Walnuts are the large, single-seeded fruits of the walnut tree. Though different species of walnut exist, the English walnut, which originated in Persia, remains the most popular species. In fact, virtually all of today's commercially-produced walnuts are either English walnuts or hybrids thereof. Other species of walnut, such as the black walnut, are seldom cultivated due to their comparatively tough shells and poor hulling qualities.
Walnuts are highly nutritious, and their health benefits have been well-known in China and India for centuries. They are just as revered in the West, however, and a large number of studies confirm the allegations of the ancient healing systems.
Packed with brain-boosting fats
Walnuts are rich in omega-3 and omega-6 fatty acids, particularly the plant-based omega-3 fat, alpha-linolenic acid. These beneficial fats, which are the same fats that comprise our brains and nervous systems, give walnuts considerable brain-boosting properties. For example, a study published in Plant Foods for Human Nutrition in November 2011 discovered that rats that were fed walnuts for 28 days demonstrated a "significant improvement in learning and memory" compared to the control group. A second study, published two years later in Nutritional Neuroscience, showed that the fatty acids in walnut extracts could prevent age-related inflammation and oxidative stress in the brain's hippocampal cells.
Studies have also linked the regular consumption of walnuts to numerous other brain-related benefits, including the prevention of neurodegenerative diseases such as dementia and Alzheimer's disease, and improved inferential reasoning, concentration spans and interneuronal signaling. Just like coconut oil, another food that boosts cognitive function, almost all of these benefits stem from walnuts' high concentrations of beneficial fats.