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Blood Oxidative Stress Impact on Health Oxidative Stress Impact on Probiotics

Does Yogurt Generate Oxidative Stress?

Yogurt is delicious and thought to be healthy with live probiotic cultures that improve our gut microbiome and immune response.  However, these bacterial cultures generate hydrogen peroxide, the principal compound of oxidative stress.  Let’s learn more about how yogurt generates oxidative stress and the potential health implications.

Streptococcus Generate Hydrogen Peroxide

Streptococcus is a diverse genus that plays a role in disease and food production.  Members of this genus generate high levels of hydrogen peroxide, the principal compound associated with oxidative stress, which deserves our attention. The table below summarizes what is known about hydrogen peroxide production by different Streptococcus species.

Streptococcus H2O2 Production TableOther Yogurt Bacteria Generate Hydrogen Peroxide

The phylogeny of the Streptococcus reveal other bacteria that may produce high levels of hydrogen peroxide.  Streptococcaceae is a family that includes the genera Streptococcus, Lactococcus, and Lactovum.  Lactococcus strains generate hydrogen peroxide.  Two more related bacteria, Lactobacillus acidophilus and L. delbrueckii subsp. bulgaricus, also generate hydrogen peroxide.  These bacteria are found in yogurt along with Streptococcus thermophilus.  Let’s learn more about how dairy processors use these bacteria.

Dairy Processing

The processing of dairy products often uses one or more probiotic strains for fermentation.  Cheese producers use Lactococcus strains to ferment pasteurized milk.  However, cheese products do not purport to have live cultures.  So the risk of any hydrogen peroxide generating bacteria is negligible.  However, most commercial yogurt products have live cultures.  Since 1981, United States Federal law dictates that yogurt must contain both S. thermophilus and L.d. bulgaricus.  Both strains are generally recognized as safe (GRAS).  The generation of hydrogen peroxide reduces bacterial contamination of yogurt, which is an advantage for yogurt producers.  However, they may not be safe to consume, if you suffer from oxidative stress.  Oxidative stress is a new concern with regards to human health. 

Blood Oxidative Stress

About 2/3 of adult Americans have Blood Oxidative Stress or BLOS.  For BLOS, a large fraction of the White Blood Cells and platelets produce high rates of Reactive Oxygen Species (ROS), such as hydrogen peroxide.  BLOS isn’t normal and the Western Diet is thought to be the primary cause of BLOS.  Higher BLOS levels may be the cause of several chronic diseases including Type 2 Diabetes and Cardiovascular Disease.  Reactive Oxygen Species (ROS) is a group of compounds associated with Oxidative Stress.  These ROS molecules alter expression profiles (enzyme production) and damage DNA.  The most common ROS molecule is hydrogen peroxide.  The figure below describes how BLOS affects the entire human body.

Blood Oxidative Stress (BLOS) Impacts Whole Body
Blood cells generate oxidative stress that circulate throughout the body.

Yogurt Generates Local, Short-Term Oxidative Stress

Yogurt bacteria generate more hydrogen peroxide.  The daily consumption of yogurt may cause local, short-term oxidative stress.  Eating yogurt is a form of bioaugmentation, the purposeful addition of a select biomass into a system.  Bioaugmentation of the small intestine increases yogurt bacteria biomass.  Sufficient levels of yogurt bacteria in the gut generates hydrogen peroxide released into the blood stream (diffusion).  How much hydrogen peroxide diffuses into the blood stream is unclear. 

Liver, Heart, and Lungs At Risk

Yogurt oxidative stress only impacts the circulatory system between the gut and lungs, as shown in the figure below.  Yogurt oxidative stress impacts the liver, since all blood flow from the gut to the liver.  Excessive yogurt oxidative stress could cause liver damage.  Mixing of gut blood dilutes the concentration of hydrogen peroxide by about 1/4th before the blood enters the heart.  Respiration (breathing) clears hydrogen peroxide from the blood.

Yogurt strains generate oxidative stress locally
Yogurt strains generate oxidative stress in the gut, which impacts the gut, heart, and lungs.

Pancreas At Risk

The pancreas may be at risk from Yogurt Oxidative Stress, as shown in the figure below.  Hydrogen Peroxide generated by yogurt bacteria in the small intestine diffuses into the blood system.  The Superior Mesenteric Vein collects and transports blood enriched with hydrogen peroxide to the liver.  However, the Portal Vein passes  by the Head of the Pancreas.  The most common region (65%) of the Pancreas for Cancer is the Head.  Long-term exposure to Oxidative Stress via the Portal Vein may be the culprit.  Hydrogen peroxide diffusing into the Pancreas may inhibit insulin production causing Pre-Diabetes or Type 2 Diabetes.

Oxidative Stress from Small Intestines Impacts Pancreas and Liver
Oxidative Stress generated in the Small Intestine diffuses into Superior Mesenteric Vein and passes by the Pancreas before entering the Liver through the Portal Vein. Diffusion of ROS into the Pancreas may increase Cancer Risk and inhibit insulin production.

How Do You Measure Yogurt Oxidative Stress?

The measurement of yogurt oxidative stress is difficult.  Yogurt oxidative stress cannot be measured in urine, since the blood processed by your kidneys will be devoid of hydrogen peroxide.  Researchers detect hydrogen peroxide in your breath, but commercial test kits are not available.  If yogurt oxidative stress becomes a concern, then commercial test kits should enter the marketplace.

Inhibition of Inflammation

Low levels of hydrogen peroxide are thought to induce inflammation via inflammasomes.  Inflammasomes clear infections when activated.  However, elevated level of hydrogen peroxide (50-100 micromolar) inhibits inflammasomes, which decreases their effectiveness at clearing infections.  For healthy individuals with low BLOS, the consumption of yogurt may cause low levels of inflammation.  Is this healthy?

Concerns Regarding  Yogurt

Yogurt manufacturers tout their product as healthy citing their probiotics.  The required bacterial cultures, S. thermophilus and L.d. bulgaricus, are touted as probiotics, but there are some concerns beyond oxidative stress.  S. thermophilus is being promoted as a potential probioticL.d. bulgaricus has a much better survival rate in the gut compared to S. thermophilus, which should be of more concern.  The hydrogen peroxide generation rate of both yogurt strains is unknown.  However, it warrants investigation by food scientists, yogurt producers, and regulators.  The internal location of yogurt oxidative stress presents a challenge to researchers.  Out of sight; out of mind.  The combination of BLOS and daily yogurt consumption could be dangerous.  For a healthy individual that consumes yogurt daily, yogurt oxidative stress could still cause health problems.  Long-term yogurt oxidative stress in the liver, heart, and lungs could increase the risk of cancers and cause coronary atherosclerosis and liver damage.

Should We Consume Yogurt After Antibiotics?

Doctors recommend yogurt to help replace healthy bacteria in the gut after taking antibioticsDoes this make sense?  Antibiotics clear out bacteria in the gut, so yogurt bacteria have little to no competition.  This increases abundance, which means more yogurt oxidative stress in the short-term.  Maybe we should consider safe probiotic supplements instead.  Or maybe yogurt producers could develop a safer product?

Health Hack for Life

If you are a curious about BLOS and want to learn more, then my eBook, “Let’s Hack Oxidative Stress” may interest you.  In my eBook, I provide more details on my simple strategy for using three lifestyle choices to reduce your Oxidative Stress and improve your health.  I have a collection of eBooks and Paperback Versions that describe general and custom Health Hacks.  The rest of the items needed for your Hack are available through Amazon or your local stores.  However, there is a simpler way to gather up all of the products for  your Hack: Buy an Oxidative Stress Hack Kit from my Store!

Blood Oxidative Stress (BLOS) Impacts Whole Body
BLOS Hack Kits include an eBook or Paperback Version of my Strategy Guide, essential products for evaluating BLOS and other important bio-indicators of health, and optional products to improve fitness and diet.

Glixin Provides Useful Information to Help You Fight BLOS

We will continue to provide thought provoking Blog Posts on health related issues caused by BLOS.  Consider subscribing to my blog and sharing posts with your family and friends that may suffer from BLOS.  Also check out the new Glixin YouTube Channel.  I’ll be posting new videos related to the Glixin Blog.  Keep BLOS out of your Health Blind Spot by learning how to use make better Lifestyle Choices.

As always, read my disclaimer and always consult with your physician before making any changes in your diet or fitness regime.

Click on the image below to download our Free Report on the Best Vitamin C Supplement for fighting Oxidative Stress.

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By Peter Stroot

Dr. Peter Stroot is an Engineer, Microbiologist, and Molecular Biologist, who has published research articles and holds patents for multiple biotechnologies. He is the Managing Member of Glixin, the World's Leader in Managing Blood Oxidative Stress or BLOS.

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