For those of us who aren't in the life sciences, is this saying too much iron is good or bad?
We had access to data describing how DNA influences iron levels, and how DNA influences years of healthy life. This showed that the same DNA variations that change your levels of iron in the blood also change how many years you spend in good health.
Now, these genetic effects are relatively small, so we can confidently say that people who carry genes which cause them to have slightly lower iron levels (i.e. one standard deviation) than the population average will be healthier, on average.
However, extrapolating that further can be dangerous - for example, anyone with iron levels three standard deviations lower will not be three times healthier, they'd have no iron in their blood and be dead.
not in life sciences too, and my interpretation of the above phrase is "if your body iron processing machine works well - good, if not - then bad" which i'd say would be pretty expected, and in general article sounds like there is positive correlation between well working iron related metabolism and longevity which seems not that surprising. They don't seem to address the machinery and nature of that correlation.
Edit: specified as negatively correlated
Haemochromatosis is a genetic disorder where individuals are unable to get rid of excess iron. If properly diagnosed, this is easily treatable with bloodletting (blood donation in this century :-)
Haemochromatosis is the sort of genetic disease that could really screw with data like this. Undiagnosed haemocromatosis leads to early death....so the correlation of excess iron to longevity should be treated as a weak piece of evidence until we can exclude people with the genetic disorder.
No, it's saying neither. The submission title could be seen as misleading.