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Posts Tagged ‘Environment’

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Hold on to your hats folks, this is not good news…

Monday, July 11th, 2011

Kulkarni et al., Popul Health Metr. 2011

Over the years, the life expectancy of an adult in the US has increased dramatically. It is almost a law of nature that with advances in medicine, nutrition, and public health (vaccinations, etc.) life expectancy increases over time. A decrease in life expectancy is a sign of something going seriously wrong.

The figure above is from a recently published paper titled, “Falling behind: life expectancy in US counties from 2000 to 2007 in an international context.” It shows changes in life expectancy for women from 1987 to 2007. You will note from the figure legend that the red on this map depicts counties in which the change was less than zero. That means that the life expectancy of women in those counties has decreased over the past two decades.

This comes on the heels of a report from the Robert Wood Johnson Foundation titled, “F as in fat: How obesity threatens America’s future.” Here are a few tidbits:

  • Colorado is the only state with an obesity rate below 20% (coming in at 19.8%)
  • A state at 19.8% obesity would have had the highest rate in 1995
  • No state has had a decline in the rate of obesity
  • Over the past 15 years, rates of obesity have doubled in seven states and rates of diabetes have doubled in 10 states

We are experiencing a crisis – and we need to make some changes. There will be no single solution, rather we will have to change our behaviors, policies, environments, practices, etc.

What are you going to change today?

“Finishing” Cattle – 3 Thoughts for the Day

Thursday, July 7th, 2011

The National Cattlemen’s (do they not recognize women ranchers yet?) Beef Association provides a fact sheet on finishing cattle on feedlots on their website. So, what is “finishing” you might ask? This is what they have to say on the matter:

“Cattle are raised on range or pasture land for most of their lives (usually 12-18 months), then transported to a feedlot for finishing. These cattle usually spend about three to six months in a feedlot, during which time they gain between 2.5 and 4 pounds per day. The cattle are fed a scientifically formulated ration that averages 70 percent to 90 percent grain. On this special diet, cattle will gain about 1 pound for every 6 pounds of feed they consume.”

So, the cattle are moved from pasture to a feedlot and are fed grain to rapidly gain weight. “Finishing,” therefore means “fattening up.”

Thought #1: Eating a bunch of grain seems like a good way to gain weight (for cows, at least, who are actually better equipped than humans to digest grains).

But, how can feeding grain to cows be more profitable than letting them eat grass?

Another quote from the fact sheet: “The abundance of feed corn in this country contributes to the economic viability of producing grain-fed cattle. In fact, it will often cost more to raise cattle on pasture because it takes longer for the animal to reach market weight. That is why grass-finished beef can be more expensive than grain-fed product.”

Thought #2: Grains result in rapid weight gain and economic subsidies keep grains cheap and plentiful (not only for cows folks).

So, does finishing cattle on grain simply result in more meat, or are there other differences between grass-fed and grain-fed beef?

To answer this question, we go to a recent scientific review (note: the entire paper is available free of charge) of the fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. First, the abstract of the paper (emphasis added):

“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.”

Another telling finding is the last column in Table 2 of this paper, which summarizes the differences in the omega-6 to omega-3 fatty acid ratios across the studies reviewed.

Table_2_-_mod

Here, what you see in each case, is a significantly lower ratio (which is what you want) of omega-6 (less desirable) to omega-3 (more desirable) fatty acids when the animals are raised on a grass-based diet as compared to grain. So, it does appear that a grain-based diet makes a difference in both the quantity (i.e., greater weight) and the quality (i.e., lower quality) of beef as compared to a grass-based diet.

Thought #3: I don’t want to be “finished off,” thank you very much. So, I think I will be avoiding the grains that so rapidly pack on the pounds for our bovine friends. I also want to eat the healthiest types of meat that I can. For that, I will be choosing grass-fed beef whenever possible.

“Eat Less and Exercise More” is Not Good Enough

Monday, June 27th, 2011

Nejm_figure

(Mozaffarian et al., NEJM 2011)

There is a recent paper out in the New England Journal of Medicine in which the investigators examined relationships between diet, behaviors, and weight over time frames of 10-20 years in over 120,000 adults in the US. The investigators found that people gained an average of 3.35 pounds every four years and that weight gain was significantly associated with higher consumption of potato chips, potatoes, sugar-sweetened beverages, unprocessed red meats, and processed meats (see figure above). Weight gain was inversely associated (less weight gain with greater consumption) with consumption of vegetables, whole grains, fruits, nuts, and yogurt.

So, you might be asking yourself – what’s the big deal? How did this paper get into a top-tier journal by confirming what we all already know – that chips and soda are bad for you and fruits and vegetables are good for you? Well, here are a few additional findings and speculations that I think make the paper more interesting than the “potato chip findings” that have been grabbing the headlines.

One of the strengths of this type of work is that the authors have looked at data for a huge number of people. This increases the likelihood that the findings have external validity or that they will be generalizable to the population at large. However, a limitation to this type of study (observational, not interventional or controlled) is that we can only make correlational inferences or talk about “associations” and not “causes.”

“You want fries with that?”

What is the “that?” It might be the case that certain types of foods are more likely to be eaten together (think burger and fries). The authors reported that there were only a few correlations between food types. For example, people more likely to eat vegetables were also more likely to eat fruit. Likewise, people more likely to eat unprocessed red meat were also more likely to eat processed meats. And, people more likely to consume low-fat dairy were less likely to consume high-fat dairy. These sorts of findings seem to make sense, probably because we largely recognize that meat of one type can often substitute for meat of another type and that dairy of one type can often substitute for dairy of another type. Less clear, however, is which foods might be serving as economic complements. The consumption of a complement is typically tied to something else. For example, you probably eat very few hot dog buns in the absence of hot dogs – the bun is an economic complement. This brings us back to the question of whether you want fries with that and what is the “that?” Chips and fries often accompany burgers, sandwiches, and sodas. Chips make people thirsty and I rarely see chips paired with water, coffee, tea, or milk. So, perhaps what we’re looking at here is clusters of foods or behaviors.

Another way to think about this is to ask yourself what percentage of chips or fries that you have eaten did you make yourself at home? It is likely that fries are often associated with eating on-the-go and chips are often associated with convenience stores and impulse purchases. True, the chips and fries don’t help, but they alone are not the entire story.

So, where do we go from here? It’s an interesting exercise to think about what foods and behaviors in your life tend to be complements or are associated with each other. It is also interesting to think about foods and behaviors that you might be able to substitute for one another to help you achieve your goals (e.g., a piece or fruit or yogurt in place of a sweet or dessert). If certain foods and behaviors are clustered together, a couple of initial substituions could help the whole house of cards begin to fall…  

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