Omega-3’s: Are You Getting Enough?

The good people at Earth Balance’s Made Just Right blog ran an article by me on omega-3s:

Omega-3’s: Are You Getting Enough?

There’s no new information here, but it might be my most concise attempt at explaining the omega-3 conundrum.

6 Responses to “Omega-3’s: Are You Getting Enough?”

  1. Jacob Dijkstra, M.D. Says:

    Considering the article below, it is prudent to be careful with taking DHA supplements.

    Serum Phospholipid Fatty Acids and Prostate Cancer Risk: Results From the Prostate Cancer Prevention Trial

    Theodore M. Brasky*,
    Cathee Till,
    Emily White,
    Marian L. Neuhouser,
    Xiaoling Song,
    Phyllis Goodman,
    Ian M. Thompson,
    Irena B. King,
    Demetrius Albanes and
    Alan R. Kristal
    *↵Correspondence to Dr. Theodore M. Brasky, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M4-B402, Seattle, WA 98109-1024 (e-mail: tbrasky@fhcrc.org).
    Received October 12, 2010.
    Accepted January 19, 2011.
    Abstract

    Inflammation may be involved in prostate cancer development and progression. This study examined the associations between inflammation-related phospholipid fatty acids and the 7-year-period prevalence of prostate cancer in a nested case-control analysis of participants, aged 55–84 years, in the Prostate Cancer Prevention Trial during 1994–2003. Cases (n = 1,658) were frequency matched to controls (n = 1,803) on age, treatment, and prostate cancer family history. Phospholipid fatty acids were extracted from serum, and concentrations of ω-3, ω-6, and trans-fatty acids (TFAs) were expressed as proportions of the total. Logistic regression models estimated odds ratios and 95% confidence intervals of associations of fatty acids with prostate cancer by grade. No fatty acids were associated with low-grade prostate cancer risk. Docosahexaenoic acid was positively associated with high-grade disease (quartile 4 vs. 1: odds ratio (OR) = 2.50, 95% confidence interval (CI): 1.34, 4.65); TFA 18:1 and TFA 18:2 were linearly and inversely associated with risk of high-grade prostate cancer (quartile 4 vs. 1: TFA 18:1, OR = 0.55, 95% CI: 0.30, 0.98; TFA 18:2, OR = 0.48, 95% CI: 0.27, 0.84). The study findings are contrary to those expected from the pro- and antiinflammatory effects of these fatty acids and suggest a greater complexity of effects of these nutrients with regard to prostate cancer risk.

  2. Jack Norris RD Says:

    Jacob,

    Thanks for passing that article on. I would think that DHA levels would be a marker for fish intake. And given that fish often contains mercury and other heavy metals which could promote cancer, I’m wondering if DHA is just a marker rather than a cause. Do you know if they controlled for fish intake (I lazily ask rather than getting a copy of the study myself).

  3. Jacob Dijkstra, M.D. Says:

    Your point is very well taken and is an example of why I get sometimes very frustrated by the results of many of these epidemiological studies. There are often too many variables. For instance, you open up a can of worms by proposing that fish consumption could be a potential cause for cancer. It could be a good study (comparing cancer rates in fish eaters and non-fish eaters), unless you already have this information, in which case I would appreciate the reference. My concern has to do with the various studies in which short chain FA, and in the above study long chain FA, have been associated with a more aggressive form of prostate cancer, although not necessarily with an increased rate of prostate cancer.

  4. Jack Norris RD Says:

    > It could be a good study (comparing cancer rates in fish eaters and non-fish eaters), unless you already have this information, in which case I would appreciate the reference.

    Now that I think about it, it’s actually the opposite of what I suggested. Fish-eaters have been shown to have lower levels of cancer than regular meat-eaters: http://veganhealth.org/articles/cancer#gencan

    > been associated with a more aggressive form of prostate cancer, although not necessarily with an increased rate of prostate cancer.

    This is another thing that seems very strange. How can it be one and not the other?

    Associating the amount of particular fatty acids in the diet or blood with disease is a really tough game. There are enough fatty acids and enough measurements that you are bound to get positive findings due to random chance (I would think). And why would DHA cause an aggressive form of prostate cancer? Who knows – maybe it does. Clinical trails do not seem unrealistic in helping to answer this particular question about DHA and prostate cancer.

  5. Scott Says:

    As a vegan, my dr says I’m not getting enough omega 3 and suggested I talk krill oil which I am reluctant since its contains fish. What are your thoughts on Krill Oil and do I have any other options.

  6. Jack Norris RD Says:

    Scott,

    Here are my thoughts on omega-3s and vegetarian diets:

    http://jacknorrisrd.com/?p=3023

Leave a Reply