Sunday, January 28, 2018

A Beef with Beans






I saw the above graphic on Facebook and decided to reality check it.

By reality check, I am making no observations on the merits of a particular dietary regime, just looking at the presented data from a scientific point of view.

I am interested in whether it is accurate and whether it is fair.

My source of data is the US Department of Agriculture’s on-line database.

General: 
It is not immediately clear to the reader than the data refers to the raw product, not the as-consumed product.  I will compare raw with raw but be aware that cooking raises the meat constituents due to moisture and fat loss and lowers the bean’s constituents due to water uptake.

Protein.
Both claim 22% protein.  The only beef I could find with 22% protein was trimmed tenderloin with only ~6% fat.   All other beef cuts have less than 20% protein.  The portrayed cut of meat looks to be about 20% fat so will only have about 16-17% protein.

Red Kidney Beans have slightly more than 22% protein - most results in the 22-24% range.

So the graphic has over reported beef and under reported beans.  Not sure why but not dramatically so.

Fibre.
Spot on.  Nil in beef, about 15g in the raw beans.

Minerals : Iron, Calcium & Magnesium.
The results reported for beef are pretty much the average results expected,  the middle of the typical range.

The results reported for the red beans are all pretty much from the top end of the typical range.  A little sneaky with this.

There is a more significant problem though.  My first thought in reading this was why don’t dieticians recommend beans to people who are anaemic?  It is usually ‘red meat and/or green leafy vegetables’.  A little reading finds that the minerals, especially iron, in beans are not bioavailable.   

Only about 2% is retained by the body. 

So the value is accurate.  But misleading. 

Cholesterol.
No issues here.  But dietary cholesterol is not considered a necessarily bad thing any more.

Water
Without a doubt water is a big issue in all areas of agriculture.  As far as I can tell the 1,480 litre figure comes from housed cattle, fed on grain.  It will be high for all farming practices but this may be a top-tier estimate.  No-one seems to report the water needs of cattle in outback Queensland.

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A few things were omitted that really should be included.

Saturated Fat.
Beef has quite high saturated fat levels and this is considered the chief culprit in blood cholesterol level, not the dietary cholesterol.  Beans have none and their fibre helps lower what is already there.

Vitamin B12
Beef provides the essential vitamin, B12.  Beans do not.

Selenium.
Beef is a good source of the mineral Selenium compared to beans.  Mind you Brazil Nuts trump everything on the Selenium front.

Contaminants.
Both beef and beans are open to contamination.  Beans from pesticides, herbicides and beef from hormones and veterinary products.

Land Use.
Brazil is the third largest bean producer (after Myanmar and India) and growing.  Where is the farmland coming from?   There is also the issue of land exhaustion.  Do they rotate crops or just keep adding fertilizers?  Is the production of fertilizer included in the water budget, I wonder?

Conclusion.
There is a confirmation bias displayed in the data presented in the graphic.


1 comment:

Moderation cuts in six days after posting.