Nutrition Miscellany: 10/4/09

Beef: Consider the Source...

Men's Health has an interesting post over the "world's most powerful eating strategies". In an earlier post I argued that what animals eat makes a significant difference in the nutrition characteristics of their meat or products (e.g., eggs). Phillip Rhodes points out that Argentinians eat on average over 30 lbs. more a year in beef, a favorite whipping boy of establishment nutritionists, without any increased risk of heart disease. What accounts for the difference? A quarter-pound of conventionally finished American beef has over four times the saturated fat and twice the calories of a grass-fed Argentinian beef patty (140 calories, 2.5 grams of saturated fat). I mentioned in earlier posts that grass-fed beef also has a more balanced Omega-6 to Omega-3 PUFA ratio and higher amounts of CLA, a "good" type of natural trans fat. There are some online sources of American grass-fed beef (e.g., U.S. Wellness Meats). [NOTE: I have not ordered shipped items from relevant vendors.]

The China Study?

I have not personally read T. Colin Campbell's 2005 study, which purports to provide an empirical foundation for a preferred vegan diet based on extensive empirical data, based in China. I'm an omnivore and proud of it (some of my favorite foods are plant-based...) and will reserve substantive comments for my own review.

[I once was criticized by one of my mentor professors in undergraduate school for relying too much on secondary sources. I also discovered that in the process of developing a documentation measure that there were issues with a widely respected and used computer user satisfaction measure in my interdisciplinary academic field (management information systems). I decided to read the original dissertation, initially intending to look at its methodology as a potential model for my own approach; on closer investigation, I soon found myself with serious doubts about the reference measure (statistical tests, deviations from scale development in the applied psychology literature, etc.) and abandoned the author's approach. A few years later, I tried to publish my criticisms of this and other MIS measures and their utilization in the literature (in fact, I was unaware of any other academic raising these issues, and I simply wanted to open a serious debate before other researchers continued to crank out research using suspect measures). My article was rejected in personal terms with predictable criticisms, e.g., why didn't I submit my own user satisfaction measure? In hindsight, it was not surprising that the editor would farm out the article to reviewers with a vested interest in the criticized measures.]

You might think this would make me sympathetic to Professor Campbell; after all, the vegan lifestyle (no meat, fish or dairy) is not widely followed and challenges a more conventional American diet. And there are some noteworthy developments, like middle-class Asians eating a more Western diet and developing similar health issues. My intuition, though, tells me that blaming meat and dairy is a red herring, especially given the fact that recent domestic health trends have not been accompanied by commensurate increases in the consumption of meat and dairy; I would also like to see more evidence of a suspect, implied zero-sum relationship with the consumption of vegetables and fruits. I suspect that there are issues with the nature and extent of carbohydrate and fat intakes, in particular, an unbalanced amount of n-6 PUFA's and trans fats, the nature of animal feeds and more prevalence of fast foods, processed foods, and refined carbohydrates. I also wonder, in the process of presenting a case for a vegan lifestyle, whether Dr. Campbell sufficiently addressed known issues related with a vegetarian or vegan lifestyle. (In fact, one of my nieces adopted a more vegetarian lifestyle before abandoning it.) There are other anecdotal observations as well, for example, Asian-Americans (including females) towering over their parents (suggesting nutritional factors).

One of my favorite pastimes during my academic career was to go around the college bookstore, shelf-reading, particularly for research methodology texts being used in other disciplines. In an analogous way, one of the things I might do with a book like Colin Campbell's is to look at the reader reviews on Amazon.com's website. I wasn't so much interested in enthusiastic readers saying how reading the book changed their lives and their views on food, but in the readers whom DISAGREED with him--and not in personal terms, but for very specific reasons. For example, there's a criticism that Campbell makes a case against a specific milk protein (casein) but doesn't examine counterbalancing effects of other milk proteins. Another notes that Campbell is the co-author of a China-based article pointing out beneficial effects of fish/fish oil, but this (among other studies) doesn't fit in with his book's pro-vegan slant. A third criticism is Dr. Campbell's tendency to jump to other broad generalizations that simply aren't true, such as the assertion that folate is exclusively available from plant sources (versus, say, organ meat). Chris Masterjohn provides a good summary of criticisms against Campbell's book and replies to Campbell's response. [I was not favorably impressed with Campbell's use of ad hominem arguments. Furthermore, I am troubled by Campbell's relationship with certain special-interest groups; a scientist must be impartial in fact and appearance.]

Turkey Legs!

I LOVE turkey; it's more than just a holiday food to me. And in that recurring holiday debate: I prefer dark meat (the color is due to higher levels of myoglobin, which facilitates oxygen transport) to white meat; being the oldest of seven growing up, I usually lucked out in getting one of the drumsticks. Later, in fact, the mother-in-law to one of my sisters was going around a few years back with a camcorder, catching me right in the middle of chomping down on a turkey leg and asking how I liked it (now THAT'S a flattering picture I won't post in my blog anytime soon...)

Carolyn Kylstra, in Men's Health post entitled "6 Power Foods You Should Be Eating", points out poultry dark meat stimulates production of the hormone cholecystokinin (CCK), which promotes a feeling of satiety, has only modestly higher calories per ounce (approximately 8) over white meat, and only about 15% of the saturated fat, which accounts for a third of total fat, is the "bad" kind.

Dr. Fernstrom points out ostriches bear only relatively low-calorie dark meat. Not to mention: "compared with white meat, [dark meat] contains more iron, zinc, riboflavin, thiamine and vitamins B6 and B12."

These facts (including, as I mentioned in a past post, the fact that egg yolks contain a lion's share of nutrients) point out the danger in blindly following conventional nutritional heuristics (e.g., low-fat/low-cholesterol) white meat, nonfat milk products or egg whites: Consider more of a "whole foods" approach and limit your portions.