Daily avocado consumption failed to reduce visceral adiposity volume in comparison to a habitual diet according to a recent randomised trial
Adding a daily avocado to the diet of those with a body mass index (BMI) over 30 for at least 6 months, does not lead to a significant decrease in visceral adipose tissue (VAT) volume in comparison to a habitual diet in which avocado consumption was limited to less than 2 per month. This was the main finding of a randomised trial by US researchers.
Visceral adiposity which can also be referred to as visceral or central obesity, is strongly and positively associated with all-cause, cardiovascular disease and cancer mortality, independently of body mass index. One factor linked to obesity is diet quality an in a comparative study of a typical Western diet, e.g., based on a higher consumption of refined grains, red/processed meats and one based on non-hydrogenated fat, vegetables, eggs and seafood, i.e., with a better diet quality, it was found that those consuming the Westernised diet were more likely to be obese. One food that is associated with a better diet quality is avocado which contains monounsaturated fatty acids, dietary fibre, essential nutrients and various phytochemicals. In fact, one study observed how avocado consumption was associated with improved overall diet quality together with a reduced risk of metabolic syndrome. Furthermore, in a randomised trial in overweight adults, half a daily avocado increased satisfaction by 26% and decreased the desire to eat by 40%. Nevertheless, other studies, while indicating a beneficial effect of avocadoes, suggest that this is limited. For instance, one comparative trial in which one group consumed a daily avocado, concluded that while there was significant weight loss, a decrease in BMI, total body fat and visceral adipose tissue, there were no differences between groups. Finally, in a 2021 study, again in which participants consumed a daily avocado, interestingly, there was a change in abdominal adiposity distribution among females but not males.
For the present study, researchers set out to establish whether daily intake of an avocado for 6 months compared to a habitual diet, could alter visceral adiposity tissue (VAT) volume and various cardiometabolic markers such as the hepatic fat fraction, systemic inflammation and in those with an elevated waist circumference. The study recruited adults aged 25 years and older, with a waist circumference of > 89 cm for women and > 101 cm for men. Participants were then randomised to receive either a daily avocado or their usual diet and those in the control diet were instructed to limit avocado intake to less than twice a month. All participants underwent 2 abdominal MRI scans, one before the study and one after 6 months and the primary outcome was the change in VAT volume based on the MRI assessment.
Daily avocado intake and visceral adiposity
A total of 1008 individuals with a mean age of 50.3 years (72.4% women) were randomised to avocado (505) or a habitual diet. The overall mean waist circumference was 109 cm and the BMI ranged from 32.9 to 33.2, with a mean VAT of 3.2 litres and a hepatic fat fraction of 9.9%.
After 6 months, the reduction in VAT volume among those taking an avocado was 0.074 litres and 0.057 litres in the habitual diet group which represented a non-significant difference (p = 0.405). Similarly, differences in the hepatic fat % (0.58 vs 0,21, p = 0.28) or changes in waist circumference (0.007 vs -0.108, p = 0.603) were also non-significant the end of the trial.
The only significant changes were in total cholesterol levels (-4.908 vs-1.96, p = 0.026) and for LDL cholesterol (-4.94 vs -2.48, p = 0.038).
Based on these findings, the authors concluded that although diet quality was improved by the addition of a daily avocado, this did not translate into clinically important improvements in either visceral adiposity or other cardiometabolic factors.
Lichenstein AH et al. Effect of Incorporating 1 Avocado Per Day Versus Habitual Diet on Visceral Adiposity: A Randomized Trial J Am Heart Assoc. 2022