Hey, time for another "vitamin D is good for you" post. Been too long since the last one. This time you can see the benefit.
"In women younger than 75, those who had 25-hydroxyvitamin D concentrations lower than 38 nanomoles per liter were more likely to have age-related macular degeneration than women with concentrations greater than 38 nanomoles per liter," says Amy E. Millen, PhD, assistant professor in the UB School of Public Health and Health Professions and lead author. "Blood concentrations above 38 nanomoles per liter were associated with at least a 44 percent decreased odds of having AMD."
Of course, this is not a double blind longitudinal intervention study with pills. So other factors might both cut eye risk and raise vitamin D levels. But while we wait for results of more definitive studies our eyes will (regrettably) age.
High vitamin D foods were found linked to lower age-related macular degeneration (AMD) risk.
In women younger than 75 years, intake of vitamin D from foods and supplements was associated with decreased risk of developing early AMD. Women who consumed the most vitamin D had a 59 percent decreased odds of developing early AMD compared with women who consumed the least vitamin D. The top food sources of vitamin D in the sample were milk, fish, fortified margarine and fortified cereal. No relationship was observed using self-reported time spent in direct sunlight.
Measures to slow our eye aging aren't the final answer. What we need: Full body repair. If we only had a time machine some of us could travel up ahead 50 years, hop out, and get cell therapies, gene therapies, and growth of replacement organs.
Update: Also see this Harvard School of Public Health article on what factors increase your risk of low vitamin D.
| Share | | Randall Parker, 2011 April 13 11:36 PM Aging Diet Eye Studies |
There's a pretty clear link between Age-related Macular Degeneration and vegetable oils, and the results have been confirmed experimentally in animals:
http://yelling-stop.blogspot.com/2011/02/linoleic-acid-and-blindness.html
Since there's such a clear mechanism explaining AMD, I'd be inclined to think that the low-Vit. D association described here may be the effect of people who consider themselves "healthy", that is, they follow the Gov't advice to eat low fat, use vegetable oils instead, and stay out of the sun, might be confounding a direct cause-and-effect relationship. Speculation on my part, but there you are.
Odd that there was NO relationship with time spent in the sun. I didn't think there was any difference between vitamin D from sunlight and from ingestion. I wonder how reliable the 'self reporting' was?
"If we only had a time machine some of us could travel up ahead 50 years"
Right on! My eyesight ain't so hot for a 34 year old, but as an 84 year old, I'd be doing great!
:-)
Doug Collins,
I can see a couple of factors at work:
- UV probably speeds up eye aging.
- As the skin gets older it makes less vitamin D in sunlight.
38 nM is 15.2 ng/ml. Majority have this level without any vitamin D supplementation. Crazies that take 5,000 units daily routinely get into 125-175 nM range (where all cause mortality very likely increases).
As a farmer I work extensively in the sun. Here in the mid-latitudes I can pick up about 20,000 IU in perhaps half an hour of going shirtless between May and August, and I do that on a regular basis. The arrival of hot weather takes at least 20 or 30 years off my "winter skin" -- I'm 62 -- just because of all the sweating.
Since I eat lots of sea fish I never used to take Vitamin D supplements in the winter, but now regularly take 4,000 IU almost daily between late October and late March. FWIW, the eyes are still about 20/15 with absolutely no need for reading glasses, and it was my desire to maintain that acuity that led me to taking supplemental D3 in the first place.
I was totally unprepared for the side-effects: my winter eczema all but vanished, and more amazingly the nail fungus problem on three of my toes resolved spontaneously. Anecdotal, I know, and with just one mouse -- me -- the statistical N-1 goes all to hell, yet there's obviously some benefit to more than one integumental component, since my barber also now complains that my hair is so thick it bogs down his clippers.
Fascinating stuff, worthy of additional (and more structured) research.
"Of course, this is not a double blind longitudinal intervention study with pills." So you want to do a double blind study of blindness, how cruel is that?
Randall,
Irony is fun, but it's not generally well understood - especially in print...
if u want to gain the benefits of vitamin d
witch is up to 50 procent deseas reduction across the board
take 5000 iu d3 a day
falow by blood test to see ur level is above 50nano per/dl
or ur just wasting ur time
if ur just reading or bloging about it
remember 5000 iu d3 a day
Randall,
I think it's time for a "Vitamin D" tag to appear on all future articles, I would like to pass this knowledge on to others, however without a simple tag to link to, it would be a waste of time.
Think about it, it would be welcomed - oh, and retroactively!
I work in Bioresearch. About a year and a half ago my lab started working on a Vitamin D3 Assay. I ended up doing a massive literature search on Vitamin D3 and reading 20-30 journal articles working on a D3 and have followed it ever since. Take this for whatever it is worth to you here are my conclusions. I AM NOT a Medical Doctor and am Not giving advise.
1) Vitamin D3 after the discovery that it prevented Rickets was generally ignored for the last 50 years until about 5 years ago.
2) Vitamin D3 is unlike the other Vitamins really it is closer to a Hormone/Prohormone than a vitamin.
3) Vitamin D2 is generally worthless ~100x less active in the human body.
4) If exposed to daylight for several hours a day for several months people typically would develop blood concentrations of D3 of 30-50ng/ml. 80-90% of the people living in the upper and lower latitudes have D3 levels 50%
9) Correlational Data/Opinion 30-50ng/ml blood levels of D3 reduce the risk of developing heart disease by ~50%
10) Correlational Data: Opinion 30-50ng/ml blood levels of D3 reduce the risk of developing Diabetes by > 30%
11) Correlational Data: People who grow up in Northern States Michigan for example have 1000x the risk of developing MS that people who grow up in Florida have. If they swap locations as an adult their risk does NOT change. It seems to be an issue of where you grew up in childhood/adolescent/very early adulthood possibly D3
12) D3 is implicated in good long term eye health.
13) Vitamin D3 research is Red Hot at the moment with many more possible problems being increased by sub optimum D3 levels.
14) Vitamin D3 appears to be a Wonder Nutrient with many systemic effects (in hindsight this might be expected from a hormone like vitamin).
15) Vitamin D3 could be the latest over hyped craze but unlike the previous ones I am Sold on Vitamin D3 the levels they are seeing of 30-70% reductions in diseases is pretty convincing and the levels of D3 I am taking are definitely in the non harmful range so on the off chance I’m wrong on my assessment I’m only out of a little money.
Sorry this dropped out of the above post.
5 Opinion: Most people living in the upper and lower latitudes have enough D3 to prevent Rickets but not enough to promote optimum health and disease reduction. 30-50ng/ml is needed for disease reduction. Most people are deficient in D3 but not to the point of getting Rickets
6 ~40,000U D3 daily or greater is required for toxicity to start showing up in people.
7 ~ 5,000U to 8000U of D3 is needed daily to reach the putative optimum levels of 30-50ng/ml for most people. (I now take 2000U in the summer when outside a lot but take 5000U daily from September through May)
8 Correlational Data/Opinion 30-50ng/ml blood levels of D3 reduce the risk of developing Cancer by >50%