Dietary fat act as a source of energy and also play a vital role in the maintenance of cell membrane lipid composition, dietary fat in addition to all these roles also induce effects on gene expression, hence may also change metabolism, growth and also cell differentiation. The regulation of dietary fat on gene expression also depends on the quality and quantity and also the type of fat ingested by an individual. In mammals, fatty acid regulated transcriptional factors like peroxisome proliferator-activated receptors (PPARα, -β, and -γ), HNF4α, necrosis factor κB and SREBP1c (sterol-regulatory-element-binding protein-1c) play a main role in regulating gene expression.
These factors are regulated by direct binding of fatty acids or oxidized fatty acids or by cell membrane receptors linked with G-protein and also activation of signalling cascades targeting the cell nucleus .Intracellular calcium level, are also involved in oxidized fatty acid regulation by regulating the cell signalling cascades targeting the cell nucleus.
Physiological response to dietary fatty acid will depend on:
1. Quantity, duration, chemical property and nature of ingested fat
2. Type of fatty acid metabolism like oxidative pathway, kinetics, and competing reactions
3. Quantity of receptors present in both nucleus and cell membrane
4. Specific transcription factors involved in the gene expression
All these mechanisms are involved in the regulation of lipid metabolism, cell growth and differentiation.
Role of PUFA on Gene Expression:
1. Expression and production of lipogenic enzymes are decreased in liver as a result of ingesting diet containing 60% of poly unsaturated fatty acid known as linoleic acid.
2. Dietary fatty acid induces the expression of gene coding for adipocyte fatty acid binding protein (ap2)
3. In the adipocyte cell line 3T3-L1, poly unsaturated fatty acid arachidonic acid (n-6) decreased the expression of SCD1 gene and also disturbed the stability of SCD1 mRNA in a dose dependant manner.
4. Poly unsaturated fatty acid linoleic acid altered the expression of eicosapentanoic acids in 3T3-L1 adipocyte cell line in a dose dependant manner.
By understanding the effect of dietary fat on the regulation of gene expression can be used to study the disease susceptibility of an individual depending on his/her eating habits or nutritional behaviour. Regulation of gene expression by dietary fat is individual specific, which is it depends on genetic makeup of an individual. We can try to understand life threatening diseases like hyper tension, cancer, cardiovascular diseases by understanding the role of nutrients like fat, protein, carbohydrate, vitamins and minerals on the regulation of gene expression.
1. In the future by understanding the effect and impact of nutrients like dietary fat, protein, carbohydrate, vitamins and minerals on complex life threatening diseases, scientists will design some food products which has the capacity to prevent or reduce onset and also impact of these life threatening diseases. That is by eating particular type of food product one can prevent or inhibit the impact of diseases like type 2 diabetes, cardiovascular diseases, and also some types of cancer.
2. Food products can be custom made on the basis of population genetics, to promote the good health and well-being of individuals belonging to that particular population.
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