Pro, Pre and Plant biotics - Tasting the Benefits of Microbes

From my presentation for MicroBio.

Summary:
Probiotics AKA beneficial bacteria  have been around forever but their potential has not been fully tapped until relatively recently. After discovering bacteria we initially showed more interest in killing them rather than working together with them. That attitude is slowly changing.

Intro-

While reading in my Microbiology textbook about probiotics I remembered a friend I had at school who consistently had digestive problems. He had said one of the few times he felt healthy was while living as a missionary in Korea. What was it about being in Korea that could have helped his digestion I wondered? He did say the he ate Kimchi every day while there. I wondered, what was so special about Kimchi that could help his digestion? 

Kimchi! http://www.cultureglaze.com

The health benefits of yogurt  are often advertised but after looking into it, I found that any fermented foods like Kimchi can also be an abundant a source of this the beneficial bacteria found in yogurt.  I wondered if there were possibly other foods like Kimchi could also have probiotics? I was delighted to find that while most often associated with yogurt, almost anything fermented can be a good source of probiotics. Foods like Sauerkraut and even Pickles, when fermented, can supply probiotics and help improve digestion.

Historical Context-

Elie Metchnikoff http://vi.sualize.us/

So where did probiotics come from? Milk fermentation and its health benefits are nothing new, since Biblical times we've been fermenting dairy and Roman historian Plinus noted the benefits of fermented dairy products.  Although we knew fermented dairy was good for us, the role of bacteria wasn’t recognized until years after the triumph of Loius Pasteur and germ theory around 1907 when Elie Metchnikoff proposed if replacing  the number of toxic bacteria in the gut with diary bacteria could normalize bowels and prolong life. Metchnikoff, a Russian, himself worked with Pasteur and in addition to being a talented scientist was an optimist about our potential to overcome disease and such a strong believer in the benefits of probiotics he drank sour milk every day until his death at 71.

Along with Metchnikoff, interest in probiotics increased during the pre-world war years. French pediatrician Henry Tissier  observed that children with diarrhea had lower numbers of Y shaped 'bifid' bacteria which were abundant in healthy children.  One of the first studies testing these claims in 1922 used Lactobacillus acidophilus in 20 patients with chronic constipation, diarrhea, and eczema and found improvements in all 3 conditions.  Unfortunately, these observations were sidelined during World War 1 and 2  periods as more emphasis was put war wound treatment with antibiotics and Alexander Fleming's magic bullet penicillin. It has taken decades to get away back away from our obsession with eradicating bacteria and start becoming more interested in living in harmony with them. More recently, interest in probiotics began to ignite once again around as evidenced by the huge growth number of publications on the topic. Since then, characterization of specific cultures and substantiation of health claims have advanced enormously.

Along those lines Pro-biotics were formally defined by UN Food and Ag Org and WHO in 1990 as live microorganisms which when administered in adequate amounts confer a health benefit on the host. This more broad definition recognizes bacteria anywhere in the body. 

Mechanism 

www.probiotic-cn.com/Lactobacillus_Helveticus

So how do they work? Without getting too specific, mainly what it comes down to is competition for space in the lining of your gut. When there are harmless bacteria already growing your gut, they get in the way of other bacteria sticking and growing that could be harmful. The good bacteria also stimulate your immune system and keep it active. 

Some types of bacteria will also last longer over time in the gut, the Bulgaris strain for example not as long lasting compared to other Lactobacillus which can stick around a lot longer.  Different parts of the gut are are also better targets for different strains of bacteria which is why only one strain of probiotics alone may not be sufficient.  Even beyond the digestive tract, bacteria can grow anywhere that presents a dark, moist conditions, so other parts of your body can also benefit from the protective effects of probiotics.

Although there are seemingly endless health claims for probiotics some are very well documented like: 

Decreased diarrhea especially when caused by antibiotics 

Increase lactose tolerance

Stimulation of immunity and decreased likelihood of infection

Reduction of allergic symptoms

Decrease cancer promoting toxins. 

Other claims have some shown evidence  but are not as exhaustively researched like: 

Reducing irritable bowel syndrome

Inhibiting Helicobacteri pylori infection (found in ulcers)
Reducing constipation 

Increase mineral metabolism and bone density stability 

Cancer prevention 

Reduction of cholesterol and triaglycerol plasma concentrations

A Flavorful Future- As understanding of probiotics continues to advance, implications Metchinikoff's initial optimism will continue to open up greater possibilities in both human health and the wellbeing of other organisms.

In 1993 prebiotics were discovered to improve bacterial to growth and activity. These “prebiotics” have been found in foods like Onion, Garlic, Leeks, asparagus, wheat and banana. The research is still fairly new but  the main takeaway is recognizing that some other foods along fermented ones act synergistically with gut flora.  Prebiotics are defined as non-digestible carbohydrates (specifically inulin and its byproducts and trans oligosacharides) that beneficially affect the host by selectively stimulating growth and/or activity of one or a limited number of bacteria in the colon. Similar to dietary fiber except that it selectively benefits certain bacterial species.

www.jollylane.com

Traditional fertilizers and pesticides have a lot of problems with sustainability, they require  huge amounts non-renewable raw chemical ingredients, confront evolving pest resistance and can have undesirable chemical byproducts. Although it may seem like a stretch that bacteria could do the job of plant fertilizers, large companies are already making huge purchases betting on the future of bacteria's role in agriculture.Taxon was acquired by DuPont and companies like Monsanto have made similar large purchases betting on the future of microbes in plant growth and protection. There are a number of other companies offering similar products so whether or not it works the demand alone give some indication that farmers and horticulturalists are seeing results. The possibilities for a mutually beneficial relationship between bacteria and humans indeed do seem limitless and will impact medications, plant health and beyond. Seeing this field continue to advance will be very exciting.

Some of the most diverse varieties of good bacteria come from equally varied food sources  These are a few that have been characterized and the many strains of bacteria they produce: 

Yogurt-Lactobacillus, bifidus, 
Kimchi Leuconostoc, Lactobacillus,  Leuconostoc species Le. mesenteroides, Le. kimchii, Le. citreum, Le. gasicomitatum, and Le. gelidum, the Lactobacillus species Lb. brevis, Lb. curvatus, Lb. plantarum, and Lb. sakei, Lactococcus lactis, Pediococcus pentosaceus, Weissella confusa, Weissella kimchii, and Weissella koreensis 
Saurkraut  A more recent study revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. Sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. 
Kombucha - Gluconacetobacter kombuchae is an anaerobic bacteria that is unique to kombucha. It feeds on nitrogen that is found in tea and produces acetic acid and gluconic acid, as well as building the scoby. Zygosaccharomyces kombuchaensis is a yeast strain that is unique to kombucha.    
Kefir