Does gut flora in smokers slow metabolism and cause weight gain?
FEEDING THE GOOD BACTERIA
WHY PROBIOTICS ARE ESSENTIAL IN PREVENTING WEIGHT GAIN WHEN QUITTING SMOKING
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Gut (and oral) flora, metabolism and smoking cessation are all connected. There’s a ton of research about dopamine, probiotics and gut flora for “normal” people, but the research into the differences and impacts of smoking cessation on gut flora and metabolism is still emerging. One thing is clear though, gut flora, diversity and composition have a huge impact on our weight.
There is a ton of information and cited research studies below providing theories of the impact of smoking cessation and weight gain as it related to the gut and oral microbiome, and I encourage you to read it since gut flora is so personal to each individual.
I’m sharing what I’m doing and taking to restore bacterial diversity, reduce buccal bacteria and increase bacteroides in my cessation, but keep in mind especially for probiotics, what works for me, may not work for you.
Polyphenols see what I take
Coconut Oil for oil pulling
I’ve put together what I found to be interesting possible connections to weight gain, smoking cessation and gut flora in my body, but since, bacteria varies by from person to person, I encourage you to a) listen to your body; b) research what strains, foods or supplements may be best for you and c) discuss with your doctor in choosing a probiotic.
The gut flora is different in smokers versus non-smokers and former smokers, with firmicutes (the bacteria associated with obesity) being lower in smokers than it is in non-smokers and former smokers ( 1 2 3 )
This study specifically suggests that the changes that occur in microbiome in smoking cessation is the cause of weight gain. ( 4 ) This study shows the change of gut flora in smokers and in cessation showing that the ratio of firmicutes to bacteroidetes in smoking cessation “flips” (favoring firmicutes) surpassing the levels of both non-smokers and former smokers ( 5 )
A study on mice exposed to cigarette smoke shows cigarette smoke changes the gut microbiome ( 6 )
Smokers have 40+% more buccal bacteria than non-smokers ( 7 )
There are many studies on the oral microbiome of smokers versus non-smokers showing that smoking caused bacteria in the oral microbiome, which may in turn affect the gut microbiome of smokers. Findings were that smokers had increased abundance of Streptococcus compared with non-smokers. ( 8 9 10 )
This 7-week study analyzed weight gain, firmicutes to bacteroidete ratio in rats based on different probiotic strains showing that certain strains that may reduce or prevent body weight gain ( 11 )
A study which analyzed diet impact on gut flora and small intestinal mucous (SIM) in rats based on high fat, high protein or high sugar diets, found that the high protein diet was most associated with stable or reduced body weight. ( 12 )
This study suggests one of the causes for increase in bacteria in smoking cessation may be the increased oxygen flow smokers have after smoking is stopped. ( 13 ) In other words, as smokers we provide gut flora with an oxygen depleted environment, when we quit, we are changing the environment to an oxygen rich environment.
In all of the studies, researchers make clear that the exact cause of the changes in the microbiome of smokers in cessation are unclear and require more research. However, some of these studies show some promise for former smokers, as with increased cessation time, the microbiome of former smokers more closely resembles the biome of never smokers.
How to restore gut flora diversity to minimize weight gain in smoking cessation
As a starting point, understand that in smoking cessation our bacterial make-up shifts from being in favor of a slender profile, and flips to a make-up with higher firmicutes, associated with weight gain or obesity.
The main four bacterias that make up the biome include bacteroidetes, firmicutes, proteobacteria actinobacteria with bacteriodetes (good bacteria) and firmicutes (bad bacteria) making up about 85-90% of the total biome. The chart above does not show it, but all four bacterias change in smokers, non-smokers, in smoking cessations and former smokers (smokers who have quit for a longer period of time, whose biome profile more closely resembles that of a non-smoker). This study breaks out the differences in microbiome by bacteria ( 14 )
Whether you smoke or not, the biome “make-up” desired for healthy weight is the one that favors a higher ratio of bacteroidetes to firmicutes (much like the current smoker has).
What’s key, in my opinion, and perhaps most relevant to smokers and cessation is that bacteroides are anaerobic bacteria, meaning they can live without oxygen and may even thrive in conditions with less oxygen. Firmicutes on the other hand are aerobic which means they need a rich amount of oxygen in order to thrive, and without oxygen they will die off as suggested in this article ( 15 )
Additionally, smokers have a higher about of buccal bacteria in the microflora, both orally and in the gut with as much as 40% higher compared to non-smokers, with a higher level of Streptococcus (the bacteria associated with tooth decay) and a lower level of Proteobacteria (the good bacteria that gets rid of the bad bacteria).
So this is just my own theory, but, if quitting smoking causes a shift in the biome because we are shifting our bodies from an oxygen depleted environment to an oxygen rich environment, and with that oxygen change we are bring with us a higher amount of buccal bacteria, and less diversity in overall flora… Perhaps there are things we can do in cessation to reduce buccal bacteria orally and in the gut, and also find probiotics and/or polyphenols that favor a higher bacteroides to firmicutes ratio assisting our bacteria to adjust to it’s new smoke-free home a little quicker.
Reducing Buccal Bacteria
These two studies examined bacteria in the mouth caused by cigarette smoking and studied having people suck on cysteine tablets (cysteine is a by product of the amino acid NAC) after smoking a cigarette and found that bacteria levels and carcinogenic acetaldehyde were reduced showing benefit. ( 16 17 ) While I could not find cysteine tablets, you may be able to replicate this effect by adding a NAC capsule to a small glass of water and using as a mouth rinse.
The Ayurvedic practice of oil pulling with coconut oil may also help to remove bacteria from the mouth. These studies and articles support the idea of oil pulling with (or without essential oils) to help reduce bacteria in the oral biome ( 18 19 ) Some essential oils that may also be helpful in reducing oral biome bacteria include tea tree oil, rosemary oil, peppermint oil, lemon oil, wild orange oil. Adding just a drop of essential oil to water or coconut oil for pulling or rinsing may help reduce bacteria.
Probiotics
This study looked at the effect of the Bifidobacterium Lactis HN019 probiotic strain on the elderly. In these studies, Proteobacteria and Bacteroidetes phyla were increased, as well as the genera of Clostridium, Bacteroides and Prevotella. On the other hand, Actinobacteria and Firmicutes phyla as well as the genera Bifidobacteria and Lactococcus were decreased. Although the study is based on elderly (and not related to smoking or cessation), this is somewhat in line the gut flora smokers in cessation may want to correct as they transition from smoker to non-smoker. ( 20 21 22 )
Another possible benefit of the strain Bifidobacterium Lactis NH019 for smoking cessation may be that it relieves constipation, a common withdrawal symptom of quitting smoking. Here are studies related to this strain and constipation not related to smoking habits. ( 23 24 )
You can read more details about the probiotic I’m taking here.
Polyphenols
Polyphenols are antioxidants and some polyphenols can alter the gut biome by reducing oxygen in the gut and intestinal tract. In simple terms, polyphenols can boost the growth of bacteroides and diminish the proliferation of firmicutes by lowering oxygen, creating an environment which favors a greater bacteroides to firmicutes ratio. This study which researched the effect of different polyphenols on the gut and microbiome in both mice and human studies ( 25 ) shows that some polyphenols may help favorably balance the microbiome - here are some of the finding
Prunella vulgaris (from honey) increases Bacteroidetes to Firmicutes ratio and restores Lactobacillus populations. Prurella vulgaris can be purchased as a supplement.
Proanthocyanidin (grape extract extract) Significantly increases Bifidobacteria - this is the bacteria that creates balance between biome bacterias and is also shown to be decreased in smokers. ( 26 )
Cocoa-derived flavanols stimulate growth and proliferation of Bifidobacterium and Lactobacillus, together with reduction in plasma C-reactive protein (CRP), which is usually elevated in smokers and drinkers.
Polyphenols (Green tea, fruits, vinegar wine) Obese volunteers had a weight lowering effect together with alteration in gut microflora.
You can read more details on the polyphenols I’m taking here.
Vitamin D
This study suggests that Vitamin D may also have a positive impact on the gut flora by increasing gut microbial diversity and also increasing the Bacteroidetes to Firmicutes ratio. ( 27 )
Diet
The foods listed by nutrient on this site are plentiful in many foods that naturally contain polyphenols, just make sure you are eating the skins of these fruits, apples as an example.
One food which is not mentioned but maybe helpful in producing good bacteria and also reducing weight gain is pickled ginger. Pickled ginger may also help detoxify the body from cadmium and lead. ( 28 29 ) So I’ll be picking up a jar to keep in my fridge to munch on in detox and as needed through cessation.
Another food I LOVE when I quit smoking is green bananas. Well not completely green, but greenish yellow. Unripe bananas are super good for the gut because they are high in resistant starch which aids in digestion. They also help to absorb vitamins and minerals and so they are great to take with supplements or add to cereal. Green bananas also fight bacterial infection in the gut which can’t be bad for smokers in cessation. Lastly they are high in Vitamin B6 which helps to produce red blood cells, aids in metabolism and helps to balance sugar levels.