Written by Graham Osbourne. Published in Sydney Morning Herald on 31 July 2012.
They can be a seat-belt for your heart, reduce the risk of diabetes and bring down cholesterol but stick to just a handful of nuts a day – raw if possible – and avoid additives like salt and sugar.
Tree nuts are increasingly regarded as wonder foods that lower the risk of heart disease, some forms of cancer and type 2 diabetes while providing essential vitamins and minerals including niacin, zinc, folic acid, selenium and magnesium.
They contain more unsaturated fats than animal proteins and can cut levels of LDL or “bad” cholesterol, according to numerous studies. And their mix of omega-3 fatty acids, protein and fibre will help you feel full and suppress your appetite.
Plus the fat content helps release satiety hormones in the digestive system, which also helps to curb hunger, adds dietitian Lisa Yates of the Australian Nut Industry Council website nutsforlife.com.au. A small snack of nuts can lessen your desire to overeat later in the day.
Despite the good news, not all nuts are necessarily nutritious.
In the supermarket snack section, “nature’s bite-sized wonders” are often drowned in salt and/or sugar.
“Anything coated with or tucked inside layers of sugar, toffee, chocolate or ice-cream isn’t going to give you much nutritional benefit, and the calories can quickly add up,” warns US Academy of Nutrition and Dietetics spokesperson Judy Caplan, R.D.
Avoid nuts packaged or roasted in oil and instead eat them raw or dry roasted, Caplan told the Huffington Post. “Roasted nuts may have been heated in unhealthy fats at high temperatures that can destroy their nutrients.” She also cautions against snacking straight from a box or tub of glazed nuts, such as honey roasted cashews or caramelised Vienna almonds.
“And don’t justify eating a Snickers bar because it’s got peanuts in it.”
Nut butters are another contentious issue, with many warning that they can pack on calories because they’re delicious and easy to eat.
Look for spreads with the fewest ingredients possible, advises Caplan, who notes that most major-brand nut butters contain hydrogenated oils, which are high in saturated fats.
The debate over the caloric content of nuts continues to rage in cyberland – but “sorting out the truth from the propaganda,” as one blogger puts it, is not entirely straightforward. Online magazine Vegsource.com has highlighted the case of vegan chef AJ, who dropped 12 pounds (5.4 kilos) in 12 weeks simply by giving up all nuts and seeds.
AJ, who is hypothyroid with a slow basal metabolic rate, says even a moderate amount of healthy fats was too much for her.
“[But] if there’s one myth that needs busting,” insists Yates, “it is that nuts are fattening.”
“Nuts are healthy high-fat food in a fat-phobic world and it is high time we moved on from thinking that the low-fat diet is going to solve our heart disease, diabetes and obesity problems.” Research has moved on from the low-fat mantra of the 80s and 90s, she says.
“Epidemiological [large population] studies have found that as nut consumption increased, body mass index decreased. We also know that nuts help prevent weight gain, which is the first step in losing weight, but like any food, healthy or not, eat too much and you may gain weight – especially if you’re eating more than you need and not burning enough through exercise.”
Yates suggests eating one handful of mixed nuts a day, just 30g, and enjoy them as a snack or add to your meals to make them more exciting.
All nuts are about equal in calories, but their nutrient profile does differ. There are 10 varieties of tree nuts: almonds, Brazil nuts, cashews, chestnuts, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts.
- Almonds are rich in vitamin E, a fat-soluble vitamin and antioxidant essential to maintaining heart health, with 20 almonds (a handful) providing 85 per cent of the recommended daily intake (RDI) of vitamin E.
- Brazil nuts – seeds from a large tree found in the Amazon rainforest – are rich in selenium, a vital mineral and antioxidant. Just two Brazil nuts a day may prevent heart disease and prostate cancer and can also enhance mood.
- Cashews are high in magnesium, needed for healthy bones, and are good sources of phytochemicals and antioxidants. A handful is about 15 cashews.
- Hazelnuts, the most fibre-rich of all the nuts, contain significant levels of B-group vitamins including folate and vitamin B6. An average handful is about 20 hazelnuts.
- Macadamia nuts are high in healthy mono-unsaturated fats, contain all the essential amino acids and have been shown to lower blood cholesterol. Fifteen macadamias make a handful.
- Pecans also reduce cholesterol and may delay age-related muscle nerve degeneration, according to a University of Massachusetts study. A handful is about 15 pecans.
- Pine nuts – the edible seeds of pine trees, removed from pine cones – contain zinc, niacin and manganese and are rich in mono-unsaturated acids. Ancient Greeks and Romans believed pine nuts were an aphrodisiac. Two tablespoons is an average serve.
- Pistachios are packed with protein, vitamin E and are an excellent source of copper and manganese. Sixty pistachios makes a 30g serving.
- Walnuts are loaded with natural plant omega-3s called alphalinoleic acid or ALA. Eating walnuts is “like wearing a seat-belt for your heart,” according to nutsforlife.com. Ten whole walnuts is the suggested average serve.
- Peanuts, technically legumes but commonly referred to as nuts, are high in vitamin E, folate (for brain development) and may reduce cognitive decline.