophan (or, more commonly, 5-HTP, the direct precursor to serotonine) to boost serotonine levels.
Comment removed (Score:3, Informative)
Re:Yes, but... (Score:3, Informative)
That depends on whether we just get older or whether we also get healthier.
So far we've been busy finding ways to keep people from dying. This is, of course, quite costy. My great grandma was bedridden for the last 15 years of her life. Just extending that span will certainly put a very heavy strain on any social budget and the institutions supposed to care for those people. If that additional lifetime can be spent active because people also stay healthy and agile longer, the only ones who have to worry are retirement fonds.
Re:No Turkey for you... (Score:3, Informative)
Because it has 33% less fat than regular milk, but still tastes about the same?
Re:Amino Acids (Score:2, Informative)
The authors of the study set out to test the hypothesis that the decreased fertility from caloric restriction results from a lack of calories. The authors predicted that if this hypothesis is true, it should not be possible to find nutrient conditions that increase lifespan without decreasing fertility. However, the authors found that they could restore normal fertility levels while maintaining the increased lifespan in calorie restricted flies by adding methionine to the flies' diet. Thus, as the authors state in the paper's abstract: "reallocation of nutrients therefore does not explain the responses to dietary restriction."
Furthermore, they found that it is primarily the lifespan increases in caloric restriction come primarily from restricting amino acids. Adding carbohydrates or fats to the diets of calorie restricted flies did not reduce the increases in lifespan due to calorie restriction. So yes, the summary is completely wrong. Restricting the intake all amino acids except for methionine could increase lifespan (in flies) without harming fertility, not the other way around as the summary implies.
Of course, it's an open question whether any of this applies to humans or whether this fountain of youth works only for fruit flies.
Re:Yes, but... (Score:3, Informative)
That was through reductions in child mortality, not extending the life of people who manage to live to adulthood. See this chart [elderweb.com] for specifics. Newborns have an extra ~30 years, but 65-year-olds only have an extra ~5, on average.
Re:Hunter-Gatherers were better off in some ways (Score:3, Informative)
Except today's hunter/gatherers are the ones who have been pushed onto the most marginal lands with the least natural productivity. The agricultural empires in general took over the best land (including using bronze weapons). If you look at Marshall Sahlins wrote, in many productive areas, hunter/gatherers spend maybe two hours a day on food related work most of the time -- and it is mostly fun and interesting and engaging work. It is things like fishing to catch just one big fish. Or collecting ripe fruit off a tree in season.