What is a "SNP," and how can they interact with the diet to contribute to diseases?

Answer 1

A "SNP" is a single nucleotide polymorphism. This is a variation in a sequence for a gene. If a SNP occurs in the DNA in regions where it does not encode for a protein, there may not be a pronounced effect on the protein function or cell. If the SNP occurs in an important region of a gene, the resulting protein may not function correctly and the effect on the cell would be great. The Controversy points out that a SNP in the gene that encodes for a key metabolic enzyme can result in PKU.
People can have thousands of SNPs in their DNA sequence and some of the SNPs that may have subtle effects (as described above) may work with factors from the environment such as diet and environmental exposures to result in the development of chronic diseases. A SNP in fat metabolism genes can change the body's response to the intake of dietary fats. Some people's LDL levels fall when their PUFA intakes increase and rise when their intakes decrease, suggesting that the SNP interacts with PUFA to reduce LDL production in the body.