A new study discovered some very unexpected and consequently extremely interesting findings. Examining the hearts of runners who had completed 25 or more marathons in the past 25 years, investigators found that the marathon runners’ coronary arteries were much more calcified than other people. This was the opposite of what was expected. Also, the people in the comparison group were not all healthy, some having the test to evaluate symptoms suggestive of heart disease. That fact would imply that the runners’ hearts should be WAY better then the comparison group. What’s the deal? Maybe too much stress on the heart? Other studies have shown that competitive endurance athletes are more prone to long term electrical disturbances of the heart. Some have shown chemical changes as we see with heart attacks following triathlons. While those chemical changes appear to not indicate meaningful heart damage, maybe this is an indication that pushing ourselves too much can be harmful. Seems common sense but then common sense is far from common.
Archive for March, 2010
Marathon weirdness
Tuesday, March 30th, 2010Fish Oil Addendun
Wednesday, March 3rd, 2010The testing results used on the fish oil lawsuit I mentioned are posted on fishoilsaety.com. Interestingly, the oils they tested are not the usual fish oils. One problematic oil was, as I anticipated, a salmon oil. Shark liver oil was a problem and several cod liver oils were also a problem.
My apologies to those of you who love cod liver oil but, adding to the concerns about adverse effects from the vitamin A in cod liver oil, now we have this.
Fish Oil Facts
Wednesday, March 3rd, 2010There are some articles appearing just now about a lawsuit claiming some big chains are selling PCB contaminated fish oil. This is interesting. Years ago I strongly urged patients to make sure that any fish oil they purchased had been tested for purity.
My rationale was concern over mercury, PCBs and other toxins. As we had evidence of growing mercury levels in people, particularly in San Francisco and New York City with both dioxins and PCBs were showing up in farm raised salmon, this seemed to be a likely problem. Then a couple of reliable independent labs (most notably ConsumerLabs.com in 2008) tested almost 70 different fish oils sold in stores and published the results.
What did they find? They found that none of the oils, including some sold by companies accused in this current lawsuit, had detectable levels of any toxins. They did find that a few did not have as much omega-3 oils as they claimed or that the capsules fell apart too easily.
There were a couple of reasons why my expectations were wrong. First, although farm-raised salmon had shown evidence of contamination, salmon was not being used for oils. Second, mercury is not very fat soluble and so is not concentrated in oil.
What is up now? Is something different? Are the fish different? As salmon oil has become a popular form of fish oil maybe my old concerns are becoming reality? Are the same fish being used (typically sardines, anchovies and mackerel) but now more laden with toxins? Was there something odd about the testing, either now or then? If it has to do with the testing, it would most likely be an issue with the current batch as the prior testing was performed by two different labs not a single lab as now.
We will all have to stay tuned to learn the answers.
Best
Michael Carlston, MD
