Understanding diet preferences

New research study
by Michael Klaper, M.D.
For whatever pressing reason you choose to consider, personal health, ecological sustainability, economic stability, or world hunger, we must learn as much as possible about how the human body functions when it is fueled largely or exclusively by plant-derived foods. The need to evolve our dietary choices towards plant-based foods grows ever more urgent as the human population continues to balloon towards ten billion people by the middle of the coming century. The land, water and other resources that are needed to produce meat, will inevitably grow much more costly. It will become increasingly necessary to dedicate arable acreage to growing plant foods that can be consumed directly by humans. A better understanding of vegan and vegetarian nutrition and physiology will permit the development of guidelines so that every person choosing to be nourished by vegetarian foods can do so with optimal health.
Over the last ten years, clinical experience and laboratory research has underscored the concept of biologic individuality. I have great interest in finding out why some people appear to do better on a pure vegetarian (vegan) diet, while others have difficulty maintaining one (the blood type theory lacks evidence - see Jan/Feb 1999 issue). Are humans metabolically required to eat the flesh of other animals for optimal health and function? Are there physical or laboratory markers that can identify people who are especially suited (or unsuited) to sustaining themselves on plant-based diets? Can nutrients consumed in animal-based foods be identified and successfully replaced by plant-derived foods?
'Why is it that some people seem to thrive on a vegetarian diet, while others report that they tried it but didn't feel very good.'
I believe we need to gather as much reliable data as possible. Through the Institute of Nutrition Education and Research, we will be conducting an in-depth, long-term nutrition study on the health effects of vegan diets. The research will consist of a registry, tracking thousands of vegans over many years, in order to document the course of their health, as well as causes of their incidence of disease and mortality. We will also be conducting non-invasive laboratory tests on blood, urine, saliva, etc. of volunteers who consume vegan, vegetarian and omnivore-type diets in order to explore key subjects in vegan physiology and nutrition. These subjects include protein requirements, blood type frequencies, mineral balance, fatty acid metabolism, carnitine function, immune status and many other critical areas.
Have you ever wondered why it is that some people seem to thrive on a vegetarian diet while others report that they tried to be a vegetarian, but they didn't feel very good? When these individuals added some meat back into their diet they felt better. Are these individuals genetically predisposed to meat eating or is there another explanation? I offer some possibilities...
At the Institute of Nutrition Education and Research we recognize that there are significant metabolic differences between people. It may well be that some of these differences may propel certain individuals towards flesh consumption. It may be, however, that the cause is not so much genetic, as acquired after birth. Virtually every person who reports adding meat back into a previously vegetarian diet is an individual who was raised on a meat-based diet.
The kind of foods one eats in their early years may set biochemical patterns that last a lifetime. For example, the human body can synthesize, from simpler molecules, some essential substances like carnitine (required for energy production) and some long-chain fatty acids (e.g. EPA, DHA, etc., needed for hormone function, membrane synthesis, etc.). People who eat meat ingest these substances. It may be that a life-long omnivore becomes functionally dependent upon a diet that contains these pre-formed nutrients. As adults, if they suddenly adopt a vegetarian lifestyle, where the foods are essentially devoid of pre-formed carnitine, EPA, DHA, etc., they may find that they are unable to synthesize all the energy-generating compounds, fatty acids, and other molecules they may require.
After months or years on a flesh-free diet, these individuals might experience deterioration of their health or energy, only to feel better upon resumption of meat ingestion. This may seem like confirmation that they are "natural meat eaters". However, it may be evidence of an acquired dependency on flesh-borne nutrients formed through early eating patterns. If this is the case, it may be possible to prevent, repair, or at least compensate for these imbalances through provision of additional nutrients, removal of inhibiting substances in the diet, varying combinations of food, etc., utilizing foods of plant-based origin or gradually removing meat from their diet. In my experience, these problems are not encountered in people raised on vegetarian diets from infancy.
It is known that, in some people, noticeable improvements in the way they feel can be achieved by merely adjusting the proportions of proteins, fats and sugars. Changing the proportion of raw vs. cooked foods can similarly have beneficial effects. Some people who feel that their health has improved after adopting a "zone" or "blood type" diet may actually be benefiting from just eating less carbohydrates, more protein, etc.
An additional thought, less than optimal function on a plant-based diet (or any diet) may not stem from a nutrient deficiency at all, but from other health conditions, like digestive dysfunction, malabsorption, parasites, adverse immune reactions, etc. To me, these are far more likely mechanisms that could explain the "failure-to-thrive" syndrome occasionally seen in vegetarians and vegans. Much more research is needed to obtain the answers to so many questions in this essential, but subtle science.
Through the Institute, we plan to investigate whether some of the individuals who re-introduced animal products into their diet could have achieved similar effects by altering their selection and quantities of plant-based foods. A goal of our research is to develop science-based guidelines to aid anyone who chooses to nourish their body on exclusively plant-based foods to do so with optimal benefits to their health and well being.