5 min readConcept sheetUsually a 2- or 5-mark answer

Nutrigenomics

Nutrigenomics studies how food affects our genes; nutrigenetics studies how our genes affect our response to food. Together they support personalised nutrition.

NutrigenomicsDiet → gene expression

NutrigeneticsGene variants → response to diet

GoalPersonalised nutrition

BasisHuman Genome Project (completed 2003)

Nutrigenomics vs nutrigenetics

NutrigenomicsHow nutrients and food compounds switch genes on or off (gene expression). E.g., polyunsaturated fatty acids act on PPAR receptors to switch on fat-burning genes; vitamin A (as retinoic acid) and vitamin D act on nuclear receptors that control genes.

NutrigeneticsHow differences in a person's genes, such as single-letter DNA changes called SNPs (single nucleotide polymorphisms), change their nutrient needs or response to food. E.g., the MTHFR variant and folate.

Both build on the Human Genome Project, which mapped human DNA.

Examples

Example	Gene link	Diet meaning
Lactose intolerance	In most adults lactase activity falls after weaning. People with lactase persistence carry a DNA variant that keeps the lactase gene switched on	Low-lactose choices such as curd and buttermilk, or small servings of milk with meals
MTHFR and folate	A common MTHFR variant makes a less active enzyme, so less active folate is formed and homocysteine can rise	Adequate folate from green leafy vegetables and pulses; high homocysteine is linked to heart disease risk
Phenylketonuria (PKU)	A faulty phenylalanine hydroxylase gene; phenylalanine cannot become tyrosine and builds up, harming the brain	Low-phenylalanine diet from birth; tyrosine supplied; avoid the sweetener aspartame

Promise and limits

PromisePersonalised nutrition: diet advice matched to a person's genes for conditions such as diabetes, obesity and heart disease, and better diet therapy for inborn errors of metabolism found by newborn screening.

LimitsMost diseases depend on many genes plus lifestyle, so a single gene test predicts little. Tests are costly, the evidence is still growing, and genetic privacy must be protected. Basic healthy eating still suits almost everyone.

Nutrition link

Nutrigenomics explains why the same diet affects people differently. For a dietitian it already guides therapeutic diets for inborn errors such as PKU (low phenylalanine) and galactosaemia (no galactose), and simple advice such as curd instead of milk for lactose intolerance.

Exam angle

2 marks: “Define nutrigenomics.” The study of how nutrients and food compounds affect gene expression; it aims at personalised nutrition.

2 marks: “Differentiate nutrigenomics and nutrigenetics.” Nutrigenomics: food acts on genes. Nutrigenetics: genetic differences change a person's response to food.

5 marks: “Write a short note on nutrigenomics.” Define both terms, give the lactose intolerance, MTHFR–folate and PKU examples, then the promise and limits.

Remember it

Nutrigenomics = food talks to genes. Nutrigenetics = genes decide how you handle food.