Nose-To-Tail Eating

In my post on ketogenic adaptation, I mentioned that the Inuit were sufficiently aware of the problems of eating excessive lean meat that they even have a name for the condition that effects those who consume only lean rabbits, when other foods are scarce. 

Why should this lean meat consumption be a problem?

Because it leads to high levels of the essential amino acid methionine in the diet.  In the body, this amino acid is used to create cysteine, via the intermediate homocysteine.  The reactions that result in the production of cysteine require vitamin B6 as a cofactor and as a result, lack of vitamin B6 in the diet (and/or excessive muscle protein consumption) results in the inability of the body to drive these conversion processes to completion, thus homocysteine builds up in the body.

All this is bad news as high levels of circulating homocysteine have been implicated in the formation of arteriosclerotic plaques, principally owing to their ability to induce the proliferation of vascular muscle cells, thus enlarging the plaque [1].

In addition, the body uses a considerable quantity of the simplest, non-essential, amino acid glycine in the metabolism of methionine.  This creates issues as glycine  (along with proline and hydroxyproline) is key to the production of collagen.  Unsurprisingly, there have been reported issues of bone fracture [2] (a likely result of there being insufficient substrates to manufacture collagen), associated with diets resulting in high homocysteine levels.

Glycine is also required (along with cysteine and glutamate) to produce glutathione, a key peptide that acts as an anti-oxidant in a number of ways, principally by reacting with dangerous peroxides.

So what is the solution?

Eat a balanced diet – i.e. the whole animal!  Skin, bone and organs have a different amino acid profile to muscle tissue.  Ensure you obtain sufficient glycine by simply eating more parts of the animals you choose to eat already.  As a starter, search online and you’ll find suppliers of bone marrow, or you local butcher will be able to provide you with marrow bones.  Look for organ meats when shopping and make your own pates.  A couple of good books to inspire this holistic approach to food:

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References

1. Sarwar, A. B. et al: Measuring subclinical atherosclerosis: is homocysteine relevant?  Clin Chem Lab Med. 2007;45(12):1667-77.

2. LeBoff, M. S. et al: Homocysteine Levels and Risk of Hip Fracture in Postmenopausal Women.  J Clin Endocrinol Metab. 2009 April; 94(4): 1207–1213.  Published online 2009 January 27. doi:  10.1210/jc.2008-1777

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