Effect of Avocados on Metabolic Syndrome Components
One hundred twenty-nine articles were included in the researchers' review.
A new review of the pharmacological effects of avocado consumption on aspects of metabolic syndrome (MetS) has found the fruit to be of benefit, particularly to the lipid profile.
Researchers conducted a review of 129 articles concerning avocado consumption. MetS consists of a group of risk factors including high blood glucose, dyslipidemia, hypertension, and obesity which can lead to an increased risk of type 2 diabetes and cardiovascular disease.
The researchers found numerous clinical studies which demonstrated lipid benefits of avocados. A 3-week trial (Colquhoun et al. 1992) of 15 women who consumed half to one and a half avocados per day found that their total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) decreased, while high-density lipoprotein cholesterol (HDL-C) was preserved. Results from another study (Alvizouri-Muñoz et al. 1992) suggest that avocado can be used to treat hyperlipidemia. For 2 weeks volunteers received a rich-monounsaturated fatty acid diet using avocado as their major source with 75% of the total fat from avocado. Results showed that the diet lessened the serum levels of TC, triglyceride (TG), and LDL-C while the level of HDL-C increased.
Regarding obesity, a randomized, crossover, controlled feeding trial (Carranza et al. 1995) of 45 obese participants found that 136g of avocado per day significantly decreased LDL particle number, small dense LDL-C, and the ratio of LDL/HDL from baseline. Significant reductions in body weight, BMI and percentage of body fat were observed in a separate controlled intervention study (Unlu et al. 2005) involving 11 participants who ate 1 avocado per day for 6 weeks.
Current antihypertensive treatments reduce mortality risk but adverse events and complexity of such agents tend to decrease treatment adherence. In light of this, research has explored medicinal plants as remedies for hypertension. Olaniyan (2014) administered 60mL of liquid extract of avocado leaf to 50 newly-diagnosed hypertensive patients with an abnormal increase in plasma cholesterol and blood pressure. The results revealed a significant reduction in the plasma levels of LDL-C and TC, and an increase in alanine transaminase (ALT) and aspartate transamine (AST) in the subjects.
The postprandial effects of avocado were shown to improve vascular health and be of anti-inflammatory benefit to volunteers who consumed avocado with hamburger (Li et al. 2013). With 68g of avocado to hamburger vasoconstriction following ingestion was not observed, while there was a significant preservation of Ikappa-B alpha as an inflammatory factor, consistent with reduced activation of the NF-kappa B inflammatory pathway. Avocado also decreased the elevated levels of TG.
The study found that the most affected biomarkers were LDL-C, HDL-C, TG, TC, and phospholipids. “According to the experimental studies reported in the literature, we observed that avocado had the most effect on lipid profile,” write the authors. However they did state that there is limited scientific evidence on avocado side effects due to contaminants or drug interactions, and that further studies would need to be conducted on the metabolic effects of different parts of the fruit.
Tabeshpour J, Razavi BM, Hosseinzadeh H. Effects of advocado (persea americana) on metabolic syndrome: a comprehensive systematic review [published online April 10, 2017]. Phytother Res. doi: 10.1002/ptr.5805