Staff PhD

Health promoting properties of milk from cows fed green plant material - The role of phytanic acid

Brita Ngum Che

Background

The increasing outbreak of stroke, and cardiac malfunction, obesity and type 2 diabetes calls for a growing need of interventional diagnosis and treatment of the Metabolic Syndrome (MS). Food stuff such as milk is a global accessible commodity and has long been suspected for its contribution to MS, due to its high concentration of saturated fatty acid. However, recent finding has shown that consumption of milk fat reduces the disposability to MS, owing to decreased fasting insulin-levels. More so, patients suffering from myocardial infection have a significantly lower intake of diary fat than healthy control subjects.

This “milk-fat-paradox”, may be attributed to the presence of health-promoting bioactives in milk fat, which overrules the impact of the saturated fatty acids. Diary fat is characterized by a very high concentration of short and medium chain fatty acid, as well as branched-chain saturated fatty acids, e.g. the chlorophyll-metabolite; phytanic acid. Since phytanic acid is derived from chlorophyll, intake of green plant material is a prerequisite for its transfer to cow milk.

Phytanic acid is of particular interest in this context because through a PPAR-dependent manner, it specifically skews the metabolism towards increased fatty acid ?-oxidation. It also induces the differentiation of brown adipose tissue and glucose uptake in hepatocytes. Thus activation of these mechanisms will reduce lipid deposition and improve glucose homeostasis, thereby lowering the risk of developing insulin resistance; a core phenomenon in MS.

Aim

This project is directed towards exploiting the health-promoting properties of milk from pasture-fed cows. This will potentially create a scientific base for the development of interventional treatments, through production of differentiated milk targeting specific risk groups. The hypothesis is that milk from pasture-fed cows has an inhibitory or reversible impact on insulin resistance, partly due to its rich content of chlorophyll-derived metabolites.

Research Outline

The bioavailability of phytanic acid as well as its concentration in green-fed cow milk versus control milk types shall be analyzed using GC-MS technique. In order to detect insulin-sensitive bioactives in diary fat, fractionation and identification of PPAR-activating shall be performed using transcription factor assay kits. Subsequently, the effects of feeding strategies on the PPAR-activating fractions shall be studied.

In order to determine phytanic acid’s effect on glucose homeostasis and insulin-dependent signalling, several culturing techniques shall be used to introduce pure phytanic acid or plasma samples from phytanic acid-fed mouse and humans into murine and porcine myotube systems that have been screened using flowcytometry. Hereunder, the chosen area of focus shall be the insulin-induced glucose uptake and glycogen synthesis, which shall be determined using radioactive tracers and enzyme assays. Also, the signalling cascade from the insulin receptor, through PPAR activation and fatty acid oxidation shall be traced by quantitative PCR and western blotting. The capability of phytanic acid in inhibiting or reversing the insulin resistant effect will also be carried out.