Nutrition

Alpha-lipoic acid (ALA) is a sulfur-containing fatty acid serving as an essential cofactor for two mitochondrial enzyme complexes — pyruvate dehydrogenase and α-ketoglutarate…

Apigenin is a plant flavone found in parsley, celery, chamomile and dried oregano. In a 2013 Diabetes paper, Escande and colleagues identified apigenin as an inhibitor of the…

Astaxanthin is a ketocarotenoid pigment produced predominantly by the microalga Haematococcus pluvialis and accumulated through the food chain in crustaceans, salmon, and trout,…

Blue Zones are regions reported to have unusually many centenarians. The popularly cited list (Buettner) includes Okinawa (Japan), Sardinia (Italy), Nicoya (Costa Rica), Ikaria…

The branched-chain amino acids leucine, isoleucine and valine are essential amino acids enriched in meat, dairy, eggs and protein supplements. Leucine in particular is a potent…

Caffeine is a methylxanthine alkaloid found in coffee, tea, and cocoa that acts as a competitive antagonist of adenosine A1 and A2A receptors, inhibiting the adenosine-mediated…

Carnosine is a dipeptide of beta-alanine and L-histidine, concentrated in skeletal muscle and nervous tissue. It operates through four mechanisms: intracellular pH buffering…

Choline is a water-soluble nutrient officially recognised as essential by the US Institute of Medicine in 1998, which set Adequate Intakes of 425 mg/day for adult women and 550…

Coenzyme Q10 (ubiquinone) is a lipid-soluble molecule essential for mitochondrial electron transport and ATP production, and an intracellular antioxidant. Endogenous levels…

Collagen peptides, also called hydrolysed collagen or collagen hydrolysate, are produced by enzymatic hydrolysis of animal collagen (typically bovine, porcine or fish skin and…

Creatine is a guanidino compound synthesized endogenously in liver and kidney from arginine, glycine, and methionine, and obtained exogenously from red meat, fish, and…

Curcumin is the principal polyphenol in turmeric (Curcuma longa) and modulates NF-kB, Nrf2, and other inflammatory and oxidative pathways. Standard curcumin has very low oral…

Dietary fiber comprises non-digestible plant polysaccharides and oligosaccharides that resist hydrolysis by human intestinal enzymes. The two principal classes are soluble fiber…

Dietary nitrate (NO₃⁻) is abundant in beetroot, leafy greens, and celery and is converted in the body to nitric oxide (NO) via a two-step cascade. Salivary glands concentrate…

EGCG is the most abundant catechin in green tea and a polyphenol with antioxidant, anti-inflammatory, and AMPK-modulating activity. Observational data link green tea consumption…

Ergothioneine is a sulfur-containing histidine betaine, predominantly in its thione tautomeric form, synthesized exclusively by fungi, certain bacteria, and cyanobacteria; humans…

Fisetin is a flavonoid found in strawberries, apples, and persimmons. In aged mice, Yousefzadeh et al. (2018, EBioMedicine) reported reduced senescent cell burden and extended…

Flavonoids are a large subclass of plant polyphenols with a 15-carbon benzo-γ-pyrone backbone, spanning six subfamilies: flavonols (quercetin, kaempferol; onions, kale),…

The glycemic index (GI) ranks foods by how rapidly their digestible carbohydrates raise blood glucose relative to pure glucose (GI = 100). GI ≤ 55 is low, 56–69 moderate, ≥ 70…

Glycine is the smallest and simplest amino acid, non-essential under normal conditions but conditionally essential in aging, pregnancy, and disease states where demand may exceed…

GlyNAC is the combined oral supplementation of glycine and N-acetylcysteine (NAC), designed to replenish both precursors of the tripeptide glutathione (γ-Glu-Cys-Gly), which…

Hydroxytyrosol is an ortho-diphenolic compound and the principal antioxidant phenol in olive oil and olive leaves; in the fruit and oil it is largely bound within the more…

Lutein and zeaxanthin are dihydroxy xanthophyll carotenoids that accumulate in the macula, where they form the macular pigment and filter blue light. Dark green leafy vegetables…

Lycopene is an acyclic, lipophilic carotenoid that gives tomatoes, watermelon and pink grapefruit their red colour. Bioavailability is higher from heat-processed tomato products…

The Mediterranean diet is an eating pattern emphasizing vegetables, fruits, legumes, whole grains, nuts, olive oil, and fish, with moderate dairy and limited red meat. Rich in…

Methionine restriction (MR) is the dietary reduction of the sulphur amino acid methionine without overall caloric restriction. Orentreich and colleagues first reported in 1993…

The MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay) is a hybrid eating pattern targeting brain health. It emphasizes leafy greens, berries, nuts, whole…

N-acetylcysteine is an acetylated form of the amino acid cysteine, used clinically as a mucolytic and as the standard antidote for paracetamol (acetaminophen) overdose. Its…

NMN is a nucleotide and NAD+ precursor in the salvage pathway, feeding into a coenzyme central to energy metabolism, sirtuin activity, and DNA repair. Oral NMN is absorbed and…

NR is a vitamin B3 form and NAD+ precursor that is metabolized via salvage pathways to increase NAD+, with NMN as a possible intermediate. Human trials reliably show that oral NR…

Eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) are long-chain polyunsaturated fatty acids found principally in fatty fish and fish oil (with algal…

Polyphenols are a structurally diverse class of plant secondary metabolites — numbering over 8,000 known compounds — defined by one or more aromatic rings bearing hydroxyl…

Pterostilbene is a dimethylated stilbene analogue of resveratrol naturally present in blueberries, grapes, and Pterocarpus marsupium heartwood. The two methoxy groups replacing…

Quercetin is a flavonoid abundant in onions, apples, capers, and berries with antioxidant and anti-inflammatory activity. It is investigated as a senolytic, though standalone…

Resveratrol is a stilbene polyphenol found in grape skins, red wine, and Japanese knotweed. It is studied as a putative sirtuin (SIRT1) activator and AMPK modulator, with effects…

Selenium is incorporated into proteins as the amino acid selenocysteine (the 21st amino acid), forming a class of enzymes called selenoproteins — 25 encoded in the human genome.…

Soy isoflavones are polyphenolic phytoestrogens — plant-derived compounds structurally similar to 17β-estradiol — concentrated in soybeans and soy-derived foods, with genistein…

Spermidine is a naturally occurring polyamine found in wheat germ, aged cheese, soy, and mushrooms, though content varies widely by source and processing. It induces autophagy,…

Sulforaphane is an isothiocyanate generated when broccoli, broccoli sprouts, and other cruciferous vegetables are chewed or chopped. It activates the Nrf2 pathway, upregulating…

Taurine is a sulfur-containing non-proteinogenic amino acid synthesized in humans from cysteine via the cysteine sulfinic acid pathway, with dietary intake from animal foods —…

Vitamin E is a family of eight fat-soluble molecules — four tocopherols (α, β, γ, δ) and four tocotrienols (α, β, γ, δ) — sharing a chromanol ring but differing in their tail:…

Menaquinone-7 is a long-chain form of vitamin K2 in which the side chain has seven isoprene units, giving it a longer half-life than vitamin K1 (phylloquinone) or MK-4. Like…