Study under review: Visceral adiposity and metabolic syndrome after very high-fat and lowfat isocaloric diets: a randomized controlled trial
Glutathione (GSH), a small peptide consisting of the amino acids L-glutamine, L-cysteine, and glycine, is present in every cell and tissue and is one of the most powerful antioxidants in the body. Reductions in GSH levels have been correlated with inflammation and a number disease states and processes including neurodegenerative disease. One of the major routes for GSH production in the body is through dietary intake of the amino acid cysteine. Cysteine absorption in the gut is inhibited by β-casomorphin-7 (BCM-7), an opioid-like peptide derived from bovine β-casein, a component of cow’s milk. In vitro studies using cultured cells have shown that opioid peptides decrease intracellular GSH levels in part by suppressing cysteine uptake into the cell.
Although milk is great source of dietary cysteine source due to its high whey content, BCM-7 is derived from certain variants of β-casein, which can reduce cysteine uptake. BCM-7 is derived from the A1, but not A2, variant of β-casein. Depending on the genetic makeup of the cow, A1, A2, or both types of β-casein are present in milk. Preliminary studies have shown that milk containing A1, but not A2 β-casein increased gut inflammation and discomfort, and reduced cognitive function in individuals with self-reported lactose intolerance. To examine whether this may occur through increased BCM-7 levels derived from A1 β-casein in cow’s milk, a clinical trial was performed and published in a recent issue of Nutrition Journal.
Cow’s milk contains two subtypes of β-casein protein, A1 and/or A2, depending on the the genetic makeup of the cow. A1 β-casein can be processed by the body to produce BCM-7, a small peptide shown to decrease glutathione (GSH) absorption and promote inflammation.
Other Articles in Issue #27 (January 2017)
Low-carbing for endurance: the oxygen problem
You might have seen more low-carb endurance athletes popping up in the past few years. This trial tested a ketogenic diet in world-class athletes, compared to two different carb regimens.
Can giving infants egg powder prevent allergies?
We've previously covered ground-breaking research on preventing peanut allergies in infants. This new study takes the same basic idea, and tests it with egg introduction and development of allergies.
Boost your immune system with … fiber?
Eat your veggies: the oldest dietary advice in the book. But what happens when you don't eat veggies, or any fiber? This rodent study looks into what might happen to your gut.
Interview: Melanie Jay MD, MS
Everyone knows obesity is a major public health issue, but what are the best ways for primary care doctors to treat it? Melanie is a researcher who studies these issues in depth.
A non-traditional use for probiotics: illness in athletes
With the gut being so important for immune health, it's no surprise that trials are starting to look at probiotics for common illnesses. This one looked at a probiotic blend to help combat colds and related conditions.
Does resistant starch impact the poop of healthy adults?
If you've ever eaten a potato that's been cooked and refrigerated, then reheated, you've eaten resistant starch. Aside from impacting your gut bacteia, will this starch affect your poop?
Interview: Deanna Busteed MS, RDN, CSSD
As a performance nutritionist at a large university, Deanna tells us about practical aspects of implementing nutrition advice for athletes.