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Tuesday, March 12, 2013

Can Colostrum Boost Immunity?



Colostrum is the milky fluid secreted by all lactating mammals, including humans, in the first few days after giving birth, before breast milk is produced.

This “first milk” contains hormones and factors that, among other things, promote cell development and growth, prime a newborn’s immune and digestive system, and help protect against infection. Like milk, it also contains protein, fat, milk sugar, vitamins, and minerals.

Sound healthful, at least for babies, but could colostrum help adults who take it in supplement form (tablets, capsules and powders)? That’s how bovine (cow) colostrum is being marketed today, often in formulas that also contain other “immune-boosting” ingredients. Colostrum supplements are promoted to treat everything from arthritis and autoimmune diseases to ulcers, colitis, and various infections, as well as to slow aging, build muscle and improve mood and athletic performance.

It’s a big leap, however, to think that bovine colostrum will benefit people. First off, colostrum’s chemistry is largely specific to each species—thus, bovine colostrum is different from human. And what’s good for newborn calves is not necessarily good for newborn humans, let alone adults.

It’s not even certain if or how much the antibodies and other special substances in bovine colostrum can survive the human digestive tract and/or be absorbed. That hasn’t stopped researchers from looking into colostrum supplements or marketers from making big claims for them.

Putting colostrum to the test

Much of the research on bovine colostrum, especially regarding athletic performance, comes from Australia. Some studies do suggest various benefits for athletes—in reducing fatigue, improving running performance, and building muscle, for instance.

But the studies have generally been small and not well designed and used varying types and doses of supplements. Most focused on young athletes. Plus, not all had positive results—and when they did, the effects were small. Colostrum supplies protein, so some of the effects on muscle may simply be due to the extra protein.

A few studies have also found that colostrum supplements affect levels of certain antibodies and/or other immune system cells in both athletes and non-athletes. But none have shown that these changes result in real-world benefits, such as reduced colds. And other studies, including a Dutch one in 2011, have found no effect on immune variables in athletes.

The Natural Standard gives bovine colostrum a C rating—meaning unclear or conflicting evidence—for everything from immune function and exercise performance to protection from infection in adults and diarrhea in children.

Bottom line: We can’t recommend colostrum supplements. On top of their benefits being unproven, their safety is unknown. Colostrum can vary in its constituents, and you don’t know exactly what you’re getting in the supplements. Contaminants such as PCBs and pesticides may accumulate in colostrum.

If there are hormones and active immune factors that are actually absorbed, who knows what effect they may have on the risk of cancer, heart disease, or immune disorders and whether they may interact with medications. Pregnant and nursing women and young children should especially avoid them.

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