Sushi (2)

Feeling somewhat vindicated for their viewpoints, bacon and butter lovers around the world cheered when a new study reported that saturated fat wasn’t a heart bully after all. (1-3) According to a meta-analysis of six trials published before 1983 in the journal, Open Heart, there exists little evidence to support that saturated fat is associated with cardiovascular disease and all-cause mortality. Their conclusion:

Dietary recommendations were introduced for 220 million US and 56 million UK citizens by 1983, in the absence of supporting evidence from RCTs. (1)

Furthermore, in their discussion, the authors report that the studies for dietary change may more support multiple lifestyle changes verses a cure-all diet for heart health:

Woodhill et al20 made an important observation that men who have suffered an myocardial infarction (MI) subsequently make multiple lifestyle changes (weight loss, smoking cessation, increase in physical activity, for example), which makes them a poor group for testing the lipid hypothesis. In this respect, the reporting of cholesterol decreases in control and intervention groups supports the observation that multiple lifestyle changes are made…

From the literature available, it is clear that at the time dietary advice was introduced, 2467 men had been observed in RCTs. No women had been studied; no primary prevention study had been undertaken; no RCT had tested the dietary fat recommendations; no RCT concluded that dietary guidelines should be introduced. It seems incomprehensible that dietary advice was introduced for 220 million Americans28 and 56 million UK citizens,29 given the contrary results from a small number of unhealthy men. (1)

Another win for fat lovers was the ease of the cholesterol guidelines with the release of the Advisory Report of the 2015 Dietary Guidelines for Americans. The Advisory Committee of the scientific report concluded: (4-6)

Cholesterol. Previously, the Dietary Guidelines for Americans recommended that cholesterol intake be limited to no more than 300 mg/day. The 2015 DGAC will not bring forward this recommendation because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report.2 35 Cholesterol is not a nutrient of concern for overconsumption. (4)

The committee still cautioned against consuming too much saturated fat, opposing the conclusions of recent meta-analysis mentioned. (1,4-6) As the federal government decides how to implement these guidelines for Americans in the future, the public is provided with yet another example of an unfilled hope of a unified dietary consensus.

 

The Fishy Story In The 2015 Guidelines

Fish oil and Mediterranean diets (7-8) that encourage weekly fish consumption have been associated with many health advantages. A recent meta-analysis reported:

The Mediterranean diet was found to be a healthy dietary pattern in terms of morbidity and mortality. By using data from the cohort studies we proposed a literature-based adherence score that can represent an easy tool for the estimation of adherence to the Mediterranean diet also at the individual level. (8)

Furthermore, just recently, the American College of Cardiology reported on the benefits of fish oil on heart health:

Taking omega-3 fatty acids appeared to lower inflammation and guard against further declines in heart function among recent heart attack survivors already receiving optimal standard care, according to results from a randomized, controlled trial to be presented at the American College of Cardiology’s 64th Annual Scientific Session in San Diego. (9)

However, are all fish and fish supplements created equal?

A recent newsletter for a distributor of some the highest-quality wild-caught fish recently brought attention to another controversy in dietary consensus, the fish story. Specifically, should you buy farmed fish or wild-caught fish? This topic introduces the concern for GMOs as well as other issues. Weatherby writes:

Panel fails to note omega-imbalance in farmed seafood

The panel recommended that people get whatever seafood they can find and afford, whether farmed or wild.  But, aside from environmental concerns about fish farming, they dropped the ball on an important nutritional distinction between farmed and wild fish.

They said “farm-raised seafood has as much or more [omega-3] EPA and DHA per serving as wild caught.” 

That is only true for farmed salmon, which typically has a bit more omega-3s than wild salmon … but much higher levels of total fat, saturated fat, and omega-6 fat. The large amount of omega-6 fat in farmed salmon blocks some of the benefit of its omega-3 fat while promoting inflammation. ..(10)

I discussed some of the downfalls in farmed fish in 2011, such as reports of concern of the following excerpted from the same newsletter:

  • They found that while farmed tilapia and catfish contain few omega-3s. They pack more omega-6s than burgers or bacon.
  • This unbalanced “omega-ratio” is proven to promote chronic low-level inflammation and the diseases that flow from it. (See “Farmed Salmon’s Diet Yields Unhealthful Cardiovascular Effects”)
  • Many people seeking omega-3s from seafood don’t know about this nutritional distinction between wild and farmed fish and fall victim to a nutritional bait-and-switch.

Furthermore, another concern I have is that the levels of toxicants in farmed fish seem to be higher than in wild-caught varieties. One journal reports:

Lipid-adjusted contaminant levels were significantly higher in farmed Atlantic salmon than those in wild Pacific salmon (F = 7.27, P = 0.0089 for toxaphene; F = 15.39, P = 0.0002 for dioxin; F > or = 21.31, P < 0.0001 for dieldrin and PCBs, with df = (1.64) for all)…(11)

The presence of these contaminants may reduce the net health benefits derived from the consumption of farmed salmon, despite the presence of the high level of n-3 fatty acids in these fish.

Another study in Environmental Health Perspectives supported this concern:

We reported recently that several organic contaminants occurred at elevated concentrations in farmed Atlantic salmon compared with concentrations of the same contaminants in wild Pacific salmon [Hites et al. Science 303: 226-229 (2004)]. We also found that polychlorinated biphenyls (PCBs), toxaphene, dieldrin, dioxins, and polybrominated diphenyl ethers occurred at higher concentrations in European farm-raised salmon than in farmed salmon from North and South America. Health risks (based on a quantitative cancer risk assessment) associated with consumption of farmed salmon contaminated with PCBs, toxaphene, and dieldrin were higher than risks associated with exposure to the same contaminants in wild salmon. Here we present information on cancer and noncancer health risks of exposure to dioxins in farmed and wild salmon. The analysis is based on a tolerable intake level for dioxin-like compounds established by the World Health Organization and on risk estimates for human exposure to dioxins developed by the U.S. Environmental Protection Agency. Consumption of farmed salmon at relatively low frequencies results in elevated exposure to dioxins and dioxin-like compounds with commensurate elevation in estimates of health risk….(12)

My thoughts:

I think the fewer burdens we put on our bodies in this chemical world we live in, the better. Furthermore, the lack of the consensus of safety on GMOs is another concern.

Finally, another fishy issue is the toxic effects from too much mercury. Here’s some links to fish with lower levels of mercury. (Another tip: make sure your selenium is optimal.)

Read more health news on walking and HIT here.

 Girl on phone

References:

  1. Harcombe Z, Baker JS, Cooper SM, et al. Evidence from randomized controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart 2015; DOI:10.1136/openhrt-2014-000196.
  2. Ward, T. Saturated Fat and CAD: It’s Complicated. theheart.org on Medscape. February 9, 2015. http://www.medscape.com/viewarticle/839360?src=wnl_edit_specol&uac=146852BY#vp_4
  3. O’Riordan. No Evidence to Support Dietary Fat Recommendations, Meta-Analysis Finds. February 12, 2015. http://www.medscape.com/viewarticle/839708?src=wnl_edit_specol&uac=146852BY#vp_2
  4. Part D. Chapter 1: Food and Nutrient Intakes, and Health: Current Status and Trends – Continued. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. February 2015. http://health.gov/dietaryguidelines/2015-scientific-report/06-chapter-1/d1-2.asp
  5. S. Department of Health and Human Services (HHS). Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Accessed at: http://www.health.gov/dietaryguidelines/2015-scientific-report/
  6. S. Department of Health and Human Services (HHS). Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Accessed at: http://www.health.gov/dietaryguidelines/2015-scientific-report/PDFs/02-executive-summary.pdf
  7. Dietary intake of differently fed salmon; the influence on markers of human atherosclerosis. Eur J Clin Invest. 2005 Jan;35(1):52-9. http://www.ncbi.nlm.nih.gov/pubmed/15638820
  8. Sofi F, Macchi C, Abbate R, Gensini GF, Casini A. Mediterranean diet and health status: an updated meta-analysis and a proposal for a literature-based adherence score. Public Health Nutr. 2014 Dec;17(12):2769-82. doi: 10.1017/S1368980013003169. Epub 2013 Nov 29.
  9. American College of Cardiology (ACC). Omega-3 Fatty Acids Appear to Protect Damaged Heart After Heart Attack. March 4, 2015. Accessed at https://www.acc.org/about-acc/press-releases/2015/03/04/16/36/omega-3-fatty-acids-appear-to-protect-damaged-heart-after-heart-attack?w_nav=S
  10. Weatherby, C. Experts’ Advice to U.S. Urges More Seafood. Seafood benefits outweigh the alleged risks, which an expert advisory panel dismissed as very low. Vital Choice Newsletter. March 6, 2015.
  11. Hamilton MC1, Hites RA, Schwager SJ, Foran JA, Knuth BA, Carpenter DO. Lipid composition and contaminants in farmed and wild salmon. Environ Sci Technol. 2005 Nov 15;39(22):8622-9.
  12. Foran JA1, Carpenter DO, Hamilton MC, Knuth BA, Schwager SJ. Risk-based consumption advice for farmed Atlantic and wild Pacific salmon contaminated with dioxins and dioxin-like compounds. Environ Health Perspect. 2005 May;113(5):552-6.