Walnuts
The only common nut with a substantial amount of plant omega-3, and a good source of polyphenol antioxidants.
What Walnuts Provide
Walnuts stand out among nuts for their fat profile: they are unusually high in polyunsaturated fat, including alpha-linolenic acid (ALA), the plant form of omega-3. They also provide magnesium, copper, and polyphenols concentrated in the thin skin. Because ALA is fragile, walnuts can turn rancid if stored warm for long periods.
Nutrition Highlights
Omega-3 ALA
One ounce of walnuts provides about 2.5 g of omega-3 ALA — by far the highest of any common nut. ALA is an essential fatty acid the body cannot make, and it is a precursor to the longer-chain omega-3 fats, though conversion is limited.
Polyunsaturated Fat
Around 13 g of polyunsaturated fat per ounce. Replacing saturated fat with polyunsaturated fat is associated with favourable effects on blood cholesterol.
Polyphenol Antioxidants
The papery skin of walnuts is rich in polyphenols, including ellagic acid and various flavonoids. These compounds are being studied for their role in protecting cells from oxidative stress.
Magnesium and Copper
A single ounce supplies roughly 45 mg of magnesium and 0.4 mg of copper. Copper is involved in iron metabolism and in the formation of connective tissue.
How to Include Walnuts in a Balanced Diet
- A small handful as a snack, ideally with fruit.
- Chopped into oatmeal, yogurt, or salad.
- Tossed through pasta with blue cheese and spinach.
- Baked into banana bread or muffins.
- Blended into pesto or a walnut sauce for roasted vegetables.
Who Might Want to Watch Portions
Walnuts are the most calorie-dense nut at about 185 kcal per ounce, so a measured portion helps. Tree nuts are a common allergen. Because walnuts are high in polyunsaturated fat, store them in an airtight container in the fridge or freezer to slow rancidity.