Hunger for long life: the ethics of caloric restriction experiments

This has been a good week for life extension research, with the Nature paper Rapamycin fed late in life extends lifespan in genetically heterogeneous mice by Harrison et al. (free News and Views) showing that the drug boosts lifespan in middle aged mice, and Science countering with Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys by Colman et al. showing that in a 20-year longitudinal study rhesus monkeys do seem to benefit from caloric restriction (CR). CR involves keeping the energy intake low, but not so low that it induces starvation.

Not everybody seems to like the experiment. The Swedish major newspaper Dagens Nyheter had an article by Per Snaprud that appeared to criticise the monkey experiment on ethical grounds. He quotes Mats Spångberg, chief veterinarian at the Swedish Institute for Infectious Disease Control, who doubts the experiment would have been approved in Sweden. The only use of monkeys in Swedish research is AIDS vaccine research. The article concludes by stating that the virus kills 2 million people every year, 270,000 of whose are children.

But ageing kills 100,000 people worldwide each day directly or indirectly. 100% of humans and monkeys are "infected".

It should be noted that a few studies of caloric restriction in humans have been done, as well as quasi-experiments like the frugal diet of Okinawa. The mainproblem is that humans are so long-lived that it is hard to draw strong conclusions from them. The real benefit from CR research will likely be a better understanding of the mechanisms of ageing and possibly "CR mimetics", drugs that trigger the same anti-ageing response as reduced food intake. Real CR is simpy too impractical for weak-willed humans in a world of culinary delights.

It might be factually true that caloric restriction monkey experiments are unlikely to be approved in Sweden for cultural and institutional reasons, but ethically it seems to me that the case for the experiment is strong. The need for understanding and limiting the ravages of aging is enormous when measured in lives lost (not to mention suffering and loss of human capital). If one doesn't think it is worth finding ways of slowing or at least understand aging (as DN journalist Hanne Kjöller seems to argue in an opinion piece today) if it reduces the life quality of the monkeys, then one should give serious consideration of not trying to find an AIDS vaccine either. After all, it is a smaller problem.

The persistent hunger likely experienced by the monkeys is presumably not too different from what monkeys would experience in the wild where food access is haphazard. If the monkeys in the CR experiment have lives worth living - which seems to be the case - the extension of these lives adds value.

This is true even if the life quality is somewhat lowered by hunger compared to monkeys who can eat as much as they like. It seems unlikely that the value of the longer life and reduction of illness can be completely offset by plain hunger (especially since older monkeys in the experiment with chronic conditions like diabetes get medical treatment). If one were to seriously believe chronic hunger to be so bad that it reduces quality of life below worth living, one should give serious thought about feeding as many wild animals as possible and kill the rest. Or invite them into the lab, where they would at least get medical treatment.

Many people suffer from scope insensitivity and the availability heuristic when it comes to ageing compared to other conditions. They do not see how much pervasive suffering it causes, and they put more emphasis on comparatively rarer causes of mortality that stand out. The result is that they try to justify the current situation, allowing the carnage to go on.

Comments

[Angus Bearn]

All a bit disingenuous. The question is whether artificial extension of lifespan, perhaps with the attendant ravages of old age, can be equated with the simple gift of healthy life in the case of AIDS. Most people would intuitively value a life-saving cure over a life-extending possibility, and rightly. The other factor is that humans are at complete liberty to self-experiment if they are curious, so no need to play with monkeys. As for free food for all wild animals and a cull for the rest well, yes, eventually we might all live together in a kind of global zoo-park. Until then... let's make a start by feeding all our people, and easing back on the people-culls of war. Then we can move onto the suffering squid. Me? Pass me another pie.

[Sasha]

Hi Anders,

I just reposted this on Felicifia, along with some opinions of my own: http://felicifia.org/viewtopic.php?f=23&t=187&p=1269#p1269

I feel like I should notify you when I repost your comments, but I don't particularly like posting on here just to promote my own. What's your professional ethicist's opinion? :)

S

[Anders Sandberg]

Sasha, I think it makes sense to add comments that point at further discussion (that is why there are trackbacks, after all). Blogs work their best when they are an interactive medium. It also makes it possible for me to notice that further interesting discussion is going on.