What is rye?
Rye is that bread that’s offered as a choice for your sandwich that you don’t choose because you don’t quite know what it is, although the term “rye” isn’t exactly foreign to you. Rye bread comes from rye flour, which comes from rye grain, and it often has more fiber than white bread does. Rye bread is usually darker and has a stronger flavor. But these superficial differences are only the beginning of the story.
More or less born in what is now present-day eastern Turkey, rye is rich with lactic acid bacteria, which serve a dual purpose: ferment the dough + make changes to the bioactive compounds unique to rye. Rye bread is known for its surprisingly beneficial impact on insulin metabolism; the academic jury is still out as far as to why, but a prime suspect remains: rye’s production of branched-chain amino acids and amino acid-containing small peptides.
Bread often gets a bad rep for instigating a high glycemic response (increased levels of glucose entering the gut following a high-glycemic meal triggers increased production of insulin). Interestingly, rye bread triggers a relatively low glycemic response and actually improves blood glucose (blood “sugar”) levels, occasionally called the “Rye Factor” (don’t read this the wrong way. Rye bread is still mostly carbohydrates).
Rye is also associated with a reduced risk of heart disease. No surprise here; anything that helps regulate blood glucose levels is likely to positively influence the heart and reduce the risk of disease.
A key part of the unique rye narrative is the bioactive (read: biologically active = bioactive), or bioavailable, compounds (I also talk about bioactivity in my recent article about naturally occurring iron levels [check it out]). When compounds are more bioactive or bioavailable, it means they exist in a form that can be readily absorbed and utilized by the body.
Picture this. You’re eating a sandwich on rye. Bioactive compounds from rye enter the gut (more scientifically, the gastrointestinal tract or “GI” tract) and bacteria living in the gut (good guys) process these compounds into a form that the body absorbs and uses. Without the right factors present to make these compounds usable by the body, they’d be nearly useless.
Rye is one of many plants that contain unique bioactive compounds, often called phytoactive compounds or phytonutrients (phyto = plant). Phytonutrients are beneficial to the human body in a different way that macronutrients (fat, carbohydrates, protein) and micronutrients (vitamins and minerals) are. Lots of studies from a continuously growing body of research associate phytonutrients and plant-based eating with reduced risk of disease, from heart disease to cancer. Interestingly, research also shows that gut bacteria regularly transform phytonutrients into more bioactive forms.
The research
My background discussion on rye got a bit out of hand (that tends to happen when you get me talking about phytonutrients and bioavailability), but let’s not forget the recent research study that prompted this post. From the University of Eastern Finland, published in the journal Microbiome, researchers investigated the contributions of lactic acid bacteria from rye and gut bacteria native to the human body. They found that the two populations of microbes produce similar compounds that contribute to health benefits associated with rye; innate human gut bacteria produce derivatives of betaine, which is also found in rye.
Betaine is associated with a reduced need for oxygen in heart muscle cells, a decreased risk of dangerous reduced blood flow, and potentially increased heart muscle performance.
The study used a) metabolomics to compare the metabolites found in rye versus naturally in the human body and b) mice and human gut models to determine the impact of gut bacteria versus lactic acid bacteria from rye. These two approaches enabled the researchers to confirm that the unique metabolites identified indeed originated from rye, as opposed to somewhere else in the human gut.
Make the rye-t choice
While I don’t intend to endorse rye as the bread of choice, I do think this discussion of rye, lactic acid bacteria, and phytonutrients is intriguing. Rye truly arrives at the party prepared to provide both the healthy compounds and the tools needed to unpack and serve those compounds for absorption and use in the human gut. I might invite rye to my next sandwich party…
Note
I’m still pondering how I can improve the “prepared party guest” analogy to describe rye and its unique components. Got an idea on how to improve it? Email me at ScienceKara.com.
Fun fact
Rye was recently selected as Finland’s national food.
If this article has you thinking more about whole grains, I wrote an article on this topic when I worked at the North Carolina Research Campus in Kannapolis. Check it out.
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