Fallos en Estudio que vincula Vit B6,9,12 y cáncer

[EndSFC]

Hola a todos,

Ayer me hicieron sabedor de este estudio que vincula la toma de vitaminas B6 y B12 con un mayor riesgo de cáncer de pulmón en los hombres (no en mujeres).

Bien, he pasado unas horas leyendo el estudio original (lo descargo desde la biblioteca de la facultad de medicina; es de pago):

https://www.ncbi.nlm.nih.gov/pubmed/28829668

Y aunque las fuerzas no me han dado para desgranarlo como quería, he buscado este análisis de un doctor sobre el mismo, y he comprobado que sus aserciones son fidedignas:

https://medium.com/@drrosswalker/vitami ... 60ce5e79d0

(Voy a pegar el texto abajo, por si desapareciese el link)

Parece evidente que es un estudio poco serio, y con una clara intencionalidad. Siendo que el tto. con vitamina B12 es tan común en la EM/SFC, creo de vital importancia aclarar esto.

Siento no tener fuerzas para traducir y realizar mi propio análisis. Sencillamente, os pongo a continuación lo que he contestado a un compañero en Facebook (en inglés) sobre el estudio, además del análisis de sus fallos realizado por un cardiólogo, al que desconozco, pero que como digo, ha elaborado un excelente análisis de este estudio:

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MÍO:
John Gabor , Thanks for the link! I am in the process of reading the FULL paper thoroughly, however I have already verified the points made by the following analysis of this paper (made by a doctor):

https://medium.com/@drrosswalker/vitami ... 60ce5e79d0

He is just right. The paper has many flaws (I'll talk about them soon). But it seems very obvious to me that this study only shows one thing: smoking causes cancer.

There's plenty of evidence showing how high doses of B12 are safe and very useful for many conditions. In addition, as this doctor points out, it would be even reasonable to think that once you have a tumor, enhancing the methylation cycle with these vitamins could make it worse... It would be just too late... However I don't think this is the case either.

Just to add something to this analysis, only a 0.16% of the non-smokers participants of the study got cancer within the 6 years of follow-up, while the 4.44% of those who smoked more than 35 years did develop cancer within this time frame...

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Dr Ross Walker

Vitamin B linked to increased risk of lung cancer
You can imagine my surprise and concern when I read this headline from one of the popular medical websites. Another headline from a different medical website on the same subject stated, “Clear link between heavy vitamin B intake and lung cancer”.

It is very easy to read the abstracts or possibly only the conclusion from an observational trial such as this and make such an outrageous, sensationalist headline.

I have obtained the full paper from the “Journal of Clinical Oncology”. The paper’s title was “Long-term, supplemental, one-carbon metabolism related Vitamin B use in relation to Lung Cancer risk in the Vitamin and Lifestyle Cohort (VITAL)”.

It is important, before you throw away all of your vitamins, to understand exactly the basis of this study. This study began in the year 2000 and involved 77,118 participants aged somewhere between 50 to 76. The participants were followed for an average of 6 years & during this time 808 people developed primary lung cancer of which 331 were men.

At the start of the study, all people were asked to fill in a questionnaire about their smoking habits, alcohol intake, diet and ingestion of Multivitamins over the prior 10 years, before the follow up period. There was no information regarding exercise or sleeping habits nor were any psychologic profiles performed on these participants apart from a rudimentary look at their education.

The basic conclusion of the trial stated there was somewhere between a 30 to 40% increased risk in lung cancer amongst men who took higher doses of the individual supplements, vitamin B6 and vitamin B12. There was no increased risk with folic acid intake, nor was there any association with standard multivitamins.

When I carefully read the entire study, it was clear that there were some significant issues and concerns around linking the sensationalist headlines and the true nature of the study. This is not a criticism of the researchers but rather a criticism of the people who clearly cannot understand science and want to create scaremongering amongst the general public.

Now let’s look at the information that comes from this purely observational trial relying on the ability of each individual in the trial to recall how many vitamins & at what doses they have swallowed over the prior 10 years (hardly particularly accurate science).

Regardless, let’s assume, purely for the sake of the argument that all of the participants in the research trial did accurately report their previous 10 year intake of vitamins. The results of the study suggested the following key points

1) There was no association between higher dose individual B group vitamin intake and lung cancer in women

2) In men who were either current higher dose individual vitamin B6 & B12 users and current or former cigarette smokers, there was a modest increase in lung cancer risk for only the more significantly cigarette-associated lung cancers. Interestingly, in the current or former smokers who used to take high dose individual supplementation of B6 & B12, but were no longer doing so, there was an even higher lung cancer risk.

3) Adeno-carcinoma accounts for 40% of lung cancer and is not always related to cigarette smoking. Interestingly, there was no increase in this form of cancer amongst the former or current smokers who consumed high doses of the individual B group vitamins.

4) There was no association between any vitamin use and lung cancer in the lifelong non-smokers.

So, what should we take from this study? This study actually reminds me of be ATBC trial performed on 29,000 Finnish smokers showing a slight increase in lung cancer in > 20 cigs/day smokers who took synthetic beta-carotene 20 mg daily over the eight years of the study period.

Synthetic vitamins are of much lower quality & have never been shown to have any therapeutic benefit.

To me, the clear message is quite obvious and that is- don’t smoke. If you are a current or former smoker, there is always the potential for a lung tumour to develop. It takes one cancer cell nine years to become 2 cm of tumour and then over the next six months, if not treated, up to 2 kg of tumour may form in your body. If you do have an undetected lung cancer brewing in your body because of your smoking habits, it may be that flogging these early cancerous cells with high doses of B group vitamins could potentially accentuate the growth of these actively mutating cells, which steal high quality nutrients at the expense of your normal cells in people who already have their immunity affected by the very dangerous habit of smoking.

Another important point for those people reading this summary in Australia is that the vast majority of American supplements are made to food standard and often have contaminants, which potentially could interact poorly with the toxins in cigarette smoke. What it says on the side of the bottle is often not what you get in the supplements in the US. Whereas supplements made in Australia are generally made to pharmaceutical grade and are of much better quality.

This particular study was not a randomised controlled trial where each participant received the same standardised B group supplement but was purely based on a questionnaire relying on a person’s memory of the intake of supplements, purchased through their own volition over the past 10 years.

The authors have raised some interesting points but have certainly proven nothing apart from the fact that smoking cigarettes is a lottery and swallowing any form of supplementation will not compensate for this extremely dangerous habit. It was quite interesting that the rates of lung cancer were higher in former users of supplementation rather than the current users. I’m not really sure why this is the case but it also raises some interesting questions.

The bottom line he is very straightforward- don’t smoke & don’t accept a one-line sensationalist headline.