Tough nuts to crack

Everyone knows that 'an apple a day keeps the doctor away', but not many appreciate the health-giving properties of nuts. Indeed, they are frequently eschewed by consumers - especially women - owing to their high fat and calorie content, although there is extremely strong evidence to substantiate countless health benefits.

The majority of nuts are nutritionally rich and contain high amounts of protein, dietary fibre, vitamin E, folate, niacin, vitamin B6 and copper, magnesium, potassium and zinc, in varying degrees. They are also a rich source of many bioactive components such as antioxidants, phytosterols and other phytoprotective substances, as well as 'healthy' monounsaturated fat. When nuts are consumed on a regular basis they can help protect against a number of chronic diseases, such cardiovascular disease (CVD), strokes, type-2 diabetes and obesity.

"The combined evidence for a cardioprotective effect from nut consumption is convincing," says professor David Richardson, chairman of the Almond Board of California's European Scientific Advisory Board. "The risk of coronary heart disease is 37% lower for those consuming nuts more than four times a week compared with those who never or seldom consume nuts, with an average reduction of 8.3% for each weekly serving. Nuts should be up there with fruit and vegetables and wholegrains; they are considered to be fundamental to several dietary guidelines."

The evidence is equally compelling to support nuts' ability to protect against type-2 diabetes in women, and obesity. Numerous studies have been carried out, including one by scientists at the Harvard School of Public Health, which involved monitoring the diets of 83,818 nurses for several years. The survey concluded that eating nuts was inversely associated with the risk of type-2 diabetes after adjusting for age, body mass index, family history of diabetes, physical activity smoking, alcohol use and total calorie intake.

"Type-2 diabetes is a growing problem and is linked to obesity and cardiovascular disease," says Jennette Higgs, nutritionist at the American Peanut Council. "Concerns regarding the fat content of nuts and peanut butter have coloured judgement of these foods despite a wealth of recent research demonstrating that consumption of nuts, including peanuts and peanut butter, can help to reduce blood cholesterol levels. Studies have shown that women who consume peanut butter five or more times per week have a 21% lower risk of developing type-2 diabetes."

Nuts can also be very effective as part of a calorie-controlled diet. A growing body of science shows that almonds may be consumed as part of a weight management program without the fear of weight gain. One study showed that even adding 320 calories of almonds to a daily diet did not cause weight gain in a group of free-living individuals. This suggests that almonds may play a satiating role in a mixed diet whether consumed in one sitting or over several eating occasions. Macadamias and peanuts also have a proven weight-loss record.

"Given that obesity in itself is a risk factor for CVD and that the type of fat consumed is more important than the total amount of fat, as a risk for chronic diseases, it would be useful to be able to recommend peanuts within weight management diets," explains Higgs. "Prospective cohort studies have shown that nut consumption can be cardioprotective in lean and obese people."

Vitamin E and selenium in some nuts may also aid the anti-ageing process and phytosterols can help prevent certain types of cancer, although the evidence is fairly indeterminate on both counts.

Many consumers are still in the dark about the benefits of nuts. In 2006, the European Prospective Investigation into Cancer (EPIC) conducted a survey to assess the relationship between diet, nutritional status, lifestyle and incidence of cancer and heart disease across 10 EU countries, which involved collecting dietary and lifestyle information from 400,000 people. The researchers found that almost half of the participants rarely consumed nuts, even though an intake of just two 30g/1oz servings per week may reduce the risk of death from chronic heart disease by 11%.

Research by the Almond Board of California last Summer found that European consumers consider nuts to be fattening, mainly as a result of a lack of understanding about the differences between saturated (bad) fat and unsaturated (good) fats. Consumers also have an innate fear of allergies as a result of nut consumption, particularly in children.

This has inevitably restricted product development, although labelling legislation has helped to appease concerns there is still a lot of education required. This is especially applicable for peanuts, as they are probably the most demonised nuts of all.

"Peanuts have been and remain an important staple food for many Asian, African and American populations, where they make a significant nutritional contribution to the diet," says Higgs. "Yet the last few decades of education on eating less fat in Britain helped to label certain foods as 'good' or 'bad' simply because of their fat content. Peanuts were one of those casualties; being some 46% fat, they were swiftly labelled as a 'baddy'.

"Peanuts and peanut butter provide a valuable nutritional supplement, being high in plant protein, the amino acid arginine, energy and fibre, as well as offering a generous supply of vitamins, minerals and phytochemicals. Nuts and peanuts' role as allergens has been blown completely out of proportion and has stopped a lot people eating them - despite the fact that 98% of us can benefit from eating nuts."

Consumer attitudes

Overall, consumer attitudes are changing, as the board's senior director, global marketing and communications, Shirley Horn explains: "In a consumer awareness, attitudes and usage study conducted by Opinion Research Corporation for the Almond Board of California, 73% of consumers rated almonds as 'good' or 'excellent' as a food that helps lower cholesterol, and 75% of respondents rated almonds as 'good' or 'excellent' as a heart-healthy food."

For manufacturers, the real concern is cross-contamination between tree-nuts and/or peanuts. "Many rebagging or value-added facilitates will handle a variety of tree nuts and/or peanuts," says Bruce Caris, VP sales and marketing at The Green Valley Pecan Company. "A clear separation of products and processing lines is essential along with a well planned and followed sanitation program. Labelling laws are requiring good identification of allergen specification on all consumer packs."

Health claims on labels may help to boost the fortunes of nuts. Several nut-related claims have been submitted for approval to the European Food Safety Authority but there is unlikely to be any agreement before 2010. They relate to nuts (including peanuts and almonds, hazelnuts, pecans, pistachios and walnuts) and their effects on heart health and weight management. Claims relating to specific nuts are also under consideration.

Once claims have been approved, consumers will be able to make more informed choices, and they may help eradicate some established myths. Additionally, food and drink manufacturers are likely to take the opportunity to develop more innovative nut-based products, where innovation so far has been largely restricted to healthy snacks, cereals or oils.

"In the US, peanut flour is used in energy drinks and power bars because the flour is high in de-fatted protein," says Higgs. "Peanut flour is used in Europe, but the EU in general is not utilising it to the same extent as the US. There is a big opportunity in salad dressings and seasonings. Adding nut ingredients to ready meals could really boost their nutritional profile, particularly their fibre and fatty acid profile."

Almonds are really flexible, says Horn, and she would like to see more adventurous food and drink applications here. "Almonds are the most versatile of nuts," she says. "Almonds add taste and crunch to virtually every type of food at any time of day. We're now seeing some wonderful innovations using almonds and almond milk for refreshing, tasty and nutritious beverages. Almond flour is a marvellous base for sauces and it adds luxurious texture to cakes, as well as being a great substitute for those on gluten-free diets."