Tree nut phytochemicals: composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts

• Published in: Nutrition research reviews 2011-12, Vol.24 (2), p.244-275
• Main Authors: Bolling, Bradley W., Chen, C.-Y. Oliver, McKay, Diane L., Blumberg, Jeffrey B.
• Format: Article
• Language: English
• Subjects: Agriculture - methods; Anti-Inflammatory Agents - analysis; Anti-Inflammatory Agents - pharmacology; Anti-Inflammatory Agents - therapeutic use; Anticholesteremic Agents - analysis; Anticholesteremic Agents - pharmacology; Anticholesteremic Agents - therapeutic use; Antineoplastic Agents, Phytogenic - analysis; Antineoplastic Agents, Phytogenic - pharmacology; Antineoplastic Agents, Phytogenic - therapeutic use; Antioxidants; Antioxidants - analysis; Antioxidants - pharmacology; Antioxidants - therapeutic use; Antiviral Agents - analysis; Antiviral Agents - pharmacology; Antiviral Agents - therapeutic use; Biological and medical sciences; Carotenoids; Feeding. Feeding behavior; Flavonoids; Fundamental and applied biological sciences. Psychology; Humans; Magnoliopsida - chemistry; Nutrient content; Nuts; Nuts - chemistry; Phenols; Phytochemicals; Phytotherapy; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plant Extracts - therapeutic use; Trees; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0954-4224; 1475-2700
• DOI: 10.1017/S095442241100014X

Tree nuts contain an array of phytochemicals including carotenoids, phenolic acids, phytosterols and polyphenolic compounds such as flavonoids, proanthocyanidins (PAC) and stilbenes, all of which are included in nutrient databases, as well as phytates, sphingolipids, alkylphenols and lignans, which are not. The phytochemical content of tree nuts can vary considerably by nut type, genotype, pre- and post-harvest conditions, as well as storage conditions. Genotype affects phenolic acids, flavonoids, stilbenes and phytosterols, but data are lacking for many other phytochemical classes. During the roasting process, tree nut isoflavones, flavanols and flavonols were found to be more resistant to heat than the anthocyanins, PAC and trans-resveratrol. The choice of solvents used for extracting polyphenols and phytosterols significantly affects their quantification, and studies validating these methods for tree nut phytochemicals are lacking. The phytochemicals found in tree nuts have been associated with antioxidant, anti-inflammatory, anti-proliferative, antiviral, chemopreventive and hypocholesterolaemic actions, all of which are known to affect the initiation and progression of several pathogenic processes. While tree nut phytochemicals are bioaccessible and bioavailable in humans, the number of intervention trials conducted to date is limited. The objectives of the present review are to summarise tree nut: (1) phytochemicals; (2) phytochemical content included in nutrient databases and current publications; (3) phytochemicals affected by pre- and post-harvest conditions and analytical methodology; and (4) bioactivity and health benefits in humans.