Loading…
Food · Animal Foods · Red Meat
food source · 3
→Iron
Like beef, lamb is red meat, and most of its iron is heme iron, which is absorbed several times more efficiently than the iron in plants. That is lamb's most solid nutritional strength.
Mechanism · Heme iron enters ring and all
The iron in lamb, beef and blood is mainly heme iron: the iron is framed by a porphyrin ring, and the gut has a dedicated route that takes in the whole molecule, so the rest of the meal matters little. The non-heme iron in plants has to be reduced before it is absorbed and is easily locked up by tea polyphenols and the phytate in grains. Calcium is the exception: it may lower the absorption of both kinds somewhat.
Numbers · Efficiency is not a reason to eat more
Estimated across a whole diet, about 14–18% of iron is absorbed from a mixed diet with meat, seafood and vitamin C, and about 5–12% from a vegetarian diet (Hurrell and Egli 2010); both figures were estimated for people whose iron stores are empty. So from the same amount of iron, far more gets in from red meat than from vegetables such as spinach. That is a point about efficiency, not a case for more red meat: in someone whose iron is already sufficient, the gut absorbs less on its own.
iron-bioavailability-hurrell-egli-2010B12 comes almost only from animal foods, and lamb is a reliable source; people who eat no animal foods at all need to take it separately.
Mechanism · Animals do not make B12 themselves
Only microbes can make B12. Sheep, too, get it from the microbes in their rumen and store it in meat and liver, so lamb is a source, not a producer; that is why strict vegetarians need to take B12 separately. Once eaten, B12 still needs stomach acid and intrinsic factor to be absorbed, and in people short of acid or of intrinsic factor, no amount eaten gets in.
Myth · Grass-fed lamb is not an omega-3 source
Grass-fed lamb fat has slightly more omega-3 than grain-fed lamb fat, but the absolute amounts are tiny, so do not count lamb as an omega-3 source; that is the job of fatty fish such as salmon. For B12, iron and zinc, lamb is much like beef.
→Zinc
Red meat is a well-absorbed source of zinc, and lamb is much like beef in this respect. Zinc takes part in immunity, wound healing and the work of hundreds of enzymes.
Mechanism · Why zinc shortage shows up everywhere
Zinc is a structural part of proteins and a cofactor for many enzymes. Wounds, taste buds, immune cells and a growing child are all places where cells turn over quickly and new protein is made all the time, so a zinc shortage tends to show up in several places at once. In plants, zinc is often locked up by phytate; meat has none, so little is lost.
Myth · Well absorbed is not the same as high
Calling red meat a well-absorbed zinc source means little is lost, not that the amount is remarkably high. Zinc from food does not lower copper; only long-term high-dose zinc supplements can interfere with copper absorption.
contrast · 1
The International Agency for Research on Cancer (IARC) placed processed meat (sausage, bacon, ham and other cured or smoked meats) in Group 1 and fresh red meat, lamb included, in Group 2A. The groups answer how certain the evidence is, not how large the harm is. The more certain risk sits with processed meat, not with fresh lamb in moderate amounts.