We are what we eat – our bodies are literally built from the food we eat. The tissues and organs in our bodies are continually streaming with new cells being created as old cells are replaced. Each tissue and organ has a characteristic direction of streaming. In the cornea of the eye, for example, new cells are born around the edge of the cornea and migrate toward the centre as they age and mature over the course of a few days and eventually disappear again. The renewal of the material in our cells is even more rapid than the cells themselves. The more metabolically active a tissue, the faster this renewal. A decline in this rate of streaming and renewal is a characteristic of aging. In fact, aging is the result of regeneration and replacement of cells not keeping up with their degeneration. The importance of a robust metabolism and adequate nutrition is very clear, and consuming a diet that supports this is the foundation of health.
Although there are universal principles that apply to health-promoting diets, like nutrient density, minimal toxicity, well-roundedness, balance, etc., the particulars of such a diet is specific to each individual. Various factors like age, gender, genetic background, non-genetic inheritance, light exposure, amount and type of physical activity, season of the year, medical history, attitudes surrounding food and eating, historic diet, occupation, stress levels, coping strategies, social context, environmental exposures, digestive health and composition of intestinal flora all impact on the nutritional requirements of individuals. Various individual food intolerances can also dictate which specific foods are well tolerated and which aren’t.
Even though it is always best to get our nutrition from good quality food, some situations warrant the judicious use of nutritional supplements to correct a deficiency or to augment nutrients that are used at higher rates than can practically be supplied by diet alone. In such situations supplementation can be extremely therapeutic.