The research activities of the water soluble vitamin laboratory are directed towards supporting the mandate of Health Canada. Various aspects of these essential micronutrients including their levels and availability in foods, their interactions with other dietary components and their roles in health and disease are investigated. One area of current research is the updating of older methods for measuring water soluble vitamins. Newer methods and modifications of old ones are often more precise or accurate and permit updating or adding vitamin values for existing or new food products to nutrient data files. Use of high performance liquid chromatography methodology permits very accurate separation and detection of different forms and derivatives of individual vitamins found in foods and biological tissues. Microplate modification of standard microbiological assay methods that measure growth response of dependent microorganisms to different levels of particular vitamins extracted from foods, decreases reagent requirements and increases the number of samples that can be measured. Current investigations are looking at vitamin levels in infant formulas and fortified food products used throughout Canada and in unique foods that are potentially important sources of nutrients for indigenous people in Canada. Results obtained contribute to the Canadian Nutrient File and other data bases that are used in nutrition surveys, and contribute to policy decisions and advice concerning vitamin requirements, fortification and recommended intakes. Accurate determination of food vitamin levels are also required to check the need for, efficacy and safety of fortification practices. The recent requirement to fortify cereal-based products with folate to increase intake levels of women at risk of becoming pregnant and decrease risk of occurrence of neural tube defects such as spina bifida demonstrates one area where accurate measure of food vitamin levels is required.
Interactions of different nutrients and other food components with particular vitamins are areas of ongoing research. Using animal models, the influence of folic acid and vitamin B12 and different kinds of dietary fats on aspects of lipid (lipoprotein profiles, lipid peroxidation) and on amino acid (transmethylation, transsulfuration) metabolism are currently being studied. Information derived could contribute to knowledge about metabolic mechanisms and suggest dietary manipulations to influence independent risk factors for coronary heart disease and atherosclerosis including serum levels of different forms of cholesterol and homocysteine. Investigation into the role of dietary fibre on gut bacterial synthesis and availability of folate could suggest alternate means of increasing folate status in target groups while decreasing long term, higher level exposures of potential risk groups such as the elderly and children. Recommendations and policies derived from such studies contribute to the health of all Canadians.