I read the obituary column. I get upset when I see people dead before their time. Sometimes you see people in their 30s, 40s and 50s dead from heart disease or cancer. The personal tragedies are too hard to read, men and women dying young and leaving behind young children and parents. Virtually always, they died before their time of a disease scientists have associated with vitamin D deficiency in one way or another.
Most people want to live as long as they can. How long is that? How long does it take the mammalian body to get too old to live? It is different for horses, dogs, apes, humans, etc. For humans, it is now somewhere around 85. As Professor Heaney has pointed out, the best we can hope for vitamin D is that it will help square off the mortality curve, with people living to their genetic potential of 85 (more or less).
A study of 3,000 old men, aged 70-81, published in October of 2011, showed just that. Dr. Johansson and colleagues from the University of Gothenburg measured vitamin D levels in these old men and then followed them for up to 8 years to see who died. Sure enough, the men with the lowest vitamin D levels died earlier than did men with higher vitamin D levels.
Johansson H, Odén A, Kanis J, McCloskey E, Lorentzon M, Ljunggren O, Karlsson MK, Thorsby PM, Tivesten A, Barrett-Connor E, Ohlsson C, Mellström D. Low serum vitamin D is associated with increased mortality in elderly men: MrOS Sweden. Osteoporos Int. 2011 Oct 19. [Epub ahead of print]
The interesting thing about this study was that the mortality rate benefit of vitamin D waned with time. That makes sense when you think about it, as everyone eventually dies. This study of old men found that, even with high vitamin D levels, the men still ended up dying. They were just less likely to die before their time.
The other thing the study showed was that levels of about 30 ng/ml was as good as it got. Only 106 of the men had levels greater than 40 ng/ml but that was no better than levels of 30 ng/ml. However, this was a study of Swedish men, and it is never clear from Scandinavian studies how many subjects consumed cod liver oil. We know the Swedes consume a lot of cod liver oil but among the men with levels above 40 ng/ml, only seven of the 106 men were reported to be taking vitamin D supplements. I doubt only seven of these men were taking cod liver oil. I think the Swedes consider cod liver oil a food, not a supplement.
The reason this is important is that modern cod liver oil has some vitamin D, but in my opinion, toxic amounts of vitamin A. One study found a 16% increase in mortality rate in individuals supplementing with vitamin D.
None of us know our genetic potential for life. We don’t know when our time is supposed to come. What we can hope for, and what vitamin D appears to do, is make it more likely you will reach your genetic potential, without becoming one of those young names in the obituary column.