Avocado, Persea Americana or Persea gratissima, also known as the alligator pear of butter fruit has been cultivated for centuries, with its agricultural roots in Mexico. In 1950s, avocado obtained great consumer awareness and interest worldwide when it became popular as a salad item. Nowadays, avocado has been a major international food item. Considering its health benefits, avocado is undoubtedly a very nutritious and valuable fruit to consume. Bellow, there are 6 reasons why we should eat avocados.
  1. Antioxidant properties. Avocados contain antioxidants like other fruits and vegetables. Antioxidants are substances that may protect the cells against the effect of free radicals that can damage the cells and have been associated with a number of diseases including heart disease and cancer. Avocados are relatively high in vitamin C (8.7mg/100g) and vitamin E (2.0mg/100g) compared to other fruits and they also contain β-carotene, lutein,and glutathione, antioxidants which have also been shown to have a protective effect.
2. High dietary Fibre. Avocado fruit carbohydrates are composed of about 80% dietary fibre, consisting of 70% insoluble and 30% soluble fibre. Avocados contain 2g and 4.6g of dietary fibre per 30g serving and one-half fruit respectively. Moderate consumption of avocado daily, could significantly help to meet the daily recommendation of  18g per day. Achieving the recommended intake of dietary fibre daily, improves the digestive system and it can potentially prevent some health conditions including heart disease and cancer, while improves a better blood sugar control in diabetics. 
3. Cardiovascular disease. Several constituents of the avocado fruit may function as bioactives and contribute to prevention of cardiovascular disease. These are the following:

       High levels of folate and vitamin B6 that have been  associated with reduced cardiovascular disease. On average, avocados contain about 0.3mg B6 and 90μg folate per 100grams of fruit.
   High monounsaturated fats accounting for the two-thirds of total fat. In particular, 1 serving of 30g contains 4.5g of fat, of which 0.5g is saturated, 0.5g is polyunsaturated and 3g monounsaturated fat. The consumption of ‘healthy fats’ such as monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), have been found to be associated with lower risk of cardiovascular disease. Interestingly, avocados decrease in saturated fat and increase in MUFA and PUFA as they ripen. 
 Phytosterols are plant sterols similar to cholesterol that act in the intestine to lower cholesterol absorption. In a wide range of studies, consumption of phytosterols has been associated with reduced risk of cardiovascular disease.Avocados, have among the highest concentrations of phytosterols of all popular fruits and β-sitosterol is the most prevalent  with an estimate d concentration of 0.76mg/g in raw fruit.
 High in potassium. Recent studies have shown that increasing potassium intake may help lower blood pressure,which is a mineral that helps normalise blood pressure.Potassium in avocado is higher than in bananas containing 152mg per 30g serving.

 3.  Anti-inflammatory properties: Conclusions from studies appeared to draw that constituents of the avocado could provide protection against UV damage, acting not only through anti-inflammatory properties but also through direct protection against damage and increased repaired activity.

4. Eye Health: Avocados may contribute to eye health since they contain a combination of MUFA and lutein and zeaxanthin and help improve carotenoid absorption from other fruits and vegetables.  

5. Blood glucose levels: Not only the fruit itself but also the leaf extracts, stems, trunks, buds, and roots of avocado tree contain high levels of a rare 7-carbon sugar, which is found to inhibit the enzyme hexokinase, the first step of in the cellular metabolism of glucose, resulting in a better blood sugar control, which is of a particular importance in diabetics. 

Resources: 

Carranza, J., Alvizouri, M., Alvarado, M.R. et al. (1995) Effects of avocado on the level of blood lipids in patients with phenotype II and IV dyslipidemias. Arch Inst Cardiol Mex 65, 342–8

Dreher, M., and Davenport, A. 2013. Hass Avocado Composition and Potential Health Effects. Critical Reviews in Food Science and Nutrition. 53, (7), 738-750

Ingram D.K. et al. 2013. Potential Health Benefits of Avocados.2013.Bioactives in Fruit:Health Benefits and Functional Foods.

Lev-Ran, A., Laor, J., Vins, M. and Simon, E. (1970) Effect of intravenous infusion of D-mannoheptulose on blood glucose and insulin levels in man. J Endocrinol 47(1), 137–8.

Naveh, E., Werman, M.J., Sabo, E. and Neeman, I. (2002) Defatted avocado pulp reduces body weight and total hepatic fat but increases plasma cholesterol in male rats fed diets with cholesterol. J Nutr 132, 2015–8.

Ojewole, J.A., Kamadyaapa, D.R., Gondwe, M.M. et al. (2007) Cardiovascular effects of Persea americana Mill (Lauraceae) (avocado) aqueous leaf extract in experimental animals. Cardiovasc J Afr 18,

Pieterse, Z., Jerling, J. C., Oosthuizen, W. et al. (2005) Substitution of high monounsaturated fatty acid avocado for mixed dietary fats during an energy-restricted diet: effects on weight loss, serum lipids, fibrinogen, and vascular function. Nutrition 21, 67–75

Rasschaert, J., Kadiata, M.M. and Malaisse, W.J. (2001) Effects of D-mannoheptulose upon D-glucose metabolism in tumoral pancreatic islet cells. Mol Cell Biochem 226, 77–81.