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The Great UK Vitamin Scare {4} – a broader perspective

This New York Times 8 April 2008 article (the U.S. position, not the U.K. one, but the principle is there)

Potential for Harm in Dietary Supplements

covers the vitamin and deaths research but also has more general points:

(1) Regulations for drugs compared with supplements are not the same

[..] Over-the-counter medications like ibuprofen, inhalers and reflux inhibitors have to be shown as safe and effective before the F.D.A. will let them be marketed. But thanks to the 1994 Dietary Supplement Health and Education Act, neither dietary supplements nor homeopathic remedies are required to provide premarket evidence of safety and effectiveness. To remove such a product from the market, the F.D.A. has to prove that it is dangerous, a challenging task for the understaffed, budget-strapped agency.

(2) No systematic collection of data on adverse effects of supplements

[..] A new federal law requires supplement manufacturers to report serious adverse effects to the Food and Drug Administration, but it depends on consumers to call in reactions. Experts say most consumers are unlikely to relate health problems to a supplement they assume to be safe, and even if they do, they may be reluctant to report an adverse effect from a self-medicated substance.

Examples of effects of overdosing with supplements

  • A dental patient with gum healing problems on high doses of a wide range of supplements
  • leg cramps – A man taking 50 mg. of vitamin B6

(3) Vitamin and mineral supplements can interfer with the working of prescribed drugs

Vitamins A, B6, B12, C, E and K; niacin; folic acid; calcium; magnesium; iron; and zinc can be hazardous when combined with various prescription drugs and over-the-counter remedies. Yet patients often fail to mention using such supplements to physicians.

(4) Structure and function claims conflated with with medical benefits

Our bodies need regular supplies of essential nutrients for growth and maintenance. They can state the concentrations in their products and what the substance is meant to do in the body. They are not meant to be able to say that megadoses have therapeutic effects.

Just because beta-carotene in carrots aids normal vision does not mean it can correct nearsightedness. Or a substance for forming blood cells will not necessarily be useful to prevent or treat a disease of blood-forming tissue like leukemia.

(5) Legally only allowed to make structure and function claims for supplements, while homeopathic remedies can claim medical effects

the example given here is for zinc. As a homeopathic supplement therapeutic claims are allowed. As a dietary supplement, it is illegal to make such a claim.

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April 19, 2008 Posted by | vitamins | , | Leave a comment

The Great UK Vitamin Scare {3} – vitamin C


3-dimensional model of vitamin C

The wiki: vitamin C covers almost every angle for anyone trying to examine whether Vitamin C is (a) worth taking as a supplement (b) could be damaging if taken in high doses.

Some questions to answer:

What is the main reason for taking high dose vitamin C?

What is a high dose?

Is natural vitamin C better for you than synthetic?

How does it work and what happens in the body?

For starters, it would appear Vitamin C would not be first choice for a suicide drug:

The LD50 (the dose that will kill 50% of a population) in rats is generally accepted to be 11.9 grams per kilogram of body weight when taken orally.[36]

If you take a lot of Vitamin C you will notice your urine changes colour. This explains why and gives an answer to how much to take:

Nature Medicine ( 7, 29 – 30 (2001) :

Forbidden Fruit: Although citrus fruits prevent and cure scurvy, they may not always be as good for you as you thought.

by J. K. Aronson, University Department of Clinical Pharmacology Radcliffe Infirmary Woodstock Rd. Oxford OX2 6HE, UK

..the body goes to great lengths to avoid excess accumulation of vitamin C, and has at least three ways of accomplishing this. First, absorption of vitamin C from the gut is highly saturable, ensuring that the amount that is absorbed reaches a maximum at relatively low doses. Second, the kidney rapidly excretes vitamin C, because its re-absorption from the renal tubules after filtration by the renal glomerulus is also highly saturable. Virtually all the vitamin C that is absorbed from the gut is thus excreted in the urine. For example, when the daily dose is increased from 200 to 2500 mg (from 1.1 to 14 mmol) the mean steady-state plasma concentration increases only from about 12 to 15 mg/l (from 68 to 85 mumol/l)—no matter how high a dose of vitamin C you take orally there is a limit to the plasma concentration that can be reached. Third, tissue uptake is also saturable. An increase in plasma concentration of vitamin C is not associated with a parallel increase in tissue concentration11. Indeed, the tissue vitamin C concentration, measured in leukocytes, saturates at 100 mg daily4 or plasma concentrations of 14 mg/l (80 mumol/l)(ref. 11).

So no matter how much you take, all you do is increase the concentrations in your urine and gut, and that can cause adverse effects12. Vitamin C is partly excreted as oxalate, and very high doses can lead to hyperoxaluria and kidney stones13, particularly after intravenous use and in people with renal insufficiency. Adverse effects in the gut include nausea, abdominal cramps and diarrhea14.

He provides a table of grapefruit drug interractions. Most people taking these drugs are warned on the packet.

From wiki: vitamin C :

The biological halflife for vitamin C is fairly short, about 30 minutes in blood plasma, a fact which high dose advocates say that mainstream researchers have failed to take into account. Researchers at the National Institutes of Health decided upon the current RDA based upon tests conducted 12 hours (24 half lives) after consumption. Mainstream medicine remains skeptical of these claims.

Vitamin C page from The Linus Pauling Instititute Micronuitrient Information Center

This is a very comprehensive info sheet, which also deals with saturation levels. Linus Pauling believed in taking massive doses of Vitamin C (and took them himself). Here, they say in the light of research since Pauling they recommend less. The toxicity section refutes a research finding on vitamin C and cancer and has an explanation at Vitamin C doesn’t cause cancer!

A link from the main page titled:

The Difference Between Dr. Linus Pauling’s Recommendations and the Linus Pauling Institute’s Recommendation for Vitamin C Intake

recommends 400 mg/day of vitamin C taking into account saturability. But there is no mention of what you would be getting anyway from a healthy diet. Assuming at least 100 mg. per day in your food, would you want to take a further 400 mg. supplement?

Right at the end it says:

…the Linus Pauling Institute’s recommendation is strictly directed towards prevention of disease in healthy individuals, not treatment of disease. Thus, individuals suffering from certain diseases may require substantially larger amounts of vitamin C to achieve optimum body levels or derive therapeutic benefits, areas that were of great interest to Linus Pauling and need to be further explored.

Food Standard Agency (UK) recommendations for Vitamin C

This a very short one-page sheet which recommended 100 mg. a day which is just above the RDA for Vitamin C.

This fact sheet has a handy chart for food sources of vitamin C. For example, 1/2 a cup of red bell pepper provides 90 mg.

The Vitamin C Foundation (Who they? Sounds impressive… but) recommends 3000 mg. a day (3 x 100). It includes a chart covering different recommendations, starting with the U.S. RDI of 60-95 mg. An associated article, The Nature of Vitamin C, deals in detail with whether ascorbic acid is vitamin C and whether “vitamin C complex” found in food is better for you than plain old ascorbic acid or its sodium or calcium salt.

Look at a standard bottle of Vitamin C from a supermarket or pharmacy. It might say it contains Vitamin C and sodium ascorbate. I would guess most people, if they bother to look at the small print on the label, would think these were separate things. Well are they? Vitamin C page from The Linus Pauling Instititute Micronuitrient Information Center provides the answer. There is now the question of whether you might need to avoid sodium ascorbate if trying to reduce sodium intake for blood pressure. I’ll find out don’t worry! Oh, and also by the way, the main page mentions taking vitamin c for high blood pressure.

The Vitamin C Foundation page is an illustration of how difficult for the ordinary person to sort fact from fiction. There is also discussion – amongst other things – of ways in which the amount of vitamin C we need might be assessed, for example based on what other species use (though they make their own).

Wiki:Vitamin C :

Most simians consume the vitamin in amounts 10 to 20 times higher than that recommended by governments for humans.[26] This discrepancy constitutes the basis of the controversy on current recommended dietary allowances (see Vitamin C as a macronutrient – Evolutionary rationales).

An adult goat, a typical example of a vitamin C-producing animal, will manufacture more than 13,000 mg of vitamin C per day in normal health and the biosynthesis will increase “many fold under stress”.[28][29]

Trauma or injury has also been demonstrated to use up large quantities of vitamin C in humans.

Mike Adams, writing in Natural News, is a believer in “natural” vitamins as opposed to synthetic ones. That aside, his February 28 2007 article

The big vitamin scare: American Medical Association claims vitamins may kill you (opinion)

deals with the issue of absolute risk over relative risk.

He has recently, 16 April 2008, written again on the vitamin scare

Vitamins A, C and E Increase Mortality! (and other nonsense from the realm of junk science)

If you look at his site you will discover he doesn’t believe pharmaceuticals are good at all, having claimed to have cured himself of type II diabetes through exercise and diet. I wonder if he would recommend not taking epilepsy drugs.

DC’s Improbable Science

Debunker site. Useful for junk science debate.

Manufacture of vitamin C

Another fascinating area, which would not have popped up without this search: who manufactures vitamin C and wholesale prices.

China makes 60 per cent of the world’s vitamin C supply, with the four leading Chinese producers making 60,000 tons. About 80 per cent of this is exported to Europe.

April 17, 2008 Posted by | ascorbic acid, calcium ascorbate, sodium ascorbate, vitamin C, vitamins | , , , , | Leave a comment

The Great UK Vitamin Scare {2} – Vitamin E



I’m taking these one at a time. The previous post mentioned B6, which was not generally mentioned in the media reports, which concentrated on the harmful effects of high doses of vitamins A ( or its precursor beta-carotene), C, D, E and mineral Selenium.

Vitamin E supplements ‘could cause up to 27 per cent increase in lung cancer’ Dail Mail 4 March 2008:

University of Seattle

{quotes}

  • A study of more than 77,000 people found that taking moderate to high doses of vitamin E led to a “slight but significant” increase in risk of the cancer
  • study is not the first to link vitamin supplements to lung cancer, with previous research showing that beta carotene, a building block of vitamin A, can raise the risk by as much as 18 per cent.
  • The increased risk was equivalent to seven per cent rise for every extra 100 milligrams of vitamin E taken per day over 10 years.
  • This translated into a 28 per cent increased risk of lung cancer for someone regularly taking a high 400 milligram dose of the vitamin.

A standard supermarket Vitamin E contains 400 iu (international units). 1 iu = 0.67 mg. or 268 mg. per 400 iu capsule.

Before this recent survey there have been newspaper health articles suggesting that vitamin E is as important as vitamin C as anti-oxidant in attacking the dreaded free-radicals.

But there were scare stories on Vitamin E as well. This BBC News report of 11 November 2004,

High dose vitamin E death warning: Elderly people could be risking their lives if they take even moderately high doses of vitamin E, evidence suggests.

based on a John Hopkins study, points out :

  • People who took daily vitamin E doses exceeding 400 “international units” (IU) per day (equivalent to about 270mg) had an increased risk of death by about 10% compared with those who did not.
  • People who took daily vitamin E doses exceeding 400 “international units” (IU) per day (equivalent to about 270mg) had an increased risk of death by about 10% compared with those who did not.
  • In the UK, the Food Standards Agency recommends a daily intake of between 3-4mg or 4.5-6 IU. It sets an upper safety limit of 540mg (800 IU) per day, which is twice as high as the level found to be harmful in the study.
  • In the US, the safety limit is as high as 1,000mg or 1,500 IU per day.
  • Vitamin E supplements have been shown to protect against cardiovascular disease and cancer.
  • In the study, there was no increased risk of death with doses of 200 IU (133mg) per day or less, and there was evidence to suggest these doses might be of some benefit.
  • The researchers said policy makers should consider lowering the maximum dose to 400 IU (about 266mg) per day.
  • Dr Richard Siow, a lecturer in the cardiovascular division at King’s College London. said: “The medical community and the public should treat these findings with a degree of caution since this analysis combines the results from a very broad spectrum of epidemiological studies carried out over 38 years, utilising doses of vitamin E supplementation between 16.5 to 2000 IU per day.”

This CBS report (16 April 2008): Vitamins A, E and beta-carotene increase mortality, not longevity: study

  • Copenhagen University Hospital
  • 67 randomized clinical trials with 232,550 participants.

One issue for these studies is which Vitamin E they use. Vitamin E hydrochloride (E HCl or dl-alpha on the label) is synthetic: ‘natural’ Vitamin E (d-alpha).

If you are into this business of trying higher levels of vitamins, one tip is that some are fat soluble (e.g. vitamin E), while others (e.g. vitamin C) are water soluble. Excess water soluble vitamins can be flushed out by the kidneys, while fat soluble ones tend to be stored in the body for longer periods.

April 17, 2008 Posted by | vitamins | | Leave a comment

The Great UK Vitamin Scare {1}

UK media have persistently refused to mention a single milligramme: the image of worried people bringing in bagloads of vitamin and mineral bottles to ask the pharmacist at Boots whether what they are taking is o.k. is ridiculous. What is the bloody internet for?

What is a high dose? It’s useless to lump all vitamins together. Each one has to be dealt with separately. The main news reports mentioned vitamins A, C, D and E. No figures were given for doses.

In any case, this issue is heated because it is a battle between the vitamin manufacturers and sellers (and their scientific data) and ‘sensible’ science (and conventional medicine). It is virtually impossible to talk about how much of any one vitamin you can take without dealing with the general debates such as do we need to take supplements at all and are we being given the facts?

Let’s take one vitamin, B6, not mentioned in the reports, and see what we can find.

It take seconds to discover the suggestion that over 200mg. per day of B6 can cause nerve damage when taken for long periods, though stopping reverses the damage.

This official looking website, Office of Dietary Supplements, under the auspices of the National Institute of Health (U.S.), in its B6 Fact Sheet suggests 100 mg. daily as the safe level. It is pretty scathing (about the efficacy of B6 (therapeutically) where there is little or no evidence. Several experiments show that placebo is effective as therapeutic doses.

The daily recommended target (RDA) in the U.S. is 1.3 mg. for men and women between 19-50 years of age : a balanced diet would (should) provide this level. A banana a day would give you 0.68 mg., a baked potato, 0.7 mg.

For lowering homocysteine levels (implicated in heart and vascular disease): 3mg. per day. Eat more healthy food! Some suggest taking 50 mg. a day (about 74 bananas). However, SEE B6 Fact Sheet :

What is the relationship between vitamin B6, homocysteine, and heart disease?

A deficiency of vitamin B6, folic acid, or vitamin B12 may increase your level of homocysteine, an amino acid normally found in your blood. There is evidence that an elevated homocysteine level is an independent risk factor for heart disease and stroke [my italics] The evidence suggests that high levels of homocysteine may damage coronary arteries or make it easier for blood clotting cells called platelets to clump together and form a clot. However, there is currently no evidence available to suggest that lowering homocysteine level with vitamins will reduce your risk of heart disease. Clinical intervention trials are needed to determine whether supplementation with vitamin B6, folic acid, or vitamin B12 can help protect you against developing coronary heart disease.

One report suggested that B6 may protect against heart disease in other ways (i.e. not connected to homocysteine).

For what sort of things do people take B6 in therapeutic doses?

That is: self-administered or under medical advice.

  • Cardiovascular disease and strokes
  • depression
  • insomnia
  • carpel tunnel syndrome
  • PMS
  • asthma
  • epilepsy

Three quite interesting areas:

(1) Pre-mentrual tension.

Said to help relieve the symptoms. Suggested it clears excess oestogen. [ {1}’ Oestrogen leads to depression because it does not only block vitamin B6 activity but also accelerates the metabolism of tryptophan, thereby leading to low serotonin levels and hence to symptoms associated with these. ‘ ]

(2) Depression

Up to 25% of people with depression may be deficient in B6.

Diagose-me.com:

A study found plasma pyridoxal-5-phosphate (active vitamin B6) levels were about 48% lower in depressed patients than in controls, a statistically significant finding. 57% of depressed patients, but none of the controls, were B6-deficient. When B6 nutriture was evaluated by enzyme stimulation testing (a more sensitive method), all the depressed patients and none of the controls were deficient. [Russ CS et al. Vitamin B6 status of depressed and obsessive-compulsive patients. Nutr Rep Int 27( 4): pp.867-73, 1983]

(3) Epileptic seizures

Role in building blocks for neurotransmitters. May reduce frequency of attacks.

(4) Diabetes

May reduce risk of nerve damage.

::

The information sheet {1} says:

Vitamin B6 supplements have been tested extensively for toxicity by a number of research groups. No evidence of toxicity has been reported in human trials using 225mg of vitamin B6 daily for one year (56), or taking 250-500mg for an average of 2.3 years (57). A review of vitamin B6 toxicity states: “there are many reports stressing the absence of toxic side effects in people taking 200-500 mg per day for extended periods” (58). This also became apparent when Brush and Perry followed 630 women who had been taking up to 200mg of pyridoxine per day for years, none reported any side-effects whatsoever (59).

refs.

57. Mitwalli A et al: Safety of intermediate doses of pyridoxine. Can Med Assoc, 131:14, 1984

59. Brush MG, Perry M: Pyridoxine and the premenstrual syndrome. Lancet, 1:1399, 1985

This by Jurriaan Plesman, a clinical nutritionist {2} discusses drug therapy over nutrition in depression.

April 17, 2008 Posted by | medicine, science, vitamins | , , | Leave a comment