If nuts aren't a staple in your diet, they ought to be. (Unless, of course, you're allergic to them.)
According to a large study, eating a small portion of nuts each day protects against heart disease, diabetes, cancer, even premature death.
The findings, published this month in the journal BMC Medicine, suggest that nuts have wide-ranging health benefits, more so than previously thought.
For the study, researchers from Britain and Norway pooled the results of 20 published studies, involving 819,448 participants, to determine the link between nut intake and the risk of various diseases.
The studies looked at all types of nuts: tree nuts (such as almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pistachios, walnuts) and peanuts and peanut butter. (Botanically speaking, peanuts are classified as legumes, not tree nuts.)
Compared with people who didn't eat nuts, those who ate one serving a day – 28 grams' worth, a small handful – cut their risk of coronary heart disease by nearly 30 per cent, the risk of cardiovascular disease by 21 per cent, the risk of diabetes by 39 per cent and total cancer by 15 per cent.
As well, the risk of dying from respiratory disease was reduced by one-half (52 per cent) and the odds of premature death fell by almost one-quarter.
Tree nuts and peanuts offered protection against heart disease, but only tree nuts were tied to a lower risk of cancer.
All it takes is 20 grams
Most of the protective effect of nuts was associated with eating 20 grams a day; eating a larger portion didn't further reduce disease risk.
Twenty grams of nuts isn't a lot. It's equivalent to 15 almonds, four Brazil nuts, 13 cashews, 14 hazelnuts, eight macadamia nuts, 20 peanuts, 13 pecan halves, 34 pistachios or 10 walnut halves.
The new findings also don't prove that eating nuts prevents chronic disease.
The studies included in the analysis were observational, meaning they followed people for years to uncover associations, not causal relationships.
Even so, previous randomized controlled trials – the gold standard for establishing cause and effect – have shown that regular nut consumption reduces LDL (bad) cholesterol in the bloodstream, enhances the body's use of blood-sugar-regulating insulin and improves the functioning of arteries.
A recent randomized trial, called the PREDIMED study, observed a lower risk of heart attack, stroke and cardiovascular death among people who ate a Mediterranean diet supplemented with 30 grams of nuts compared to those who followed a standard low-fat diet.
Nuts are an excellent source of heart-healthy unsaturated fats, plant protein and fibre. Hazelnuts, almonds, pecans, cashews and peanuts, for example, contain mainly monounsaturated fat, the type that's tied to lowering blood cholesterol and benefiting insulin and blood-sugar levels.
Nuts also deliver antioxidants such as vitamin E and flavonoids, along with plenty of folate, potassium and magnesium, a mineral that helps regulate blood pressure and blood sugar.
They're also a good source of phytosterols, plant compounds that have cholesterol-lowering and anti-inflammatory properties.
Walnuts, unlike other nuts, also contain alpha-linolenic acid (ALA), an omega-3 fatty acid thought to help guard against cardiovascular disease and Type 2 diabetes.
Raw versus roasted
Contrary to popular belief, roasting nuts – which I regularly do to enhance their flavour (see sidebar) – does not diminish their nutritional value.
A 28-gram serving of raw and dry roasted almonds, for instance, contain virtually identical calories (174 and 179, respectively) and the same amounts of protein, fibre, calcium, iron, magnesium, potassium, B vitamins and vitamin E.
Roasting may even increase the availability of certain beneficial compounds such as flavonoids.
More not always better
You can get too much of a good thing. Because nuts are high in fat and calories, eating more than a handful each day could lead to weight gain.
Depending on the nut, a small handful (20 g) delivers anywhere from 110 (cashews, pistachios) to 145 calories (macadamia).
Not bad. But eat one-half cup of almonds (about three handfuls), for example, and you'll pack in 415 calories.
Substitute nuts for less healthy foods, such as cookies, candy, soft drinks, chips and refined (white) starchy foods. To prevent overdoing it, assemble portions in snack-sized bags. Eating nuts in the shell may also help you eat less since it takes time to crack them open.
Avoid sugar-coated nuts (such as maple or honey glazed), which can deliver 8 grams of added sugar (two teaspoons worth) per 28 grams.
SEVEN CREATIVE WAYS TO ADD NUTS TO YOUR DIET
There are plenty of tasty ways to add nuts to your diet besides eating them out of your hand.
To boost the flavour of nuts, toast them before eating. Place shelled whole nuts on a baking sheet and then roast for five to 10 minutes in a 350-degree F oven until golden brown.
Use a food processor or high-speed blender to grind nuts into a powder. Blend ground almonds, cashews or macadamia nuts into smoothies to infuse extra protein, fibre and antioxidant content. Add ground nuts to burger and meatloaf recipes.
Replace breadcrumbs with ground nuts in recipes. Pulse nuts in a food processor to desired "crumb" size. Top a casserole or mac and cheese with a nut crust, or bread fish or chicken with nut crumbs before baking or pan-frying.
Add whole, chopped or slivered nuts to leafy green and vegetable salads. My go-to nuts for salads include toasted almonds, hazelnuts, pecans and walnuts. Toss chopped roasted walnuts or pistachios with hot, cooked whole-wheat pasta, extra virgin olive oil, lemon zest and crumbled goat's cheese.
Top oatmeal, roasted vegetables and grain pilafs with chopped nuts. Sprinkle chopped, toasted nuts over yogurt and berries.
Toss whole raw cashews, almonds or peanuts into a stir-fry. Nuts add plant protein to vegetable stir-fries and they also pair well with chicken and shrimp.
Make your own trail mix with a variety of raw nuts, shredded unsweetened coconut flakes, chopped dried apricots and carob chips.
Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto