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be healthier and younger than one would expect when you know their age on their identity

cards? To reach the 100

th

birthday is no longer such an outstanding event. The genetic

characteristics of centenarians have certainly not been manipulated, even if some scientists

might dream of doing that while imagining caring for adults in laboratories and fantasising

about at least 5% of them living up to 1400 years and the rest dying for reasons other than old

age

(6)

. The longevity of animals serving as models in geroscience studies is achieved by

modifying genetic and hormonal settings to lengthen survival at a cellular level

(1, 8, 9)

. As

mentioned above, the increase in human life span is mainly due to recent beneficial

environmental changes and is hardly due to genetic modification.

Potentials to enhance longevity in humans

Geroscience has identified a number of features with the potential to enhance

longevity in humans, but intensive, long term and very careful studies are necessary before

most of these measures could be really applied

(7)

. Exercise is well known to be of benefit for

health and healthy aging. Other measures and factors are less appropriate for immediate use

for clinical or public health purposes. Dietary restriction in terms of calorie intake enhances

life in rodents and is known to reduce risks for some common chronic diseases

(10)

, but

proposing dietary restriction as a general public health intervention is probably not feasible.

While changes in dietary intake and certain food items might modulate the effects of dietary

restriction, much more research is necessary to achieve this goal. Methods proved to be useful

in public health and public health nutrition, such as carefully conducted epidemiological

prospective cohort studies and validated dietary assessment schemes linked to metabolic

indicators, might contribute considerably to valuable research results.

From the eight ‘geroscience interventions with translational potential’ listed by

Kaeberlein et al.

(7)

, which included exercise and dietary restriction, two drugs have been

singled out: metformin and rapamycin. Interest in metformin has now reached the point where

it is to be tested in a randomized, double-blind clinical trial. The Targeting Aging with

Metformin (TAME) trial tries to find out whether metformin can delay the onset of another

age-related condition in people already living with an obvious sign of aging (E. Check

Hayden, Nature , 522, 2015) (see Kaeberlein 11). Another intervention involves the use of

rapamycin which enhances longevity in rodents and other geroscience models and which

seems to improve immune and cardiac functions in rodents and immune functions in elderly

people. While the drug is already used in the treatment of cancer patients, and its influence on

aging seems to be linked to this function, its testing is still hampered by methodological and

ethical problems. Other interventions with ‘translational potential’ involve rather complex

approaches, and it is difficult to envisage the potential of public health interventions in the

foreseeable future for NAD precursors, modifiers of telomere dysfunctions, hormonal and

circulated factors, and mitochondrial-targeted therapeutics

(7)

.

How to measure the biological age

Of more immediate interest for public health than potential interventions to delay

aging are geroscience attempts to measure ‘biological age’. There are questionnaires

promising to estimate the years the respondent still has to live. These attempts make use of