On the Lighter Side > Complementary Medicine

vitamin suppliments

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another_someone:
The point I was trying to make was that what we need is the right balance.  Potassium and sodium need to be in balance, so unless you know which you have too much of and which you have too little, you don't know which to reduce and which to increase.  The same is for iron/zinc/copper/vitamin C - unless you know which you are short of, you could end up exacerbating an existing imbalance.

The problem is that the present tendency is just to pile stuff on, without thinking about whether it draws you closer or away from a position of balance.

I accept that the body is actually quite tolerant to quite a wide range of imbalance (after all, in the real world, nobody can ever have a high precision balance in their diet), but if you are in imbalance, and want to correct for that, then you should at least be aware of which direction you are out of balance, rather than just snatching the first set of pills you see on the shelves.

Bored chemist:
That's a fair point but what about the fact that twice the recomended intake of most vitamins probably won't do you any harm. You might not know intelectually which nutrients you are short of but the body is quite good at both restricting uptake and increasing excretion of those things it has lots of.
I know that, since I don't like fresh fruit, I probably miss out on some vitamins and minerals. I take multivitamin pills. I think it's easy enough for my body to sling out the excess of those which it doesn't need, but impossible for it to create them if I take too little.
With an excess it can maintain the balance; with a shortage it's a bit stuck.

iko:

--- Quote from: Bored chemist on 29/03/2007 19:41:29 ---That's a fair point but what about the fact that twice the recomended intake of most vitamins probably won't do you any harm. You might not know intelectually which nutrients you are short of but the body is quite good at both restricting uptake and increasing excretion of those things it has lots of.
I know that, since I don't like fresh fruit, I probably miss out on some vitamins and minerals. I take multivitamin pills. I think it's easy enough for my body to sling out the excess of those which it doesn't need, but impossible for it to create them if I take too little.
With an excess it can maintain the balance; with a shortage it's a bit stuck.

--- End quote ---

I agree 100%, Bored chemist.

You know what I miss in this hightech Era, since my interest in cofactors started a couple of decades ago? A quick and inexpensive full vitamin-cofactor screening test for peripheral blood, a tiny strip of thermal paper with little names and digits, to exclude in seconds a deficiency issue and go on with all the other possible diagnostic hypotheses.
These days nutritional deficiencies are relatively rare and their treatment quite cheap, so there is no research interest. Nevertheless I cannot accept the idea to rely only on clinical signs, diet and social histories to exclude -for example- a beriberi diagnosis.  This disease was described 120 years ago and the cure is an inexpensive vial in the drawer (thiamine 100mg) plus a sterile syringe. Sometimes it could be too late anyway: it takes approx. 6 hours to restore vital functions.
There are technical problems too: not in all the vitamin deficiencies you can count on the plasma concentrations for a proper diagnosis, and some cofactors still need sophisticated tests.
Basically there is no commercial and cultural interest.
Times are changing a bit now, and you find reports of B12 and folate deficiency in the elderly (not to mention the ongoing vitamin D3 'tsunami') that could have been done at least 20 years ago.
I remind you B12 deficiency as particularly insidious and tricky.
We discussed this recently with Dr. Beaver in the 'Pneumonia and dementia' topic:
http://www.thenakedscientists.com/forum/index.php?topic=6820.0
I tried to explain how much this issue seems to be neglected by most.

George seems too much worried to umbalance a natural condition, but I insist in saying that at the recommended doses it might be only a waste of money at worst.
BTW George, I am still waiting for your comments on the 'Shanghai report' and the engineers versus docs issue...where everything started from, last August.
When you get bored of vitamin intoxication issues, of course.

ikod
 

paul.fr:

--- Quote from: Bored chemist on 29/03/2007 19:41:29 ---That's a fair point but what about the fact that twice the recomended intake of most vitamins probably won't do you any harm. You might not know intelectually which nutrients you are short of but the body is quite good at both restricting uptake and increasing excretion of those things it has lots of.
--- End quote ---

Extracts from a docomentary, interviewing Professor Melhus.


Professor Melhus: When we look at known risk factors for osteoporosis, such as age, smoking, physical activity, they can partly explain why it's so common with osteoporosis and bone fractures in Sweden, but that can not explain everything. And then, even more surprising, is that we have a diet rich in calcium, which should protect our bones.

Narration: So Professor Melhus began to look for another explanation. And there was something in particular about the Swedish diet that made him suspicious. It was exceptionally high in vitamin A.

Professor Melhus: We eat dairy products, oily fish, such as herring and salmon, we consume cod liver oil, vitamin supplements, all which contain high levels of vitamin A, and on top of that we are the only European country which fortifies low fat dairy products with vitamin A.

Narration: This triggered an alarm for Professor Melhus. Because there was evidence that huge doses of vitamin A damaged animal bones.

Professor Melhus: Since we knew about these harmful effects of vitamin A on animal bones, we wanted to see if this also could be occurring in humans.

Narration: So Professor Melhus launched his own investigation. From a database of sixty six thousand women aged over forty, he looked for cases of bone fracture. He then checked the diet of these women to see if their vitamin A intake was particularly high. And the results seemed to confirm his suspicions.

Professor Melhus: When I saw the results from our study I was really surprised, although I knew the experiments done in animals, it was hard to accept the fact that vitamin A, a vitamin, had negative effects on bone in humans.

Narration: Professor Melhus then went further. He did a series of bone scans to work out what level of vitamin A was linked to weaker bones. His results suggested that long term consumption of even relatively small quantities of vitamin A were having a dramatic effect.

Professor Melhus: What we saw was that a vitamin intake above 1.5 milligrams per day, which is approximately twice the recommended daily intake, there was a reduction in bone density about ten per cent, and the risk of hip fracture had doubled.

Narration: If Professor Melhus was right then the implications were staggering. An intake of 1.5 milligrams per day is a level that can be reached from food alone. And it will be exceeded by taking just a single capsule of some high strength vitamin A supplements. So, tablets that people take every day to improve their health might actually be slowly, silently, weakening their bones. For Professor Melhus, the implication is clear.

Professor Melhus: Based on our research I think people should continue to eat a healthy, normal balanced diet. But since supplements containing high levels of vitamin A may have adverse effects, I cannot recommend people to take them routinely.

Narration: Professor Melhus has now done another study that suggests the same risk also applies to men. And since his original work, studies from America have supported his findings, but there has been some other research which has not found the same link.


Professor Andrew Renwick: I am concerned, although the, the evidence is not totally consistent, there have now been a number of studies showing a link, and I'm convinced that a high intake of vitamin A will give an increase risk of bone fracture.

iko:
Hi paul.fr,

Good point for a discussion.
I checked prof. Melhus's report in the NEJMed:

Serum retinol levels and the risk of fracture.Michaelsson K, Lithell H, Vessby B, Melhus H.
Dept. Surgical Sci., Section of Orthopedics, Univ. Hosp. Uppsala, Sweden. karl.michaelsson@surgsci.uu.se

BACKGROUND: Although studies in animals and epidemiologic studies have indicated that a high vitamin A intake is associated with increased bone fragility, no biologic marker of vitamin A status has thus far been used to assess the risk of fractures in humans.
METHODS: We enrolled 2322 men, 49 to 51 years of age, in a population-based, longitudinal cohort study. Serum retinol and beta carotene were analyzed in samples obtained at enrollment. Fractures were documented in 266 men during 30 years of follow-up. Cox regression analysis was used to determine the risk of fracture according to the serum retinol level.
RESULTS: The risk of fracture was highest among men with the highest levels of serum retinol. Multivariate analysis of the risk of fracture in the highest quintile for serum retinol (>75.62 microg per deciliter [2.64 micromol per liter]) as compared with the middle quintile (62.16 to 67.60 microg per deciliter [2.17 to 2.36 micromol per liter]) showed that the rate ratio was 1.64 (95 percent confidence interval, 1.12 to 2.41) for any fracture and 2.47 (95 percent confidence interval, 1.15 to 5.28) for hip fracture. The risk of fracture was further increased within the highest quintile for serum retinol. Men with retinol levels in the 99th percentile (>103.12 microg per deciliter [3.60 micromol per liter]) had an overall risk of fracture that exceeded the risk among men with lower levels by a factor of seven (P<0.001). The level of serum beta carotene was not associated with the risk of fracture.
CONCLUSIONS: Our findings, which are consistent with the results of studies in animals, as well as in vitro and epidemiologic dietary studies, suggest that current levels of vitamin A supplementation and food fortification in many Western countries may need to be reassessed.

N Engl J Med. 2003 Jan 23;348(4):287-94.

In the introduction you find this phrase:
"In a study of dietary patterns in Europe, the intake of vitamin A in Scandinavia was up to six times as high as the intake in southern Europe (3)".

This is a huge difference compared to normal diets, so a risk of toxicity in terms of bone metabolism can be expected.
Unfortunately, vitamin D levels were not evaluated in such a large study (2322 men).  It's a real pity, because vitamin D interacts closely with retinol (similar receptors) that seems to prevent vitamin D toxicity in terms of calcium metabolism.
A chance of a deeper look in this complex phenomena has been missed.
We are used to learn things from little bits here and there.

ikod

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