Gut Microbes Might Reflect Health, Diet of Older Americans

Probiotics for Elders

Story at-a-glance -

  • Recent research shows microflora in seniors living in long-term care facilities is less diverse, and significantly correlates with measures of frailty, co-morbidity, markers of inflammation and other factors that contribute to aging and death. According to the authors, seniors may need certain dietary supplements to improve their microbial health
  • People over 60 can have as much as 1,000-fold less "friendly" bacteria in their guts compared to younger adults, and increased levels of disease-causing microbes
  • Previous research found that consumption of the probiotic strain known as Bifidobacterium lactis resulted in increases in both the number and disease-fighting capacity of white immune cells, thereby bolstering the immune system in aging seniors
  • The best way to ensure optimal gut flora is to regularly consume traditionally fermented or cultured foods and avoid sugar and processed foods

By Dr. Mercola

Probiotics, along with a host of other microorganisms, are so crucial to your health that researchers have compared them to "a newly recognized organ." In fact, your microflora – a term used to describe the bacteria, fungi, viruses and other microbes that make up your microbial inner ecosystem – impact far more than your digestive tract.

Mounting research indicate the bacterial colonies residing in your gut may play key roles in the development of cancer, asthma, allergies, obesity, diabetes, autoimmune diseases and even brain-, behavioral- and emotional problems like ADHD, autism and depression.

Recent research also shows that your diet, and subsequently the microorganisms present in your gut, can affect how well you age.

The study was published in the journal Nature1, and some of the findings were surprising: the microflora in persons in long-term care not only was less diverse, but significantly correlated with measures of frailty, co-morbidity, markers of inflammation and other factors that contribute to aging and death. According to the authors, the implications of these findings are that senior citizens may need certain dietary supplements to improve their microbial health.

Probiotics Become Increasingly Important as You Age

Previous research has shown that around age 60, there is a significant drop in the number of bacteria in your gut. According to Dr Sandra McFarlane from the microbiology and gut biology group at the University of Dundee, people over 60 typically have about 1,000-fold less "friendly" bacteria in their guts compared to younger adults, and increased levels of disease-causing microbes2, making them more susceptible to gastrointestinal infections and bowel conditions like IBS.

As you age, your cellular immunity also declines.3 These are the white cells that are absolutely critical to your ability to fight infection and life-threatening diseases such as cancer. A nine-week long New Zealand study4 of seniors between the ages of 63 and 84 found that consumption of the probiotic strain known as Bifidobacterium lactis resulted in increases in both the number and disease-fighting capacity of white cells. In fact, the greatest improvement was seen in seniors with the worst immune system responses prior to the study.

Your Gut Bacteria Help Protect Against Food-Borne Illness

Other recent research has found that Lactobaccilus reuteri, one of the more than 180 species of Lactobacilli, commonly found in the human gut, can help protect against foodborne infection5. However, just because a study has not been done with a particular strain does not mean it is not effective.  These studies need to be paid for and most are not done unless there is a potential to commercialize a strain.  Nevertheless, according to an article in the Arizona State University news blog:

"Their results demonstrate that this beneficial or probiotic organism, which produces an antimicrobial substance known as reuterin, may protect intestinal epithelial cells from infection by the foodborne bacterial pathogen Salmonella. The study examines for the first time the effect of reuterin during the infection process of mammalian intestinal cells and suggests the efficacy of using probiotic bacteria or their derivatives in future therapies aimed at thwarting Salmonella infection.

... The results of this study may provide fundamental knowledge for development of new probiotics and other functional food based strategies... Intestinal infections by non-typhoidal Salmonella strains induce diarrhea and gastroenteritis, and remain a leading source of foodborne illness worldwide. Such infections are acutely unpleasant but self-limiting in healthy individuals. For those with compromised immunity however, they can be deadly and the alarming incidence of multi-drug resistant Salmonella strains has underlined the necessity of more effective therapeutics.

The use of benign microorganisms offers a promising new approach to treating infection from pathogens like Salmonella and indeed, L. reuteri has been shown to help protect against gastrointestinal infection and reduce diarrhea in children."

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Remember, 90 Percent of the Genetic Material in Your Body is NOT Yours

For every cell in your body there are about ten bacterial cells. The microflora in your gut plays an active role in a wide variety of diseases, and, naturally, it stands to reason they affect your health status throughout your life. For the reasons mentioned above, the importance of probiotics increase with advancing age, but maintaining a healthy gut is really essential from birth onward.

If you want to dig into the research, check out the Human Microbiome Project (HMP)6, whose goal is to characterize microbial communities found at multiple human body sites and to look for correlations between changes in the microbiome and human health. There you can find 15 demonstration projects investigating the role of microflora and conditions like psoriasis, Crohn's disease, obesity, acne and more. A recent article in The Hindu quotes Dr. Julie Segre, senior investigator at the U S National Institute of Health7:

"The Microbiome project is a process of discovery. We need to start thinking of ourselves as super-organisms. This is the second genome – the bacterial genomes as well as the human genomes, all of that is part of the true genetic content of a human."

... The hope is that this research will pave the way for more personalized treatments which could help get our bacterial communities get back on the right track. The Microbiome project sees any one person's microbes as one community. So rather than studying them individually, they are studying the microbes and their genetic material collectively."

Microbes Affect Your Health in a Myriad of Ways

Researchers have also discovered that your gut bacteria play key roles in:

  1. Behavior: A study published in Neurogastroenterology & Motility8 found that mice lacking in gut bacteria behave differently from normal mice, engaging in what would be referred to as "high-risk behavior." This altered behavior was accompanied by neurochemical changes in the mouse brain. According to the authors:
  2. "Bacteria colonize the gut in the days following birth, during a sensitive period of brain development, and apparently influence behavior by inducing changes in the expression of certain genes."

  3. Gene Expression: Your gut flora is a very powerful epigenetic variable. As noted above, researchers have also discovered that the absence or presence of gut microorganisms during infancy permanently alters gene expression.
  4. Through gene profiling, they discerned that absence of gut bacteria altered genes and signaling pathways involved in learning, memory, and motor control. This suggests that gut bacteria are closely tied to early brain development and subsequent behavior. These behavioral changes could be reversed as long as the mice were exposed to normal microorganisms early in life. But once the germ-free mice had reached adulthood, colonizing them with bacteria did not influence their behavior.

    In a similar way, probiotics have also been found to influence the activity of hundreds of your genes, helping them to express in a positive, disease-fighting manner.

  5. Diabetes: Bacterial populations in the gut of diabetics9 differ from non-diabetics, according to a study from Denmark. In particular, diabetics had fewer Firmicutes and more plentiful amounts of Bacteroidetes and Proteobacteria, compared to non-diabetics. The study also found a positive correlation for the ratios of Bacteroidetes to Firmicutes and reduced glucose tolerance. According to the authors: "The results of this study indicate that type 2 diabetes in humans is associated with compositional changes in intestinal microbiota."
  6. Sugar nourishes pathogenic bacteria, yeast, and fungi in your gut, which may actually harm you more than its ability to promote insulin resistance.  One of the major results of eating a healthy diet (low in sugars and grains; high in whole raw foods and fermented or cultured foods) is that it allows your beneficial gut bacteria to flourish, and they secondarily perform the real "magic" of restoring your health. There are other studies that show optimized gut flora can help prevent type 1 diabetes.

  7. Autism: Establishment of normal gut flora in the first 20 days or so of life plays a crucial role in appropriate maturation of your baby's immune system. Hence, babies who develop abnormal gut flora are left with compromised immune systems and are particularly at risk for developing disorders such as ADHD, learning disabilities and autism, particularly if they are vaccinated before restoring balance to their gut flora.
  8. To get a solid understanding of just how this connection works, I highly recommend reviewing the information shared by Dr. Natasha Campbell-McBride in this previous interview.

    Download Interview Transcript

  9. Obesity: The make-up of gut bacteria tends to differ in lean vs. obese people. This is one of the strongest areas of probiotic research to date, and you can read about a handful of such studiesin my previous article, Probiotics May Help Fight Obesity. The bottom line is that restoring your gut flora is an important consideration if you're struggling to lose weight. Studies have also documented the beneficial effects of probiotics on a wide variety of disorders, including the following10:
  10. Inflammatory bowel disease (IBD) Irritable bowel syndrome (IBS) Constipation and diarrhea
    Colon cancer Eradication of H. pylori infection, which is associated with ulcers Vaginal infections
    Strengthened immune response Eczema Rheumatoid arthritis
    Cirrhosis of the liver Hepatic encephalopathy Chronic fatigue syndrome

How to Optimize Your Gut Flora

A healthy diet is the ideal way to maintain a healthy gut, and regularly consuming traditionally fermented or cultured foods is the easiest way to ensure optimal gut flora. Healthy options include:

Fermented vegetables of all kinds  (cabbage, carrots, kale, collards, celery spiced with herbs like ginger and garlic) Lassi (an Indian yogurt drink, traditionally enjoyed before dinner) Tempeh
Fermented raw milk such as kefir or yogurt, but NOT commercial versions, which typically do not have live cultures and are loaded with sugars that feed pathogenic bacteria Natto Kim chee


Just make sure to steer clear of pasteurized versions, as pasteurization will destroy many of the naturally occurring probiotics. For example, most of the "probiotic" yogurts you find in every grocery store these days are NOT recommended. Since they're pasteurized, they will be associated with all of the problems of pasteurized milk products instead. They also typically contain added sugars, high fructose corn syrup, dyes, and/or artificial sweeteners; all of which are detrimental to your health.

Consuming traditionally fermented foods will also provide you with the following added boons:

  • Important nutrients: Some fermented foods are excellent sources of essential nutrients such as vitamin K2, which is important for preventing arterial plaque buildup and heart disease. Cheese curd, for example, is an excellent source of both probiotics and vitamin K2. You can also obtain all the K2 you'll need (about 200 micrograms) by eating 15 grams, or half an ounce, of natto daily. They are also a potent producer of many B vitamins
  • Optimizing your immune system: Probiotics have been shown to modulate immune responses via your gut's mucosal immune system, and have anti-inflammatory potential. Eighty percent of your immune system is located in your digestive system, making a healthy gut a major focal point if you want to maintain optimal health, as a robust immune system is your number one defense system against ALL disease
  • Detoxification: Fermented foods are some of the best chelators available. The beneficial bacteria in these foods are very potent detoxifiers, capable of drawing out a wide range of toxins and heavy metals
  • Cost effective: Fermented foods can contain 100 times more probiotics than a supplement, so just adding a small amount of fermented foods to each meal will give you the biggest bang for your buck
  • Natural variety of microflora: As long as you vary the fermented and cultured foods you eat, you'll get a much wider variety of beneficial bacteria than you could ever get from a supplement

How to Identify a High Quality Probiotic Supplement

That said, if you don't enjoy the taste of fermented foods, taking a probiotic supplement is definitely advised. However, before you give up on fermented foods, it is best to start with small amounts like half a teaspoon and use them as a condiment integrated with your food, like as a salad dressing.  If you still don't want to use them then it is important to note that while I do not generally advocate taking a lot of supplements, a high quality probiotic is an exception. I recommend looking for a probiotic supplement that fulfills the following criteria, to ensure quality and efficacy:

  • The bacteria strains in the product must be able to survive your stomach acid and bile, so that they reach your intestines alive in adequate numbers
  • The bacteria strains must have health-promoting features
  • The probiotic activity must be guaranteed throughout the entire production process, storage period and shelf life of the product

Through my years of clinical practice, I've found that no single probiotic supplement works for everyone. However, more people seem to respond favorably to Lactobacillus sporogenes than any other probiotic, so when in doubt, that's a great place to start.