Milk and other fresh dairy products are having a hard time as of late. The industry is being singled out in trade negotiations. The public is being encouraged to move away from these products in favour of alternatives such as almond, cashew, soy, and coconut varieties. Then last week, Health Canada proposed reducing the emphasis on this essential part of the diet in the next installment of the Canadian Food Guide.
Now there's another hit to dairy's reputation although this has nothing to do with economics or nutrition. In this case, it has to do with infectious disease. An American conglomerate of researchers has recently revealed one of the ingredients in milk may be necessary for the growth of potentially lethal Clostridium difficile bacteria. The results suggest we may want to give milk products a second thought when we're on antibiotics or medications to manage stomach acid.
C. difficile is different from others familiar pathogens such as Escherichia coli and Staphylococcus aureus. When this species is in an unwelcome environment, such as a highly diverse bacterial population, it stays in a dormant state, known as a spore. In this form, it is completely harmless. In order for it to cause problems, it must awake from its slumber through a process known as germination.
Researchers have known for years germination inside us only occurs when there is a lack of proper bacterial diversity in the gut. This usually happens when we take antibiotics but can also occur when we take medications to deal with stomach acid, heartburn, and gastric reflux. But what hasn't been known is the trigger to allow these bacteria to germinate. Unveiling this mystery was the ultimate goal for these researchers.
When C. difficile germinates, two categories of molecules are required to complete the process. The first is bile salts. These are produced by the liver and sent to the intestines to improve digestion. The second are amino acids, which are the building blocks for proteins. Of the twenty possible options, the prime suspect is a molecule known as glycine. It's the smallest in size and appears to have the best germination potential.
Because bile salts are common in the intestines, the team figured they were not the limiting factor. Instead, they believed the germination trigger hinged on glycine levels. When they tested this in the lab, their hunch was confirmed. Without glycine, the spores could not transform.
With this in hand, the team ventured to find what could possibly allow germination to continue in the absence of glycine. One option was to look for a molecule that looked like glycine and mimicked its function. Because of the rather unique structure of this amino acid, the chances for success were dim at best.
The other option was to look at what happened to the cells after being exposed to glycine. If the team could find a surge in a third type of molecule during this process, they might be able to force germination by increasing that chemical's concentration. This approach was more likely to lead to success.
As expected, the team found a rise in that third molecule. It happened to be a rather common chemical element we all tend to look for in our daily diets. It's calcium. When the team added calcium to spores in absence of glycine, they germinated.
This one experiment provided answers on how a calcium influx might improve the survival of C. difficile in the lab. Yet the team still needed to figure out how germination might work in the body. They worked with mice to find out if normal calcium levels in the gut would lead to the same transformation seen in the lab. There was no doubt. The calcium found in the diet of the mice led to an increase in germination.
Even though these results marked a milestone, the team was not finished. They wanted to go one step further into the human realm. They wanted to find out how the use of antibiotics and gastric reflux medications may be contributing to C. difficile infection.
The answer, however, was already known. Both these drug types already were known to reduce the absorption of calcium in the intestines. This meant a higher concentration of the element would be present during treatment. Add in the lack of microbial diversity, some bile salts, and possibly some glycine from the diet, and you have the perfect conditions for an infection.
Based on the results, the authors suggest people who are taking these medications reduce their calcium levels to keep C. difficile at bay. This includes reducing dairy and other calcium supplemented products during treatment. This would lead to a passive form of infection prevention. If this recommendation turns out to be successful, it could one day be considered for policy.
As for those who can't live without their daily consumption of milk, there may be a silver lining. Increasing vitamin D levels can increase the absorption of calcium into the intestines. The authors suggest increasing Vitamin D intake may be enough to reduce the problems with calcium. This too will need to be proven in trials. However, in light of the situation facing milk and dairy, the research will be well worth the effort.
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