Nuts provide numerous health benefits and are one of the best sources of primary proteins, essential unsaturated fats, minerals and vitamins. The combination of nutrients in nuts is superior to that found in any animal product, and nuts should, if possible, become a regular component of the diet. Nuts have a high-fat content, but in view of their exceptional nutrient density, they offer concentrated nutrition with a relatively low-calorie content. In spite of their high-fat content, nuts will not be fattening if consumed in moderation. Unfortunately, nuts are quite expensive, although this depends on the grade of nuts and the place of purchase, and the inclination is to forgo the pleasure of making regular use of this commodity. Most nut recipes will require that the nuts be liquidised or processed in some way, and one can purchase broken nuts which are cheaper, for this purpose. On a weight-for-weight basis nuts are very good value for money and, in addition, the versatility of nuts makes them a culinary delight. Nuts can be eaten raw, they can be used to prepare delicious nut milks, creams and sauces, and they can be used in a variety of other ways in cooked meals. It only takes a small quantity of nuts to achieve great results, and even expensive nuts can be used for making creams and milks that will compare favourably in price with dairy products. Where economic considerations are paramount, however, oilseeds can be used to substitute for many of the qualities of nuts, and they can replace nuts in most recipes which require them.
The protein composition of nuts and oilseeds is of exceptional quality, and the essential amino acids are well supplied. The proteins are also readily digestible, and do not require the excessive stomach acid secretion necessary for the digestion of animal proteins, thus making them totally compatible with other plant foods. Moreover, just 150g of nuts will supply all the protein needs of the average adult and it should thus be self-evident why the addition of even small quantities of nuts to meals will ensure that the amino acid requirements are met.
Nuts and oilseeds have a high fat content, but the fat is present as unsaturated fats, and the accessory nutrients required for metabolizing these fats are also present, thus ensuring maximum utilization of these nutrients without the detrimental effects associated with the use of animal fats. The fatty acids, palmitic acid, oleic acid and linoleic acid form the largest portion of the fatty acid composition of nuts71 and seeds, but the relative amounts of these vary in the different products. In nuts, the monounsaturated fats, rich in oleic acid, are the most abundant, and nuts thus provide a healthy source of energy whilst at the same time being
friendly to the cardiovascular system. Almonds, for example, contain 52% fat but 67% of this is in the form of monounsaturated fat and this, together with the proteins and fibre in whole almonds, contributes to a lowering of blood cholesterol levels.72 The high-oil content of nuts can thus be of particular benefit to people living in cold environments to provide additional heat energy.
The oils in whole nuts and seeds also come prepacked with antioxidants which prevent the formation of free radicals which are associated with tumour development. Antioxidant substances have been found in sesame seeds,73 and vitamin E, a natural antioxidant, is present in high concentrations in whole nuts and seeds. Other compounds in seeds and nuts also contribute to a lowering of cholesterol levels, thus making these high-fat foods extremely user friendly. In this regard, it can be mentioned that sesame seeds contain the compound sesamin, a lignin from sesame oil, which lowers cholesterol levels by decreasing the rate of absorption from the intestine, increasing the rate of faecal excretion and inhibiting its formation in the liver.74 For vegan vegetarians, nuts and seeds together with oil rich legumes form the most important source of fats, and it is essential that these be used to effectively to maintain adequate body weights. It is important to note here again that growing children need higher proportions of fat than adults, and nuts and seeds can be used to augment their fat supplies.17 Even adults that struggle to maintain adequate BMI’s, can increase their fat consumption by adding more of these oil rich foods to their diets.
The nutrient and amino acid composition of some of the more common nuts and seeds is given in tables 7.15 and 7.16.
Almonds Prunus amygdalus (var. dulcis)
The almond tree, Prunus dulcis, is closely related to the peach, plum and apricot tree, but the seed rather than the fleshy fruit, is the edible portion. The seeds of apricots have many things in common with almonds, and they, like almonds, are also utilized in the manufacture of traditional almond products such as marzipan. Almonds constitute the world’s largest nut crop with California producing some 70% of the total world crop annually. Almonds are available in a number of varieties, the most common of which is the Nonpareil variety which is a flat nut and has a mild, sweet flavour. Other common varieties include the Mission variety which is a round nut with a rough dark skin particularly suited to roasting, the Carmel variety which is similar to the Nonpareil variety and the California variety which is a blend of several related varieties. Another type of almond is the bitter almond which contains high concentrations of benzaldehyde, which give it a pungent flavour, and for this reason it is not widely cultivated. Almonds are the most alkaline of all nuts and this, together with their balanced composition of nutrients, makes them one of the most beneficial foods. Almonds have a 52% fat content, and 67% of this is in the form of unsaturated fat, consisting mainly of palmitic, oleic and linoleic acids.71,72 The combination of essential oils, proteins and fibre in almonds have been found to lower cholesterol levels, and almonds are also one of the richest sources of vitamin E, which is a natural anti-oxidant, preventing the formation of free radicals. Moreover, almonds supply appreciable quantities of the B-group vitamins, particularly niacin, and are also rich in calcium, and magnesium which promotes healthy nerve function. Almonds consist of 18,6% protein, and if combined with other nuts, particularly cashews and Brazil nuts, the protein availability improves. Almonds are ideal companions of cereals,75 and should, therefore, be one of the nuts of choice for muesli and other breakfast foods. Another way to enjoy almonds, is to convert them into almond butter or nut milk, the latter being particularly tasty and value for money. If almonds are blanched, then the brown skin is easily removed, and they have a milder flavour and a softer texture and nut butters made from blanched nuts may thus have greater eye appeal and a milder taste.
Table 7.15. The composition of selected nuts and seeds. The figures are for 100g portions. (Adapted from ref. 37)
Table 7.16. The essential amino acid composition of selected nuts and seeds, with values for rump steak and chicken given for comparison. The figures are for 100g portions. Values for arginine and histidine are given because they too can be limiting. (From ref. 17)
Brazil nuts (Bertholletia excelsa)
As the name suggests, Brazil nuts are native to Brazil. They consist of 14,4% protein and are the richest natural source of the amino acid methionine. Combining Brazil nuts with other nuts, particularly cashews and pistachios, or with grains and legumes, will thus greatly enhance the overall protein availability from these food combinations. Legumes are generally poor in methionine and rich in lysine, and the two thus form the perfect partners. With a little bit of imagination, meals can be prepared that are not only nutritious, but are also tasty. Use the nuts to create delicious nut butters, sauces or creams and milks, and in this way create meals which taste rich and creamy whilst at the same time being free from the unhealthy side effects normally associated with such meals.
Cashew nuts (Anacardium occidentale)
Cashew nuts are also native to Brazil and they were introduced to India by the Portuguese. Today India is the greatest producer of cashew nuts. cashew nuts are the actual fruits of the Cashew tree, but the tree also produces a false fruit known as a cashew apple, which is very popular in the regions where the trees grow. Cashew nuts have high concentrations of essential amino acids, but the methionine concentration is limiting. To obtain maximum benefit from the proteins, cashew nuts should be combined with Brazil nuts or other foods to augment the supply of methionine. Moreover, cashews are a good source of zinc and other minerals and vitamins. Cashew nuts can be expensive and it is advisable to find a supplier of broken nuts, as these are less expensive. If the nuts are to be used in cooking, it makes little difference if they are broken or whole. Nuts are easily stored, and broken cashew nuts can be bought in bulk when the price is right, and kept in the freezer.
The beauty of cashew nuts is their versatility. The low-fibre content makes it possible to create the smoothest creams which are truly delicious and unique in taste. Moreover, cashews make a superb milk and the best sauces. If blended in water, the resultant milk will naturally thicken to a creamy sauce if brought to the boil, and other ingredients can then be added to create the sauce of choice. In this way white sauces, garlic sauces, sour creams or sweet creams can be created which will be a delight, and they will be economical too. A little nut cream can also be added to stews as a finishing touch to create a stroganoff type of taste.
Chestnuts (Castanea sativa )
The sweet chestnut is a true nut, and like the oak and the beech it belongs to the family Fagaceae. Chestnuts are native to the Mediterranean region, and the Romans were responsible for their distribution in Europe. In France and in Italy, some 200 varieties of chestnuts are cultured. Chestnuts can be eaten raw, but they are normally cooked or roasted and are often used as a stuffing. One of the most delicious ways of eating chestnuts is, however with sugar, and glazed chestnuts are a popular delicacy in Europe and the Far East. In regions where chestnuts are common, they are also ground into flour and used for making porridge and even bread, or they are eaten as a vegetable. Chestnuts have a lower protein- and fat-content than most other nuts but they are nevertheless a nutritious food, rich in carbohydrates and are very adequately supplied with vitamins and minerals. In view of their composition, one can partake more liberally of chestnuts than of the other nut varieties.
Coconut (Cocos nucifera)
Coconuts probably originated on the islands of the Malayan Archipelago but today they are distributed throughout the tropical regions of the world. The coconuts are the stones of the drupes borne by the coconut palm, and the endosperm of these stones is the edible portion. The endosperm can be eaten raw, or it is dried and used in confectionery or for the extraction of oil. The oil of the coconut is unusual, in that it is rich in saturated fats (86%) and contains only small amounts of mono- and polyunsaturated fats. The oil in coconuts is best consumed in the coconut as it then comes prepacked with all the necessary ingredients for metabolizing it.
Hazel nuts (Corylus avellana)
Hazel nuts are also known as Filberts or Cob nuts depending on their country of origin. They contain a high proportion of essential oils and supply a well-balanced mixture of vitamins and minerals. Hazel nuts contain a high concentration of vitamin E which prevents oxidation of the polyunsaturated fats, and it is also one of the few nuts which contains vitamin A, which is a natural antioxidant and has cancer-preventing properties. The B-group vitamins are also well represented in hazel nuts, particularly vitamin B5 and B6. Moreover, hazel nuts are an excellent source of minerals, particularly the minerals manganese, selenium and zinc, but the protein composition is such that combinations with other nuts, grains or legumes are required in order to obtain the maximum benefit. Hazelnut butters make a pleasant spread and will add variety to the table.
Macadamia nuts (Macadamia ternifolia)
Australia is the home of the macadamia nut, but today it is cultivated in many countries, particularly Hawaii and African countries. The macadamia is a member of the protea family (Proteaceae) and the stones it produces are known for their very hard shells. Macadamias have a very high oil content (73,7%) and they make a superb, snow-white cream or milk if blended in water. The high-fat content also makes macadamia nuts ideally suited for making nut butters. Moreover, macadamia nuts are rich in calcium, magnesium, phosphorous and vitamins.
Pecan nuts (Carya illinoensis)
Pecan nuts belong to the family Juglandaceae, to which also the walnut belongs. Pecans are
native to the southern states of the USA and to Mexico. Like hazel nuts, pecan nuts do not contain high concentrations of essential amino acids, and their total protein content is also quite low. Their fat content is, however, high and they contain a good balance of minerals and vitamins, including vitamin A. The oil in pecan nuts is also rich in essential oils.71 Pecan nuts make great snacks, they can also be used in breakfast foods and be used in baking.
Pistachio nuts (Pistacia vera)
Pistachio nuts grow in very dry areas in poor soil, and they have been grown for centuries in the Mediterranean region, and are the nuts of choice in the Middle Eastern countries. Pistachio nuts are delicious, and they are excellent food value, being a good source of fibre, proteins with a good blend of essential amino acids, vitamins and minerals.76 The amino acid tryptophan is, however, in short supply, and in order to obtain maximum protein value it would be good to combine pistachios with other sources of this amino acid, such as seeds, some legumes, particularly soya beans, or cashew nuts. Pistachios are a good source of the minerals calcium, potassium and iron and they have a high vitamin A content. Moreover, they are nutrient-dense and offer an excellent balance of calories for concentrated nutrition. Pistachios can be milled, used in desserts, breads or savoury products and will be an asset in any kitchen.
Walnuts (Juglans regia)
Walnuts come in two varieties, the European walnut and the black walnut which originates from America. These nuts provide a balanced all-round nutritional package, with all the main nutritional components being present in useful amounts.77 The protein content of the black walnut is higher than that of the European walnut, but both provide excellent protein value because of their balanced composition of essential amino acids. Combinations with other protein sources would, once again, improve protein availability. Add walnuts to muesli or enjoy them just as they are.