Here at Mark’s Daily Apple, we’re pretty picky about our oils, but one oil that we can truly get on board with is walnut oil.
Of all the oils, walnut oil is clearly one of the healthiest. In the olden days, it was used to cure many ailments including stomach and skin problems, tuberculosis (although, admittedly, the jury is out on just how successful that might have been!), hair loss and diabetes.
Today, however, walnut oil is more revered as a healthy source of fat, containing roughly 72% polyunsaturated fat. Walnuts are high in alpha-linoleic acid, an essential fatty acid that is converted to EPA and DHA (long-chain omega-3s) in the body. Furthermore, walnut oil is also a great source of omega-9, which helps maintain artery health, as well as omega-6 (you gotta have some of ‘em), which is important for skin and hair growth as well as maintaining a healthy reproductive system.
So let’s take it to the lab and put walnut oil to the test! In a study conducted by University of California-Davis, researchers found that hamsters that ate walnut-infused feed had significantly lower levels of endothelin, a naturally occurring chemical that causes inflammation of arteries and plaque accumulation in vessels (both of which are linked to heart disease). In addition, consumption of walnuts was associated with a 64% increase in the elasticity of arteries and was found to prevent endothelial dysfunction (which has been linked with coronary artery disease and other cardiac ailments) in patients with high cholesterol.
Other pros for walnut oil (and walnuts in general) are that they are a great source of antioxidants, delivering more than 20 mmol antioxidants per 100 grams (making it one of the best sources of antioxidants among tree nut varieties). Specifically, walnuts are a great source of ellagic acid, which helps detoxify potential cancer-causing substances and helps limit the replication of cancer cells. To help these antioxidants along, walnuts are a very good source of manganese and copper, two minerals that act as catalysts in antioxidant reactions. Finally, walnuts are also a natural source of melatonin, a hormone produced by the pineal gland that is thought to play a role in regulating sleep.
Although slightly more expensive than other oils, walnut oil is a delicious and easy-to-use oil to use in food preparation. It has a light, delicate flavor and scent that makes it a good match for fine balsamic vinegars, red wine vinegars and tarragon white vinegar when used in salad dressings and can also be used to add flavor to grilled fish or meat dishes. When using it in cooking, chefs suggest that you avoid using it at high temperatures, as the heat can turn the oil bitter and destroy some of its antioxidant properties.
Like any healthy unsaturated fat, walnut oil is best when stored in a cool place and should be used up or tossed out within six weeks after first opening.