Their study, funded as part of MBIE’s Food for Health programme and published in Plant Foods for Human Nutrition, is the first to examine the direct effect of avocados on gut health.
Macronutrients in food such as dietary fibre are known to alter gut microbiota composition and metabolic activity, so the team fed rats different diets that included 5, 10 or 15% avocado for six weeks. Dr Paturi says they were surprised to find the avocado had no noticeable effect on bacterial populations in the rats’ guts compared with the control. But their study did find other beneficial health effects.
The gut bacteria metabolised the dietary fibre in the avocado to produce short-chain fatty acids (SCFAs) as a result of fermentation. SCFAs are associated with a number of health benefits including the stimulation of cells to produce antimicrobial peptides called defensins, which play an important role in immune protection. The research showed higher concentrations of defensins in the gut tissues of the avocado-fed rats. Dr Paturi says this is not solid proof of beneficial activity in the body itself but higher levels are probably better for gut health.
Another change to the gut lining has more straightforward benefits. SCFAs are also the fuel for goblet cells. Goblet cells produce mucus in a healthy gut that protect gut tissue. The team found significantly more goblet cells in the gut wall in rats on the 15% avocado diet. Dr Paturi says this finding implies avocado also positively influences gut mucus secretion.
As this trial was working with a known safe and beneficial food, Dr Paturi says the next step could be a move straight into testing with humans.
“This is exciting research,” says New Zealand Avocado chief executive Jen Scoular. “It potentially opens the door to a whole new area of benefit we hadn’t seen before.
“It would be great to see this research followed up to find out if it translates into real benefits for human gut health,” Ms Scoular says.
