Nuts are increasingly recognized for their unique nutritional value, taste and health benefits. They are dry fruits with edible seeds and hard shells, with cashews, walnuts, almonds, chestnuts, pistachios, and hazelnuts being the most abundant. Nuts are rich in monounsaturated and polyunsaturated fatty acids, vitamins, minerals, fibers, carotenoids, and phytosterols. There are a lot of health benefits of nuts i.e. reduce risk factors for chronic diseases. They are also easy to transport. However, most antioxidants are found in the pellicle, which can be lost when skin is removed.
The nutritional composition and health benefits of some selected nuts are discussed below. These nuts are composed of important nutrients like proteins, vitamins, minerals, fatty acids and lipids etc.
1: Protein
Nuts contain a lot of proteins and essential amino acids. Among them almonds, peanuts, and pistachios are the major sources of proteins. While chestnuts contain least protein. Protein content differs due many factors like harvest year, post-harvest storage, and processing method. Seed storage proteins are the main type in nuts and can cause nut allergies. Common nuts with adverse allergic reactions include almonds, hazelnuts, walnuts, pecan nuts, and pistachios.
2: Vitamins
Nuts are essential for a balanced diet, containing fat-soluble vitamins and antioxidants like α-tocopherol (vitamin E). They promote health, fight aging, improve brain function, and promote healthy skin. Nuts’ nutritional value depends on their chemical composition, cultivar, meteorological factors, and production practices. Nuts like walnuts, almonds, pine nuts, and hazelnuts are rich in vitamin E, B vitamins, and vitamin C.
3: Minerals
Nuts contain nutrients such as magnesium and potassium and are considered heart-healthy food when consumed in moderation. They protect against coronary heart disease and are high in potassium, particularly pistachio and cashew nuts. Pine nuts, cashews, and almonds contain higher levels of zinc and iron.
4: Fiber
Fiber is a health-promoting nut ingredient, inversely related to obesity, type two diabetes, cancer, and cardiovascular disease. Almonds have the highest fiber content, while cashews, chestnuts, hazelnuts, pistachios, and walnuts all have varying amounts. Factors affecting fiber content include genotype, crop year, and weather conditions.
5: Lipids and Fatty Acids
Almonds have a unique fatty acid profile, consisting of monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids, with a predominance of oleic, linoleic, palmitic, or stearic acids. The genotype also affects the fatty acid profile, with changes observed in the individual amount of each fatty acid and the sum of unsaturated and saturated (SFA) fractions. Chestnuts have the lowest fat content compared to other nuts, but contain a high quantity of essential fatty acids, either saturated or unsaturated, linked to health processes and chronic diseases.
Hazelnuts have one of the highest fat contents, above 60%. The fat in hazelnuts is mainly composed of MUFA, with oleic acid being the major individual monounsaturated fatty acid. Polyunsaturated fatty acids represent the second major fraction in hazelnut fat, almost exclusively due to the content of linoleic acid. SFA can also represent the second major group of fatty acids, influenced by the higher content of palmitic acid. Walnuts have a high fat content, with average values surpassing only hazelnuts.
6: Phenolic Compounds
Nuts contain phenolics, which have numerous health benefits, including cardioprotective, neuroprotective, antidiabetic, anti-inflammatory, and antioxidant properties. They also improve flood lipoprotein profile and gut microbiota. Each nut species has its typical phenolic profile and content, with chestnuts having a high content of phenolics, almonds having a high content, and peanuts having high levels of procyanidins. Variation in phenolic content is related to genotype, cultural practices, climate conditions, fruit ripeness stage, storage, and post-harvest settings.
7: Aroma and Flavor Compounds
The aroma of nuts is influenced by geographical origin, thermal processing, and microorganism presence. Aldehydes are the major volatiles in almonds, with a bitter-almond flavor. Processing changes the number and chemical classes of compounds. Pyrazines, formed by the Maillard reaction, are the major aromatic compounds in peanuts and other nuts. Roasting improves the fruit’s commercial viability and sensory characteristics.
Conclusion
Nuts are rich in nutrients and they have immense beneficial impacts on human health. Although they are quite expensive than other fruits but they have a lot of benefits. They should be consumed moderately. Excessive consumption is not good for health.