Health & Wellbeing

Trial concludes vitamin D and fish oil don't lower incidences of heart disease or cancer

Trial concludes vitamin D and ...
Both omega-3 fish oil and vitamin D supplements have been found to be no better than a placebo in preventing cancer or cardiovascular events
Both omega-3 fish oil and vitamin D supplements have been found to be no better than a placebo in preventing cancer or cardiovascular events
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Both omega-3 fish oil and vitamin D supplements have been found to be no better than a placebo in preventing cancer or cardiovascular events
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Both omega-3 fish oil and vitamin D supplements have been found to be no better than a placebo in preventing cancer or cardiovascular events

The findings of one of the largest placebo-controlled trials into the beneficial effects of vitamin D and fish oil ever conducted have just been published and, despite some hyperbolic media releases, the overall results found both supplements were no better than the placebo in lowering incidences of cancer or cardiovascular events.

The rigorous and well designed trial started with over 25,000 healthy subjects over the age of 50. Each participant was randomly, and blindly, assigned one of four daily combinations: 2,000 units of vitamin D and 1 gram of fish oil, the vitamin D and a placebo, the fish oil and a placebo, or two placebos.

The study followed the subjects for over five years, tracking the onset of major cardiovascular events or invasive cancers, and the results will certainly disappoint anyone with a stake in these supplements. The conclusion of the omega-3 study was, "Supplementation with n−3 fatty acids did not result in a lower incidence of major cardiovascular events or cancer than placebo." The conclusion of the vitamin D study was pretty much the same, "Supplementation with vitamin D did not result in a lower incidence of invasive cancer or cardiovascular events than placebo."

However, digging into the more granular detail in the study reveals some specific findings that some researchers are pushing to the foreground. JoAnn Manson, one of the key researchers on the study, focuses on two specific secondary datapoints suggesting, "omega-3s were associated with a reduction in risk of heart attacks across our study population, especially among participants who had lower than average fish intake," and vitamin D could be associated with lower rates of cancer deaths starting from one to two years into the study.

In an editorial accompanying the dual studies, published in the New England Journal of Medicine, John F. Keaney and Clifford J. Rosen suggest "these "positive" results need to be interpreted with caution. As well as noting, in regards to the fish oil conclusion, that these positive results have not been consistently observed across other large omega-3 trials, Kearney and Rosen offer a reminder that, "medical literature is replete with exciting secondary end points that have failed when they were subsequently formally tested as primary end points in adequately powered randomized trials."

Jane Armitage, from the University of Oxford, also questions the veracity of some of these secondary conclusions, suggesting while "they did see fewer heart attacks among those taking the fish oils," there was also no overall effect seen on all other cardiovascular events, so this needs to be interpreted cautiously.

In many ways this research seems to be a perfect litmus test in how problematic the reporting of scientific research can be. The headline on the research from the Washington Post is, "Fish-oil drugs protect heart health, two studies say," while the New York Times reports the exact same research with the headline, "Vitamin D and Fish Oils Are Ineffective for Preventing Cancer and Heart Disease."

Neither headline is specifically incorrect, however it may be slightly disingenuous to concentrate on a particular study's secondary effect when the overall primary finding was negative. The press release from Brigham and Women's Hospital does nothing to avoid such cherrypicking, leading with the subtitle "Findings show omega-3 fatty acids reduced risk of heart attacks, especially among African Americans; vitamin D reduced cancer deaths over time."

Again, these statements are not technically incorrect, but they are certainly not in line with the researcher's own published journal conclusions that clearly state both high-dose vitamin D and omega-3 supplementation do not reduce the incidence of cancer or major cardiovascular events.

The omega-3 study was published in the New England Journal of Medicine, as was the vitamin D study.

Source: Brigham and Women's Hospital via EurekAlert

11 comments
Des
In a study like this, where we are interested in long term effects, one needs to know if the secondary conclusion about benefits maybe showing up after two years can be substantiated by excluding all heart attacks and cancers that occurred in the first two years. If one starts the trial and a cancer, for example has already started developing, then one may not see any benefit. There should be sufficient number of trialists to exclude the first two years and only look at the "chronic" benefits. What about even longer effects?
michael_dowling
I think 5 years is indeed too short a timeframe to test the usefulness of these two supplements. 10 years should be the minimum.
see3d
The problem with this study is that 2,000IU of D3 does not raise the blood serum levels of an average population high enough to show the cancer reduction effects. Also, the rate of intake to blood levels varies by an order of magnitude between individuals. That makes the conclusions of this study worthless. The ongoing study done at grassrootshealth dot net shows an 80% reduction in breast cancer rates when low vs high blood serum levels are compared.
Cwolf
1. The only useful variable is serum level. The relationship between dosing and serum levels varies by body weight and the starting serum level. D deficient folks would require 7,000 IU/day for 8 weeks to normalize serum levels (repeat as necessary). In addition, in any trial, compliance is a major issue. Not measuring serum levels means they don't know if folks took the pills. 2. Both cancer and CVD are generally long latency diseases. Reversing/treating diseases in 50 year olds is difficult, especially if they didn't change other behaviors (drinking, smoking, etc.). 3. Even if this was a well-designed study, there are other important outcomes where vitamin D has demonstrated solid results. Wagner et al demonstrated: Achieving 40-60 ng/ml (100-150 nmol/L) blood serum levels: - 59% lower risk of preterm birth - 60% lower risk of preterm birth in twins - Virtually eliminates pre-eclampsia - Supplementing up to 6400 IU/day is safe and effective during pregnancy & lactation -Reduction in many conditions of pregnancy – Gestational diabetes, bacterial vaginosis, post-partum depression -Eliminates racial disparity – In the US the preterm birth rate among African American women is 1.5 times that of Caucasian women
chinamike
Reading this article gave me heart disease and cancer, I am sure. I will continue to consume O3 fat, as it does more than just what is mentioned here; it keeps my skin healthy. Before I took fish oil capsules, a few times a year--Autumn through early Spring--my skin gets itchy and dry. After fish oil, NOPE. Also helps my hair I would think, although I never had a dry hair issue.
marc49
According to this research, vitamin D supplements do not prevent heart disease or cancer. Yet, numerous studies show that regular sun exposure is protective against both diseases. It has been surmised that sun exposure's protective effect is due to the production of vitamin D by the skin. People fail to realize that sunlight also stimulates the production of nitric oxide, serotonin, endorphin, BDNF and other photoproducts that are vital to human health. Nitric oxide is the likely photoproduct that lessens heart disease among people who have high sun exposure. As to cancer, there may not be one single factor, but rather a combination of many factors. Here's what we do know: An Iranian study showed that women who totally avoided sun exposure had 10-times the breast cancer risk as women who were regularly out in the sunlight.
Rusty Harris
Last yearly checkup, asked my doctor about some of these "studies". She said, Fish oil isn't expensive, and until a really long term study is done, it won't hurt to continue taking them. So, I do.
ljaques
I think we can clearly conclude that reading or watching MSM articles and news can cause cancer and heart disease, or at least make you want them. <sigh> The MSM clearly does not know squat about science and it blatantly disregards any cautions in order to sell papers or get eyes on screen. This just adds to all the other data points which prove that we should no longer trust the MSM for anything. In the meantime, I'll continue with doctor-ordered 5000IU of D and a gram of fish oil/omega 3 daily. It can't hurt and my skin likes it.
Mik-Fielding
This does seem like a somewhat flawed study. The first thing that is noticeable that there is no mention of whether they refer to vitamin D2 or D3. If it is the former (the synthetic type), as many studies are based upon then the research is utterly meaningless as vitamin D2 is not very effective for anything and is indeed, toxic in anything but small quantities. As others here have noted, the study would need to be over a much longer period of time to evaluate any results meaningfully as well. Also, it is not a fair conclusion regarding the many other health giving properties of these substances, as it cancer and heart disease is the only markers of their usefulness. This happens far too often with this sort of study which so often appear to be an exercise in convincing people that there is no point in taking them at all, for any reason and therefore best to rely on products that have been produced specifically for whatever by the pharmaceutical companies. I.E. they want to profit from your ailment, so they can't have you medicating yourself, can they?
thurstjo63
Just recently New Atlas was promoting another study that actually showed the dangers of bandwidth that 5G relies on in the millimeter wave (MMW), has been linked to health problems from eye and heart problems to pain and immune system effects and tired to say it was safe!?! Now 2000 units of vitamin D and 1 gram of a generic fish oil which anybody with half a brain knows is very low for any normal sized adult human being (who need a minimum of 4000-8000 units per day) is considered a well designed study!?! Consider the fact that given how polluted the oceans are that only high quality fish oils instead of fish oil from rancid stocks that could lead to a need for higher levels of antioxidants to compensate for it. As well, consider that what is considered the optimal range for humans which means that they have between 50 and 70 ng/ml in their blood they would need to have 10,000 units per day! Note that this was tracked across many outcomes including breast cancer, pain, diabetes by the D*action study run by GrassrootsHealth.