Nutritional medicine is a holistic approach to the interactions of both nutrition and environment on human health. Nutrients are the building blocks of our physical body. When the body is supplied with the correct balance of foods, vitamins and minerals we remain healthy. All humans are unique in terms of biochemistry, metabolism, anatomy and genetics. Our internal environment differs in gut flora, integrity of the intestinal wall and the immune system. All of these affect our ability to process foods, absorb nutrients and detoxify and expel wastes.When assessing nutritional status we need to include the impact of the external environmental factors. These include exposure to toxicity from heavy metals, fertilizers, pesticides, synthetic chemicals including pharmaceutical and recreational drugs. In addition,  food additives, flavorings and colorings or particular foods themselves may lead to sensitivities, allergies and intolerances. Chronic parasitic, fungal, bacterial and viral infections can disturb our internal environment.  Poor sleep and psycho-social stresses also affect and our ability to cope effectively and impact on our health.