April 16, 2008 (Times of London): The review of 67 studies involving more than 230,000 people is republished today by the Cochrane Collaboration, an international organisation for evidence-based research. The review found no evidence that the nutrition supplements extend life. On the contrary, vitamins A and E and beta carotene appear to slightly increase premature death rates among those taking them. Vitamin C and selenium have no effect.
http://www.timesonline.co.uk/tol/life_and_style/health/article3754205.ece
And a mere 200 percent of the government's current Daily Value of supplemental vitamin A in the form of retinol can increase the risk of birth defects and liver damage. Indeed, the National Academy of Science's Institute of Medicine has recommended revisions in the Daily Values, including a lower amount of vitamin A, but the changes have not yet been instituted. (Consumer Reports)
READER COMMENT:
After a bit of research on the internet it appears that there may be some fundamental errors in the report.
ScienceDaily (Mar. 1, 2007)
http://www.sciencedaily.com/releases/2007/02/070228172604.htm
It appears that this report has been around for a couple of months already and it is interesting that the press are only just now picking up on it. To paraphrase some of the key points which suggest it may be quite flawed:-
1. Two large studies that fit the criteria used by the Danish scientists were excluded. These studies were published in the Journal of the National Cancer Institute in the USA and The Lancet. If they had been included none of the reported effects in mortality would be significant.
2. The mean duration of the selected trials was 2.7 years - are we really saying that these things are going to kill you in less than three years?
3. Most trials used included other dietry supplements and pharmaceutical drugs which could all interfere or mask the effects that can be attributed to the antioxidents.
4. And finally, but just as importantly, the causes of death in the trials were not even considered!! These could include accidents or other causes that have nothing to do with diet or oxidative stress.
In short the whole report looks statistically very dubious even though the experts views above are from the Linus Pauling Institute which does have its own interest in promoting nutritional supplementation.
jake, london,
The United States Pharmacopeia (USP) has a voluntary testing program called the Dietary Supplement Verification Program. The USP Dietary Supplement Verification mark shows that the supplement has passed USP tests to ensure that it contains the ingredients listed on the label, contains the amount of each ingredient listed on the label, dissolves effectively, does not contain harmful contaminants, and was manufactured using safe and sanitary procedures.
(According to:
http://lpi.oregonstate.edu/f-w03/multi.html)
This table lists our recommended daily doses of the 18 nutrients that a multivitamin should contain. It also lists the safe upper limits for each nutrient from all sources, since the high doses in some multivitamins, combined with fortified foods, other supplements, and your daily diet, could push your intake of some nutrients to potentially harmful levels. Sticking close to the recommended doses should keep you well within the safe range.
Nutrient
VITAMINS Vitamin A 3,000 IU 2,300 IU 10,000 IU Thiamin (B1) 1.2 mg 1.1 mg Not established Riboflavin (B2) 1.3 mg 1.1 mg Not established Niacin (B3) 16 mg 14 mg 35 mg Vitamin B6 1.3 mg 1.3 mg 100 mg Vitamin B12 2.4 mcg 2.4 mcg Not established Folate (folic acid) 400 mcg 400 mcg 1,000 mcg Vitamin C 90 mg 75 mg 2,000 mg Vitamin D 400 IU 400 IU 2,000 IU Vitamin E 22 IU (natural)
33 IU (synthetic) 22 IU (natural)
33 IU (synthetic) 1,500 IU (natural)
1,100 IU (synthetic) Vitamin K 120 mcg 90 mcg Not established MINERALS Calcium 200 mg 200 mg 2,500 mg Copper 0.9 mg 0.9 mg 10 mg Magnesium 100 mg 100 mg 350 mg (from supplements only) Phosphorus 100 mg or less 100 mg or less 4,000 mg (through age 70) Potassium 80 mg 80 mg Not established Selenium 55 mcg 55 mcg 400 mcg Zinc 11 mg 8 mg 40 mg
The limit applies to retinol, or vitamin A palmitate or acetate. It's higher for vitamin A from
beta-carotene, though the exact limit is not known.
Depending on diet and sun exposure, older people may need up to 1,000 IU. Source:
Institute of Medicine, our review of the literature, and the opinions of our nutrition consultants.
http://health.discovery.com/fansites/dr-oz/aging/supplements_print.html
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Vitamins and supplements can be beneficial to your health, but the number of choices available today can be overwhelming. Use the guide below to see the optimum daily dosage of many vitamins, minerals and supplements.
VITAMINS OPTIMUM A More than 2,500 IU is too much (unless you have an eye condition called wet macular degeneration).
If you're worried about arterial aging and memory, make sure you get the anti-inflammatory/antioxidant vitamins E and C and the homocysteine-lowering vitamins folate, B6, and B12; vitamin D, magnesium, and calcium; and lutein and lycopene. If you're concerned about osteoporosis, arthritis, or immune aging, pay careful attention to your intake of calcium, magnesium, selenium, lycopene, and vitamins B6 , B12, and D.
Choices you might consider (talk to your doctor about these and all choices):
Coenzyme Q10 200 milligrams day (if on a statin) or for all over age sixty.