Replacement of white bread with whole kernel rye bread makes you smarter
If you remove white bread from your diet, and replace it with fiber-rich and whole kernel rye bread, your brain may start to function better. And probably your chance of dementia decreases as well. We make these bold statements after reading about a small experiment carried out by Swedish researchers at the University of Lund on one and a half dozen test subjects.
The researchers gave 19 healthy and non-smoking subjects aged 20-33 years a meal with rye bread every night for 3 days. This rye bread consisted for 85 percent of entire rye kernels, and for 15 percent of white flour.
On another occasion, the subjects were given an evening meal with white bread for 3 days. At both meals the subjects consumed 50 grams of starch each time.
On the morning after the evening meal, the researchers determined the concentration of BDNF in the subjects' blood. BDNF is a hormone that keeps brain cells young and vital, and also stimulates them to form new connections.
Already on the first day after the first evening meal with rye bread, the researchers saw more BDNF in the blood of the test subjects in the morning than on the day after an evening meal with white bread.
This situation remained unchanged during the experiment, which lasted 3 days.
"It has been suggested that one possible mechanism behind the promotion of health benefits on glucose tolerance and appetite regulation of whole grain rye is connected to the gut fermentation of the dietary fiber, and production of short chain fatty acids by the gut microbiota", write the researchers.
"Thus, an increase in plasma butyrate by 30% and an increase of both plasma acetate and plasma propionate by 10% were observed at fasting after the intake of rye kernel-based bread the previous evening, compared to the white bread evening meals." [PLoS One. 2016 Mar 18;11(3):e0151985.]
"Interestingly, it has been shown that administration of sodium butyrate may upregulate the BDNF levels in the frontal cortex." [Biol Psychiatry. 2007 Jul 1;62(1):55-64.]
"In terms of the gut microbiota, previous observations have revealed that the BDNF concentrations are lower in germ-free mice compared to controls, and it was concluded that the gut microbiota plays a role in increasing the brain BDNF levels. In addition, another animal study showed that prebiotic feeding (fructo-oligosaccharides and galacto-oligosaccharides) increased the expression of BDNF [...], indicating involvement of gut microbiota [...] in rats."
"However, no correlations between short chain fatty acids [...] and BDNF could be confirmed in this study."
"In the present study, the results indicate potential semi-acute (10.5 h) effects of whole grain rye on the neuronal integrity marker BDNF. Further studies are however needed to support this finding."
Nutrients. 2018 Aug 16;10(8).
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