Are We Consuming Enough Omega-3 Fatty Acids In Our Diet?

Published at: 04:12 pm - Thursday December 17 2009

Are we consuming enough Omega 3 Fatty Acids in our diet?

This is a two part question:

  1. We need to know our current dietary intake of Omega-3s
  2. We need to know if our Omega-3/Omega-6 ratio is correct.

Current Dietary Intake of Omega-3s

In 2004 the Agency for Healthcare Research & Quality contracted Tufts-New England Medical Center to perform a comprehensive examination of two representative samples of the American population. The results are as follows:

fish1

fish2

Interestingly, Tufts observed that only 25% of the first sample reported any amount of daily EPA or DHA intake, indicating an enormous skew.

The study concludes:

  1. Men consume significantly less ALA than women.
  2. Adults consume more ALA than youths.
  3. Subjects with a history of CVD (cardiovascular disease) consume less ALA than those without CVD.
  4. People who had a Poverty Index Ratio index (PIR) of 1.3 consumed less ALA and LA than people who had a PIR >1.3.
  5. Non-Hispanic whites, non-Hispanic blacks, and Mexican Americans all had a significantly higher intake of both ALA and LA compared to other groups.

Another study published in the American Journal of Clinical Nutrition examined over 33,000 men who had benign prostate enlargement between 1986-1994. This study found the following:

fish3

Please note that these data are given by quintile, not mean (average). The circled numbers are the 3rd quintile (60%). This is likely higher than the mean in this case.

Taken together, we have the following data:

Average American Omega-3 Intake (AJCN depicts 3rd Quintile)

NHANES Data

CSFII Data

AJCN Data
ALA (mg)

1330

1300

1010
EPA (mg)

40

28

70
DHA (mg)

70

57

130

Omega-3/Omega-6 Ratio

Rather than looking at minimum dietary intake of Omega-3s, scientists recommend examining the ratio of Omega-6s to Omega-3s in our diets. This is because the two polyunsaturated fatty acids work synergistically to control many metabolic processes. It has been suggested that humans have evolved on a diet of 1:1 Omega-6s to Omega-3s. The above data yields a ratio of 9:1 to 10:1 Omega-6s to Omega-3s. A very high omega-6/omega-3 ratio promotes the pathogenesis of many diseases, including cardiovascular disease, cancer, inflammatory and autoimmune diseases. On the other hand a low omega-6/omega-3 ratio exerts suppressive effects. Most research today indicates that ratios between 2:1 to 5:1 exert the most suppressive effects, depending on the disease in question.

Sources

  1. Agency for Healthcare Research and Quality. Evidence Report/Technology Assessment Number 94. “Effects of Omega-3 Fatty Acids on Cardiovascular Disease” (http://www.ahrq.gov/downloads/pub/evidence/pdf/o3cardio/o3cardio.pdf)
  2. American Journal Clinical Nutrition 2002;75:689–97 (http://www.ajcn.org/cgi/reprint/75/4/689.pdf)
  3. Biomed Pharmacother. 2002 Oct;56(8):365-79 (http://www.ncbi.nlm.nih.gov/pubmed/12442909)
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