Steve Steeves and Dr. Jaffe Clarify the Fish Oil Controversy: Are they helpful, harmful and what’s going on…
What’s the issue: A team from the academic Fred Hutchinson Cancer Research Centre in Seattle warns us: ‘There is really no evidence that taking dietary supplements is beneficial to health, and there is increasing evidence that taking high doses is harmful.’ In addition, Dr. Kristal says: ‘As we do more and more of these studies – and I have been involved in them most of my career – we find high doses of supplements have no effect or increase the risk of the disease you are trying to prevent.’ … There is not really a single example of where taking a supplement lowers chronic disease risk.’*
Where we agree: We agree on the importance of making clinical and policy decision based on “rational, scientific medicine (and medicines) whose efficacy has been confirmed in impartial, reproducible clinical trials.”
Where we disagree: In this recent trial, Dr Kristal’s team was “unclear to the mechanism Omega 3 fats could cause cancer. It was also not possible to tell for certain whether the elevated blood levels were due to men taking supplements or eating fish rich in omega-3s”. More importantly they do not distinguish sources and forms of omega 3 as we discuss below. They also do not distinguish increases in inactive omega 3 precursors (ALA) and active forms (EPA and DHA).
Scientists like Drs. Kristal are quite selective in the studies they cite and their analysis appears to be incomplete in many ways.
For example, they cite prominently a fatally flawed Finnish study that showed heavy smokers were not benefited and may have been harmed by ‘high dose beta carotene’.
First, using a synthetic ‘work-alike beta carotene’ is not the same as the team of natural carotenoids that are similar molecules with different helpful places in the body where they act. The more of one isolated form that is given the more imbalanced become the body pools of that family of molecules.
Second, the ‘high dose’ used in this study was relative the amounts to avoid deficiency disease (RDA or DVI) and actually low compared to what experienced practitioners use in such high risk people.
The research cited by those who propose harm includes common commercial omega 3 preparations that do not distinguish among the three forms of Omega 3 fats (ALA, EPA, and DHA). In really healthy people, inactive ALA can convert into active EPA. Unwell people convert ALA poorly if at all. Simply knowing that you have taken a mix of active and inactive forms tells little if anything about the benefit or risk of the active forms.
Finally, studies they cite have clear flaws and strong selection bias toward their conclusion while ignoring literature that disagrees and provide weak rather than strong support for the dismissive conclusion they draw.
In sum, when absence of data is confused as data of absence of benefit and used to draw conclusions the issues get confused rather than clarified. Scientists such as and Kristal are so selective in their analysis that they appear to know the answer before they start.
Dr. Kristal seems comfortable standing on the scientific quicksand of design-flawed meta analyses and other observational studies that do not distinguish among the forms of nutrients taken when the same name can refer to natural, standardized, items assayed for activity and lack of toxins or items that are not properly characterized and often either lack activity and/or contain toxins.
When all forms of vitamins, minerals, essential and conditionally essential nutrients are lumped together you get a mix of the helpful and the unhelpful. Often, the most commonly consumed forms are lesser in quality. Most studies start by using only the most common commercial kinds of nutrients… such impure or inactive ingredients PIH would never include or recommend or use in scientific studies.
In addition, those who dismiss supplements without referencing studies that do not support their view appear to fulfilling their own ‘prophecy’. As my grandmother pointed out, when we look only at the bathwater (of work-a-like nutrients that don’t work and may harm) we may throw out the baby (of safer, effective nutrients that do help)! (Dr. Jaffe)