Rusty conclusions about iron deficiency

Iron deficiency anaemia is a big problem. WHO estimates that about 2 billion people — that’s roughly one in three — lack enough iron in the diet. And the consequences are grave for health and the economies of developing countries. So of course people are focused on ways to combat iron deficiency. Two hog the limelight: supplementation by adding iron to the diet and biofortification, breeding to add more iron to the staples that make up the diet. A recent paper in The Lancet reviews the story of iron deficiency and how to treat it. ((Michael B Zimmermann and Richard F Hurrell, Nutritional iron deficiency, The Lancet, 370 (9586), 11 August 2007-17 August 2007, Pp 511-520.)) Perhaps not surprisingly, the study concludes that “targeted iron supplementation, iron fortification of foods, or both, can control iron deficiency in populations”. And yet, having said that “dietary iron bioavailability is low in populations consuming monotonous plant-based diets,” the authors do not appear to have seriously considered the idea of trying to attack that monotony instead. Maybe enriching and diversifying those plant-based diets to include more dark green leafy vegetables and more pulses would be as effective, with additional benefits in other realms. But that kind of intervention isn’t nearly as glamorous, and gets little attention.

Of course, it could be that solving the problem of iron deficiency will just give rise to other difficulties. Another paper suggests that iron deficiency protects us against some of the epidemic contagious diseases that have hitched along as people crowded together in agriculturally-fed cities. ((S Denic and M Agarwal, Nutritional iron deficiency: an evolutionary perspective. Nutrition. 2007, 23:603-14. Epub 2007 Jun 20.)) Maybe iron deficiency — at least in moderation — is a good thing?

What do you know about biodiversity?

That it has absolutely nothing to do with agriculture! That’s the only conclusion to be drawn from a report on the CABI blog about a study in the journal Biological Conservation. It reports a survey of “the general public” in the Cairngorm Mountains in Scotland, which tried to discover what they knew about biodiversity. (I’ve pinched my headline direct from them.) You might think the Cairngorms are not a very agricultural place, but you would be wrong. There’s a great deal of farming up there, to say nothing of timber industries. And some of the conservation efforts seek to duplicate farming practices that have fallen by the wayside. But to hear CABI tell it, even though the survey included foresters and “farmer students” there seemed to be almost no understanding of how agricultural practices are part and parcel of landscapes and their ecology. Bah!

A quick clean-up

Just updated WordPress, the software behind the site. I’ve checked everything I can think of, and it all seems to work. If something’s not as you expected, just holler.

All cows are not equal

Cows produce milk, right? Its qualities vary among breeds, with creamy Jersey milk at one end and that skimmed milk cow at the other. And the quantity varies within a breed, which is how we got to the monster lactation machines that are the modern Friesian. But until this morning I had no idea that there was a distinct difference in the type of milk produced by cows within a breed.

Apparently, the major protein in milk, beta-casein, comes in two different forms, called A1 and A2 (original, huh). Some cows have both forms of casein in their milk, some only A1 and some only A2. (Students of genetics will want to know the ratios. I can’t seem to find them.) The A2 corporation, which has registered and trademarked A2 milkâ„¢, says that the A2 form is the original, and that at some point in the past a mutation produced A1. It also hints strongly that as a result, pure A2 milk is better for you. There seems to be some evidence floating around out there, but none of it is overwhelmingly positive.

Anyway, one can determine which cows produce what milk with a simple DNA test, and this morning’s awakening came from a report about the first dairy farm in the US to separate the milk from its A2 cows. A dairy company in Lincoln, Nebraska has started to market A2 milk in the US. To say they are cagey about the exact health claims they are making for this premium priced product would be the understatement of the week.

“To say there is no controversy over this would not be correct,” said Timothy Thietje, CEO of The Original Foods Company, a Nebraska-based marketer of A2 Milk.

“But to say there’s a substantial body of evidence both in terms of science and the response from people who use the product is correct.”

Right.

All this started in New Zealand and Australia, where the milk is marketed without the approval of the milk boards; what would all those other farmers do? But could this, just possibly, be a case in which reducing diversity might be good for you?