Deoxyribonucleic acid (DNA), the blueprint for life, is contained in every cell of the human body and every living organism for that matter. Everything about you—from the color of your hair to the hand you write with—comes from tightly coiled helical structures inside your cells. That’s pretty amazing right! For a long time, however, we were taught that DNA was fixed. If you struggled to lose weight, you would blame it on bad genes. But new discoveries have shown us that DNA is not our destiny.
After the Human Genome Project, scientists and clinicians were able to use a trove of tools and technologies to explore how genes affect complex diseases. Based on various biomedical studies, researchers have developed sophisticated diagnostic tools to identify a patients’ risk for diseases, such as diabetes, cardiovascular disease, and cancer. Taking it one step further researchers are designing more sophisticated treatment modalities that target the genes involved in diseases.
If DNA is fixed, you’d be right to wonder how new treatments can change DNA. Truth is DNA is only part of the story of how you become, well, you. The epigenome helps to explain the rest of the story. Epigenome refers to the layer of specialized chemical tags that lie above the DNA-histone complex (DNA wraps itself around histones so it can fit inside of cells.) The epigenetic tags shape the structure of the genome. Epigenetic tags can tighten or relax genes, which turns genes on or off. What determines whether epigenetic tags are turning genes on or off? The environment, nutrition, and lifestyle choices all affect the epigenome. In essence, the epigenome is the middleman between the external environment and our genes. Biomedical research drives us closer to understanding how the environment and genetics plays a role in our health. At the same time, scientists are exploring how microorganisms inhabit the human body influences health.
In the United States, the Human Microbiome Project is one of many international efforts geared toward studying microbial communities that reside in various organs in the body, such as the lung, urogenital tract, and gut. The human microbiome consist of a collection of organisms that are much smaller than our cells, yet they make up 99% of the body’s total genetic information—outnumbering human cells ten to one. So it makes sense that the expansive microbial genome plays an essential role in health and disease.
Anyone who has gone to the dentist because of tooth decay, gingivitis, or periodontal disease, for example, has experienced the effects of microbial imbalances. The overgrowth of nasty bacteria in plaque in the mouth eats away at protective teeth enamel. And if it is not caught in time it progresses beyond just the tooth enamel and works into the gums. Bacteria and inflammation eventually destroys the gums and the supportive tissues that keep teeth firmly seated in their sockets. Taking things one step further, oral bacteria has long been associated to cardiovascular disease. Various studies have also linked microbial flora in the lungs to respiratory disease, type 2 diabetes, and irritable bowel syndrome. Researchers found that gut microbes differed between lean and overweight individuals. In particular, the microbial communities in obese individuals produced proinflammatory molecules and a toxin called lipopolysaccharide (LPS), which promotes chronic inflammation and triggers insulin and leptin resistance to cause weight gain.
Is the Microbiome Fixed or Flexible?
It is definitely flexible! Like human DNA, the microbial DNA is inherited too. Infants pick up their microbiome as they pass through the birthing canal. A mother’s vaginal microbiota is composed of healthy bacteria. Cesarean sections, unfortunately, do not afford children the same beneficial microbiome as a vaginal birth. Furthermore, a cesarean delivery has been associated with childhood obesity, as well as an increased risk for asthma, eczema, and type II diabetes. So if possible it is better to opt for a vaginal delivery.
But just as the epigenome allows DNA to be modified, the microbial genome can be influenced by environmental factors, such as the environment and diet. While more work is needed to understand the effects of microbiome on human health, data shows that microbes are readily transferable from person to person and person to environment. Which is a good thing because it means that our microbial genome is not fixed and they are in fact things that we can do to enhance the microbial environment in our bodies to promote health not disease. Here are a few tips:
- Drink plenty of water because it keeps your digestive system healthy.
- Consume foods that are high in fiber, which helps digestion run smoothly and prevents constipation.
- Go for a walk or engage in some form of physical activity. Incorporate physical activity into your daily routine because it speeds up digestion by increasing blood flow and tightening up muscles involved in digestion.
- Boost good gut bacteria with foods that contain healthy bacteria, such as yogurt and kefir, or probiotic supplements.
Much like the epigenome, the microbial communities can be modified through diet lifestyle changes.