Review: fatty acid profiles and antioxidant content in grass-fed and grain-fed beef.

[Darryl Shaw]

A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef.

Abstract

Growing consumer interest in grass-fed beef products has raised a number of questions with regard to the perceived differences in nutritional quality between grass-fed and grain-fed cattle. Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries. Fat conscious consumers will also prefer the overall lower fat content of a grass-fed beef product. However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A). It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.

http://www.nutritionj.com/content/9/1/10

See also:

Effects of conventional and grass-feeding systems on the nutrient composition of beef. (http://jas.fass.org/cgi/content/full/86/12/3575)

Fatty acid analysis of wild ruminant tissues: evolutionary implications for reducing diet-related chronic disease. (http://www.nature.com/ejcn/journal/v56/n3/pdf/1601307a.pdf)

[Paul Epstein]

thanks for the article. provides a good summary of the non-ethics benefits of grassfed beef.

However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A).

is this supposed to be a negative? i have never tasted a distinctive grass flavour in grass fed beef although it definitely has a unique flavour which almost everyone i know seems to prefer.

although i would hazard that grassfed is more the norm around here and i probably grew up on it.

It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.

not sure what this means?

[Arien Malec]

It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.

not sure what this means?

Grass-fed has a higher % of fat that is n-3 and CLA, but grain fed has more fat overall. There may be no difference in the actual amount of both consumed between grass and grain fed.

Another example of the same thing: If a bag of balls has 50% red balls and another bag has only 25% red balls but twice the overall number of balls, they both have the same number of red balls.

If you care about the ratio of n-3/n-6 and CLA/total fat, grass fed is better. If you think the absolute amount of n-3 and CLA consumption is more important, there may be no big difference.

Clear?

[Paul Epstein]

thanks.

i didnt realise there was debate about total quantity vs ratio. ive always beleived the ratio was the important part...(assuming you are getting enough total fats)...

[Steven Low]

The problem is the ratios are what matter for o3/o6, so the screwed up grain fed portions are actually POOR QUALITY compared to grass fed.

But of course you can't put that conclusion in a paper because the factory farms are probably paying for it

[Paul Epstein]

the article seems overwhelmingly positive to grassfed. the parts i quoted above seem like a poor attempt to add some ballance to the article (talking about flavour and cooking methods)

factory farms dont need to bias scientific papers because they have what the majority of consumers seek, cheap product :D

[Chad Cilli]

Little known factoid.... People from foreign countries actually seem to prefer our grain fed beef. I worked for a company that did international business, and I was quite often told that our beef tasted better. And have even heard people comment that the beef tastes better in America because it is grain fed.

I think much like how 85% lean beef tastes better than 95% lean beef (to some people at least) the increased fat content actually enhances the flavor. Just my 2 cent observation, but perhaps that's why that was put into the article.

In any case, it still comes down to omega 3 : 6 balance. The balance is more important than some arbitrary number of grams of omega 3.