Study sheds light on the health benefits of rye
The bread industry is under increased pressure from shifting consumer trends. Sales at the 143-year-old UK bread firm Warburton dropped last year for the third year running, for instance. Revealing the result last month Warburton's blamed a “continuing decline in the core market”. The company has even recruited Hollywood heavyweights Sylvester Stallone and Robert De Niro to head its latest advertising campaigns.
Aimee Benson, consumer insight director at market research firm Kantar, said: “Bread is in long-term decline. The industry is trying to reinvigorate, adding seeds and looking at bagels or wraps, but it's still not really saving the category.
“More and more people are choosing gluten-free options, perhaps buying bread less frequently or choosing to remove bread from their diets altogether.
“I don't think people are doing it necessarily because they are Coeliac. What we are seeing is the rise of 'lifestylers' – people who are not necessarily medically diagnosed but who are trying to cut gluten out of their diet.”
The news of more evidence that eating rye comes with a variety of health benefits, could offer crumbs of comfort to chefs and bakers who are increasingly embracing rye.
A new study from the University of Eastern Finland, published in the journal Microbiome, analyzed the bacteria found in rye sourdough – which is used to make rye bread – and found that it contains high levels of lactic acid bacteria.
In addition to fermenting the dough, these bacteria also modify bioactive compounds found in rye, said the study. They produce branched-chain amino acids and amino acid-containing small peptides, which are known to have an impact on insulin metabolism, among other things.
The study found that gut microbes and microbes found in sourdough produce compounds that are partially the same. However, gut microbes also produce derivatives of trimethylglycine, also known as betaine, contained in rye.
An earlier study by the research group has shown that at least one of these derivatives reduces the need for oxygen in heart muscle cells, which may protect the heart from ischemia or possibly even enhance its performance.
The findings can explain some of the health benefits of rye, including better blood sugar levels and a lower risk of cardiovascular diseases.
Rye can be traced back to what is now known as present-day eastern Turkey, from where it has spread to many cuisines across the world. In Finland, for example, rye has been consumed for thousands of years, and it was recently selected as the country's national food.
Although the health benefits of rye are long known, the underlying mechanisms are still poorly understood. For instance, the so-called 'rye factor' refers to the lower insulin response caused by rye than, for example, wheat bread. Eating rye makes blood sugar levels fall slower, which leads to beneficial effects on the health - for a reason that remains unknown.
A significant factor contributing to the health benefits of rye are its bioactive compounds, or phytochemicals, which serve as antioxidants. In addition, gut microbes seem to play an important role in turning these compounds into a format that can be easily absorbed by the body, making it possible for them to have a greater effect.
"The major role played by gut microbes in human health has become more and more evident over the past decades, and this is why gut microbes should be taken very good care of. It's a good idea to avoid unnecessary antibiotics and feed gut microbes with optimal food - such as rye," noted researcher Ville Koistinen.
Health benefits of whole grain cereals may be linked to the alteration of serotonin production in the intestines
Another recent study by the University of Eastern Finland and the International Agency for Research on Cancer discovered that adults consuming whole grain rye have lower plasma serotonin levels than people eating low-fibre wheat bread.
This study, published in The American Journal of Clinical Nutrition, found that the consumption of cereal fibre from rye or wheat reduced serotonin levels in the colon of mice. In light of the results, the health benefits of whole grain cereals may be linked, at least in part, to the alteration of serotonin production in the intestines, where the majority of the body's serotonin is produced.
'Contribution of gut microbiota to metabolism of dietary glycine betaine in mice and in vitro colonic fermentation'
Authors: Ville M. Koistinen, Olli Kärkkäinen, Klaudyna Borewicz, Iman Zarei, Jenna Jokkala, Valérie Micard, Natalia Rosa-Sibakov, Seppo Auriola, Anna-Marja Aura, Hauke Smidt & Kati Hanhineva