Macadamia nuts are the oily fruit of the Macadamia tree, also called the Queensland nut tree, belonging to the Proteaceae family and native to Australia. These nuts are round, very similar to hazelnuts and are enclosed in a hard shell, just like the common nuts. Since the shell is really very hard, these nuts are usually sold already shelled. Macadamia nuts provide vitamins, such as E and group B, and mineral salts, such as magnesium, potassium, calcium, iron, zinc and copper (Moodley et al, J Environ Sci Health, 2007 - Ros, Nutrients, 2010 - USDA Food Composition Databases). These oily fruits are also very rich in monounsaturated fatty acids, or good fats, especially oleic and palmitoleic acids, and, therefore, show a protective effect on the cardiovascular system, as demonstrated by a study published in the Journal of Nutrition by a team of the Pennsylvania State University (Griel et al, 2008). Based on this study, Macadamia nuts have been demonstrated to be able to lower total and LDL cholesterol levels. Moreover, also based on a scientific research (Garg et al, Lipids, 2007), Macadamia nuts are also valuable sources of polyphenols, antioxidant substances, and show anti-inflammatory properties, able to counteract oxidative stress and thrombosis. According to the same study, these effects are observed after the introduction for 4 weeks of macadamia nuts in a quantity ranging from 40 to 90 g calculated on the basis of the energy needs of each study participant (corresponding to 15% of total energy requirements). For what concerns how many and when to eat them, macadamia nuts have a sweet taste that reminds that of coconut and are an excellent breakfast or snack for children, adolescents but also sporty people and in general all adults given the healthy properties just described. However, these nuts are also a high calorie food, 100 grams of macadamia provide about 700 kcal, so do not exceed with the quantity. Finally a recommendation, if Macadamia nuts are really beneficial for humans, they are not so good for pets, indeed, for dogs and cats can be toxic and may cause poisoning effects. So do not give your dog or your cat these nuts!