Nuts (tree nuts and peanuts) are nutrient dense foods with complex matrices rich in unsaturated fatty and other bioactive compounds: high-quality vegetable protein, fiber, minerals, tocopherols, phytosterols, and phenolic compounds. Contrary to expectations, scientific studies suggest that regular nut consumption is unlikely to contribute to obesity and may even help in weight loss. The biological mechanism explaining this fact is that the healthier plant sterols (phytosterols) interfere with cholesterol absorption by having a better affinity with the cellular membranes. (Cholesterol is a fat only contained in animal-based foods, such as meat, dairy, eggs, fish, etc.).
If then it’s no longer a mystery that including a few nuts in our daily diet can elevate the quality of the dietary fat introduced, what are the oleaginous fruits possessing a more optimal balance between the essential omega-6 and omega-3 fatty acids? (See also my previous posts on the benefits of nuts and the importance of the omega-6/omega-3 ratio).
If, anyway, you are too rushed to check my previous post on omega-3 fats, let’s keep the main facts short and sweet.
Essentially, omega-3 fats are not introduced enough in our daily diet. The detrimental dietary shift occurred after the industrial era and the advent of the intensive farming that led to an unprecedented mass production of seed oils rich in omega-6 fats. The social health issue started when evidence was found between the onset of chronic diseases (diabetes, neurological illnesses, hypercholesterolemia, arthritis) and the increased consumption of omega-6 fats. In fact, omega-6 compete with omega-3 fats in the regulation of inflammatory processes in the human body (more specifically, omega-3s sooth inflammation whereas omega-6s promote it).
Walnuts are the only tree nuts containing significant amounts of omega-3 fats and, as the other nuts, they are versatile to consume both mixed with fresh fruit and cereals in a bowl at breakfast and with salads as appetizing lunch or dinner side-dish. Even more so, walnuts can be eaten by themselves as snacks.
Walnuts were also the first whole food to receive a health claim from the FDA. In July 2004, the FDA approved the following claim:
Supportive but not conclusive research shows that eating 1.5 oz of walnuts per day, as part of a low saturated fat and low cholesterol diet, and not resulting in increased caloric intake may reduce the risk of coronary heart disease.
Nutritional content of walnuts
The omega-3 fatty acid content of walnuts is nearly 10 times greater than pecans, the next highest nut, and 40 to 500 times greater than most other nuts. Checking out the table below, look in particular at the column ALA, the omega-3 fat contained in vegetable foods:
The best way to include walnuts in the diet
While it’s recommended to get an amount of walnuts variable from 4 to 7 per day, surer is the fact the PUFA are more susceptible to oxidation than MUFA. For this reason, it’s better to eat raw, in-shell walnuts than peeled off or as oil. As a matter of fact, the antioxidants of nuts are located in their pellicle or soft outer shell and 50% or more of them are lost when the skin is removed.
Walnut storage and handling
Walnuts kept in their shell have a shelf life of 12 months when stored in a cool, dry environment. An unopened package of shelled walnuts has a similar shelf life. Opened packages and chopped walnuts should be kept refrigerated or frozen in an airtight container for no longer than 6 to 12 months.
While vegetable omega-3 fats do not represent the best-absorbed form by the human body (marine foods like algae oil and fish are the best omega-3 sources, as seen in a previous post), varying our diet by including walnuts daily and seafood twice a week can guarantee balanced nutrition without the need to resort to food supplements.
To get more information and dietary hints about walnut consumption, you can also visit the website of the California Walnut Commission: www.walnuts.org.