In the Institute of Human Nutrition (directed by Alan Jackson), Philip Calder, Bob Grimble and Liz Miles have focused on identifying the influence of nutrients, especially fatty acids and antioxidants, on: inflammatory and immune responses of relevance to host defence; inflammatory disorders, cardiovascular disease and clinical nutrition; the mechanisms of action of these nutrients; nutrient-genotype interactions which confer responsiveness; and on programming effects.
The group has demonstrated that omega-3 fatty acids stabilize advanced atherosclerotic plaques, decreasing the risk of acute cardiovascular events. Also, production of the inflammatory cytokine TNFa by mononuclear cells is more sensitive to the effects of omega-3 fatty acids in some genotypes. Again, to translate basic discoveries into the clinic, the health and cost benefit of a simple tool to identify and direct the care of patients with poor nutritional status has been demonstrated [Marinos Elia, Steve Wootton] and recommended for acceptance into clinical practice (MUST tool). The NICE Nutrition Guideline Group (Mike Stroud, chair) has facilitated the transition from research at Southampton into national policy.
The overall objective for the research within Human Nutrition is to determine how biological, psychological or sociological constraints, mediated by food and nutrient availability, limit the ability of individuals or groups within society to function optimally, and to derive suitable interventions to remove the limiting constraints. Our objective is to enable health to be maintained at all ages, and to enable the rapid return to health for those in whom any disease process has an important nutritional component.
Our specific research projects are designed to understand:
- the energy and nutrient requirements for the processes which enable normal growth and development,
- the energy and nutrient requirements which enable the body to withstand insult from the environment.
Vulnerability is most frequently the result of a measure of social exclusion, physical and emotional poverty. At all stages of life the current and past the nutritional environment plays a critical part in determining overall health. Access to adequate food of good quality is a privilege which is not yet enjoyed by many and accounts for a substantial part of ill-health present in society. Thus there is a direct link between our two objectives based upon the observation that in part the ability to withstand environmental insults is set during early life as a result of the interaction between an individual's genes, and the nutritional environment during early growth. An understanding of the biological and sociological limitations to function, and the link between the two, is a pre-requisite for determining the most cost effective solutions for the population at large.
We have developed a rodent model in which metabolic function during postnatal life is set by dietary variations in the mother during pregnancy. Modifications of the macronutrient content of the mother's diet within the habitual range of consumption leads to a resetting in the unborn fetus of key regulatory centres in the brain, expressed as altered hormonal responses and modified metabolic capacity for immune and inflammatory responses, hepatic, renal and cardiovascular function. These effects appear to be modulated by epigenetic and non-genetic intergenerational changes.
Our clinical studies explore the changes in micronutrients, lipid and protein metabolism which underlie the complex inflammatory and immune responses associated with cardiovascular disease, inflammatory bowel disease, cystic fibrosis and HIV/AIDS. With international collaborators we have been especially interested to determine how common nutritional deficiencies found during pregnancy, such as iron, folate and vitamin A, interact to limit the normal development of the unborn child. We have shown that factors, which determine the rate of protein synthesis and amino acid oxidation in the mother relate directly to the growth of the fetus.
We are carrying out population studies to determine the most effective interventions to alleviate ill-health. We are particularly interested in food-based dietary interventions which will alleviate poor nutrition and access to diets of good quality. Together with the community health trust we are exploring interventions to improve low birth weight amongst women who derive from the Indian subcontinent and other at risk groups. Currently, we are assessing the effectiveness of a simple screening tool to identify those at risk of malnutrition in the community, especially amongst the elderly, and suitable interventions to reduce hospital admission, length of stay and complications.
