“Multivitamins”. What are they?
August 5. 2024
“Multivitamins have no effect”, “Multivitamins do not prolong life”, Multivitamins are a waste of money” and other similar headlines we have now seen in the past weeks in various
Danish newspapers and other media.
The observational study
All these headlines are based on an observational study from the United States that has been published June 26. this year.
An observational study is a study in which researchers “observe” different data, such as cohort studies and cross-sectional studies.
Observational studies are a relatively cheap research method because they do not require an intervention into the behavior of an experimental group. More simply, they involve observing how the selected data are distributed in relation to a certain behaviour such as taking a supplement and a certain outcome such as quality of life or mortality.
In the current study (Multivitamin use and mortality risk in 3 prospective US cohorts, JAMA Network Open. 2024;7(6):e2418729), data from three such observational studies were used. From the data, it was concluded that there is no significant effect of multivitamin use on life expectancy, which is the factor that has been focused on in the study.
Strangely enough, the focus is on life expectancy even though the authors themselves write in the introduction that the population’s motivation for taking multivitamins is to prevent disease.
But the incidence of disease does not appear in the data we see presented in the article in JAMA (Journal of the American Medical Association). The authors focus only on the length of life. They actually use the word mortality, but it is rather meaningless, since the mortality is approx.100% for us humans.
The investigation has been heavily hyped by the mainstream media, so we have to take it seriously., We need to clear away the worst misunderstandings.
The strange thing is that if this study had shown that multivitamins were healthy and good for us, it would not have been accepted for publication precisely because it was an observational study. Because such observational studies rank low on the scale of evidence in scientific studies.
The reason is that observational studies have quite a few sources of error, sources of bias. The data in the study come from people themselves, who have answered the questions that the researchers have asked. Moreover, the study is neither half, nor fully or double blinded, so it requires extreme objectivity from researchers. But for now, let’s ignore study quality, bias and the usual researcher bias when we talk about vitamins.
Let’s look at what these “multivitamin pills” really are.
When I write like that, it’s because these standard multivitamin pills from the supermarket are also not my cup of tea. Most multivitamin pills contain a wide range of vitamins and minerals, typically 100% of the recommended daily dose, in Denmark also called the RI (reference intake). This RI dose is far too small for some substances (vitamin C, vitamin D, selenium, etc.), while, especially for iron, it is far too large. Other ”multivitamins contain largely unabsorbable salts of some of the substances (magnesium, selenium etc.)
Briefly about iron
Those who have heard my lectures for the past 30 years also know that you should not buy vitamin pills with iron, unless you have been diagnosed with iron deficiency or are pregnant in the last trimester.
The body normally loses about 2 mg of iron per day. Since most multivitamin pills contain about 14 mg of iron, there is a theoretical net surplus of 12 mg of iron each day. And this iron accumulates in a protein, the phase reactant ferritin.
In this way, over the years, simply by taking multivitamin pills, you can build up a supply of iron in this ferritin. Iron is one of the most powerful catalysts for the formation of free radicals (ROS), which, in excess, can cause great damage to cell membranes and DNA in particular.
If a small child is brought to the emergency room because he has eaten a whole jar of ordinary multivitamin pills from the supermarket, then the doctor worries primarily about one thing; it is the intake of the large amount of iron.
Iron is easy and quick to raise the level in the body if you lack it, but incredibly difficult to get rid of if you have have too much. It must be done with intravenous treatment with substances such as Desferoxamine or EDTA, both of which bind iron. But it is difficult and slow. The age-old bloodletting method is almost faster.
Serum Ferritin is an important marker, and if it is above 200 µg/l, there is an increased risk of cardiac vascular diseases and cancer. So you have to be careful with iron. It is a double-edged sword.
Summa summarum: Never take multivitamin pills with iron, unless you have been diagnosed with iron deficiency in the form of low S-Ferritin.
Back to the study
When you consider that a cohort of people has been taking these multivitamin pills for years, then you suspect that they have obtained both good and bad ingredients. Honestly, it is completely impossible to come up with a qualified assessment when you (and the researchers) really have no idea what the people answering questionnaires have consumed.
I could easily formulate a multivitamin pill that mainly has a negative effect on the body. The pill will be cheap. With sufficient advertising money, it would probably be sold by the large supermarket chains, which look at price, discounts and shelf life.
I could use sodium selenite as the selenium. It is quite cheap, and I could declare it as selenium. It just that it’s hardly absorbed into the body. So the effect that can halve the incidence of heart disease and death, well, it will not occur.
I could use chromium chloride as chromium. It is quite cheap, but it is also quite inactive in comparison to chromium yeast, in which chromium chloride is converted to GTF chromium (glucose tolerance factor), which stabilizes blood sugar. Chromium chloride does not have this effect, but can be declared as chromium on the packaging, and then most people think that they get enough.
Every single one of the ingredients found in multivitamin pills can be declared in this way, even if the ingredient is in a (often cheap) form that has no positive biological effect. As I wrote above, you can easily construct a very cheap pill with a fine declaration, but without any kind of positive effect.
This is not to say that there are only such “junk pills” in the study. I just want to illustrate that when you have not defined the quality or content of what the study participants have actually eaten, it is more than difficult to form an overview of something as varied as the term “multivitamin pills”.
And when the product being studied is not a well-defined product, it is, to put it mildly, frivolous to conclude anything health related from the given data, and the authors are content with concluding, that they saw no difference in mortality risk in the two groups.
Let me end by saying that vitamins and minerals rarely help anything.
– You just mustn’t lack them.
The most important thing is, of course, a healthy diet, and where this fails in terms of content, you should supplement with vitamins and minerals of good quality.
Take care of yourself and others.
Claus Hancke
Specialist in general medicine