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Beta carotene (supplements) increase cancer and death rates

It is the studies on beta-carotene (what appears to be the “strongest” carotenoid, which is the plant family of Poison/”Vitamin A” compounds) that are often used as the “example” for the mainstream to badmouth ALL supplements, particularly anything in the “antioxidant” category of supplements.  While many/most supplements are unnecessary, some are toxic (including all forms of Vitamin D by mouth, including cod liver oil, and potassium iodide, see other posts on this blog-forum about those), and many are unhelpful (get your ESSENTIAL nutrients right FIRST by testing, not guessing, then addressing, this is my specialty), there are none out there that are as toxic as all of the members of the Poison/”Vitamin A” family.

First, an important quote from the paper linked directly below:

Three trials testing specifically beta-carotene supplementation showed moderate (relative risk (RR) ranging from 1.07 to 1.18), often not statistically significant, increases in all-cause and cancer mortality(7–9) while another(10) has not (RR=1.02).

OK, so they have THREE trials suggesting that SPECIFICALLY BETA-CAROTENE SUPPLEMENTATION INCREASED CANCER AND DEATHS.  What’s the answer then?  Well, obviously, it is to kill some more people early through more research!!!  *slaps forehead*  Below is the paper where they STOPPED the beta-carotene supplements EARLY because, well, they don’t really talk about WHY, because talking about KILLING PEOPLE EARLY is not something they really want to highlight now, is it?

Antioxidant vitamins supplementation and mortality: a randomized trial in head and neck cancer patients. (full study pdf attached)

We conducted a randomized controlled trial with a-tocopherol (400 IU/day) and b-carotene (30 mg/day) supplements among 540 head and neck cancer patients treated by radiation therapy. Supplementation with b-carotene was discontinued during the trial.
Patients were randomly assigned to receive a daily supplementation consisting of vitamin E (1 capsule of 400 IU DL-a-tocopherol) and b-carotene (1 capsule of 30 mg) or placebos during radiation therapy and for 3 years after radiation therapy ended. Concerns about adverse effects of beta-carotene supplementation prompted the investigators to halt the use of beta-carotene after the first 156 patients had been enrolled. The trial was continued with a-tocopherol alone.

So then, it would only be prudent to look up those three other papers on early deaths from beta-carotene, right?  Here we go.

The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers.

”Unexpectedly, we observed a higher incidence of lung cancer among the men who received beta carotene than among those who did not (change in incidence, 18 percent; 95 percent confidence interval, 3 to 36 percent). We found no evidence of an interaction between alpha-tocopherol and beta carotene with respect to the incidence of lung cancer. Fewer cases of prostate cancer were diagnosed among those who received alpha-tocopherol than among those who did not. Beta carotene had little or no effect on the incidence of cancer other than lung cancer.
Total mortality [number of deaths] was 8 percent higher (95 percent confidence interval, 1 to 16 percent) among the participants who received beta carotene than among those who did not, primarily because there were more deaths from lung cancer and ischemic heart disease.”

Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease

We conducted a multicenter, randomized, double-blind, placebo-controlled primary prevention trial — the Beta-Carotene and Retinol Efficacy Trial — involving a total of 18,314 smokers, former smokers, and workers exposed to asbestos. The effects of a combination of 30 mg of beta carotene per day and 25,000 IU of retinol (vitamin A) in the form of retinyl palmitate per day on the primary end point, the incidence of lung cancer, were compared with those of placebo.

On the basis of these findings, the randomized trial was stopped 21 months earlier than planned; follow-up will continue for another 5 years.
Conclusions:  After an average of four years of supplementation, the combination of beta carotene and vitamin A had no benefit and may have had an adverse effect on the incidence of lung cancer and on the risk of death from lung cancer, cardiovascular disease, and any cause in smokers and workers exposed to asbestos.

The study was stopped early, you say? Where have we seen that before?  Oh yes, up in the first paper I linked above.  Do you see the pattern, and how this is not coincidence?  Make sure you catch that ALL causes of death were increased in the beta-carotene and retinyl palmitate (both forms of Poison/”Vitamin A”) group.  ALL CAUSES.

β-Carotene Supplementation and Incidence of Cancer and Cardiovascular Disease: the Women’s Health Study

BACKGROUND: In observational studies, individuals with high intakes of fruits and vegetables containing β-carotene experience lower risks of developing cancer. However, the few randomized trials of β-carotene supplementation show no overall benefits; some even suggest harm. This trial was designed to test the effects of β-carotene supplementation in women.

METHODS: The Women’s Health Study is a randomized, double-blind, placebo-controlled trial originally testing aspirin, vitamin E, and β-carotene in the prevention of cancer and cardiovascular disease among 39 876 women aged 45 years or older. The β -carotene component was terminated early after a median treatment duration of 2.1 years (range = 0.00-2.72 years). Statistical tests were two-sided.

WAIT, WHOA!!!  The “beta-carotene component was terminated EARLY”?  Do they say WHY in the paper?  They do, and it reeks of covering up the problems that they saw.

Following discussion with officials from the National Cancer Institute (Bethesda, MD) and the independent Data and Safety Monitoring Board of the Women’s Health Study, the β -carotene component of the trial was terminated early on January 18, 1996, primarily because of the null findings on β-carotene and cancer incidence after 12 years of randomized treatment from a companion trial of 22 071 male health professionals in the Physicians’ Health Study (15). In addition, two other trials had suggested that β-carotene may even be associated with harmful effects among individuals at high risk for lung cancer (13,14,18). The aspirin and vitamin E components of the trial presently continue uninterrupted.

Null findings sounds like nothing, right?  WRONG.  Null findings mean that what they found doesn’t support their hypothesis!  Here’s the title of a paper that I think will say enough:  Why null results do not mean no results: negative findings have implications for policy, practice, and research.  My interpretation of their results and what they wrote is that they saw increased disease and deaths, they consulted with others about it, and to protect the perception of their research (and to hopefully not KILL too many others early), they terminated that part of the study.

RESULTS: Among women randomly assigned to receive β-carotene (50 mg on alternate days; n = 19 939) or placebo (n =19 937), there were no statistically significant differences in incidence of cancer, cardiovascular disease, or total mortality after a median of 4.1 years (2.1 years’ treatment plus another 2.0 years’ follow-up).
By the mid-1990s, the findings from six trials (10-15) testing the effect of β-carotene supplementation on cancer incidence and mortality had been published. The data from these trials generally have not supported the promising findings from observational studies, and two of these trials (13,14) even suggested harm.

So, they stopped the beta-carotene supplementation early, but there was no association of increased disease or death rates with the supplementation group?  Why did they need to stop the supplementation group again exactly?  Maybe the answer is in the actual numbers.

The authors try to say that there was no statistically significant differences in disease rates or mortality.  However, the authors of the first paper I linked felt that the data supported the possibility of beta-carotene being harmful.  These authors even list two studies where harm is suggested from beta-carotene.  I’m going to post the actual study results below, they can be found in the link if you want to double-check me.  The first number will be for the beta-carotene supplemented group, the second number will be for the unsupplemented group.

All cancers:  378 vs. 369

Years 1 & 2 combined cancers:  219 vs. 214

Years 3 & 4 combined cancers:  159 vs. 155

Deaths from cancer:  31 vs. 28

Myocardial infarction:  42 vs. 50

Stroke:  61 vs. 43

Death from cardiovascular causes:  14 vs. 12

All important cardiovascular events:  116 vs. 102

Years 1 & 2 combined all important cardiovascular events:  74 vs. 65

Years 3 & 4 combined all important cardiovascular events:  42 vs. 37

Death from any causes:  59 vs. 55

If I was a betting man, I’d say that betting on beta-carotene supplementation causing early death and disease was a nearly guaranteed winner.  Does it make sense why they terminated the supplementation now?  Note how the researchers specifically tried to downplay and ignore the very obvious trend in the disease and mortality rates.  This is pervasive through the literature, trying to turn something bad into something good.  Also, note how the problems STAYED for the two years AFTER the supplementation was stopped!  Poison/”Vitamin A” must be detoxed and then minimized afterwards if you want to get away from all the long-term problems it will cause.  Those other two papers mentioned in the quote were already covered above.

And finally, a paper summarizing all of this:  CHEMOPREVENTION OF LUNG CANCER: The Rise and Demise of Beta-Carotene

Beta-carotene and retinoids were the most promising agents against common cancers when the National Cancer Institute mounted a substantial program of population-based trials in the early 1980s. Both major lung cancer chemoprevention trials not only showed no benefit, but had significant increases in lung cancer incidence and in cardiovascular and total mortality. A new generation of laboratory research has been stimulated.

Rational public health recommendations at this time include: 1. Five-A-Day servings of fruits and vegetables, a doubling of current mean intake; 2. systematic investigation of the covariates of extremes of fruit and vegetable intake; 3. discouragement of beta-carotene supplement use, due to adverse effects in smokers and no evidence of benefit in non-smokers; 4. multilevel research to develop and evaluate candidate chemoprevention agents to prevent lung and other common cancers; and 5. continued priority for smoking prevention, smoking cessation, and avoidance of known carcinogens in the environment.

Based on all of the above, if it were me, I would make sure that NONE of my supplements–including multi-vitamins–contained ANY beta-carotene.

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Dr. Garrett Smith, the "Nutrition Detective"
Licensed Naturopathic Physician (NMD) in Arizona, home of the Love Your Liver program
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