Monday, January 22, 2007

Food-derived Peptides Lower Blood Pressure

Fresh from the heels of my cliffhanger post on blood pressure (BP) is this ...
Naturally occurring molecules in a number of foods are being found to lower BP. I've been reading like a fiend and I'm convinced that bioactive peptides really can do what researchers have been theorizing, and demonstrating, they can do.

What Are Bioactive Peptides?

A peptide is a small strand of amino acids. A protein is a large strand of amino acids. Biologically active (bioactive) peptides are essentially small proteins that produce an effect in the body. In this case, they lower blood pressure. That isn't all they do, but that's what I'll focus on here.

The peptides are derived from dietary protein. There are a number of sources for that protein, including milk, fish (sardines, mackerel), brewers yeast, and wheat germ.

The original protein, the milk casein or sardine muscle from whence the peptide came, is inactive. It needs to be cleaved before it can wield its charms. Some of that cleaving takes place naturally in our gut by cleaving or lysing enzymes. Some of it can be performed by enzymatic action of bacteria before we even eat the protein (fermented milk). And some peptides are produced synthetically in a lab by the lysing activities of man and his patented processes.

Thus, some amount of these peptides are made available when we eat certain foods. Foods can also be peptide-spiked. Or you can take a peptide supplement.


One method by which these peptides are thought to lower BP is by inhibiting the enzyme ACE in our body.1 ACE inhibitors, the synthetic kind, are prescribed to lower blood pressure, and are big business for the pharmaceutical industry (Accupril, Altace, Capoten, Vasotec, etc.).

Food-derived ACE inhibiting peptides may also lower BP by mechanisms not fully understood. Some were found to relax vessels through opiate activity (no kidding). Others prompted release of vasorelaxing chemicals (e.g. nitric oxide).

The sum of these peptides' effects is good news for people looking for a non-pharmacological means of lowering BP:
  • Not only do food-derived peptides lower BP, they do so without (so far) the side effects seen with synthetic drugs, such as a dry cough and edema.

  • They can be had at a lower cost, benefiting not only consumers but the healthcare industry as a whole.

  • They can be used for prevention since they don't lower pressure beyond a normal range, even in the presence of multiple doses. Yet, increasing dosage can increase BP-lowering effect.

Below are a few products:
(Click product for a description. For Pro-Activ fermented milk, scroll down to bottom. Just because I show these products doesn't mean I endorse them :)

Here are a spattering of studies:

A fermented milk high in bioactive peptides has a blood pressure–lowering effect in hypertensive subjects (2003, Finland)

A randomized, double-blind, placebo-controlled trial of casein protein hydrolysate (C12 peptide) in human essential hypertension (2004, US)2

Effect of casein hydrolysate, prepared with protease derived from Aspergillus oryzae, on subjects with high-normal blood pressure or mild hypertension (2005, Japan)

Effect of powdered fermented milk with Lactobacillus helveticus on subjects with high-normal blood pressure or mild hypertension (2005, Japan)

Antihypertensive effect of valyl-tyrosine, a short chain peptide derived from sardine muscle hydrolyzate, on mild hypertensive subjects (2000, Japan)

Antihypertensive effect and safety evaluation of vegetable drink with peptides derived from sardine protein hydrolysates on mild hypertensive, high-normal and normal blood pressure subjects (2002, Japan)

And a few overviews:

Bioavailability of angiotensin I converting enzyme inhibitory peptides (2004, Belgium)
Food-derived bioactive peptides--opportunities for designing future foods (2003, Finland)
Effects of milk-derived bioactives: an overview (2000, Australia)

If you peruse the links above, you'll notice a trend. Can you spot it? I have a suspicion why this trend might exist, I wonder if anyone else has a take on it.

1 ACE is the acronym for Angiotensin-Converting Enzyme. An ACE inhibitor slows the conversion of angiotensin I to angiotensin II - the latter being a potent vasoconstrictor. ACE inhibitors also slow the breakdown of bradykinin, a potent vasodilator. Together, these actions make ACE inhibitors pretty darn effective at keeping blood vessels the smooth throughways they were meant to be, at least for some people.

2 See my post, C12 Peptide for Blood Pressure Control, for some stats on C12 Protein.

Thanks to Melinda for setting me down this path.

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