Fountain of Youth for Heart Health May Lie in the Gut
- Changes in the gut microbiome with aging have an adverse impact on vascular health
- Diets high in probiotic-rich cultured food and prebiotic fiber could play a role in preventing heart disease by promoting a healthy gut microbiome
Why do blood vessels naturally stiffen and degrade as we age, boosting cardiovascular disease risk? New University of Colorado Boulder research has identified a surprising new culprit - and it lives in your gut.
Researchers gave young mice and old mice broad-spectrum antibiotics to kill off the majority of bacteria living in their gut, aka their gut microbiome.
Then they assessed the health of their vascular endothelium (the inner lining of their blood vessels) and the stiffness of their large arteries.
They also measured blood levels of inflammatory compounds, tissue-damaging free-radicals, antioxidants and the blood-vessel-expanding compound nitric oxide in both groups.
After three to four weeks of the treatment, the young mice saw no change in vascular health. The old mice, however, saw vast improvements on all measures.
"When you suppressed the microbiome of the old mice, their vascular health was restored to that of young mice," said senior author and professor Doug Seals, "This suggests there is something about those microorganisms that is causing vascular dysfunction."
To assess what that something may be, the researchers then took fecal samples from another set of mice and had them genetically sequenced, comparing the gut bacteria living in the old mice with that in the young.
In the old mice, there was an increased prevalence of microbes that are pro-inflammatory and have been previously associated with diseases.
To drill down further, the researchers measured blood levels of metabolites--small molecules produced by the gut microorganisms and absorbed into the bloodstream--in old and young mice.
Old mice had three times as much TMAO (trimethylamine N-oxide), a metabolite shown in previous studies to be linked to increased risk of atherosclerosis, heart attack and stroke.
"We have long known that oxidative stress and inflammation are involved in making arteries unhealthy over time, but we didn't know why arteries begin to get inflamed and stressed. Something is triggering this," Seals said. "We now suspect that, with age, the gut microbiota begins producing toxic molecules, including TMAO, which get into the blood stream, cause inflammation and oxidative stress and damage tissue."
The authors believe that diets high in probiotic-rich cultured food (yogurt, kefir, kimchi) and prebiotic fiber could play a role in preventing heart disease by promoting a healthy gut microbiome.
They're also studying a compound called dimethyl butanol, found in some olive oils, vinegars and red wines, which blocks the bacterial enzyme required to produce TMAO. Ultimately, it could be developed into a dietary supplement.
This research, along with studies linking an aging microbiome to gastrointestinal, immune and brain aging, offers one more reason to keep our resident bacteria healthy, notes an editorial accompanying the article in the Journal of Physiology.
As its authors put it:
"The fountain of youth may actually lie in the gut."
Probiotic Products Available in the UK
Interestingly, these drinks/foods are not actively allowed to use the word ‘probiotic’ on their labelling. The European commission has banned the use of the word since scientific studies so far have not met the standard of proof required for ‘health claims’ to be made, and the commission judged the word ‘probiotic’ implies a health claim.
This means that products available in our supermarkets tend to use phrases like ‘live active cultures’ or ‘gut friendly cultures’ on their labelling.
Here’s a roundup of products that are designed to be probiotic:
Biomel Drinks and Shots
Biomel claim their probiotic cultures are 10x stronger than yoghurt and kefir cultures. As well as ‘billions’ of live active cultures, their drinks contain Vitamins B6, D and Calcium, are plant- based (coconut milk) and suitable for vegans. More info on the Biomel website
Bio-Tiful Dairy kefir
Made from British milk and live cultures which include around 40 different strains of bacteria and yeasts. Products include milk drinks, smoothies and quark. More info on the Bio-Tiful Dairy website
Yakult drinks contain 6.5 billion bacteria called Lactobacillus casei Shirota. They’re named after the scientist Dr Shirota who cultivated this unique strain that is scientifically proven to reach the gut alive. More info on the Yakult website
Actimel contains a combination of live cultures, including the L Casei Danone® strain which is exclusive to Danone, along with Vitamins B6 and D. More info on the Actimel website
If you'd like to have a closer look and see how healthy your diet is, have a look at the tools and databases in Weight Loss Resources. You can check if your diet is balanced, how many calories you eat (and how many you need!), track how many servings of fruit and veg you eat in a day, and look up the calorie, protein, carbohydrate, fat and fibre content of over 20,000 foods. Try it free.
References and Sources
Suppression of the gut microbiome ameliorates age‐related arterial dysfunction and oxidative stress in mice. J Physiol. doi:10.1113/JP277336
Press Release from University of Colorado Boulder
Wikipedia Probiotic page