From:  Nutrient-driven immunometabolism in metabolic disease

 Key challenges and future directions in precision immunonutrition.

Source of variability/ChallengeSpecific impact on diet-immune responseFuture research directions
Host geneticsDifferential nutrient sensing (e.g., VDR, PPAR polymorphisms) [194]Genotype-stratified dietary intervention trials [186].
Gut microbiomePersonal “metabolic filter” determining SCFA, tryptophan metabolite output [189]Develop microbiome-based algorithms for dietary response prediction [207].
Sex differencesHormonal regulation of immune cell metabolism [196, 197]Mandatory sex-stratified design and analysis in all clinical trials [208].
Aging (inflammaging)Accumulation of senescent, pro-inflammatory immune cells [198]Test “senolytic” drugs combined with specific anti-inflammatory nutrients.
Measurement and toolsLack of dynamic, clinically accessible biomarkers of immunometabolism healthDevelop wearable sensors for real-time inflammation and metabolite monitoring [191, 204].

PPAR: peroxisome proliferator-activated receptor; SCFA: short-chain fatty acid; VDR: vitamin D receptor.