A great hoax has been perpetrated against the public’s health.
A flawed analysis purported that omega-3s somehow cause prostate cancer. The media turned this faulty report into headline news stories.1
One fact that should have immediately discredited this report was that none of the study subjects were apparently taking fish oil supplements, nor were they eating meaningful amounts of cold-water fish.
Not only did the study authors admit they had no idea how the study subjects obtained their omega-3s, but the percentages of plasma omega-3s was so low that men in this study were ingesting insufficient amounts of omega-3s in their diet. 1
How does Life Extension know this? We have been testing omega-3 levels in our members for several years. In a test that measures long-term intake of omega-3s, members who take fish oil capsules score an average of 8.42%.
The authors of this flawed analysis did a short-term measurement of omega-3 plasma levels just one time and then followed the men for up to 9 years. Average plasma readings of 4.48% meant no prostate cancer, but if the level went up a mere fraction—to 4.66%—prostate cancer incidence supposedly soared. 1
The difference in omega-3 content (0.18%) was so trivial that it could not explain the effect on prostate cancer risk. The variance was so tiny that if a man ate salmon the night before, he could have fallen into the higher omega-3 group even if he never ate fish again over the entire multi-year course of the study.
Remarkably, the media proclaimed that 4.66% was a high level of omega-3 whereas 4.48% was a low amount. Both these levels are insufficient to achieve meaningful disease protection. As you’ll read in the meticulous rebuttal starting on the next page, there were other factors that explained why certain men in this study may have had greater prostate cancer incidence.
The media was quick to quote conventional doctors who cautioned against fish oil supplements or even eating omega-3-rich foods based on this flawed analysis. Overlooked was the low plasma levels of omega-3s showing these men were not consuming anywhere near the amounts of omega-3s they would have obtained from cold-water fish or supplements. Also discarded by critics was that a one-time plasma measurement of short-term omega-3 status had nothing to do with what these men ingested over the subsequent 6-9 years.
This may be the first report that seeks to discredit a food/supplement (omega-3s) where the human study subjects were not taking fish oil capsules or ingesting significant amounts of cold-water fish.
The tragedy is that millions of men worldwide may stop eating fish and revert to diets high in saturated fats that have been shown to be involved in the development of atherosclerosis, a leading cause of disability and death in modern societies.
This article represents Life Extension’s initial rebuttal to a spurious attack on omega-3s that was blown out of proportion by the media.
Several scientific studies have found a reduction in prostate cancer associated with increased omega-3 intake. 2-12 A recent report purportedly showed the opposite.1
This report was based on a single blood test of plasma fatty acids in a group of 834 men who were followed up to six years to assess prostate cancer risk (low- and high-grade disease). A smaller group of 75 men was followed up to nine years to assess only high-grade prostate cancer risk.
The results showed that slightly higher omega-3 plasma percentages from this single blood test were associated with a greater risk of low-grade (44%) and high-grade (71%) prostate cancers over the multi-year follow-up.
This report was turned into news stories with headlines blaring “Omega-3 fatty acids may raise prostate cancer risk .”
Omitted from the media frenzy was the fact that this study was not about fish oil supplement users. The authors admitted they did not know how the study participants achieved what turned out to be very low omega-3 plasma percentages in all groups.
In fact, omega-3 plasma levels were only about 40% of what would be expected in health-conscious people taking the proper dose of fish oil.1,13 The insufficient levels of plasma omega-3s in all the study subjects were overlooked by the media. Had these very low plasma levels of omega-3s been recognized, it would have been apparent that this report had no meaning for those who boost their omega-3 consumption through diet and supplements.
Also absent from the reporting was that more men with slightly higher omega-3 plasma levels had confounding risk factors for greater risk of contracting prostate cancer at baseline, such as having higher PSA scores and a positive family history. Although the authors attempted to statistically control for some of these risk factors in their analysis, the concern remains that the baseline data was confounded and therefore the statistical analysis invalid, and that the reported results are compromised by higher rates of preexisting disease along with a genetic predisposition, not because of the minuscule variance in the amount of their plasma omega-3.
Prostate cancer sharply increases by 120 to 180% in men who have a first-degree relative who had contracted prostate cancer. Nearly double the men who contracted prostate cancer in this study had a positive family history, and although the researchers attempted to statistically control for this confounding factor, this fact was conveniently overlooked by the mainstream media as omega-3s were instead labeled the culprit.
Associating a one-time plasma omega-3 reading with long term prostate cancer risk is ludicrous. That’s because plasma omega-3 changes rapidly with short-term dietary changes. It does not reflect long-term incorporation of omega-3 into cells and tissues. In this report, differences in baseline omega-3 blood measures were so trivial that if a man had just one salmon meal the night before, he could have wound up in the “higher” omega-3 group even if he never ingested another omega-3 again.14
Numerous flaws in this report render its findings useless for those who supplement with purified fish oils and follow healthy dietary patterns.
Prostate cancer is a slow-developing malignancy that can take decades to manifest as clinically relevant disease. Commonly recognized risk factors for contracting prostate cancer are diet, body mass, race, family history, hormone status, and age.15,16
An under-recognized risk factor associated with developing prostate cancer is coronary artery disease.17 We at Life Extension long ago observed that men with clogged coronary arteries often developed prostate cancer (and vice versa). A renowned prostate oncologist named Stephen Strum, MD, made a similar observation and established a common factor behind coronary heart disease and prostate cancer, i.e., bone loss.
Coronary artery disease is clearly linked with osteoporosis,18 as lack of vitamin K prevents calcium from binding to bone and instead allows it to infiltrate and harden the arteries. The ensuing bone loss results in the excessive release of bone-derived growth factors that fuel prostate cancer propagation and metastasis.
Long after Dr. Strum published his elaborate correlation, a 2012 study of 6,729 men showed coronary artery disease to be associated with a 35% increased risk of prostate cancer.17
The reason we bring up the connection of heart disease and prostate cancer is that the authors of the controversial study apparently failed to assess overall baseline health status of the study subjects. We initially suspected that men in the higher group of plasma omega-3 (which turned out to be low by our standards) were more likely to have coronary heart disease. That’s because men with heart disease are told by their cardiologists to eat less red meat and more cold-water fish. So it would not be surprising if the plasma percentage of omega-3 was higher in men with prostate cancer as they may have been trying to eat healthier to avoid bypass surgery or a sudden heart attack.
When we asked the authors of the report if they assessed the baseline cardiovascular status of the subjects, their reply was, “No, I don’t believe this to be the case.”
Family History Predisposition
If your father or brother develops prostate cancer, your odds of getting it are about 120 to 180% greater than if you don’t have this family history.19
In the report attacking omega-3s, men who contracted prostate cancer had almost double the proportion of first-degree relatives with a history of prostate cancer compared with controls. Although the study authors apparently attempted to control for this baseline risk factor through the use of statistical modeling of selected variables (multivariate analysis), this confounding factor calls into question much of this report’s negative findings, but was not even mentioned in the media’s rush to create headline grabbers.
Men with a family history of prostate cancer often have witnessed the long-term death spiral that prostate cancer patients suffer through. As a result, they attempt to adapt healthier lifestyles to avoid becoming a victim of their hereditary genes.
Since eating well-done red meat has long been associated with increased prostate cancer risk, men with unfavorable family histories are more likely to include at least some cold-water fish in their diets, and therefore have higher omega-3 percentage plasma levels. This does not mean the marginally higher omega-3 levels observed in this flawed analysis caused their prostate cancer.
This is partially corroborated with the data from the study participants who did not develop prostate cancer, but had higher plasma percentage levels of pro-inflammatory omega-6 fats. This indicated these individuals had little concern about what they ate since they had about half the family history rate of prostate cancer.
Fortunately there may be ways to alter family history genetic predispositions for prostate cancer by eating lots of cruciferous vegetables, maintaining youthful hormone balance, ensuring optimal vitamin D status, and taking compounds that favorably alter gene expression like metformin and curcumin.20-28
Baseline PSA Higher in Those Who Contracted Prostate Cancer
Prostate specific antigen (PSA) is a blood marker of prostate disease.
Standard laboratory reference ranges often allow PSA to reach 4.0 ng/mL before flagging a potential problem. A more progressive view of the PSA is that any number over 2.4 ng/mL should be viewed with suspicion, with a digital rectal exam performed and a follow-up PSA blood test done in three months.
Life Extension has published comprehensive articles about how to properly interpret PSA results, but to state it succinctly: Aging men with PSA readings greater than 2.4 ng/mL are at higher risk for developing clinically relevant prostate cancer and should initiate aggressive steps to reverse the underlying process.
In the report that associated higher omega-3 blood levels with increased prostate cancer incidence, 41.1% of the men who went on to develop prostate cancer had baseline PSA readings greater than 3.0 ng/mL. In the group that did not develop prostate cancer, only 7.3% has a PSA baseline reading greater than 3.0 ng/mL.
Although the study researchers attempted to statistically control for other confounding factors in their analysis like family history, age, and education level, this PSA finding implies that many of the men who developed prostate cancer already had it (pre-existing disease) when the baseline plasma omega-3 level was measured. This finding of 5.6 times more men who developed prostate cancer with a baseline PSA level greater than 3.0 ng/mL compared to the “no cancer” group is impossible to rationally discount. To reiterate, below is the data on the baseline PSA readings from the report the media used to discredit omega-3s:
- 7.3% of the “No Cancer” group had PSA of ≥3.0 ng/mL.
- 41.1% of the “Total Cancer” group had PSA of ≥3.0 ng/mL.
This critical piece of data was ignored in the tabloid-like media articles that erroneously blamed the increase in prostate cancer on omega-3s.