Eating nuts may help lower cholesterol levels, US research suggests.
The review of 25 studies, involving nearly 600 people, showed eating on average 67g of nuts - a small bag - a day reduced cholesterol levels by 7.4%.
The US Loma Linda University team believes nuts may help prevent the absorption of cholesterol.
UK experts said the research showed nuts were an important part of a healthy diet, but warned against eating nuts covered in sugar or salt.
Previous work has indicated eating nuts regularly is beneficial, but the Archives of Internal Medicine study set out to put an accurate figure on the effect.
The people involved ate 67g of nuts a day on average, over a period of three to eight weeks.
As well as improving cholesterol levels, it also reduced the amount of triglyceride, a type of blood fat that has been linked to heart disease.
However, the impact was least pronounced among the overweight.
It is not yet clear why nuts have this effect, although one suggestion is that it is down to the plant sterols they contain, which are thought to interfere with cholesterol absorption.
Lead researcher Joan Sabate said increasing nut consumption as part of a healthy diet should be recommended.
He added: "The effects of nut consumption were dose related, and different types of nuts had similar effects."
Ellen Mason, senior cardiac nurse at the British Heart Foundation, agreed, but she urged people to go for unsalted nuts.
"Apart from salted peanuts at the pub, nuts in sugary cereals or the traditional Christmas selection, nuts have been largely lacking in our diets in the UK," she added.
The study was carried out by independent researchers, although it was partly funded by the International Tree Nut Council Nutrition Research and Education Foundation.