Different Theories on How it Works
It is an inescapable fact that how we eat affects how we feel, and how well our bodies function to prevent major disease. There is nothing alternative about the role of diet in health and disease. There is a consensus of agreement that a bad diet leads to disease, and a good diet prevents disease. It is the definition of bad diet and good diet that is the cause of (oftentimes-heated) debate between conventional medicine and complementary medicine practitioners. The conventional approach to a healthy diet is the food group approach taught in the hierarchical food pyramid model. The foods near the bottom of the pyramid (grains, fruits, vegetables) should be eaten in greater quantities than foods near the top of the pyramid (dairy, high protein foods, fats, sweets). This school of thought is a one-size-fits-all, all-foods-fit, more vs. less approach- in other words, a homogeneic diet for heterogeneic individuals. Complementary approaches to a healthy diet might include a vegetarian diet (eliminates the consumption of meat), a macrobiotic diet (traditionally eaten, local, and seasonally grown diet, and one which also balances yin and yang- the universal rhythms of nature) or an ayurvedic diet (each individual makes food choices according to what will best balance their unique constitutional type, or dosha, of which there are three primary types- vata, pitta, kapha), among others.
Nutrition has a tremendous impact on immunity. The immune system protects the body from destructive pathogens and toxins from outside the body, such as bacteria, viruses, and parasites, or from within, such as malignant cells. In simplest terms, the job of the immune system is to identify those things that are self (belonging in the body) and those that are non-self (foreign bodies). When the immune system recognizes non-self bodies, it neutralizes or destroys them by a host of defense mechanisms involving many different organs, structures, and substances. These defense mechanisms include white blood cells, bone marrow, the lymphatic system (spleen, tonsils, thymus, and lymph nodes, as well as lymph fluid circulating in lymph vessels, specialized cells found in various tissues, and specialized substances found in the blood).
The immune system defends the body so attentively and silently that most people are unaware of the smorgasbord of potentially harmful pathogens and toxins they encounter in the course of a day. While some people do not get sick even when exposed to these pathogens and toxins, many do. In the past thirty years, systematic studies have confirmed that protein-calorie malnutrition and or moderate deficiencies of trace minerals and vitamins (particularly zinc, iron, selenium, vitamins A, B6, C, E and folate) result in significantly impaired immune response, leading to frequent severe infections and disease, and ultimately resulting in increased mortality. Researchers continue to explore whether mixtures of specific nutrients might restore immune function. Preliminary studies suggest that glutamine and arginine (nonessential amino acids), dietary nucleotides, and omega-3 fatty acids may hold promise in stimulating immune function. The best way to prevent and/or minimize the chances of becoming ill is to take preventative lifestyle measures to strengthen the immune system, and ultimately the body. A varied natural whole-foods plant-based diet, with adequate amounts of nutritive and non-nutritive compounds, plays a critical role in maintaining the health of the immune system.
Eating introduces an enormous load of potential antigens into the body and into contact with the intestinal wall. Of these antigens, a small fraction may escape degradation and stimulate the gut lymphoid system. For unknown reasons the oral tolerance of some people varies from the norm, producing an inflammatory allergic reaction to food components which ultimately leads to increased intestinal permeability and transfer of antigens. This process of antigens and microorganisms being released into circulation from the permeable gut is known as translocation or leaky gut. Many common pharmaceuticals also contribute to this phenomenon of increased intestinal permeability. The incomplete digestion, absorption, and metabolism of food components with the concomitant sequelae associated with the inflammatory processes and increased intestinal permeability compromise an already overburdened immune system, posing the risk of malnutrition and infection. Avoidance of food allergens and maintenance of protective gut microflora is crucial for minimizing gut inflammation, infectious disease, and malnutrition.
Nutrition also plays a critical role in the bodys activation or detoxification of chemicals. The body pool of toxins consists of toxins consumed voluntarily through the ingestion of alcohol, tobacco, drugs/medications, involuntarily through industrial and agricultural pollutants that end up in the food, air, and water supply, and internal toxins produced from energy metabolism in the cell and bacterial fermentation in the gut. The body undergoes detoxification processes by eliminating waste products (toxins) through urine, feces, sweat, and liver detoxification. The liver is a chemical detoxification powerhouse, having the ability to bind toxins, split toxins, and neutralize toxins through Phase I and Phase II enzyme pathways to convert into a more stable and excretable form. The liver also has the ability to bioactivate these toxins into unstable highly reactive compounds. These enzyme pathways rely on nutrients (protein, carbohydrates, fat, vitamins, minerals, and trace elements) and non-nutritive compounds (fiber and phytochemicals) to assist in the bioactive and detoxification processes. Adequate nutrition helps to insure proper functioning of both Phase I and Phase II detoxification by inhibiting activation of toxins, and enhancing detoxification of toxins. Nutritionally inadequate intakes of nutrients and non-nutritive compounds involved in Phase I and II enzyme pathways can significantly impair detoxification, allowing a progressive build-up of toxic metabolites.
Decades of research make it evident that the act of eating is clearly of great consequence, promoting life and health or disease and death. Every day new scientific discovery empowers individuals with new prospects for health and longevity simply by the choice of what they put into their bodies. However, apart from the treatment of gross nutritional deficiencies, medically prescribed diets (diabetes, renal disease), and rare metabolic disorders, nutrition therapy generally falls outside of mainstream conventional medicine practices. Nutrition therapy in an integrative model is used to prevent and treat illness, and to restore the body to a healthy balanced functioning level. Nutrition therapy incorporates principles of nutrition, biochemistry, physiology, genetics, behavioral science, and food science to address the health needs of each individual. Nutrition therapy, despite myriad theories and practices, can be broadly divided into two approaches: dietary modification (a food as medicine approach), and dietary supplementation.
Conditions it Works Best For
Nutritional therapy may be of help with almost any condition or ailment, as food is the basis and fuel for all the chemical processes that take place in the body. As a preventative measure, many studies have shown that plant-based diets rich in grains, vegetables, fruits, legumes, nuts, seeds, herbs and spices can reduce incidence of obesity, heart disease, hypertension, cancer, diabetes, kidney disease, and gallbladder disease. There is also evidence that exclusion or elimination diets are beneficial in managing various chronic conditions, including rheumatoid arthritis, asthma, hyperactivity, migraine, and PMS.
Federally funded research is under way examining the beneficial effect of nutritional therapy on various conditions including adenomatous polyp recurrence, diabetes, non-melanoma skin cancer, cardiovascular health, care of the elderly, HIV, and prostrate cancer. Based on medical society and clinical guidelines and recommendations, nutritional therapy is now accepted as part of a therapeutic regimen for the treatment of postmenopausal osteoporosis, diabetes, hypertension, and coronary heart disease.
Disease management is not the only time and reason to utilize nutrition therapy. In fact, as disease does not happen overnight, but from a lifetime of deficiencies and excesses, it is essential to recognize that nutrition therapy can, and should, be applied at any time during the lifecycle from infancy to old age. Adequate nutrition before and during pregnancy has greater potential for long-term impact than it does at almost any other time. Nutrition in infancy is also critically important for growth and later development. Optimal nutrition during childhood to adulthood will very likely favorably modify some of the degenerative changes of aging. Nutritional health in the later years is not only influenced by the present physical state and activity of the individual, but also by the long-standing food habits to which a person has been subjected throughout growth and maturity.