Thursday, April 17, 2008

Antioxidant pills 'increase risk of early death'

More bad news for pill poppers and health freaks generally. The claim that antioxidants in food are somehow different is just deep faith. Note that in the madhouse that is the medical literature, a Cochrane study is unusually authoritative

Researchers at Copenhagen University carried out a review of 67 studies on 230,000 healthy people and found "no convincing evidence" that any of the antioxidants helped to prolong life expectancy. But some "increased mortality".

About 12 million Britons supplement their diets with vitamins and the industry is worth 330 million pounds. But little research has been done on the long-term health implications.

The Department of Health said yesterday that people should try to get the vitamins they need by eating a balanced diet and advised care in taking large doses of supplements. A spokesman said: "There is a need to exercise caution in the use of high doses of purified supplements of vitamins, including antioxidant vitamins, and minerals. Their impact on long-term health may not have been fully established and they cannot be assumed to be without risk. "Anyone concerned about their diet should speak to their doctor or dietitian."

Antioxidants, including vitamins A, E, C and beta-carotene and selenium, are said to mop up compounds, called free radicals, which cause disease. It is this action that researchers believe may cause problems with the defence system. The Danish research, released by the influential Cochrane Library, applied only to synthetic supplements and not to vitamins that occur naturally in vegetables and fruit.

It found that vitamin A supplements increased the risk of death in healthy people by 16 per cent. Taking beta-carotene was linked to a 7 per cent increased risk, while regular users of vitamin E supplements increased the risk of an early death by four per cent.

Although the review found no significant detrimental effect caused by vitamin C, it found no evidence that it helped ward off disease. Millions take it in the hope of avoiding a common cold.

Goran Bjelakovic, who led the review, said: "We could find no evidence to support taking antioxidant supplements to reduce the risk of dying earlier in healthy people or patients with various diseases. "If anything, people in trial groups given the antioxidants beta-carotene, vitamin A, and vitamin E showed increased rates of mortality."

But Patrick Holford, a nutritionist who has formulated supplements for the company Biocare, said: "Antioxidants are not meant to be magic bullets and should not be expected to undo a lifetime of unhealthy habits. "When used properly, in combination with a healthy diet full of fruit and vegetables, getting plenty of exercise and not smoking, antioxidant supplements can play an important role in maintaining and promoting overall health."

A spokesman for the Health Supplements Information Service said: "People should get all the vitamins and minerals they need from their diet, but for the millions who are not able to do that, vitamins can be a useful supplement and they should not stop taking them."

However, Catherine Collins, of the British Dietetic Association, said: "This study is deeply worrying and shows that there should be more regulation for vitamins and minerals. "The public can buy vitamins as easily as sweets. They should be treated in the same way as paracetamol with maximum limits on the dosage."



My most frequent commenter has put up a long comment on this post in which he accused the Cochrane authors above of “cherry-picking” what they studied. Cherrypicking is indeed a common and often fatal flaw in meta-analyses but I would be surprised if Cochrane authors had done it irresponsibly.

I did not look closely at the study myself because the finding is one that was already well-substantiated. See here and here, for instance. It is true, however, that a single author -- Bjelakovic -- seems to be behind much of the review literature. That does not, however, erase the original studies that he reviews and his acceptance as a Cochrane reviewer indicates a judgment that his reviews are indeed representative.

Mumps outbreak

A large mumps outbreak in the United States in 2006 may have been caused by the failure of the vaccine, federal health experts reported Wednesday. In a study reported in the April 10 issue of the New England Journal of Medicine, authors urge a more effective mumps vaccine or changes in vaccine policy to eradicate the disease. The study found that 84 percent of people between the ages of 18 and 24 who became ill in the outbreak had received the second recommended dose. The national incidence of mumps was 2.2 per 100,000. The highest incidence was in persons 18 to 24 years of age, with an incidence 3.7 times that of all other age groups combined.

"Despite a high coverage rate with two doses of mumps-containing vaccine, a large mumps outbreak occurred, characterized by two-dose vaccine failure, particularly among Midwestern college-age adults who probably received the second dose as schoolchildren," the study authors wrote. "A more effective mumps vaccine or changes in vaccine policy may be needed to avert future outbreaks and achieve the elimination of mumps."

The authors conclude that further studies are needed to help evaluate national vaccine policy, including whether the administration of a second dose of MMR [measles-mumps-rubella] vaccine at a later age or the administration of a third dose would provide higher or more durable immunity.

Mumps is a disease caused by a virus that usually spreads through saliva and can infect many parts of the body, especially the parotid salivary glands. These glands, which produce saliva for the mouth, are found toward the back of each cheek, in the area between the ear and jaw. In cases of mumps, these glands typically swell and become painful. Mumps was common until the mumps vaccine was licensed in 1967. Before the vaccine, more than 200,000 cases occurred each year in the United States. Since then the number of cases has dropped to fewer than 1,000 a year, and epidemics have become fairly rare.


1 comment:

Anonymous said...

"Antioxidant pills 'increase risk of early death'"

I suspect overly uncritical enthusiasm has trumped the usual critical edge of my favorite blogger. I usually like metastudies which compare oranges to oranges, but in this case, my BS detector started pinging the more I looked into it, with smoke eventually coming out its top.

I don't think this is a nail in any coffin, being a metastudy based on the single variable of mortality, which lumping massively different TYPES of studies and then selects only 47 (not 68) studies in which people by necessity DIED since that's what they decided to study, by a researcher whose every publication is about how the evils of vitamin pills. There have been THOUSANDS of papers and HUNDREDS of large studies about anti-oxidants that show positive health effects, along with the obvious MECHANISM of free-radical scavenging effects. Admittedly, there may be a devil or two in the details, but discovering these SPECIFIC details is called progress, whereas smearing the entire vitamin industry stinks of political and territorial bias.

The study included Vitamin A. That's what the body makes, as needed, from beta carotene. But vitamin A is NOT an "anti-oxidant", or even suggested as one by sellers, AND it is clearly toxic at large doses, which any dime store book on vitamins points out. Beta carotene is over twice as long and really *is* a massively effective anti-oxidant. Oddly enough this relates to your Robin post. Many creatures show bright red-orange coloring in order to display their high beta-carotene stores have not been used up due to being sickly.

Note also that Vitamin E comes in two mirror images, and most pills contain both the natural one and the wrong one in an equal ratio.

They started their list with 815 studies (of THOUSANDS that exist), excluding 405 because there were no deaths in them. They conclude, based on the remaining 68 that: “The pooled effect of all supplements vs. placebo or no intervention in all randomized trials was not significant.”

THEN THEY TOSSED OUR ANOTHER 21 STUDIES calling them “high-bias” (cherry-picking alert!), leaving ONLY 47 STUDIES (!), which finally their "analysis" detected an increased mortality risk of only three of the supplements evaluated: vitamin A, beta-carotene, and vitamin E, all fat-soluble, unlike vitamin C and selenium.

Very many of the participants in these studies were SMOKERS, and indeed anti-oxidants can be bad for smokers since anti-oxidants, being tonic to health in general, cause established tumors to grow more vigorously. THAT'S WHY THE MAIN TREATMENT OF CANCER IS POISONS KNOWN AS CHEMOTHERAPY AGENTS, which work by KILLING ALL GROWING CELLS, which is why it makes your hair fall out. To treat cancer, you poison the person. To make it worse, you give them vitamins. Might THIS effect have a bit to do with the general "mortality" results of this metastudy?! Why doesn't their abstract mention TYPES of mortality, there being a mere top few? Are they hiding a cancer devil that trumps a heart angel?

Note that only fat-soluble anti-oxidants had a slight negative effect, not water soluble ones like vitamin C, fat–solubility being a boon for a vitamin getting out of the blood stream or its lipid carriers into cells. Many others were ALREADY IN HOSPITALS with the study being about treatment of disease, such as death from heart attacks, or, surprise surprise, CANCER. Thus HEADLINES are now giving long term nutrition advice based on acutely sick hospital patients. SUCH PATIENTS ARE ALMOST ALWAYS ON UPWARDS OF A DOZEN HIGH DOSE PRESCRIPTION MEDICINES and have tubes sticking out of various orifices. In other words, most vitamin studies are done on DYING PEOPLE!!!

Yet there are few large ("low bias") studies of disease PREVENTION (or treatment) based on unpatentable vitamin pills. There's no money to be made in it, so that's that. I doubt this study was one of their final 47: "Men with a high intake of vitamin E are 65% less likely to develop colorectal adenomas (precursors to colon cancer) compared to men with low vitamin E intake." (Tseng et al. 1996). There are HUNDREDS, even THOUSANDS of such small scale ("high bias") studies that show benefits of anti-oxidant pills.

And might the MEDICAL as well as the POLITICAL community really *want* a healthy population? EXAMPLE A, your honor: the former AND EXISTING "food pyramid" that says to eat starch instead of meat since dietary cholesterol or saturated fat causes heart disease (WHICH IS A BALD FACED LIE, as you well know).

* * *

Related speculations:

Humans are one of the only mammals, including other primates, that have lost the ability to make our own vitamin C, the body's main anti-oxidant and protein builder. This can only mean that in our evolutionary past we got a LOT of anti-oxidants in the diet (many of them can recycle vitamin C so intake needn't actually be in that form).

Modern farm animals eat starches (grains and corn), instead of a natural diet of green prairie plants, and have been bred to barely resemble their original natural form as well (chickens can't even fly), so their meat contains little vitamin C. We kill them before they show signs of physical aging.

Finally, there may be a relation between our million year diet of mainly seafood (since it has been recently established that it migration of humans out of Africa occurred mainly along now-underwater coasts), so had a very low carbohydrate diet.

Also, modern humans may require more anti-oxidants than they get from modern diets DUE TO THE CARBOHYDRATE LOAD WE HAVE HAD LITTLE TIME TO ADAPT TO. Modern starchy diets cause much bigger digestive bursts (digestion BEING oxidation) than seafood cooked up with seaweed (many of which are a form of algae) and seagrass etc. which are chock full of anti-oxidants.

Wikipedia claims: "Seaweeds are extensively used as food by coastal peoples, particularly in East Asia, e.g. Japan, China, Korea, Taiwan, and Vietnam, but also in Indonesia, Peru, the Canadian Maritimes, Scandinavia, Ireland, Wales, Philippines, and Scotland, among other places."

One theory of why we are "hairless apes" who can swim and dive readily is that we indeed evolved in a marine environment.

Another point about carbohydrates and anti-oxidants is that Eskimos eat mainly fish, with little in the way of veggies at all, yet are perfectly healthy. This also suggests that a low-carb diet creates less free radicals and so requires fewer anti-oxidants.

I looked it up: fish don't provide many anti-oxidants.