What a nut! Research supports health benefit claims

Dr Alexandra Chisholm.
Dr Alexandra Chisholm.
A recent national survey has shown New Zealanders aren't eating enough nuts, despite research showing frequent consumption is an effective way to get essential nutrients, University of Otago nut group researcher Dr Alexandra Chisholm says.

The university's department of human nutrition has been conducting research since the mid-1990s. Nuts studied have included almonds, walnuts, Brazil and mixed nuts, including peanuts.

For the past 10 years, the nut group has been investigating the health effects of eating fresh New Zealand hazelnuts sourced from Uncle Joe's Walnuts and Hazelnuts in Blenheim.

The group has produced 18 papers on the effects of hazelnuts on the diet and is looking at the health benefits of the nuts and seeds on a group of older women with type 2 diabetes.

''We knew from earlier studies that other nuts helped to reduce blood cholesterol and had a good effects on blood fats, and heart health and we were keen to see whether hazelnuts were similar.

''What made these nuts especially attractive was not only their composition, which is similar to almonds, but that they were grown in New Zealand, so we knew they would be fresh.''

It is established science that nuts are a convenient package of healthy fats, protein, fibre, minerals and vitamins, she says.

''Vitamin E and a number of other micronutrients often in short supply in the typical Western diet are found in nuts.''

Brazil nuts contain substantial amounts of selenium, an essential trace element, so the daily inclusion of a couple of Brazil nuts in the diet significantly enhances selenium status and antioxidant activity.

Hazelnuts help to reduce blood cholesterol and have good effects on blood fats, and indicators for heart health.

The types of fats in nuts are mainly mono unsaturated fats together with some poly unsaturated fats, including plant omega 3 fats in walnuts. Mono unsaturated fats are the type found predominantly in the Mediterranean diet.

One of the main barriers to regularly eating nuts is a concern about weight gain due to the fact that nuts are high in fat and energy dense.

''We have shown that consuming one serving of nuts a day [30g], and up to 60g of nuts per day does not cause increases in body weight, especially when nuts are eaten in place of unhealthy foods.''

So a small handful, five times a week is recommended, although smaller amounts less frequently are also good.

''Research shows that people tend to like nuts, and they continue to like nuts even after eating them daily for several weeks - they don't get bored with eating them.''

For those who eat vegetarian or especially vegan diets, nuts can be an important source of protein.

Overseas studies following tens of thousands of people over many years have found that the health effects of eating nuts was evident well into old age.

''Our research has shown that all nut forms are effective, whether whole, sliced, or as nut meal.''

-The University of Otago is looking for participants in its nut study for older women with type 2 diabetes. If interested, phone (03) 479-8153.


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