By William Parker, PhD, Associate Professor of Surgery, Duke University School of Medicine
Post-industrial cultures face a barrage of pandemics of allergic and autoimmune diseases. (Pandemics are epidemics which occur in multiple regions of the planet simultaneously.) These pandemics involve a hyperactive immune system which attacks harmless environmental and self-derived targets, producing allergic and autoimmune diseases, respectively.
The shocking fact is that, for the most part, we know exactly why this happens. These pandemics are preventable.
Each autoimmune disease and each allergic disease has three important contributors. The first is called the trigger. The second is genetics. The third is the actual cause of the allergic and/or autoimmune disease. Most of the triggers and the genetics occur (and have occurred for many generations) without the pandemics, so these are not the actual cause, per se. Thus, even though the triggers and the genetics are important, they are not the cause. This is fortunate, since there is nothing we can do about genetics, and it is generally impossible to avoid all triggers which might stimulate the onset of allergy and autoimmune diseases. We simply can’t live in a sterile bubble and avoid every dust mite allergen, mold spore, virus and pollen grain on the planet.
This leads us to the third factor behind pandemics of allergic and autoimmune disease. This is the actual cause. This cause involves changes in our culture so that our genetics do not match our environment. These changes have profoundly affected the “ecosystem of the human body”, which we call the human biome. We know of four primary ways that we have altered the ecosystem of the human body, making it susceptible to allergic and autoimmune disease.
- Depletion of “keystone” species from the ecosystem of the human body affects both allergic and autoimmune disease. The introduction of toilets, water treatment facilities, and modern medicine into Western culture had some expected results. We got rid of many infectious diseases and parasites. Unfortunately, this nice result had some unexpected consequences: Our immune systems are now essentially “bored”, and like teenagers with nothing to do, are out causing trouble. The species we lost from our ecosystem turned out to be “keystone”: without them, the system gets unbalanced. There is very little to be done about this at the present time by the typical person. We absolutely do not recommend that people stop good hygiene practices. Washing your hands and your baby prevents the spread of pathogens, and this is important. On top of that, you can’t get the keystone organisms (sometimes called “old friends”) that the immune system really misses by practicing sloppy hygiene. Those keystone species are long gone from our environment. Short of obtaining some black-market organisms of unknown quality in a desperate, death-defying act, we must wait on modern medicine to fix this problem by re-introducing the right organisms in a controlled and safe fashion. Fortunately, the other three factors listed below can be controlled by the typical individual. Because this first factor is out of our control, it is extremely important to control the other three. We already have this one strike against us, and we don’t need any more.
- Psychological stress is well recognized as a factor that influences both allergic and autoimmune disease. It is unclear whether Western culture is particularly prone to psychological stress compared to traditional (agrarian and hunter-gatherer) cultures, but it is clear that increased psychological stress is bad for our immune health. It pays to reduce our psychological stress.
- Vitamin D deficiency, like the other factors described above, affects both allergic and autoimmune conditions. Inadequate levels of vitamin D were probably relatively rare before the industrial revolution, when sunlight was the main source of light for our labor, but this problem now affects over half the population due to the use of indoor lighting and sunscreen. Sporadic exposure to the sun which causes severe sunburn and subsequent skin cancer is not a good option. Fortunately, we don’t need to move our offices out of the air-conditioning to get our vitamin D. Supplements are available in the grocery store. It pays to keep our vitamin D levels up.
- Deprivation from mother’s milk is yet another factor which affects both allergic and autoimmune disease. By the time our babies are born, they were already exposed to an environment (the womb) affected by depletion of keystone species. Our babies may have also been exposed to an environment where psychological stress and inadequacy of vitamin D have affected their immune system. To be deprived of breast milk adds further to the potential milieu of insults suffered by the immune system.
Research in my lab at Duke has shown very large differences between breast milk and baby formulas in terms of how they help a baby’s healthy, necessary bacteria grow. Simply put, if you mix normal bacteria with breast milk in a test tube, the bacteria do the normal things that they would do in your baby. If you mix the same exact bacteria with baby formula in a test tube, the bacteria grow in a completely different way. The normal mode of bacterial growth in the gut is to form protective films of living bacteria we call “biofilms”. Mother’s milk helps this happen. Infant formulas, on the other hand, induce the bacteria into prolific growth as single, free-floating cells. The bacteria grow very fast, but they remain nomadic and don’t stick together. The difference is huge and can easily be seen in a test tube with a simple experiment. Infant formulas are just not the same as mother’s milk in terms of how they affect healthy bacterial growth.
We know that the development of our baby’s immune system is dependent on the friendly bacteria in our baby, and now we know how much the normal growth of this friendly bacteria depends on breast milk. With this in mind, it seems more than worthwhile to avoid yet another risk factor. It pays to give our babies breast milk.
Thus, we see that our environment has changed. Just as obesity has become pandemic because we no longer need exercise to survive and because extremely rich food is widely available, so have pandemics of immune disease emerged because of changes in our environment. Fortunately, we can compensate for most of these changes, and it is hoped that modern medicine will soon take care of the loss of keystone species that affects us all even if we do our best to control all other factors.
Much of this information is taken from a recent review entitled “A prescription for clinical immunology: The pills are available and ready for testing.” (10-pages with 50 references: Current Medical Research and Opinion, 28:1193-1202) Much of this information is also available in an article entitled “Reconstitution of the human biome as the most reasonable solution for epidemics of allergic and autoimmune diseases.” (11 pages with 109 references: Medical Hypotheses,77:494-504.)
The author, William Parker, is an immunologist at Duke University who has published numerous peer-reviewed papers describing the interaction between the immune system and the environment. The ideas that William presents here were developed in collaboration with a diverse team of scientists that includes Michael Muehlenbein, an anthropologist, Sarah Perkins, a parisitologist, and Staci Bilbo, a neurobiologist.