Could an 'elixir of life' really increase your lifespan?

A chemical elixir can add 10 years to your life! According to the media, anyway. How much of the claim that an amino acid cocktail can boost longevity should be taken with a pinch of salt?
For starters, the study was carried out in mice. Giuseppe D'Antona at Pavia University in Italy and his colleagues added a cocktail of three branched-chain amino acids (BCAA) - isoleucine, leucine and valine - to the feed of young nine-month-old mice.
Compared with mice that were fed regular, unsupplemented chow, which survived an average 774 days, the BCAA-fed mice on average lived to the ripe old age of 869 days. As D'Antona's team point out, the BCAA-fed mice lived 12 per cent longer.
When the mice were tested at middle age - 16 months - those fed the BCAA mixture were also able to run for longer on a treadmill, and better maintain balance on a rotating rod. So not only did the diet help them live longer, the mice also had higher endurance and better motor coordination.
Co-author Enzo Nisoli at the University of Milan in Italy told UK newspaper The Daily Telegraph:
This is the first demonstration that an amino acid mixture can increase survival in mice
The team think that the BCAA cocktail may trigger an increased production of mitochondria - the cell compartments that produce energy - in the muscles. The BCAA-fed mice also had an increased expression of the SIRT1 gene, thought to be involved in longevity, though the authors admit "further investigation is needed to assess the role of SIRT1 induction in BCAA-enriched mixture on mice survival".
So, is this BCAA cocktail really the "elixir of life" the media is proclaiming it to be?
Downing amino acid cocktails is already known to be beneficial in some cases. Many formulations of BCAA are already used by bodybuilders, as they are known to help build muscle.
A similar mixture has also been shown to help elderly individuals regain muscle lost to sarcopenia - a degenerative condition associated with ageing.
A diet loaded with BCAAs is even thought to help brain-damaged mice recover, and improve performance in a learning task.
But it's important to remember this effect, like the one in the current study, was only seen in mice. It's notoriously difficult to transfer findings from mouse studies to humans - some scientists even argue that many lab mice are out of shape, and not representative of mice in general, let alone humans.
What's more, the researchers only tested the BCAA-supplemented diet on a small number of mice. The lifespans of 30 BCAA-fed mice were compared with those of 30 mice fed regular chow.
Though that hasn't stopped the UK's Daily Mail newspaper running with the unsubstantiated headline: "Body builder protein powder 'could increase life expectancy by 10 years'".
It's certainly an interesting study but don't start stockpiling protein powder just yet.

Journal reference: Cell Metabolism, DOI:10.1016/jcmet.2010.08.016

**Published in "New Scientist"