Your immune system is your ticket to a long, healthy life -- or a traitor that turns on you (because of lifestyle choices, genetics, environmental toxins or who knows what) and fuels disease and chronic conditions. You are born with innate immunity -- it lives in your skin and mucous membranes. Its job is to block viruses, bacteria and other harmful substances from entering your body and to alert your body when it's under attack by stimulating production of inflammatory signals. It is made up of secretions and fibers that block the invasion of germs and move them out of the body, and of enzymes in sweat, tears and saliva that kill germs. It also contains dendritic cells that direct other immune system cells to the location of invading pathogens and tentacled macrophages (that means "big mouth" in Greek) that patrol the surface looking for potential infectors to snag.
Your active or adaptive immunity is what develops over time in reaction to invading infections or unhealthy cells that have mutated, such as cancer cells. It's also evoked when you get a vaccination against a specific threat. White blood cells are the army that defends you -- they include lymphocytes (B- and T-cells) and others that target bacteria or take out the trash. This complex system turns out to act and react in ways that researchers are just discovering.
1. High-fat diets hide cancer cells from the immune system, allowing them to thrive. Researchers from MIT, Harvard and Cold Springs Research Laboratory have found that a fatty diet interrupts the conversation between cells in your intestines that help identify rogue cells and immune cells that patrol the gut looking for cancer cells to disable. When they can't talk to each other, you have an increase in your risk for colon cancer.
Overall, when working correctly, immune cells kill off cancer cells. However, when the immune system can't keep up with the challenges thrown at it (often because of destructive lifestyle choices), instead of guarding against cancer, it may help cancer cells thrive.
2. You have memory B- and T-cells. Day to day, B-cells produce antibodies, killer T-cells attack infected tissue and helper T-cells support B-cell production of antibodies. Those antibody levels can sink over time. But there are also versions of T- and B-cells that remember their first encounter with an infection. So, you can battle off repeat exposures to specific culprits -- sometimes for decades. Research shows that people who contracted COVID-19 and then were vaccinated have vast stores of these memory immune cells -- providing extra immunity.
3. When you're sick, some symptoms are NOT from your illness, but from your immune response. If you get a stuffy nose from a cold-producing rhinovirus, it is not the virus that triggered it, but the inflammatory response of your immune system. Infection in your nasal passages causes histamines to be released that then dilate blood vessels and increase the migration of white blood cells to infected tissue lining your nose -- and you get plugged up. When you get the flu, that fever-achy feeling is also from your immune system's response.
4. Frequent gastrointestinal problems (from constipation to gut pain) and slow-to-heal cuts and bruises may signal immune system weakness. Nearly 70% of your immune system is located in your gut! Those gastro woes are likely related to immune-damaging stress, highly processed foods, added sugars and red meat in your diet, along with a lack of fiber-rich fruits and vegetables.
Plus, gut distress weakens the immune system. According to a study in Gut Microbes, you need a healthy gut biome to enable your body to present disease-causing invaders to antibodies and killer T-cells so they can be vanquished.
Bottom Line: Keep your gut and immune system strong and happy with smart choices. Avoid obesity and high-fat foods, eat lots of fiber-rich veggies and fruit, exercise regularly, get quality sleep and -- this may surprise you -- hydrate, hydrate, hydrate. That keeps your immune-cell-transporting lymphatic system flowing smoothly.
Mehmet Oz, M.D. is host of "The Dr. Oz Show," and Mike Roizen, M.D. is Chief Wellness Officer Emeritus at Cleveland Clinic. To live your healthiest, tune into "The Dr. Oz Show" or visit sharecare.com.
(c)2021 Michael Roizen, M.D. and Mehmet Oz, M.D.
King Features Syndicate